Clinicai characteristics and mortality in mechanically ventilated COVID-19 patients: prospective cohort study / Características clínicas y mortalidad en pacientes COVID-19 ventilados mecánicamente: estudio de cohorte prospectivo

Abstract Introduction: Factors associated with mortality among mechanically ventilated COVID-19 patients have been scarcely studied in Latin America. Objective: To identify factors associated with mortality in mechanically ventilated COVID-19 patients. Methods: This prospective study was undertaken in a single center between April and October 2020, recruiting COVID-19 patients managed with mechanical ventilation. We excluded patients who died within the first 24 hours after endotracheal intubation. Clinical characteristics, laboratory results, ventilation interventions, and outcomes were collected and compared between the deceased and surviving groups. The association between these factors and hospital death was examined, and relevant covariates were included in a multivariate logistic regression model. Results: A total of 273 patients were included (72.5% male), the mortality rate was 37% (95% CI 31% - 43%), and the median age was 63 years (IQR 52-72). The most frequent comorbidity was hypertension (45%). Factors associated with mortality were: older age (OR 1.08; 95% CI 1.051.11), male gender (OR 2.79; 95% CI 1.30-6.01), immunosuppression (OR 3.98; 95% CI 1.57-10.06), thrombocytopenia (OR 3.84; CI 95% 1.47-10.01), driving pressure (OR 1.20; 95% CI 1.07-1.34) and the use of dialysis (OR 4.94; 95% CI 2.56-9.51). Chronic hypertension (OR 0.35; 95% CI 0.17-0.71) and fever on admission (OR 0.51; 95% CI 0.27-0.98) were found to have a protective effect. Conclusions: Older age, male sex, immunosuppression, thrombocytopenia, increased driving pressure, use of dialysis, absence of fever, or arterial hypertension were associated with an increased risk of mortality among mechanically ventilated COVID-19 patients.

Resumen Introducción: Es poco lo que se han estudiado en América Latina los factores asociados con mortalidad en pacientes con COVID-19 ventilados mecánicamente. Objetivo: Identificar los factores asociados con mortalidad en pacientes con COVID-19 manejados con ventilación mecánica. Métodos: Este estudio prospectivo se adelantó en un solo centro entre los meses de abril y octubre de 2020 e incluyó pacientes con COVID-19 manejados con ventilación mecánica. Se excluyeron pacientes que fallecieron en las primeras 24 horas después de la intubación orotraqueal. Se recopilaron datos de las características clínicas, resultados de laboratorio, intervenciones ventilatorias y desenlaces, y se hizo una comparación entre el grupo de pacientes fallecidos y el grupo de sobrevivientes. Se examinó la asociación entre estos factores y la muerte intrahospitalaria, y las covariables relevantes se incluyeron en un modelo multivariable de regresión logística. Resultados: Se incluyó un total de 273 pacientes (72.5% hombres), la tasa de mortalidad fue del 37% (IC 95% 31% - 43%), la mediana de edad fue de 36 años (RIC 52-72) y la comorbilidad más frecuente fue la hipertensión (45%). Los factores asociados con mortalidad fueron: edad avanzada (OR 1.08; IC 95% 1.05-1.11), género masculino (OR 2.79; IC 95% 1.30-6.01), inmunosupresión (OR 3.98; IC 95% 1.57-10.06), trombocitopenia (OR 3.84; CI 95% 1.47-10.01), presión de distensión (OR 1.20; IC 95% 1.07-1.34) y el uso de diálisis (OR 4.94; IC 95% 2.56-9.51). La presencia de hipertensión (OR 0.35; IC 95% 0.17-0.71) y de fiebre (OR 0.51; IC 95% 0.27-0.98) al momento de la hospitalización demostraron tener un efecto protector. Conclusiones: Se encontró asociación entre la edad avanzada, el sexo masculino, la inmunosupresión, la trombocitopenia, una presión de distensión elevada, el uso de diálisis, la ausencia de fiebre o de hipertensión y un mayor riesgo de mortalidad en pacientes con COVID-19 ventilados mecánicamente.

Ischemic gangrene of the penis due to Fournier's gangrene following traumatic transurethral catheterization: A case report.

Fournier's gangrene is a life-threatening fascial infection. We report a case of a 65-year-old diabetic man with a history of obstructive prostate growth who developed ischemic penile gangrene following traumatic transurethral catheterization. Despite initial debridement, progressive necrosis necessitated total penectomy and cystostomy. This case highlights the potential for devastating consequences of failed catheterization and the importance of early urologic intervention.

Safety and Pharmacokinetics of a Combined Antioxidant Therapy against Myocardial Reperfusion Injury: A Phase 1 Randomized Clinical Trial in Healthy Humans.

Myocardial reperfusion injury (MRI) accounts for up to 50% of the final size in acute myocardial infarction and other conditions associated with ischemia-reperfusion. Currently, there is still no therapy to prevent MRI, but it is well known that oxidative stress has a key role in its mechanism. We previously reduced MRI in rats through a combined antioxidant therapy (CAT) of ascorbic acid, N-acetylcysteine, and deferoxamine. This study determines the safety and pharmacokinetics of CAT in a Phase I clinical trial. Healthy subjects (n = 18) were randomized 2:1 to CAT or placebo (NaCl 0.9% i.v.). Two different doses/infusion rates of CATs were tested in a single 90-minute intravenous infusion. Blood samples were collected at specific times for 180 minutes to measure plasma drug concentrations (ascorbic acid, N-acetylcysteine, and deferoxamine) and oxidative stress biomarkers. Adverse events were registered during infusion and followed for 30 days. Both CAT1 and CAT2 significantly increased the CAT drug concentrations compared to placebo (P < .05). Most of the pharmacokinetic parameters were similar between CAT1 and CAT2. In total, 6 adverse events were reported, all nonserious and observed in CAT1. The ferric-reducing ability of plasma (an antioxidant biomarker) increased in both CAT groups compared to placebo (P < .001). The CAT is safe in humans and a potential treatment for patients with acute myocardial infarction undergoing reperfusion therapy.

Assessment of the Activity of Nitroisoxazole Derivatives against Trypanosoma cruzi.

The development of new compounds to treat Chagas disease is imperative due to the adverse effects of current drugs and their low efficacy in the chronic phase. This study aims to investigate nitroisoxazole derivatives that produce oxidative stress while modifying the compounds' lipophilicity, affecting their ability to fight trypanosomes. The results indicate that these compounds are more effective against the epimastigote form of T. cruzi, with a 52 ± 4% trypanocidal effect for compound 9. However, they are less effective against the trypomastigote form, with a 15 ± 3% trypanocidal effect. Additionally, compound 11 interacts with a higher number of amino acid residues within the active site of the enzyme cruzipain. Furthermore, it was also found that the presence of a nitro group allows for the generation of free radicals; likewise, the large size of the compound enables increased interaction with aminoacidic residues in the active site of cruzipain, contributing to trypanocidal activity. This activity depends on the size and lipophilicity of the compounds. The study recommends exploring new compounds based on the nitroisoxazole skeleton, with larger substituents and lipophilicity to enhance their trypanocidal activity.

Cardiac Sympathetic Denervation as a Treatment for Ventricular Arrhythmias Refractory to Conventional Treatment: A Case Series.

Background: Ventricular arrhythmias are a leading cause of sudden death. The objective of this study was to characterise the results of patients with ventricular arrhythmias refractory to standard medical management, undergoing Video-assisted thoracoscopic cardiac sympathetic denervation (VAT-CSD) during 2012-2022 in Cali, Colombia. Methods: This was an observational retrospective study, using the Institutional General Thoracic Surgery Database for patient identification and retrospectively reviewing the clinical charts for data description and analysis. Results: Clinical records of 19 patients who underwent VAT-CSD for ventricular arrhythmia were analysed. The patients were predominantly male (73.7%) with an mean age of 62 years. Ischaemic heart disease was the main underlying condition (52.6%); all individuals had a diagnosis of heart failure, with comorbidities such as hypertension (63.1%), acute MI (57.8%) and diabetes (26.3%) also present. The procedure was performed bilaterally in 89.4% of cases and was successful with minimal perioperative complications. Postoperative follow-up showed improvement in symptoms, including a significant reduction in the number of ICD shocks and emergency department visits. Conclusion: VAT-CSD is a viable, safe and palliative therapeutic option for patients with ventricular arrhythmias who have not responded to conventional treatments, achieving a significant decrease in symptoms with low mortality and perioperative complications.

Capsaicinoids and Their Effects on Cancer: The "Double-Edged Sword" Postulate from the Molecular Scale.

Capsaicinoids are a unique chemical species resulting from a particular biosynthesis pathway of hot chilies (Capsicum spp.) that gives rise to 22 analogous compounds, all of which are TRPV1 agonists and, therefore, responsible for the pungency of Capsicum fruits. In addition to their human consumption, numerous ethnopharmacological uses of chili have emerged throughout history. Today, more than 25 years of basic research accredit a multifaceted bioactivity mainly to capsaicin, highlighting its antitumor properties mediated by cytotoxicity and immunological adjuvancy against at least 74 varieties of cancer, while non-cancer cells tend to have greater tolerance. However, despite the progress regarding the understanding of its mechanisms of action, the benefit and safety of capsaicinoids' pharmacological use remain subjects of discussion, since CAP also promotes epithelial-mesenchymal transition, in an ambivalence that has been referred to as "the double-edge sword". Here, we update the comparative discussion of relevant reports about capsaicinoids' bioactivity in a plethora of experimental models of cancer in terms of selectivity, efficacy, and safety. Through an integration of the underlying mechanisms, as well as inherent aspects of cancer biology, we propose mechanistic models regarding the dichotomy of their effects. Finally, we discuss a selection of in vivo evidence concerning capsaicinoids' immunomodulatory properties against cancer.

Violencia de género en mujeres confinadas durante la pandemia por SARS-CoV-2 / Gender-based violence in confined women during the SARS-CoV-2 pandemic

Resumen: Objetivo: Identificar la presencia de violencia de género en mujeres confinadas, debido a la pandemia por Covid-19 en la región Costa de Oaxaca. Materiales y métodos: Investigación cuantitativa, descriptiva, correlacional y de corte transversal en 50 mujeres mayores de 18 años, que permanecieron al menos 1 mes confinadas debido a la pandemia por Covid-19, a quienes aplicaron un cuestionario que empleó el Índice de Severidad de Violencia de Pareja, respetando las recomendaciones éticas pertinentes de la Ley General de Salud en Materia de Investigación para la Salud. Los datos fueron procesados en el programa estadístico SPSS versión 21 y se empleó estadística descriptiva y el coeficiente de correlación de Pearson. Resultados: Se encontró una prevalencia de violencia psicológica de 90%, 72% de las mujeres notificaron violencia física y 64% fueron víctimas de violencia sexual. Se observa correlación positiva entre la edad con la violencia física (r= 0.405, p=0.004), violencia psicológica (r= 0.416, p= 0.003) y la violencia sexual (r= 0.527, p=0.000); se observa correlación negativa en las variables escolaridad y violencia física (r= -0.538, p= 0.000), violencia psicológica (r= -0.488, p= 0.000), violencia sexual (r=-0.411, p= 0.003). Conclusiones: La violencia de género es un tema que ha tomado gran relevancia en los últimos años, y que en la actualidad sigue siendo preocupante. A pesar de que se ha difundido información, sigue existiendo violencia dentro de los hogares mexicanos, en la Costa de Oaxaca durante el confinamiento por Covid-19 la violencia de género ha sido altamente prevalente, por lo que se requiere implementar medidas tendentes a prevenir y tratar la violencia de género.

Abstract: Objective: To identify the presence of gender-based violence in women confined due to the Covid-19 pandemic in the Oaxaca Coast Region Materials and methods: Quantitative, descriptive, correlational and cross-sectional research in 50 women over 18 years of age who remained at least 1 month in confinement due to the Covid-19 pandemic, who applied a questionnaire using the Intimate Partner Violence Severity Index, respecting the pertinent ethical recommendations of the General Health Law on Health Research. The data were processed in the SPSS version 21 statistical program and descriptive statistics and Pearson´s correlation coefficient were used. Results: A prevalence of psychological violence was found to be 90%. 72% of the women reported physical violence and 64% were victims of sexual violence. A positive correlation was observed between age and physical violence (r= 0.405, p= 0.004), psychological violence (r= 0.416, p= 0.003) and sexual violence (r= 0.527, p=0.000); a negative correlation was observed in the variables schooling and physical violence (r= -0.538, p= 0.000), psychological violence (r= -0.488, p= 0.000), sexual violence (r= -0.411, p= 0.003). Conclusions: Gender-based violence is an issue that has taken great relevance in recent years, and that currently continues to be of concern. Despite the fact that information has been disseminated, violence continues to exist within mexican homes. In the Oaxaca Coast during the confinement by Covid-19, gender-based violence has been highly prevalent, which is why it is necessary to implement measures to prevent and treat gender-based violence.

XPS Study on Calcining Mixtures of Brucite with Titania.

In this work, we studied the phases in a Mg-Ti-O system using a 1:1 formulation of MgO:TiO2, mixing synthetic brucite of Mexican origin with TiO2 microparticles of high purity, with a heat treatment at 1100 °C for 1 h. Due to its valence electrons, TiO2 can contribute to the sintering process to improve density in MgO products. The raw materials and formulation by XPS and X-RD techniques were characterized. The results demonstrate the presence of different oxidation states in titania and the formation of different oxides in the Mg-Ti-O system when mixed and calcined at 1100 °C; additionally, we estimated the formation of vacancies in the crystal lattice during the transformation from hexagonal brucite to magnesia with a cubic structure centered on the faces. Its thermal behavior is indicated by the MgO-TiO2 phase diagram.

MgO-ZrO2 Ceramic Composites for Silicomanganese Production.

The deterioration of the refractory lining represents a significant problem for the smooth operation in the ferroalloys industry, particularly in the production of silicomanganese, due to the periodic requirements of substitution of the damaged refractory. Within this context, magnesia refractories are commonly employed in the critical zones of the furnaces used in silicomanganese production since the slag involved in the process has a basic character. The behavior of MgO-ZrO2 ceramic composites with different ZrO2 nanoparticles (0, 1, 3, and 5 wt.%) contents in the presence of silicomanganese slags is proposed in this manuscript. XPS, XRD and SEM-EDX were used to evaluate the properties of the ceramic composite against the silicomanganese slag. The static corrosion test was used to evaluate the corrosion of the refractory. Results suggest that corrosion is controlled by the change in slag viscosity due to the reaction between CaZrO3 and the melted slag. Besides, ZrO2 nanoparticles located at both triple points and grain boundaries act as a barrier for the slag advance within the refractory. The utilization of MgO refractories with ZrO2 nanoparticles can extend the life of furnaces used to produce silicomanganese.

Polyphenolic Composition and Antioxidant Activity (ORAC, EPR and Cellular) of Different Extracts of Argylia radiata Vitroplants and Natural Roots.

Plant biochemistry studies have increased in recent years due to their potential to improve human health. Argylia radiata is an extremophile plant with an interesting polyphenolic profile. However, its biomass is scarce and occasionally available. Argylia in vitro biomass was obtained from tissue culture and compared with in vivo roots regarding its polyphenolic and flavonoid content. Different solvents were used to prepare extracts from the in vitro tissue of callus and aerial plant organs and in vivo roots. UPLC-MS/MS was used to assess the chemical composition of each extract. ORAC-FL and scavenging of free radicals (DPPH and OH) methods were used to determine the antioxidant capacity of extracts. Furthermore, the biological activity of the extracts was established using the cellular antioxidant activity method. The vitroplants were a good source of polyphenols (25-68 mg GAE/100 g tissue FW), and methanol was the most efficient solvent. Eight polyphenolic compounds were identified, and their antioxidant properties were investigated by different chemical methods with EPR demonstrating its specific scavenging activity against free radicals. All extracts showed cellular dose-dependent antioxidant activity. The methanolic extract of vitroplants showed the highest cellular antioxidant activity (44.6% and 51%) at 1 and 10 µg/mL of extract, respectively. Vitroplants of A. radiata are proposed as a biotechnological product as a source of antioxidant compounds with multiple applications.

Proangiogenic Effect of Affinin and an Ethanolic Extract from Heliopsis longipes Roots: Ex Vivo and In Vivo Evidence.

Angiogenesis, the formation of new blood vessels, underlies tissue development and repair. Some medicinal plant-derived compounds can modulate the angiogenic response. Heliopsis longipes, a Mexican medicinal plant, is widely used because of its effects on pain and inflammation. The main bioactive phytochemicals from H. longipes roots are alkamides, where affinin is the most abundant. Scientific studies show various medical effects of organic extracts of H. longipes roots and affinin that share some molecular pathways with the angiogenesis process, with the vasodilation mechanism of action being the most recent. This study investigates whether pure affinin and the ethanolic extract from Heliopsis longipes roots (HLEE) promote angiogenesis. Using the aortic ring rat assay (ex vivo method) and the direct in vivo angiogenesis assay, where angioreactors were implanted in CD1 female mice, showed that affinin and the HLEE increased vascular growth in a dose-dependent manner in both bioassays. This is the first study showing the proangiogenic effect of H. longipes. Further studies should focus on the mechanism of action and its possible therapeutic use in diseases characterized by insufficient angiogenesis.

Determination of Antioxidant Activity by Oxygen Radical Absorbance Capacity (ORAC-FL), Cellular Antioxidant Activity (CAA), Electrochemical and Microbiological Analyses of Silver Nanoparticles Using the Aqueous Leaf Extract of Solanum mammosum L.

PURPOSE: The importance of studying polyphenolic compounds as natural antioxidants has encouraged the search for new methods of analysis that are quick and simple. The synthesis of silver nanoparticles (AgNPs) using plant extracts has been presented as an alternative to determine the total polyphenolic content and its antioxidant activity. METHODS: In this study, aqueous leaf extract of Solanum mammosum, a species of plant endemic to South America, was used to produce AgNPs. The technique of oxygen radical absorption capacity using fluorescein (ORAC-FL) was used to measure antioxidant activity. The oxidation of the 2´,7´-dichlorodihydrofluorescein diacetate (DCFH2-DA) as fluorescent probe was used to measure cellular antioxidant activity (CAA). Electrochemical behavior was also examined using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Total polyphenolic content (TPH) was analyzed using the Folin-Ciocalteu method, and the major polyphenolic compound was analyzed by high performance liquid chromatography with diode array detector (HPLC/DAD). Finally, a microbial analysis was conducted using Escherichia coli and Bacillus sp. RESULTS: The average size of nanoparticles was 5.2 ± 2.3 nm measured by high-resolution transmission electron microscopy (HR-TEM). The antioxidant activity measured by ORAC-FL in the extract and nanoparticles were 3944 ± 112 and 637.5 ± 14.8 µM ET/g of sample, respectively. Cellular antioxidant activity was 14.7 ± 0.2 for the aqueous extract and 12.5 ± 0.2 for the nanoparticles. The electrochemical index (EI) was 402 µA/V for the extract and 324 µA/V for the nanoparticles. Total polyphenolic content was 826.6 ± 20.9 and 139.7 ± 20.9 mg EGA/100 g of sample. Gallic acid was the main polyphenolic compound present in the leaf extract. Microbiological analysis revealed that although leaf extract was not toxic for Escherichia coli and Bacillus sp., minor toxic activity for AgNPs was detected for both strains. CONCLUSION: It is concluded that the aqueous extract of the leaves of S. mammosum contains nontoxic antioxidant compounds capable of producing AgNPs. The methods using AgNPs can be used as a fast analytical tool to monitor the presence of water-soluble polyphenolic compounds from plant origin. Analysis and detection of new antioxidants from plant extracts may be potentially applicable in biomedicine.

Dependence of the Ripeness Stage on the Antioxidant and Antimicrobial Properties of Walnut (Juglans regia L.) Green Husk Extracts from Industrial By-Products.

Walnut green husk (WGH) is a waste generated by the walnut (Juglans regia L.) harvest industry. It represents a natural source of polyphenols, compounds with antioxidant and antimicrobial activities, but their activity could be dependent on the ripeness stage of the raw material. In this study, the effect of the different ripeness stages-open (OH) and closed (CH) husks-on the antioxidant and antimicrobial properties of WGH extracts were analyzed, emphasizing the influence of the extracts in inhibiting Escherichia coli growth. The ripeness stage of WGH significantly affected the antioxidant activity of the extracts. This was attributed to the different polyphenol profiles related to the mechanical stress when the husk opened compared to the closed sample. The antimicrobial activity showed inhibition of E. coli growth. OH-extracts at 96 µg/mL caused the lowest specific growth rate (µmax = 0.003 h-1) and the greatest inhibition percentage (I = 93%) compared to CH-extract (µmax = 0.01 h-1; I = 69%). The obtained results showed the potential of the walnut green husk, principally open husk, as an economical source of antioxidant and antimicrobial agents with potential use in the food industry.

Synthesis of Silver Nanoparticles Using Aqueous Leaf Extract of Mimosa albida (Mimosoideae): Characterization and Antioxidant Activity.

The search for sensitive and rapid analytical techniques for the determination of natural antioxidants is an area in constant growth due, among other aspects, to the complexity of plant matrices. In this study, silver nanoparticles prepared with the aqueous extract of Mimosa albida leaves were used to assess their polyphenolic content and antioxidant capacity. Silver nanoparticles were characterized by different techniques. As a result, nanoparticles of 6.5 ± 3.1 nm were obtained. The total phenolic content in the extract was 1320.4 ± 17.6 mg of gallic acid equivalents GAE. 100 g-1 and in the nanoparticles 257.3 ± 5.1 mg GAE. 100 g-1. From the phenolic profile analyzed by ultra high-performance liquid chromatography (UPLC) with a diode-array detector (DAD), the presence of apigenin and luteolin in the plant extract is postulated. The antioxidant capacity measured by oxygen radical absorbance capacity ORAC-fluorescein assay was 86917 ± 6287 and 7563 ± 967 µmol ET g-1 in the extract and nanoparticles respectively. Electrochemical analysis by cyclic voltammetry (CV) confirmed the effective reduction capacity of the Mimosa albida leaves extract to reduce Ag ions to AgNPs and differential pulse voltammetry (DPV) suggested the presence of two main reducing agents in the extract. From this study, it was concluded that the aqueous extract of Mimosa albida contains reducing agents capable of synthesizing silver nanoparticles, which can be used in the phytochemical industry.

The Short-Term Effects of Roux-en-Y Gastric Bypass on Renal Excretion of Sodium and Its Association with Blood Pressure.

INTRODUCTION: Bariatric surgery has been shown to be effective in reducing weight and has benefits, such as lowering blood pressure. An increase in urinary sodium excretion has been suggested as a possible mechanism. This study explored changes in sodium excretion and their correlation with blood pressure after Roux-en-Y gastric bypass. MATERIALS AND METHODS: This study was conducted on 28 obese participants with body mass index (BMI) of 44.54 ± 7.81 kg/m2 who underwent gastric bypass. Before surgery and at the third and sixth months after gastric bypass, blood pressure, urinary sodium concentration, 24-hour (24-h) urinary sodium excretion, and fractional excretion of sodium were evaluated. In addition, serum sodium and potassium levels were determined. Nonparametric tests were used to analyze the data. RESULTS: Blood pressure decreased after surgery and remained at low levels over the 3- and 6-month periods. The urinary sodium concentration increased at 3 months after surgery; however, the 24-h urinary sodium excretion and urine volume decreased. Interestingly, although some associations between variables were observed, significant correlations between the 24-h urinary sodium excretion and the systolic, diastolic, and mean blood pressures were found. In addition, the urine volume was higher in the sixth month than in the third month following surgery. CONCLUSIONS: In the months immediately following surgery, a low-salt and low-volume diet favors decreases in urine volume and 24-h urinary sodium excretion. In addition, in the sixth month after surgery, an association between blood pressure and 24-h urinary sodium excretion was observed.

Comparación de Tres Procedimientos de Extinción de la Evitación Discriminada en Humanos / Comparison of Three Extinction Procedures on Discriminated Avoidance Learning in Humans

Resumen En la evitación discriminada, una respuesta emitida durante la señal impide la aparición de un estímulo aversivo. La extinción de las respuestas de evitación se ha estudiado como la terminación de la relación instrumental entre la respuesta y el estímulo aversivo. Su compresión ha sido primordial para comprender el mantenimiento de la respuesta de evitación en humanos. Se compararon tres procedimientos de extinción de la respuesta de evitación en humanos. Veintisiete participantes, aprendieron una tarea de evitación discriminada dividida en dos fases: Pavloviana, con apareamientos de dos señales (Estímulo Condicionados; EC 1 y EC2) con un sonido (90 dB, 60 Hz), e Instrumental, donde la respuesta R1 ante el EC1 o la respuesta R2 ante el EC2 evitaba el sonido. Posterior a estas fases, fueron asignados a tres grupos, cada grupo experimentó diferentes procedimientos de extinción; (Estímulo Incondicionado, EI) donde R1 no termino con la señal, pero si con el sonido, (EC) donde R1 termino con la señal, pero no con el sonido, y (EC/EI) donde R1 no termino con ninguno de los estímulos (señal, sonido). En todos los grupos R2 continuó evitando el sonido. Los resultados mostraron que las respuestas de evitación R1 disminuyeron en los grupos EC y EC/EI, y no se extinguieron en el grupo EI. Estos resultados enfatizan la importancia de la terminación de la señal en el mantenimiento del aprendizaje de evitación discriminada.

Abstract In discriminated avoidance, a response emitted during the signal prevents the appearance of an aversive stimulus. The extinction of avoidance responses has been studied as the termination of the instrumental relationship between the response and aversive stimulus. Its understanding has been essential to understand the maintenance of the avoidance response in humans. Three procedures of avoidance response extinction in humans were compared. Twenty-seven participants learned a discriminated avoidance task divided into two phases: Pavlovian, with pairings of two signals (Conditioned Stimulus (EC) 1, EC2) with a sound (90 dB, 60 Hz), and Instrumental, in which R1 response to the EC1 or R2 response to EC2 prevented sound. After these phases, participants were assigned to three groups, each group experienced different extinction procedures; (Unconditioned Stimulus, EI) where R1 did not end with the signal, but with the sound, (EC) where R1 ended with the signal, but not with the sound, and (EC / EI) where R1 did not end with any of the stimuli (signal, sound). In all groups R2 continued avoiding sound. Results show that R1 responses decreased (were extinguished) in the EC and EC / EI groups, but didn't in the EI group. These results emphasize the importance of signal termination in maintaining discriminated avoidance learning.

Factors associated with failure of postoperative nausea and vomiting prophylaxis in a high complexity health center in Cali, Colombia: case-control study / Factores asociados con la falla de la profilaxis de náusea y vómito posoperatorio en un centro de salud de alta complejidad en Cali, Colombia: estudio de casos y controles

Abstract Introduction: Postoperative nausea and vomiting (PONV) negatively impact patients undergoing surgical procedures under anesthesia. The scientific evidence on the risk factors for PONV after antiemetic prophylaxis is unsatisfactory, so there is a need to identify the factors associated with the occurrence of PONV. Objective: To identify the factors associated with failed prophylaxis for PONV in patients at Fundación Valle del Lili in 2017. Methods: Case-control study. Patients admitted to the post anesthesia care unit after having undergone surgery under general anesthesia were included. The cases were patients who, despite receiving antiemetic prophylaxis, had PONV, and those who did not develop these symptoms after prophylaxis, were considered the control group. A bivariate analysis was conducted using the Mann-Whitney U test, Fisher's exact test, or x2, according to the type of variable. Finally, crude odds ratios were estimated and subsequently adjusted via a logistic regression. Results: A total of 80 cases and 332 controls were included. The median age for all patients was 47 years. Women represented 61.6% (n = 254). The variables associated with PONV were age (odds ratio [OR] = 0.98, 95% confidence interval [CI] 0.96-0.99, P = 0.013), female (OR = 3.02, 95% CI 1.66-5.47, P < 0.001) and the use of desflurane during surgery (OR = 2.82, 95% CI 1.097.30, P < 0.032). Conclusion: Female sex and the use of desflurane during surgery increase the odds of experiencing PONV, regardless of pharmacological antiemetic prophylaxis. Moreover, elderly patients show lower odds of developing this complication.

Resumen Introducción: La náusea y el vómito posoperatorios impactan negativamente en los pacientes sometidos a procedimientos quirúrgicos bajo anestesia. La evidencia científica sobre los factores de riesgo para náusea y vómito posoperatorios después de profilaxis antiemética es insatisfactoria, por lo que es necesario identificar los factores asociados con su presentación. Objetivo: Establecer los factores asociados con la profilaxis fallida de náusea y vómito posoperatorios en pacientes de la Fundación Valle del Lili en el 2017. Métodos: Se realizó un estudio de casos y controles. Se incluyeron los pacientes que ingresaron a la unidad de cuidados posanestésicos luego de haber sido intervenidos quirúrgicamente bajo anestesia general. Los casos fueron los pacientes que a pesar de recibir profilaxis antiemética presentaron náusea y/o vómito posoperatorio, mientras los controles fueron aquellos que no presentaron estos síntomas después de la profilaxis. Se realizó un análisis bivariado con la U de Mann-Whitney, el test exacto de Fisher o X2, según el tipo de variable. Finalmente, se estimaron odds ratios crudos que después fueron ajustados por medio de una regresión logística. Resultados: Se incluyeron 80 casos y 332 controles. La mediana de edad para todos los pacientes fue 47 años. Las mujeres representaron el 61.6% (n = 254). Las variables asociadas con náusea y vómito posoperatorios fueron: edad (OR=0.98, IC 95% 0.96-0.99; p = 0.013), ser mujer (OR = 3.02, IC 95% 1.66-5.47; p < 0.001) y el uso de desflurano durante el procedimiento quirúrgico (OR = 2.82, IC 95% 1.09-7.30; p <0.032). Conclusiones: El sexo femenino y el uso de desflurano durante el procedimiento quirúrgico aumentan la oportunidad de tener náusea y vómito posoperatorios, a pesar de una profilaxis farmacológica antiemética. Por otra parte, en pacientes con edades mayores se observa una disminución de la oportunidad de presentar esta complicación.

Validation of a predictive index of neoplasia in unexplained weight loss / Validación de un índice predictivo de neoplasia en pérdida de peso inexplicada

Background: Involuntary weight loss (IWL) is associated with a bad prognosis. A causal diagnosis is difficult and the priority is to identify those patients at risk of a serious underlying disease, such as malignant neoplasia. Objective: External validation of a prognostic index of neoplasia in patients with IWL. Methods: Patients referred for IWL from 2005 to 2014 to the Department of Internal Medicine, of a specialty care hospital in Mexico City were studied. Al of them underwent an evaluation consisting of medical history, physical examination and basic laboratory studies, those patients without an apparent cause of IWL, were included. A probability of neoplasia according to Hernández prognostic index was calculated. Complementary diagnostic studies were performed until a causal diagnosis was reached, or the cases were classified as "unknown cause", if the etiology was not possible to find after one year of follow-up. A binarian logistic model was constructed with five variables age, leucocyte count, albumin, lactic dehydrogenase and alkaline phosphatase levels, and a prediction rule was developed. Results: 130 Patients were included and 45 of them (30%) had a neoplastic cause of IWL. The prediction rule according to Hernández criteria, correctly classified 65% of the patients (sensitivity 29%, Specificity 85%, positive predictive value 50% and negative predictive value 69%). When the original index was modified in two categories (high and low probability), it showed a sensitivity of 84.4% and a negative predictive value of 85.7%. Conclusion: The Hernández index has a limited value as a screening tool.

Introducción: la pérdida involuntaria de peso es un factor de mal pronóstico. Su diagnóstico causal es difícil y es prioritario identificar los casos que tienen una enfermedad grave subyacente. Objetivo: validar un índice pronóstico de neoplasia en pacientes con pérdida involuntaria de peso. Métodos: pacientes referidos por pérdida involuntaria de peso de 2005 a 2014, fueron evaluados mediante historia clínica y exámenes básicos de laboratorio; en el estudio fueron incluidos los pacientes sin causa aparente después de la evaluación. Se calculó la probabilidad de neoplasia, según el índice de Hernández. Se realizaron estudios complementarios hasta identificar una causa o fueron clasificados como "causa desconocida", si no se encontró la etiología después de un año de seguimiento. Se construyó un modelo de regresión logística binaria con las variables edad, cifras de leucocitos, albúmina, deshidrogenasa láctica y fosfatasa alcalina; con la ecuación resultante se predijo neoplasia como causa de pérdida involuntaria de peso. Resultados: se incluyeron 130 pacientes, 45 tuvieron causa neoplásica (30%). La ecuación de predicción clasificó correctamente a 65% de los sujetos analizados (especificidad 85%, sensibilidad 29%, valor predictivo positivo 50%, valor predictivo negativo 69%). Al modificarse el índice original en dos categorías (probabilidad alta y baja), mostró una sensibilidad del 84.4% y un valor predictivo negativo del 85.7%. Conclusión: el índice tuvo baja sensibilidad, lo que limita su uso como prueba de tamizaje.

Impacto de hiperleucocitosis en la morbimortalidad de pacientes en fase de inducción con el protocolo centroamericano para el tratamiento de leucemia linfoblástica aguda 2015, del servicio de Oncología del Hospital Nacional de Niños Benjamín Bloom, enero, 2017 ­ marzo, 2018 / Impact of hyperleukocytosis in the morbidity and mortality of patients in induction phase with the Central American protocol for the treatment of acute lymphoblastic leukemia 2015, of the Oncology service of the Benjamin Bloom National Children's Hospital, January, 2017 - March, 2018

La leucemia linfoblástica aguda (LLA) constituye el 80% de todas las leucemias agudas de la infancia. La Asociación de Hemato-Oncología Pediátrica de Centroamérica (AHOPCA) elaboró un protocolo de tratamiento en 2015, resultando imprescindible la asignación del riesgo de recaída. La hiperleucocitosis, el conteo de glóbulos blancos mayor de 100,000/mm3, es factor pronóstico desfavorable reconocido en niños con leucemia determinando mayor grado de recaídas y morbilidades. Este estudio tuvo como objetivo determinar el impacto de la hiperleucocitosis en pacientes con leucemia linfoblástica aguda en fase de inducción con el protocolo de AHOPCA 2015. Se realizó un estudio descriptivo, correlacional, de corte transversal entre enero, 2017 - marzo, 2018. Se obtuvieron 75 pacientes con LLA, de éstos, sólo 14 presentaron hiperleucocitosis y del resto se tuvo acceso sólo a 51 expedientes. Se recolectaron los datos epidemiológicos, clínicos, de laboratorio, medidas terapéuticas, principales morbilidades durante la fase de inducción y se revisó el estado actual. Se recolectaron en Microsoft Excel 2016 a través de tablas dinámicas y contingencia 2x2, y se analizaron en www.openepi.com con los métodos exactos de Fisher y T de Student, obteniendo valor P y odds ratio. La prevalencia de hiperleucocitosis es 18.6%, la mayoría entre 5 a 10 años y provienen de la zona urbana de San Salvador. Las manifestaciones hemorrágicas de piel y mucosas son el hallazgo estadísticamente más frecuente en los pacientes con hiperleucocitosis (P<0.05). No hubo diferencias en las medidas terapéuticas establecidas para ambos grupos. Durante la fase de inducción los pacientes con hiperleucocitosis presentaron más convulsiones, sepsis y neumonía (P < 0.05). Además de presentar mayor riesgo de insuficiencia renal aguda, síndrome de encefalopatía posterior reversible y síndrome de lisis tumoral (P< 0.05). Ningún paciente falleció. La hiperleucocitosis representa un impacto en la morbilidad durante la fase de inducción en pacientes con leucemia linfoblástica aguda con el protocolo AHOPCA 2015. No determinó riesgo para mortalidad

Phaseolus acutifolius Lectin Fractions Exhibit Apoptotic Effects on Colon Cancer: Preclinical Studies Using Dimethilhydrazine or Azoxi-Methane as Cancer Induction Agents.

Phaseolus acutifolius (Tepary bean) lectins have been studied as cytotoxic molecules on colon cancer cells. The toxicological profile of a Tepary bean lectin fraction (TBLF) has shown low toxicity in experimental animals; exhibiting anti-nutritional effects such as a reduction in body weight gain and a decrease in food intake when using a dose of 50 mg/kg on alternate days for six weeks. Taking this information into account, the focus of this work was to evaluate the effect of the TBLF on colon cancer using 1,2-dimethylhydrazine (DMH) or azoxy-methane/dextran sodium sulfate (AOM/DSS) as colon cancer inductors. Rats were treated with DMH or AOM/DSS and then administered with TBFL (50 mg/kg) for six weeks. TBLF significantly decreased early tumorigenesis triggered by DMH by 70%, but without any evidence of an apoptotic effect. In an independent experiment, AOM/DSS was used to generate aberrant cryptic foci, which decreased by 50% after TBLF treatment. TBLF exhibited antiproliferative and proapoptotic effects related to a decrease of the signal transduction pathway protein Akt in its activated form and an increase of caspase 3 activity, but not to p53 activation. Further studies will deepen our knowledge of specific apoptosis pathways and cellular stress processes such as oxidative damage.