Risk factors for acute kidney injury in patients hospitalized with COVID-19 / Fatores de risco para lesão renal aguda em pacientes hospitalizados com COVID-19

Abstract Introduction: Acute kidney injury (AKI) occurs frequently in COVID-19 patients and is associated with greater morbidity and mortality. Knowing the risks of AKI allows for identification, prevention, and timely treatment. This study aimed to identify the risk factors associated with AKI in hospitalized patients. Methods: A descriptive, retrospective, cross-sectional, and analytical component study of adult patients hospitalized with COVID-19 from March 1 to December 31, 2020 was carried out. AKI was defined by the creatinine criteria of the KDIGO-AKI guidelines. Information, regarding risk factors, was obtained from electronic medical records. Results: Out of the 934 patients, 42.93% developed AKI, 60.59% KDIGO-1, and 9.9% required renal replacement therapy. Patients with AKI had longer hospital stay, higher mortality, and required more intensive care unit (ICU) admission, mechanical ventilation, and vasopressor support. Multivariate analysis showed that age (OR 1.03; 95% CI 1.02-1.04), male sex (OR 2.13; 95% CI 1.49-3.04), diabetes mellitus (DM) (OR 1.55; 95% CI 1.04-2.32), chronic kidney disease (CKD) (OR 2.07; 95% CI 1.06-4.04), C-reactive protein (CRP) (OR 1.02; 95% CI 1.00-1.03), ICU admission (OR 1.81; 95% CI 1.04-3.16), and vasopressor support (OR 7.46; 95% CI 3.34-16.64) were risk factors for AKI, and that bicarbonate (OR 0.89; 95% CI 0.84-0.94) and partial pressure arterial oxygen/inspired oxygen fraction index (OR 0.99; 95% CI 0.98-0.99) could be protective factors. Conclusions: A high frequency of AKI was documented in COVID-19 patients, with several predictors: age, male sex, DM, CKD, CRP, ICU admission, and vasopressor support. AKI occurred more frequently in patients with higher disease severity and was associated with higher mortality and worse outcomes.

RESUMO Introdução: Lesão renal aguda (LRA) ocorre frequentemente em pacientes com COVID-19 e associa-se a maior morbidade e mortalidade. Conhecer riscos da LRA permite a identificação, prevenção e tratamento oportuno. Este estudo teve como objetivo identificar fatores de risco associados à LRA em pacientes hospitalizados. Métodos: Realizou-se estudo descritivo, retrospectivo, transversal e de componente analítico de pacientes adultos hospitalizados com COVID-19 de 1º de março a 31 de dezembro, 2020. Definiu-se a LRA pelos critérios de creatinina das diretrizes KDIGO-LRA. Informações sobre fatores de risco foram obtidas de prontuários eletrônicos. Resultados: Dos 934 pacientes, 42,93% desenvolveram LRA, 60,59% KDIGO-1 e 9,9% necessitaram de terapia renal substitutiva. Pacientes com LRA apresentaram maior tempo de internação, maior mortalidade e necessitaram de mais internações em UTIs, ventilação mecânica e suporte vasopressor. A análise multivariada mostrou que idade (OR 1,03; IC 95% 1,02-1,04), sexo masculino (OR 2,13; IC 95% 1,49-3,04), diabetes mellitus (DM) (OR 1,55; IC 95% 1,04-2,32), doença renal crônica (DRC) (OR 2,07; IC 95% 1,06-4,04), proteína C reativa (PCR) (OR 1,02; IC 95% 1,00-1,03), admissão em UTI (OR 1,81; IC 95% 1,04-3,16) e suporte vasopressor (OR 7,46; IC 95% 3,34-16,64) foram fatores de risco para LRA, e que bicarbonato (OR 0,89; IC 95% 0,84-0,94) e índice de pressão parcial de oxigênio arterial/fração inspirada de oxigênio (OR 0,99; IC 95% 0,98-0,99) poderiam ser fatores de proteção. Conclusões: Documentou-se alta frequência de LRA em pacientes com COVID-19, com diversos preditores: idade, sexo masculino, DM, DRC, PCR, admissão em UTI e suporte vasopressor. LRA ocorreu mais frequentemente em pacientes com maior gravidade da doença e associou-se a maior mortalidade e piores desfechos.

Risk factors for acute kidney injury in patients hospitalized with COVID-19.

INTRODUCTION: Acute kidney injury (AKI) occurs frequently in COVID-19 patients and is associated with greater morbidity and mortality. Knowing the risks of AKI allows for identification, prevention, and timely treatment. This study aimed to identify the risk factors associated with AKI in hospitalized patients. METHODS: A descriptive, retrospective, cross-sectional, and analytical component study of adult patients hospitalized with COVID-19 from March 1 to December 31, 2020 was carried out. AKI was defined by the creatinine criteria of the KDIGO-AKI guidelines. Information, regarding risk factors, was obtained from electronic medical records. RESULTS: Out of the 934 patients, 42.93% developed AKI, 60.59% KDIGO-1, and 9.9% required renal replacement therapy. Patients with AKI had longer hospital stay, higher mortality, and required more intensive care unit (ICU) admission, mechanical ventilation, and vasopressor support. Multivariate analysis showed that age (OR 1.03; 95% CI 1.02-1.04), male sex (OR 2.13; 95% CI 1.49-3.04), diabetes mellitus (DM) (OR 1.55; 95% CI 1.04-2.32), chronic kidney disease (CKD) (OR 2.07; 95% CI 1.06-4.04), C-reactive protein (CRP) (OR 1.02; 95% CI 1.00-1.03), ICU admission (OR 1.81; 95% CI 1.04-3.16), and vasopressor support (OR 7.46; 95% CI 3.34-16.64) were risk factors for AKI, and that bicarbonate (OR 0.89; 95% CI 0.84-0.94) and partial pressure arterial oxygen/inspired oxygen fraction index (OR 0.99; 95% CI 0.98-0.99) could be protective factors. CONCLUSIONS: A high frequency of AKI was documented in COVID-19 patients, with several predictors: age, male sex, DM, CKD, CRP, ICU admission, and vasopressor support. AKI occurred more frequently in patients with higher disease severity and was associated with higher mortality and worse outcomes.

Quality of life and response to treatment in cats with hypersomatotropism: the owners' point of view.

OBJECTIVES: The aim of this study was to collect clinical information from owners of cats with hypersomatotropism (HS) distributed worldwide, assessing the impact of HS and its treatments on cats' quality of life (QoL) and survival time. METHODS: A survey focused on clinical presentation, diagnostic procedures, treatments, cats' QoL and disease progression was distributed worldwide to owners of cats with HS. The owner's perception of the cats' QoL before and after or during treatment was defined using a score ranging from 1 (poor) to 5 (excellent). Improvement following treatment (IFT) was quantified using a score ranging from 1 (absent) to 5 (obvious). Different treatment groups, including at least five cases, were compared. RESULTS: A total of 127 cats were included from at least 11 different countries. Among these, 120 (95%) were diabetic and 7 (5%) were not. Out of 120 diabetic cats, 55 (46%) were treated with insulin as a single treatment (INS). Other treatments were not mentioned to owners in 35/120 (29%) cases. The median QoL score at diagnosis was 2 (range 1-5) and improved after treatment in all groups. Cabergoline (4; range 1-5), radiotherapy (4; range 2-5) and hypophysectomy (5; range 4-5) showed better median IFT scores compared with INS (3; range 1-5) (P = 0.046, P <0.002 and P <0.0001, respectively). Hypophysectomy IFT proved superior to cabergoline (P = 0.047) and was equal to radiotherapy IFT (P = 0.32). No difference was found between cabergoline and radiotherapy IFT (P = 0.99). The median survival time (MST) was 24 months (range 0-75 months). Cats treated with INS showed shorter MST (22 months; range 0-69 months) compared with cats treated with causal treatments combined (36 months; range 3-75 months) (P = 0.04). CONCLUSIONS AND RELEVANCE: Not all cats with HS will have diabetes mellitus. Causal treatments seem associated with the greatest improvements in perceived cats' QoL and survival; such treatments should therefore be discussed with owners. Cabergoline could be an effective alternative management option.

Xanthinuria secondary to allopurinol treatment in dogs with leishmaniosis: Current perspectives of the Iberian veterinary community.

Xanthinuria is a significant adverse effect in dogs on long-term allopurinol for treatment of leishmaniosis. The study aims to investigate how the Iberian veterinary community (IVC) identifies, manages, and proactively prevents xanthinuria secondary to allopurinol treatment. A cross-sectional study was conducted using an online survey, translated into two languages, and disseminated to the IVC via social networking forums. Respondents were asked to share their treatment regimens, adverse effects attributed to treatment, as well as preventive and reactive measures against xanthuria. Of two-hundred and thirty respondents, 99.6% prescribe allopurinol for canine leishmaniosis. Xanthinuria was estimated to happen in less than one out of every four dogs by 91.7% of the clinicians. Xanthinuria has been detected by 71.6% of respondents at least once. Three out of every four respondents inform owners about deleterious effects of allopurinol, and 28.4% consider implementing a change in diet in advance of treatment as a proactive measure. To monitor xanthinuria, urinalysis and diagnostic imaging are used by 71.2% and 31% of clinicians respectively. When xanthinuria is detected, 43.2% of the respondents discontinue allopurinol, 24% replace it by nucleotide-analogs, 14.9% reduce its dosage, and 3.1% split its dosage but increase administration frequency. Additional measures are taken by 72.1% of the respondents, 59.4% of whom prescribe a low-purine diet. The IVC recognizes xanthinuria as a fairly common secondary effect of long-term allopurinol treatment in dogs with leishmaniosis and recommends periodically monitoring and preventive measures.

Use of Deoxycorticosterone Pivalate by Veterinarians: A Western European Survey.

This study aims to gather knowledge about the use of deoxycorticosterone pivalate (DOCP) by Western European Veterinarians (WEV) in dogs with typical hypoadrenocorticism. An observational cross-sectional study was conducted using an online survey, translated into four languages and disseminated to veterinary affiliates and mailing lists in six countries of Western Continental Europe. Respondents were tasked to share their therapeutic approach to hypoadrenocorticism, whether they preferred DOCP or fludrocortisone and the specific practical use of DOCP. One-hundred and eighty-four responses were included. Of these, 79.9% indicated that they preferred prescribing DOCP over fludrocortisone as a first-line treatment for mineralocorticoid supplementation. A total of 154 respondents had used DOCP at least once. Eighty percent of those who reported their initial dosage prescribed 2.2 mg/kg. After starting DOCP, 68.2% of the respondents assess electrolytes 10 and 25 days after administration following manufacturer instructions. In stable dogs, electrolytes are monitored quarterly, monthly, semi-annually, and annually by 44.2%, 34.4%, 16.9%, and 4.6% of respondents respectively. When treatment adjustment is required, 53% prefer to reduce dosage while 47% increase the interval between doses. Overall, DOCP is the preferred mineralocorticoid supplementation among WEV. Reported variability underlies the need to investigate the best strategies for DOCP use and therapeutic adjustments.

Priapism in a patient on hemodialysis and with COVID-19. Case report / Priapismo en paciente en diálisis y con COVID-19. Reporte de caso

Abstract Introduction: Priapism is rare in dialysis patients. It is associated with several risk factors inherent to therapy and kidney disease. This condition has been reported in severe COVID-19 cases, probably caused by coagulopathy secondary to the infection. However, it has not been reported in patients with mild COVID-19. Case presentation: A 65-year-old patient on hemodialysis and with mild COVID-19 presented with a 30-hour painful penile erection. Physical examination revealed an erection, but no other significant findings were observed. Based on the clinical history, physical examination and laboratory test results, the patient was diagnosed with ischemic priapism. Corpora cavernosa drainage was performed and two injections of epinephrine (each with a dose of 2mL of epinephrine solution 1/100 000) were administered, achieving complete resolution of the symptoms. Conclusions: At the time of writing this case report, there is no information available on cases of priapism in patients with mild manifestations of COVID-19, nor is it clear how the risk of thrombosis should be assessed in this group of patients. From a pathophysiological point of view, factors related to dialysis and kidney disease could have predisposed this patient to priapism, although the role of SARS-CoV-2 infection is uncertain. Therefore, further studies are required to confirm or rule out the association between COVID-19 and priapism in dialysis patients.

Resumen Introducción. El priapismo es una condición infrecuente en pacientes en diálisis que se puede presentar por factores inherentes a esta terapia y a la enfermedad renal. Por otra parte, es una entidad que se ha reportado en pacientes con síntomas severos de COVID-19 y se ha asociado a coagulopatía secundaria a la infección, pero de la que no hay registro en casos leves de esta enfermedad. Presentación de caso. Paciente masculino de 65 años en hemodiálisis y con infección por SARS-CoV-2 con síntomas leves, quien consultó al servicio de urgencias de un hospital de cuarto nivel por erección peneana dolorosa de 30 horas de evolución. Al examen físico se evidenció la erección, sin otros hallazgos relevantes. Con base en la historia clínica, el examen físico y los resultados de laboratorio, se diagnosticó priapismo isquémico y se realizó drenaje de senos cavernosos y aplicación de dos inyecciones de epinefrina (cada una con una dosis de 2mL de solución de epinefrina 1/100 000), lográndose resolución completa de la condición. Conclusiones. Hasta el momento de la elaboración del presente reporte de caso no hay información disponible de casos de priapismo en pacientes con manifestaciones leves de COVID-19, y tampoco hay claridad de cómo se debe evaluar el riesgo de trombosis en este grupo de pacientes. Desde el punto de vista fisiopatológico, factores relacionados con la diálisis y la enfermedad renal pudieron predisponer a este paciente al priapismo, aunque no es claro el rol de la infección por SARS-CoV-2. Por tanto, se requieren estudios que permitan confirmar o descartar la asociación entre COVID-19 y priapismo en pacientes en diálisis.

Ribozyme Mutagenic Evolution: Mechanisms of Survival.

Primeval populations replicating at high error rates required a mechanism to overcome the accumulation of mutations and information deterioration. Known strategies to overcome mutation pressures include RNA processivity, epistasis, selection, and quasispecies. We investigated the mechanism by which small molecular ribozyme populations can survive under high error rates by propagating several lineages under different mutagen concentrations. We found that every population that evolved without mutagen went extinct, while those subjected to mutagenic evolution survived. To understand how they survived, we characterized the evolved genotypic diversity, the formation of genotype-genotype interaction networks, the fitness of the most common mutants for each enzymatic step, and changes in population size along the course of evolution. We found that the elevated mutation rate was necessary for the populations to survive in the novel environment, in which all the steps of the metabolism worked to promote the survival of even less catalytically efficient ligases. Besides, an increase in population size and the mutational coupling of genotypes in close-knit networks, which helped maintain or recover lost genotypes making their disappearance transient, prevented Muller's ratchet and extinction.

ANCA-associated rapidly progressive glomerulonephritis in a patient with IgA nephropathy, case report / Glomerulonefritis rápidamente progresiva asociada a ANCA en un paciente con nefropatía por IgA, reporte de caso

Abstract IgA nephropathy is the most common glomerulonephritis, in which less than 10% of patients have a rapid decline of renal function. The histological findings of this group resemble those of vasculitis, with presence of crescents and fibrinoid necrosis. The coexistence of IgA nephropathy and neutrophil anti-cytoplasmic antibodies is infrequent, and the pathogenic role of these antibodies in IgA nephropathy is unclear. Here we describe a case of a patient with IgA nephropathy, rapidly progressive glomerulonephritis and neutrophil positive anti-cytoplasmic antibodies, and literature review is presented.

Resumen La nefropatía por IgA es la glomerulonefritis más frecuente, en la cual menos del 10% de los pacientes cursan con deterioro rápido de la función renal. Los hallazgos histológicos de este grupo semejan los de vasculitis, con presencia de semilunas y necrosis fibrinoide. La coexistencia de nefropatía por IgA y anticuerpos anticitoplasma de neutrófilo es infrecuente y no está claro el rol patogénico de estos anticuerpos en la nefropatía por IgA. A continuación, se describe un caso de un paciente con nefropatía por IgA, glomerulonefritis rápidamente progresiva y anticuerpos anticitoplasma de neutrófilo positivos y se realiza una revisión de la literatura referente al tema.

Diminishing-returns epistasis decreases adaptability along an evolutionary trajectory.

Populations evolving in constant environments exhibit declining adaptability. Understanding the basis of this pattern could reveal underlying processes determining the repeatability of evolutionary outcomes. In principle, declining adaptability can be due to a decrease in the effect size of beneficial mutations, a decrease in the rate at which they occur, or some combination of both. By evolving Escherichia coli populations started from different steps along a single evolutionary trajectory, we show that declining adaptability is best explained by a decrease in the size of available beneficial mutations. This pattern reflected the dominant influence of negative genetic interactions that caused new beneficial mutations to confer smaller benefits in fitter genotypes. Genome sequencing revealed that starting genotypes that were more similar to one another did not exhibit greater similarity in terms of new beneficial mutations, supporting the view that epistasis acts globally, having a greater influence on the effect than on the identity of available mutations along an adaptive trajectory. Our findings provide support for a general mechanism that leads to predictable phenotypic evolutionary trajectories.

Benefit of transferred mutations is better predicted by the fitness of recipients than by their ecological or genetic relatedness.

The effect of a mutation depends on its interaction with the genetic background in which it is assessed. Studies in experimental systems have demonstrated that such interactions are common among beneficial mutations and often follow a pattern consistent with declining evolvability of more fit genotypes. However, these studies generally examine the consequences of interactions between a small number of focal mutations. It is not clear, therefore, that findings can be extrapolated to natural populations, where new mutations may be transferred between genetically divergent backgrounds. We build on work that examined interactions between four beneficial mutations selected in a laboratory-evolved population of Escherichia coli to test how they interact with the genomes of diverse natural isolates of the same species. We find that the fitness effect of transferred mutations depends weakly on the genetic and ecological similarity of recipient strains relative to the donor strain in which the mutations were selected. By contrast, mutation effects were strongly inversely correlated to the initial fitness of the recipient strain. That is, there was a pattern of diminishing returns whereby fit strains benefited proportionally less from an added mutation. Our results strengthen the view that the fitness of a strain can be a major determinant of its ability to adapt. They also support a role for barriers of transmission, rather than differential selection of transferred DNA, as an explanation of observed phylogenetically determined patterns of restricted recombination among E. coli strains.

Valoración de las habilidades comunicativas en la entrevista clínica de estudiantes de último año de medicina de la Universidad de Antioquia, por medio de la escala CICAA / Communicational skills assess, through CICAA scale, of final year medicine students' clinical interview of Universidad de Antioquia

Introducción: La comunicación es, en la actualidad, una competencia imprescindible en la formación médica. La escala CICAA, concebida desde una perspectiva multidimensional de acuerdo a los criterios de Kalamazoo, es un instrumento usado para la evaluación de las diversas tareas comunicativas en la entrevista clínica. Sujetos y métodos: Dos observadores, uno con formación en ciencias sociales y el otro, médico, analizaron de manera independiente las entrevistas de los estudiantes de último año de medicina de la Universidad de Antioquia de acuerdo a la escala CICAA. Se midió el acuerdo entre observadores (kappa de Cohen), la consistencia interna de la escala (alfa de Cronbach) y su fiabilidad (coeficiente de correlación intraclase, CCI). Resultados y conclusiones: Los resultados mostraron una puntuación total de las mujeres más alta que la de los hombres (p < 0,05). Aunque se observaron diferencias en las calificaciones dadas a cada ítem entre observadores (kappa de Cohen < 0,20), las propiedades psicométricas de la escala fueron adecuadas (alfa de Cronbach > 0,7; CCI > 0,7). Como fortaleza en la comunicación, se identificó la cordialidad de los estudiantes en los encuentros

Introduction: Currently, communication is an essential competence in medical training. CICAA is a scale conceived from a multidimensional perspective according to Kalamazoo's criteria, this is an instrument used to assess different communicational tasks in clinical interview. Subjects and methods: Two observers, one with a background in social sciences and another physician, independently analyzed clinical interviews of final year medicine students' of the Universidad of Antioquia, according CICAA scale. The raters agreement (Cohen's kappa), internal consistency of the scale (Cronbach's alpha) and reliability (intra-class correlation coefficient, ICC) were measured. Results and conclusions: In the results was displayed that women had a total score higher than men (p < 0. 05). Although differences were observed in the ratings given to each item among observers (Cohen's kappa < 0.20), the psychometric properties of the scale were appropriate (Cronbach's alpha > 0.7; ICC > 0. 7). As a fortress in the students communication, was identified the friendliness of students in the clinical interview

Partitioning the fitness components of RNA populations evolving in vitro.

All individuals in an evolving population compete for resources, and their performance is measured by a fitness metric. The performance of the individuals is relative to their abilities and to the biotic surroundings--the conditions under which they are competing--and involves many components. Molecules evolving in a test tube can also face complex environments and dynamics, and their fitness measurements should reflect the complexity of various contributing factors as well. Here, the fitnesses of a set of ligase ribozymes evolved by the continuous in vitro evolution system were measured. During these evolution cycles there are three different catalytic steps, ligation, reverse transcription, and forward transcription, each with a potential differential influence on the total fitness of each ligase. For six distinct ligase ribozyme genotypes that resulted from continuous evolution experiments, the rates of reaction were measured for each catalytic step by tracking the kinetics of enzymes reacting with their substrates. The reaction products were analyzed for the amount of product formed per time. Each catalytic step of the evolution cycle was found to have a differential incidence in the total fitness of the ligases, and therefore the total fitness of any ligase cannot be inferred from only one catalytic step of the evolution cycle. Generally, the ribozyme-directed ligation step tends to impart the largest effect on overall fitness. Yet it was found that the ligase genotypes have different absolute fitness values, and that they exploit different stages of the overall cycle to gain a net advantage. This is a new example of molecular niche partitioning that may allow for coexistence of more than one species in a population. The dissection of molecular events into multiple components of fitness provides new insights into molecular evolutionary studies in the laboratory, and has the potential to explain heretofore counterintuitive findings.

Genetic background affects epistatic interactions between two beneficial mutations.

The phenotypic effect of mutations can depend on their genetic background, a phenomenon known as epistasis. Many experimental studies have found that epistasis is pervasive, and some indicate that it may follow a general pattern dependent on the fitness effect of the interacting mutations. These studies have, however, typically examined the effect of interactions between a small number of focal mutations in a single genetic background. Here, we extend this approach by considering how the interaction between two beneficial mutations that were isolated from a population of laboratory evolved Escherichia coli changes when they are added to divergent natural isolate strains of E. coli. We find that interactions between the focal mutations and the different genetic backgrounds are common. Moreover, the pair-wise interaction between the focal mutations also depended on their genetic background, being more negative in backgrounds with higher absolute fitness. Together, our results indicate the presence of interactions between focal mutations, but also caution that these interactions depend quantitatively on the wider genetic background.

Mechanisms and selection of evolvability: experimental evidence.

The vast number of species we see around us today, all stemming from a common ancestor, clearly demonstrates the capacity of organisms to adapt to new environments. Understanding the underlying basis of differences in the capacity of genotypes to adapt - that is, their evolvability - has become a major research field. Several mechanisms have been demonstrated to influence evolvability, including differences in mutation rate, mutational robustness, and some kinds of gene interactions. However, the benefits of increased evolvability are indirect, so that the conditions required for selection of evolvability traits are expected to be more limited than for traits that confer immediately beneficial phenotypes. Moreover, just because a trait can affect evolvability does not mean that it actually does so in a particular environment. Instead, some other function of the trait may better explain its success. Nevertheless, there is accumulating experimental evidence that some traits can increase the evolvability of a genotype and that these traits do influence evolutionary outcomes. We discuss recent theory and experiments that demonstrate the potential for traits that influence evolvability to arise and be selected.

Infección en pacientes quemados del Hospital Universitario San Vicente de Paúl, Medellín, Colombia / Infection in burn patients at Hospital Universitario San Vicente de Paúl, Medellín, Colombia

Objective: To describe the incidence of infection among burn patients, the microbiological behavior of such infections and to explore the involved risk factors. Material and methods : Prospective survey carried out at the Burn Unit of University Hospital San Vicente de Paúl (Medellín, Colombia) in the period August 1, 2006, to July31, 2008. All burn patients of any age admitted to the Burn Unit were included. Results : Of the total of 655 patients, 85 patients developed infection (12,9%), distributed as follows: 63 skin infections (9.6%), 15 urinary tract infections (2.2%), and 7 pneumonias (1.0%).Skin culture isolates showed Pseudomona aeruginosa in 22 cases (20.4%), Staphylococcus aureus in 21 (19.4%), Acinetobacter baumannii in 12 (11.1%), Enterobacter cloacae in 10 (9.3%), Enterococcus faecalis in 9 (8.3%), and Klebsiella pneumoniae, Proteus mirabilis, Staphylococcus epidermidis and Escherichia coli in two cases, each one (1.9%). Deep second degree and third degree burns developed infection more frequently, as did extended burns, probably due to greater systemic compromise, a protracted hospitalization and a larger number of surgical procedures. Conclusions: The incidence of infection and the most commonly isolated microorganisms vary among each institution. Thus, the importance of recording epidemiological data and being aware of the microorganisms responsible for infection at each burn unit. Risk factors for the development of infection are body area burned, depth of burns, and age.

Objetivo: Describir el comportamiento microbiológico y la incidencia de infecciones en los pacientes quemados, y explorar los factores de riesgo involucrados en el desarrollo de la infección. Materiales y métodos. Se llevó a cabo un estudio prospectivo de cohortes, entre el 1º de agosto de 2006 y el 31 de julio de 2008. Se incluyeron los pacientes quemados de cualquier edad, que fueron hospitalizados en ese periodo en la Unidad de Quemados del Hospital Universitario San Vicente de Paúl, Medellín, Colombia.Resultados. De 655 pacientes, 85 presentaron infecciones (12,9%) distribuidas así: 63 infecciones de la piel (9,6%), 15 infecciones urinarias (2,2%) y 7 neumonías (1,0%). En los cultivos de piel se aisló: Pseudomonas aeruginosa en 22 casos (20,4%), Staphylococcus aureus en 21 (19,4%), Acinetobacter baumannii en 12 (11,1%), Enterobacter cloacae en 10 (9,3%), Enterococcus faecalis en 9 (8,3%) y Klebsiella pneumoniae, Proteus mirabilis, Staphylococcus epidermidis y Escherichia coli en 2 casos cada uno (1,9%). Las quemaduras de segundo grado profundo, las de tercer grado y las quemaduras extensas, presentaron mayor riesgo de desarrollar infecciones, probablemente debido al mayor compromiso sistémico, a la estancia hospitalaria prolongada y al mayor número de procedimientos quirúrgicos. Conclusiones. La incidencia de infecciones y los gérmenes involucrados más comúnmente varían según cada centro de referencia. De ahí, la importancia de que cada unidad de quemados establezca cuáles son sus propios datos epidemiológicos y conozca los microorganismos responsables de las infecciones de sus pacientes. Los factores de riesgo que repercuten de forma importante sobre estos procesos son:el porcentaje de superficie corporal comprometida, la profundidad de las quemaduras y la edad del paciente.

The continuous evolution in vitro technique.

In vitro experimentation techniques were developed in response to the necessity of exploring new molecular structures and functions and to better understand evolutionary phenomena that shape organismal and molecular populations. The advancement of these techniques has allowed further exploration of more complicated evolutionary dynamics. One such technique is the continuous evolution in vitro (CE) method, to which this unit is devoted. The CE method is characterized by continuous cycles of amplification of RNA molecules that occur without much participation of the researcher. This feature allows us to evolve lineages in which the evolutionary phenomena occurring at the molecular level more closely mimic what happens in organismal populations in the present, or what may have happened in RNA populations during the RNA world stage of life.

Quasispecies-like behavior observed in catalytic RNA populations evolving in a test tube.

BACKGROUND: During the RNA World, molecular populations were probably very small and highly susceptible to the force of strong random drift. In conjunction with Muller's Ratchet, this would have imposed difficulties for the preservation of the genetic information and the survival of the populations. Mechanisms that allowed these nascent populations to overcome this problem must have been advantageous. RESULTS: Using continuous in vitro evolution experimentation with an increased mutation rate imposed by MnCl2, it was found that clonal 100-molecule populations of ribozymes clearly exhibit certain characteristics of a quasispecies. This is the first time this has been seen with a catalytic RNA. Extensive genotypic sampling from two replicate lineages was gathered and phylogenetic networks were constructed to elucidate the structure of the evolving RNA populations. A common distribution was found in which a mutant sequence was present at high frequency, surrounded by a cloud of mutant with lower frequencies. This is a typical distribution of quasispecies. Most of the mutants in these clouds were connected by short Hamming distance values, indicating their close relatedness. CONCLUSIONS: The quasispecies nature of mutant RNA clouds facilitates the recovery of genotypes under pressure of being removed from the population by random drift. The empirical populations therefore evolved a genotypic resiliency despite a high mutation rate by adopting the characteristics of quasispecies, implying that primordial RNA pools could have used this strategy to avoid extinction.

La edad sobre el factor masculino y su efecto en la fertilidad de pareja / The effect of age on the male factor and its outcome regarding couples’ fertility

Objetivo: realizar un análisis de las anomalías en los parámetros seminales y su correlación con la edad por medio de espermogramas de pacientes queingresaron a la Unidad de Medicina Reproductiva GESTAMOS, por infertilidad.Métodos y materiales: se realizó un estudio descriptivo de corte transversal de 226 espermogramas obtenidos entre enero de 2005 y enero de 2008, loscuales se examinaron mediante el análisis estándar de acuerdo con la Organización Mundial de la Salud(OMS) y el protocolo del Laboratorio de Andrología del Centro de Fertilidad y Esterilidad CECOLFES, y se analizaron los índices de Correlación de Pearsonpor medio del programa BioStat® 2007 para el respectivo análisis estadístico.Resultados: se analizó un total de 226 espermogramas, los cuales presentaron 73,5 percent de alteraciones significativas en cualquiera de sus parámetros. La disminución en la movilidad progresiva rápida (astenozoospermia) se observó en 65 percent de los casos con tendencia a la baja, con relación a la edad en el 0,04 percent por año. Del mismo modo, se presentaron anomalías en la morfología espermática (teratozoospermia) en 52,2 percent de los espermogramas, con una tendencia al aumento en 0,02 percent de los casos por año. La disminución en la concentración espermática estuvo presente en 28 percent de las muestrascon un descenso en 0,01 x 106/mL por año.Conclusiones: se evidenció una disminución importante de la calidad espermática de la poblaciónestudiada superior a la reportada por la literatura mundial con más relevancia a medida que aumenta la edad de los pacientes, siendo la movilidad progresivarápida y la morfología las más afectadas, las cuales se encuentran estrechamente ligadas a la capacidad fecundante del paciente.

bjective: analysing abnormalities in seminal parameters and their correlation with age through spermograms of patients admitted tothe GESTAMOS Reproductive Medicine Unit for infertility.Methods and materials: this was a descriptive cross-sectional study of 226 spermograms collected between January 2005 and January 2008. Theywere examined by standard analysis according to WHO guidelines and CECOLFES Fertility and Sterility Centre’s Andrology Laboratory protocol.BioStat® 2007 statistical analysis software was used for analysing Pearson correlation Indices. Results: a total of 226 spermograms presented 73,5 percent significant changes in all their parameters. Decreased rapidly progressive mobility (astenozoospermy) was observed in 65 percent and such downward trend was related to age (0,04 percent per year). Abnormalitiesin sperm morphology (teratozoospermy) were presented in 52,2 percent, having an upward trend (0,02 percent per year). Decreased sperm concentrationwas observed in 28 percent (0,01 x 106/mL per year decrease).Conclusions: there was a significant decrease in the study population’s sperm quality which was greater than that reported in the literature. Thiswas more relevant in the sense that as patients’ age increased then the rapidly progressive mobility and morphology of their sperm became most affected,this being closely related to patients’ fertilising capacity.

Gel purification of radiolabeled nucleic acids via phosphorimaging: Dip-N-Dot.

RNA and DNA oligonucleotides radiolabeled with (32)P or (33)P often require gel electrophoresis to remove undesired side and/or degradation products. Common ways to visualize these molecules after electrophoresis are by ultraviolet (UV) shadowing, which necessarily reduces the specific activity of the oligonucleotide, and by autoradiography using film, which is cumbersome and increases the cost of generating the radiolabeled molecule. A more cost-effective method is to physically inject the gel with a "Dip-N-Dot" solution of dye and radionuclide after electrophoresis but prior to phosphorimaging. The gel can be overlaid on its computer-generated image, allowing the labeled molecules to be visualized quickly.

Darwin's concepts in a test tube: parallels between organismal and in vitro evolution.

The evolutionary process as imagined by Darwin 150 years ago is evident not only in nature but also in the manner in which naked nucleic acids and proteins experience the "survival of the fittest" in the test tube during in vitro evolution. This review highlights some of the most apparent evolutionary patterns, such as directional selection, purifying selection, disruptive selection, and iterative evolution (recurrence), and draws parallels between what happens in the wild with whole organisms and what happens in the lab with molecules. Advances in molecular selection techniques, particularly with catalytic RNAs and DNAs, have accelerated in the last 20 years to the point where soon any sort of complex differential hereditary event that one can ascribe to natural populations will be observable in molecular populations, and exploitation of these events can even lead to practical applications in some cases.