Abstract Introduction: Optisol-GS is the most widely used corneal preservation medium worldwide, there is little evidence to compare it against Eusol-C as a corneal preservation medium. Objectives: To evaluate the viability of endothelial cells between two different corneal preservation media. Materials and Methods: It is a prospective, longitudinal, and comparative study, which was carried out in the eye bank of Hospital General de México "Dr. Eduardo Liceaga", from where the corneas of suitable donors were collected, the right cornea was preserved in Optisol-GS and the left in Eusol-C. Two evaluations were carried out on day 1 and 5. Endothelial cell density, coefficient of cell variation and hexagonality were analysed. Results: The decrease in endothelial cells on day 5 after collection of the corneoscleral tissue was 8.149% in the corneas stored in Optisol-GS and 7.614% in Eusol-C p=0.006. Cell variation increased 1.634% in Optisol-GS and 8.942% in Eusol-C p=0.948. Cell hexagonality decreased 6.988% in Optisol-GS and 9.480% in Eusol-C p=0.936. Conclusions: No superiority was found when comparing these two media, which shows that Eusol-C is as effective as Optisol-GS for corneal preservation for at least five days.

Resumen Objetivo: Describir los resultados maternos y perinatales de pacientes con diagnóstico prenatal de gastrosquisis atendidos en un centro de referencia obstétrica de Medellín. Método: Estudio observacional, descriptivo y retrospectivo, llevado a cabo en la Clínica Universitaria Bolivariana en fetos con diagnóstico prenatal de gastrosquisis desde el 1 de enero de 2010 hasta el 31 de julio de 2021. Resultados: Se identificaron 54 gestantes con diagnóstico prenatal de gastrosquisis. En el 63% era su primer embarazo y el 27,8% eran adolescentes. La duración promedio de la gestación fue de 35 semanas y 6 días. La cesárea fue la vía más común (98,1%) y la indicación más frecuente fue sufrimiento de asa 66,7%. El 55,6% de los neonatos requirieron más de una intervención quirúrgica para el cierre de la pared abdominal. Las complicaciones más frecuentes fueron anemia (66,7%) e íleo posoperatorio (72,2%). La mortalidad fue del 13%. Conclusiones: Se evidencian algunas características similares a las reportadas en otras series. La mayor presentación fue en primer embarazo, la causa de finalización de la gestación fue sufrimiento de asas (demostrando la importancia del seguimiento ecográfico), y las complicaciones más frecuentes fueron anemia e íleo posoperatorio presentados por la prematuridad. La mortalidad comparada con la de otras instituciones locales fue menor.

Abstract Objective: To describe the outcomes of maternal and perinatal in patients diagnosed with prenatal gastroschisis that received medical care at an obstetric reference center in Medellin. Method: Observational, descriptive and retrospective study in fetuses with a prenatal diagnosis of gastroschisis performed in the Clínica Universitaria Bolivariana between January 1st 2010 and July 31st 2021. Results: Were included 54 pregnant women with prenatal diagnosis of gastroschisis. The 63% were their first pregnancy and 27,8% were adolescents. The average duration of gestation was 35 weeks and 6 days. Cesarean section was the most common way of delivery (98,1%) and the most frequent indication was suffering from loop (66,7%). The 55,6% of neonates required more than one surgical intervention for closure of the abdominal wall. The most frequent complications were anemia (66,7%) and postoperative ileus (72,2%). A mortality of 13% was presented. Conclusions: Some characteristics like reported in other series are evident. The greatest presentation was in the first pregnancy, the cause of termination of pregnancy was suffering from loops (demonstrating the importance of ultrasound monitoring) and the most frequent complications were anemia and postoperative ileus presented by prematurity. Mortality, compared to other local institutions, was lower.

Resumen La evidencia que relaciona la terapia oncológica con la incidencia por COVID-19 varía según el tipo de terapia administrada. La incidencia informada en pacientes que reciben tratamiento oncológico varía entre 1 y 4%. El objetivo del presente estudio fue determinar la incidencia por COVID-19 en pacientes oncológicos en tratamiento activo y evaluar si existe asociación con el esquema recibido. Se utilizó una cohorte retrospectiva que incluyó de forma consecutiva a los pacientes adultos que realizaron tratamiento ambulatorio desde marzo/2020 hasta abril/2021 en un Hospital Público de referencia. El evento principal fue el diagnóstico confirmado de COVID-19. La asociación con los tratamientos oncológicos fue evaluada mediante regresión logís tica multivariada ajustando por edad, sexo, localización del tumor, cobertura de salud y localidad de residencia. Se incluyeron 463 pacientes, mediana de edad 58 años (RIC = 47-66), 73.3% (n = 337) mujeres. La incidencia de COVID-19 fue 5.6% (n = 26) con una tasa de mortalidad del 12% (n = 3). El riesgo de infección fue mayor en los que estaban realizando tratamiento únicamente con anticuerpos monoclonales, 14.3% vs. 4.9% (OR-ajustado = 3.3, p = 0.03) y aquellos en tratamiento con inhibidores de puntos de control inmunológicos, 23.1% vs. 5.1% (OR-ajustado = 5.8, p = 0.03). La quimioterapia citotóxica, sola o en combinación con anticuerpos mo noclonales, no presentó mayor riesgo de infección. La edad, sexo, sitio tumoral, cobertura de salud y localidad de residencia no se asoció con la incidencia de COVID-19. En base a nuestros resultados, el tratamiento con anticuerpos monoclonales o inhibidores de puntos de control inmunológicos se asoció con mayor incidencia de infección por COVID-19.

Abstract Evidence linking anticancer therapy with the incidence of COVID-19 varies according to the type of therapy administered. The reported COVID-19 incidence in patients receiving antineoplastic treatment varies between 1 and 4%. The aim of this study was to determine the incidence of COVID-19 in cancer patients under active treatment and to assess whether there is an association with the received anticancer therapy. It was a retrospective cohort that consecutively included adult outpatients who underwent treatment in a referral center from March 2020 to April 2021. The primary endpoint was the confirmed diagnosis of COVID-19. The association with anticancer treatments was evaluated using multivariate logistic regression adjusting for age, sex, tumor site, health coverage status, and place of residence. The sample included 463 patients, the median age was 58 years (IQR = 47-66), 73.3% (n = 337) were women. The incidence of COVID-19 was 5.6% (n = 26) with a mortality rate of 12% (n = 3). The risk of infection was higher in patients undergoing treatment only with monoclonal antibod ies, 14.3% vs. 4.9% (adjusted OR = 3.3, p = 0.03) and those in treatment with immunotherapy, 23.1% vs. 5.1% (adjusted OR = 5.8, p = 0.03). Cytotoxic chemotherapy, alone or in combination with monoclonal antibodies, did not present an increased risk of infection. Age, sex, tumor site, health coverage, and place of residence did not show association with the incidence of COVID-19. Based on our results, treatment with monoclonal antibodies or immunotherapy was associated with a higher rate of COVID-19 infection while chemotherapy did not modify the incidence of COVID-19.

Abstract INTRODUCTION Urinary tract infection is the second-leading reason for consults in primary health care. Bacterial urinary tract infections are the most common, of which Escherichia coli is the main etiologic agent. Antimicrobial resistance and multidrug resistance complicate effective community treatment, especially if resistance is caused by extended-spectrum beta-lactamase production. WHO recommends that antimicrobial susceptibility be evaluated in different regions of the world at different times. Community-acquired E. coli’s susceptibility to colistin has not yet been studied in Cuba, and mcr-1 gene screening is necessary. OBJECTIVE Evaluate community-acquired uropathogenic E. coli isolates’ susceptibility to antibiotics, including colistin, and identify extended-spectrum beta-lactamase–producing bacteria. METHODS We conducted a descriptive cross-sectional study that included 281 community-acquired uropathogenic E. coli isolates (153 from the Isle of Youth Special Municipality’s Hygiene, Epidemiology, and Microbiology Center and 128 from Microbiology Laboratories of 7 institutions in Havana) from June 2016 through July 2018. We used the disk diffusion method to determine susceptibility to ampicillin, ampicillin/sulbactam, cefazolin, trimethoprim/sulfamethoxazole, ciprofloxacin, nitrofurantoin and fosfomycin. The disk elution method was used to determine susceptibility to colistin. The combined disk method was used to identify extended-spectrum beta-lactamases. Estimates were made regarding the frequency and percentages of antimicrobial susceptibility and resistance, as well as multidrug-resistance patterns. RESULTS Of the 281 isolates, 68.3% (192/281) were resistant to ampicillin, 54.8% (154/281) were resistant to ciprofloxacin, and 49.5% (139/281) were resistant to trimethoprim/sulfamethoxazole. Resistance to colistin was not detected. On the other hand, 14.2% (40/281) were susceptible to the 8 antibiotics we evaluated, 22.1% (62/281) showed resistance to only 1 antibiotic, and 63.7% (179/281) were resistant to 2 or more antibiotics. In the extended-spectrum beta-lactamase determination, 34.5% (97/281) had inhibition zones ≤14 mm with cefazolin. Of those with inhibition zones, 64.9% (63/97) were positive in the phenotype test, and 35.1% (34/97) were negative. In extended-spectrum beta-lactamase–producing bacteria, 1.6% (1/63) were resistant to fosfomycin, and 3.2% (2/63) were resistant to nitrofurantoin. The most common multidrug-resistance pattern (22.9%; 30/131) was to ampicillin/sulbactam, ampicillin, cefazolin, ciprofloxacin, and trimethoprim/sulfamethoxazole. CONCLUSIONS Uropathogenic E. coli resistance to the antibiotics most frequently used in community medical practice is quite common, and extended-spectrum beta-lactamase–producing bacteria is the mechanism for beta-lactam antibiotic resistance. Multidrug-resistance patterns include resistance to the antibiotics most used in community-acquired infections. Fosfomycin and nitrofurantoin are the most active in extended-spectrum beta-lactamase producing bacteria. All the isolates were susceptible to colistin.

Resumen Este trabajo presenta los resultados del proyecto de investigación relacionado con la integración energética llevado a cabo en la fábrica de azúcar del Ingenio Risaralda S.A. Se muestra el desarrollo para cada una de las etapas de mejoramiento ejecutadas para reducir el vapor demandado para la elaboración de azúcar. Para alcanzar el objetivo propuesto fueron intervenidas las operaciones unitarias de calentamiento de jugo crudo, evaporación de jugo clarificado, cristalización de sacarosa y secado de azúcar húmeda. Los resultados del proyecto generaron una reducción del 19.2% en el consumo específico de vapor, pasando de 1,450 a 1,172 lbmvapor/TCM [657.6 a 531.5 kgvapor/TCM]. Igualmente, como producto de la implementación del proyecto de integración energética entre los años 2017 y 2020, se muestran los beneficios relacionados con el incremento de la venta de energía eléctrica en 3.3 GWh entregados a la red nacional.

Abstract This manuscript presents the results of the energy integration project carried out in Risaralda Sugar Mill. We show the stages of the executed project to reduce the steam demanded for the production of sugar. To achieve the proposed objective were intervened the following unit operations: heating raw juice, evaporation of clarified juice, crystallization of sucrose and drying of wet sugar. The project results generated a 19.2% reduction in the specific steam consumption, going from 1,450 a 1,172 lbmvapor/TCM [657.6 a 531.5 kgvapor/TCM]. The benefits are also showed in terms of the increase in the sale of electrical energy by 3.3 GWh delivered to the national grid, as a result of the implementation of this project between 2017 and 2020.

ABSTRACT Collared peccaries (Pecari tajacu) roam the forests of natural areas in America. Wild collared peccary appears to be a carrier for bacteria associated with infections in humans and animals, however, the presence of diarrheagenic E. coli (DEC) pathotypes has not been studied in the captive collared peccary. This study aimed to study the prevalence of DEC, the susceptibility to antibiotics, and the frequency of β-lactamase genes (ESBL) in captive collared peccary faeces. DEC strains were identified in 44.4% (N=56) of the E. coli-carrying peccaries under study. The following DEC strains were identified: ETEC (35.7%), EAEC (28.6%), STEC (21.4%) and EPEC (14.3%). Most of the identified DEC strains belonged to clade I (58.9%). The genetic marker rfbO157 was not found in any STEC strain. Of the DEC strains, 67.9% (N=38) were considered multidrug resistant and were not susceptible to ampicillin (75%) nor to carbenicillin (51.8%). The combination of the genes blaTEM + blaCTX and blaTEM + blaSHV (6 strains respectively) was the most frequent among the DEC strains. It is concluded that captive collared peccaries are carriers of DEC strains that carry β-lactamase blaTEM, blaCTX and blaSHV genes and are not susceptible to ampicillin. Given the current efforts of the Wildlife Management Units (WMU) to reintroduce the collared peccary into natural areas, these captive collared peccaries act as carriers of diarrheagenic E. coli strains and therefore a potential source of gastrointestinal disease in humans and animals.

Abstract Background: The intrinsic sensitivity limitations of basic parasitological methods, along with the particular biological characteristics of parasites, make these methods ineffective to differentiate morphologically indistinguishable species. Molecular detection and characterization techniques could be used to overcome these problems. The purpose of this work was to standardize molecular polymerase chain reaction (PCR) techniques, described in the literature, for the detection and molecular characterization of intestinal protozoa and other pathogens in humans. Methods: DNA was extracted from human or animal feces, previously washed or cultured in Boeck Drbohlav's Modified Medium. DNA extraction was performed with Machery-Nagel extraction kits. The standardization of the PCR, nested-PCR or RFLP techniques was carried out according to the literature. For each molecular technique performed, the sensitivity of the test was determined based on the minimun quantity required of DNA (sensitivity A) and the minimum quantity of life forms that the test detected (sensitivity B). Results: Sensitivity A was 10 fg for G. duodenalis, 12.5 pg for Entamoeba histolytica or Entamoeba dispar, 50 fg for Cryptosporidium spp., 225 pg for Cyclospora spp. and 800 fg or 8 fg for Blastocystis spp. after performing a 1780 bp PCR or 310 bp nested PCR, respectively. The sensitivity B was 100 cysts for G. duodenalis, 500 cysts for E. histolytica or E. dispar, 1000 oocysts for Cyclospora spp. and 3600 or four vegetatives forms for PCR or nested PCR of Blastocystis spp., respectively. Conclusions: The molecular detection of protozoa and chromist was achieved and the molecular characterization allowed the genotyping of some of the parasites such as Giardia duodenalis, Cryptosporidium spp., and Blastocystis spp. This study summarizes the molecular techniques for epidemiological studies in humans and animals, and helps in the investigation of their transmission sources in countries where intestinal parasites are a public health problem.

Resumen Las plaquetas tienen un papel central en diferentes escenarios fisiológicos, incluyendo la hemostasia; se unen unas con otras en la agregación plaquetaria, lo cual permite formar un coágulo plaquetario. Para que la agregación sea apropiada se requiere del complejo glicoproteico IIb/IIIa (GPIIb/IIIa) en la superficie plaquetaria. Toda alteración funcional plaquetaria, hereditaria o adquirida, impide la formación adecuada del coágulo y se manifiesta como hemorragia. Las enfermedades plaquetarias hereditarias son raras y, hasta recientemente, fueron ignoradas. Una de las más reconocidas y estudiadas es la trombastenia de Glanzmann (TG), entidad en la cual el número de plaquetas puede ser normal pero la función está alterada. Es un padecimiento autosómico y recesivo que causa hemorragia de diferente intensidad toda la vida y en la cual el problema radica en precisamente en la GPIIb/IIIa. Las hemorragias son típicamente mucocutáneas: equimosis, púrpura, epistaxis, gingivorragia; menos frecuentes son la hemorragia gastrointestinal, hemartrosis o en sistema nervioso central. La hiperpolimenorrea es común en las mujeres y llega a ser tan importante que amerita transfusiones en la menarca. La TG afecta a todos los grupos étnicos y su prevalencia varía entre 1/40,000 y 1/400,000. A pesar de esta información acerca de la TG en el mundo, hay pocas guías o recomendaciones basadas en la opinión de expertos y experiencias unicéntricas. En México la TG es rara y no se cuenta con una recomendación general para su diagnóstico y tratamiento. El objetivo de este documento fue establecer un consenso y hacer sugerencias generales para su diagnóstico y tratamiento.

Abstract Platelets have a central role in several physiological scenarios including hemostasis. Platelets bind each other during platelet aggregation allowing the proper formation of the clot; to be appropriate, platelet aggregation requires the glycoproteic complex IIb/IIIa (GPIIb/IIIa). Every platelet function abnormality both, congenital or acquired, impedes clot formation and favors bleeding episodes. Hereditary platelet abnormalities are rare and, until recently, they were almost ignored. Among these disorders, Glanzmann Thrombasthenia (GT) is a widely recognized abnormality in which platelet counts may be normal, but their function is affected. GT is an autosomal, recessive disease that causes life-long bleeding of different intensity. Main biochemical abnormality resides in GPIIb/IIIa. Bleeding is typically mucocutaneous: easy bruising, purpura, and nose and gum bleeds; less frequently are gastrointestinal bleeds, hemarthrosis, or intracranial. Menorrhagia and hyperpolymenorrhea are common findings in in women and may be the cause of anemia requiring blood transfusions at fertile age. GT affects all ethnic groups and its prevalence ranges between 1/40,000 to 1/400,000. Despite this worldwide information regarding GT, only a few guidelines and recommendations have been published, most of them based on expert opinions. In Mexico, GT is rare and there is not a general recommendation regarding its diagnosis and treatment. The aim of this document was to establish a consensus to suggest a general guideline for the diagnosis and treatment of GT in Mexico.

ABSTRACT Introduction: Extraintestinal Escherichia coli is one of the main pathogens causing infections associated to health care, with a high impact on health, due to its morbidity and mortality. Objective: Describe the clinical behavior of extraintestinal E. coli in Cuban hospitals, and determine antimicrobial resistance and betalactamase production. Methods: A descriptive cross-sectional study was conducted at the Microbiology National Reference Laboratory of Pedro Kourí Tropical Medicine Institute from May 2017 to June 2018. The study included 119 Escherichia coli isolates causing extraintestinal infections in 30 hospitals from various geographic areas in the country. Identification was based on the API 20E system, and determination of in vitro susceptibility to 16 antimicrobials on the automated system VITEK-2 and the disk diffusion method, except for colistin, for which the disk elution method was used. Phenotypical detection was also performed of AmpC extended-spectrum betalactamase and metallobetalactamase. Results: The most common disorders caused by extraintestinal E. coli were surgical wound infection (23.5%), bloodstream infection (20.7%), respiratory infections (17.6%), skin infections (16.8%) and urinary tract infection (12.6%). A predominance was found of resistance to betalactams, which ranged between 61.3% y 89.1%, whereas 79.8% and 80.5% of the isolates were resistant to trimethoprim / sulfamethoxazole and tetracycline, respectively. Amikacin, fosfomycin, colistin and carbapenemics displayed greater in vitro activity. 43.7% produced extended spectrum betalactamases, 7.6% plasmid AmpC and 0.8% metallobetalactamase. Conclusions: The low sensitivity of extraintestinal E. coli isolates to first-line antimicrobials and the detection of a metallobetalactamase producing isolate are evidence of the need to maintain continuous surveillance of this pathogen, for which the treatment options are ever more restricted.

RESUMEN Introducción: Escherichia coli extraintestinal constituye uno de los principales patógenos causantes de infecciones asociadas a la asistencia sanitaria con un alto impacto en la salud por su morbilidad y mortalidad. Objetivo: Describir el comportamiento clínico de E. coli extraintestinal en hospitales cubanos, así como determinar la resistencia antimicrobiana y la producción de betalactamasas. Métodos: Se realizó un estudio descriptivo de corte transversal, durante el período de mayo 2017 a junio 2018, en el Laboratorio Nacional de Referencia de Microbiología del Instituto de Medicina Tropical “Pedro Kourí" que incluyó 119 aislados de Escherichia coli causantes de infecciones extraintestinales en 30 hospitales de diferentes áreas geográficas del país. Se llevó a cabo la identificación mediante el sistema API 20E y la determinación de la susceptibilidad in vitro a 16 antimicrobianos por el sistema automatizado VITEK-2 y el método de difusión por disco, excepto para la colistina que se empleó el método de elución de disco. Se realizó, además, la detección fenotípica de betalactamasa de espectro extendido, de tipo AmpC y metalobetalactamasa. Resultados: E. coli extraintestinal causó con mayor frecuencia infección de herida quirúrgica (23,5 %), infección del torrente sanguíneo (20,7 %), infecciones respiratorias (17,6 %), infecciones de piel (16,8 %) e infección del tracto urinario (12,6 %). Predominó la resistencia a betalactámicos que osciló entre 61,3 % y 89,1 %, mientras que 79,8 % y 80,5 % de los aislados fueron resistentes a trimetoprim/sulfametoxazol y tetraciclina, respectivamente. La amikacina, la fosfomicina, la colistina y los carbapenémicos mostraron mayor actividad in vitro. El 43,7 % produjo betalactamasas de espectro extendido, 7,6 % AmpC plasmídica y 0,8 % metalobetalactamasa. Conclusiones: La escasa sensibilidad en los aislados de E. coli extraintestinal a los antimicrobianos de primera línea, así como la detección de un aislado productor de metalobetalactamasa evidencia la necesidad de mantener un monitoreo continuo de este patógeno para el cual las alternativas de tratamiento son cada vez más restringidas.

ABSTRACT Cardiac masses are a diagnostic and therapeutic challenge. They are often found incidentally and assessment eventually confirms the presence of a heart tumor. They are neoplasms that originate in any layer of the heart and are divided into primary and secondary. The primary ones have a 0.001 - 0.03% incidence in autopsies, contrasting with the 20-40 times higher frequency of the secondary ones. We present the case of a 28-year-old patient diagnosed one year before with infiltrating transverse colon adenocarcinoma in whom intra-abdominal lymph node chain metastases were confirmed three months ago, receiving surgical treatment and chemotherapy. Later, he began with tachycardia and presented to his health care center where a transthoracic echocardiogram was performed, which showed a tumor-like image in the right ventricle. The CT-scan showed an unresectable complex tumor mass and the patient died at home, under palliative care, a month or so after discharge.

RESUMEN Las masas cardíacas constituyen un reto diagnóstico y terapéutico. Muchas veces se descubren casualmente y la evaluación confirma, finalmente, la presencia de un tumor cardíaco. Estos son neoplasias originadas en cualquier capa del corazón y se dividen en primarios y secundarios. Los primarios tienen una incidencia en autopsias de 0,001 - 0,03%, que contrasta con la frecuencia 20-40 veces mayor de los secundarios. Se presenta un paciente de 28 años de edad diagnosticado 1 año antes de adenocarcinoma de colon transverso infiltrante, en quien hace 3 meses se constató metástasis a cadena ganglionar intraabdominal y se realizó tratamiento quirúrgico más quimioterapia. Posteriormente comenzó con taquicardia y acudió a su centro de salud donde se le realizó un ecocardiograma transtorácico que constató una imagen de aspecto tumoral en ventrículo derecho. Por tomografía se demostró una masa tumoral compleja inoperable y el paciente falleció en su hogar, bajo cuidados paliativos, un mes y medio después del egreso.

ABSTRACT Cervical cancer (CC) is one of the most common gynecological tumors and an important health problem, especially in developing countries. The vast majority of patients in early stages are cured of the disease with surgical treatment and with concomitant chemoradiotherapy in locally advanced stages. However, in patients with recurrent, persistent, or metastatic cervical CC, the effectiveness of treatment is limited, except for the combination of chemotherapy based on platinum doublets plus bevacizumab, the treatment that has achieved the best results to date. Programmed cell death-1/PD ligand-1 (PD-1/PD-L1) inhibitors could be a novel and cutting-edge therapeutic option to improve clinical outcomes in this group of patients. Thus far, there are a few Phase I/II clinical trials that have assessed the usefulness of pembrolizumab and nivolumab in this group of patients; these include the KEYNOTE 028, KEYNOTE 158, and CHECKMATE 358 trials, in which clinical benefit has been proven with PD-1/PD-L1 inhibitors in recurrent, persistent, or metastatic CC, as second-line treatment. There are also some ongoing trials that could provide further evidence on the PD-1/PD-L1 pathway as a therapeutic target in CC. In this review, we will focus on the usefulness of these PD-1/PDL1 inhibitors in CC, as well as on trials that are still in the recruitment phase, to confirm their effectiveness in this clinical setting.

RESUMEN A pesar de su alta toxicidad, el cianuro es usado en diversos procesos industriales, y como resultado, grandes volúmenes de aguas residuales de cianuro deben ser tratados antes de su descarga. Una alternativa atractiva a los métodos químicos convencionales de descontaminación es la degradación enzimática por la enzima cianuro dihidratasa, la cual es capaz de convertir cianuro en amonio y ácido fórmico. No obstante, la inactivación de esta enzima a pH superior a 8.5 y su poca termoestabilidad han sido el principal impedimento para la implementación exitosa de esta alternativa de biorremediación. En el presente estudio, las propiedades catalíticas de células completas de Escherichia coli que sobre expresan el gen de cianuro dihidratasa de Bacillus pumilus se estudian bajo condiciones similares a las encontradas en aguas residuales industriales de cianuro y los resultados se discuten en comparación con las de la enzima purificada. Además, se determinó la capacidad de las células completas para degradar el cianuro libre en aguas residuales resultantes del proceso de extracción de oro. Las características de la enzima intracelular, relativa a la enzima purificada, incluyeron un incremento en la termoestabilidad (>60% actividad a 50°C), así como mayor tolerancia a metales pesados y en menor medida al pH (20% actividad residual a pH 9.0). Por otra parte, la degradación enzimática del 70% del cianuro libre en la muestra industrial (concentración inicial 528 mM) se logró solo después de la dilución de la muestra. Sin embargo, el incremento en la termoestabilidad observado para CynD intracelular sugiere que las células completas de E. coli que sobre expresan CynD son adecuadas para procesos que operan a temperaturas elevadas (50°C), una limitación observada para la enzima purificada.

ABSTRACT Despite its high toxicity, cyanide is used in several industrial processes, and as a result, large volumes of cyanide wastewater need to be treated prior to discharge. Enzymatic degradation of industrial cyanide wastewater by cyanide dihydratase, which is capable of converting cyanide to ammonia and formate, is an attractive alternative to conventional chemical methods of cyanide decontamination. However, the main impediment to the use of this enzyme for the biodegradation of cyanide is its intolerance to the alkaline pH at which cyanide waste is kept and its low thermoresistance. In the present study, the catalytic properties of whole Escherichia coli cells overexpressing a cyanide dihydratase gene from Bacillus pumilus were compared to those of the purified enzyme under conditions similar to those found in industrial cyanide wastewater. In addition, the capacity of whole cells to degrade free cyanide in contaminated wastewater resulting from the gold mining process was also determined. The characteristics of intracellular enzyme, relative to purified enzyme, included increased thermostability (>60% activity at 50°C), as well as greater tolerance to heavy metals, and to a lesser extent pH (20% activity remaining at pH 9.0) On the other hand, enzymatic degradation of 70% of free cyanide (initial concentration 528 mM) in the industrial sample was achieved only after dilution. Nevertheless, the increased thermostability observed for intracellular CynD suggest that whole cells of E. coli overexpressing CynD are suited for process that operate at elevated temperatures (50°C), a limitation observed for the purified enzyme.

Abstract Introduction: Resprouter species, by regenerating rapidly, can maintain an optimal carbon balance and improve the resilience of ecosystems that have been disturbed or are at high risk of fire. Objective: To assess the effect of light availability and soil moisture on the ecophysiological variables of six resprouter species planted under cover of Pinus halepensis Mill. Materials and methods: Arbutus unedo L., Rhamnus alaternus L., Quercus ilex L., Quercus faginea Lam., Fraxinus ornus L. and Acer granatense Boiss. were planted in plots with three pine densities per hectare: HD = 800 to 1 100, MD = 300 to 600 and LD = 100 to 250. The species were also grown in the nursery, trying to maintain the same solar radiation conditions. Photosynthesis (A), stomatal conductance (Gs), photosystem II maximum efficiency (Fv/Fm) and water use efficiency (IWUE) were measured. Results and discussion: Evergreen sclerophyll species (A. unedo, R. alaternus and Q. ilex) showed higher photosynthetic capacity, lower photoinhibition and lower IWUE than deciduous species. In HD, plants showed lower photosynthetic capacity (P < 0.01) and higher photoprotection (P < 0.001). The IWUE was similar under the three pine forest densities. In the nursery, A was high under 100 % and 50 % light conditions; Gs was higher under 20 % conditions; and IWUE was high under 100 % light. Conclusion: The physiological variables of the species were conditioned by shading and changes in water demand produced by tree cover.

Resumen Introducción: Las especies rebrotadoras, por la rapidez de su regeneración, pueden mantener el balance óptimo de carbono y mejorar la resiliencia de los ecosistemas perturbados o que tienen alto riesgo de incendios. Objetivo: Evaluar el efecto de la disponibilidad de luz y la humedad del suelo sobre las variables ecofisiológicas de seis especies rebrotadoras plantadas bajo cubierta de Pinus halepensis Mill. Materiales y métodos: Arbutus unedo L., Rhamnus alaternus L., Quercus ilex L., Quercus faginea Lam., Fraxinus ornus L. y Acer granatense Boiss. se plantaron en parcelas con tres densidades de pinos por hectárea: DA = 800 a 1 100, DM = 300 a 600 y DB = 100 a 250. En vivero, las especies también se cultivaron tratando de mantener las mismas condiciones de radiación solar. Se midieron la fotosíntesis (A), la conductancia estomática (Gs), la eficiencia máxima del fotosistema II (Fv/Fm) y la eficiencia en el uso del agua (IWUE). Resultados y discusión: Las especies esclerófilas perennifolias (A. unedo, R. alaternus y Q. ilex) mostraron tendencias de mayor capacidad fotosintética, menor fotoinhibición y menor IWUE que las caducifolias. En DA, las plantas mostraron menor capacidad fotosintética (P < 0.01) y mayor fotoprotección (P < 0.001). La IWUE fue similar bajo las tres densidades de pinar. En vivero, la A fue alta en condiciones de 100 % y 50 % de luz; Gs fue mayor en condiciones de 20 %; y la IWUE fue alta bajo 100 % de luz. Conclusión: Las variables fisiológicas de las especies estuvieron condicionadas por el sombreo y cambios en la demanda hídrica producidos por la cubierta arbórea.

RESUMEN Se muestran los resultados de una investigación de la lixiviación con cianuro de un mineral aurífero sulfuroso con materia carbonosa. Se aplicó un diseño experimental de análisis factorial 2k de tres variables con réplicas en el centro, empleando el método de superficie de respuesta (MRS). Se condujeron pruebas de cianuración en botella rotatoria para estudio del efecto de ciertas variables seleccionadas sobre la recuperación de Au y determinar los parámetros óptimos para lograr su máxima recuperación en el proceso. Los resultados obtenidos demuestran que el mineral presenta un alto grado de lixiviabilidad en cianuro, obteniéndose una recuperación de Au promedio del 93,65%, con una concentración de cianuro de sodio [NaCN] de 2,5 g/L y un tiempo de lixiviación de 12 horas.

SUMMARY The results of a research into the cyanide leaching of a sulphurous gold ore with carbonaceous matter are shown. An experimental design of factorial analysis 2k of three variables with replicates in the center was applied, using the response surface method (MRS). Cyanidation tests in rotating bottles were conducted to study the effect of certain selected variables on Au recovery and to determine the optimal parameters to achieve maximum Au recovery in the process. The results obtained show that the mineral presents a high degree of cyanide leachability, obtaining an average Au recovery of 93.65%, with a sodium cyanide [NaCN] concentration of 2.5 g/L and a leaching time of 12 hours.

SUMÁRIO O artigo apresenta os resultados de uma pesquisa sobre a lixiviação com cianeto de um minério de ouro sulfuroso com matéria carbonácea. Aplicou-se um delineamento experimental de análise fatorial 2k de três variáveis com réplicas no centro, utilizando o método da superfície de resposta (MRS). Foram realizados testes de cianetação em uma garrafa rotativa para estudar o efeito de certas variáveis selecionadas na recuperação de Au e para determinar os parâmetros ideais para alcançar a recuperação máxima no processo. Os resultados obtidos mostram que o mineral apresenta um alto grau de lixiviação em cianeto, obtendo uma recuperação média de Au de 93,65%, com uma concentração de cianeto de sódio [NaCN] de 2,5 g/L e tempo de lixiviação de 12 horas.

Abstract The barchata (Ziziphus obtusifolia [Hook, ex Torr. & A. Gray]) is a common shrub in northwestern Mexico. This plant is traditionally used to combat gastrointestinal and degenerative diseases. In the present work the antioxidant and antimicrobial capacity of extracts obtained from barchata branches was evaluated. Extracts were obtained with different solvents: acidified ethanol (EtOH-ac) and water (Ac). Each one was evaluated for its antioxidant capacity measured by the inhibition of the ABTS radical, DPPH, and the hemolysis test. The antimicrobial activity was carried out in Escherichia coli and Staphylococcus aureus and in parallel the antiviral effect was evaluated, using the Av08 bacteriophage as an enteroviral model. Ac and EtOH-ac extracts inhibited ABTS and DPPH radicals, showing values from 17.41 ± 0.02 to 25.03 ± 3.73 mmol/ETge, respectively. In the hemolysis test, higher percentages of inhibition were found in the Ac extract with 46.3%, while in the ethanol one it was 36.8 %. In the inhibitory capacity on E. coli and S. aureus, inhibition haloes of 8.00 to 12.90 mm in diameter were obtained for both extracts against both bacteria. In the antiviral assay it was observed that the Ac extract at the concentration of 10 mg/mL and time of 60 minutes showed a reduction of up to 7.40 log10 PFU/mL of the Av08 bacteriophage. These results suggest the presence of several bioactive compounds with antioxidant and antimicrobial potential on bacteria and viruses of interest; as well as a protective effect of the aqueous extracts on human erythrocytes.

Resumen La barchata (Ziziphus obtusifolia [Hook. ex Torr. & A. Gray]) es un arbusto común en el noroeste de México. Esta planta se utiliza tradicionalmente para combatir padecimientos gastrointestinales y degenerativos. En el presente trabajo se evaluó la capacidad antioxidante y antimicrobiana de extractos obtenidos de ramas de barchata. Se obtuvieron extractos con diferentes solventes: etanol acidificado (EtOH-ac) y agua (Ac). A cada uno se le evaluó su capacidad antioxidante medida por la inhibición del radical ABTS, DPPH, y la prueba de hemólisis. La actividad antimicrobiana se realizó en Escherichia coli y Staphylococcus aureus y en paralelo se evaluó el efecto antiviral, utilizando al bacteriófago Av08 como modelo enteroviral. Los extractos Ac y EtOH-ac, inhibieron los radicales ABTS y DPPH mostrando valores desde 17.41 ± 0.02 a 25.03 ± 3.73 mmol/ETge, respectivamente. En la prueba de hemólisis se encontraron porcentajes de inhibición más elevados en el extracto Ac con 46.3 %, mientras que en el etanólico fue de 36.8 %. En la capacidad inhibitoria sobre E. coli y S. aureus se obtuvieron halos de inhibición que variaron de 8.00 a 12.90 mm de diámetro para ambos extractos contra ambas bacterias. En el ensayo antiviral se pudo observar que el extracto Ac en la concentración 10 mg/mL y tiempo de 60 minutos presentó una reducción de hasta 7.40 log10 PFU/mL del bacteriófago Av08. Estos resultados sugieren la presencia de varios compuestos bioactivos con potencial antioxidante y antimicrobiano sobre bacterias y virus de interés; así como, efecto protector de los extractos acuosos sobre eritrocitos humanos.