Identification of two novel RRM2B variants associated with autosomal recessive progressive external ophthalmoplegia in a family with pseudodominant inheritance pattern.

RRM2B encodes the p53-inducible small subunit (p53R2) of ribonucleotide reductase, a key protein for mitochondrial DNA (mtDNA) synthesis. Pathogenic variants in this gene result in familial mitochondrial disease in adults and children, secondary to a maintenance disorder of mtDNA. This study describes two patients, mother and son, with early-onset chronic progressive external ophthalmoplegia (PEO). Skeletal muscle biopsy from the latter was examined: cytochrome c oxidase (COX)-negative fibres were shown, and molecular studies revealed multiple mtDNA deletions. A next-generation sequencing gene panel for nuclear-encoded mitochondrial maintenance genes identified two unreported heterozygous missense variants (c.514 G > A and c.682 G > A) in the clinically affected son. The clinically affected mother harboured the first variant in homozygous state, and the clinically unaffected father harboured the remaining variant in heterozygous state. In silico analyses predicted both variants as deleterious. Cell culture studies revealed that patients' skin fibroblasts, but not fibroblasts from healthy controls, responded to nucleoside supplementation with enhanced mtDNA repopulation, thus suggesting an in vitro functional difference in patients' cells. Our results support the pathogenicity of two novel RRM2B variants found in two patients with autosomal recessive PEO with multiple mtDNA deletions inherited with a pseudodominant pattern.

ALC1/eIF4A1-mediated regulation of CtIP mRNA stability controls DNA end resection.

During repair of DNA double-strand breaks, resection of DNA ends influences how these lesions will be repaired. If resection is activated, the break will be channeled through homologous recombination; if not, it will be simply ligated using the non-homologous end-joining machinery. Regulation of resection relies greatly on modulating CtIP, which can be done by modifying: i) its interaction partners, ii) its post-translational modifications, or iii) its cellular levels, by regulating transcription, splicing and/or protein stability/degradation. Here, we have analyzed the role of ALC1, a chromatin remodeler previously described as an integral part of the DNA damage response, in resection. Strikingly, we found that ALC1 affects resection independently of chromatin remodeling activity or its ability to bind damaged chromatin. In fact, it cooperates with the RNA-helicase eIF4A1 to help stabilize the most abundant splicing form of CtIP mRNA. This function relies on the presence of a specific RNA sequence in the 5' UTR of CtIP. Therefore, we describe an additional layer of regulation of CtIP-at the level of mRNA stability through ALC1 and eIF4A1.

Therapy Prospects for Mitochondrial DNA Maintenance Disorders.

Mitochondrial DNA depletion and multiple deletions syndromes (MDDS) constitute a group of mitochondrial diseases defined by dysfunctional mitochondrial DNA (mtDNA) replication and maintenance. As is the case for many other mitochondrial diseases, the options for the treatment of these disorders are rather limited today. Some aggressive treatments such as liver transplantation or allogeneic stem cell transplantation are among the few available options for patients with some forms of MDDS. However, in recent years, significant advances in our knowledge of the biochemical pathomechanisms accounting for dysfunctional mtDNA replication have been achieved, which has opened new prospects for the treatment of these often fatal diseases. Current strategies under investigation to treat MDDS range from small molecule substrate enhancement approaches to more complex treatments, such as lentiviral or adenoassociated vector-mediated gene therapy. Some of these experimental therapies have already reached the clinical phase with very promising results, however, they are hampered by the fact that these are all rare disorders and so the patient recruitment potential for clinical trials is very limited.

Increased dNTP pools rescue mtDNA depletion in human POLG-deficient fibroblasts.

Polymerase γ catalytic subunit (POLG) gene encodes the enzyme responsible for mitochondrial DNA (mtDNA) synthesis. Mutations affecting POLG are the most prevalent cause of mitochondrial disease because of defective mtDNA replication and lead to a wide spectrum of clinical phenotypes characterized by mtDNA deletions or depletion. Enhancing mitochondrial deoxyribonucleoside triphosphate (dNTP) synthesis effectively rescues mtDNA depletion in different models of defective mtDNA maintenance due to dNTP insufficiency. In this study, we studied mtDNA copy number recovery rates following ethidium bromide-forced depletion in quiescent fibroblasts from patients harboring mutations in different domains of POLG. Whereas control cells spontaneously recovered initial mtDNA levels, POLG-deficient cells experienced a more severe depletion and could not repopulate mtDNA. However, activation of deoxyribonucleoside (dN) salvage by supplementation with dNs plus erythro-9-(2-hydroxy-3-nonyl) adenine (inhibitor of deoxyadenosine degradation) led to increased mitochondrial dNTP pools and promoted mtDNA repopulation in all tested POLG-mutant cells independently of their specific genetic defect. The treatment did not compromise POLG fidelity because no increase in multiple deletions or point mutations was detected. Our study suggests that physiologic dNTP concentration limits the mtDNA replication rate. We thus propose that increasing mitochondrial dNTP availability could be of therapeutic interest for POLG deficiency and other conditions in which mtDNA maintenance is challenged.-Blázquez-Bermejo, C., Carreño-Gago, L., Molina-Granada, D., Aguirre, J., Ramón, J., Torres-Torronteras, J., Cabrera-Pérez, R., Martín, M. Á., Domínguez-González, C., de la Cruz, X., Lombès, A., García-Arumí, E., Martí, R., Cámara, Y. Increased dNTP pools rescue mtDNA depletion in human POLG-deficient fibroblasts.

Nail Cancer: Review of the Two Main Types of an Underestimated Disease.

Neoplastic lesions (benign or malignant) in the nail region are rare when compared to lesions in the rest of the skin. Despite advances in diagnostic modalities, their diagnosis is frequently delayed or overlooked for days, months, or even years when they are misrecognized or when their approach is not appropriate. Undoubtedly, malignant tumors are the most important lesions since an inopportune diagnosis or treatment can drastically change the patient's prognosis. A review of all the scientific evidence on the two main malignant neoplasms of the nail apparatus (melanoma and squamous cell carcinoma) was carried out using the PubMed search engine from 2003 to 2022, in order to expose the appropriate diagnostic approach and treatment of these nail lesions to avoid delays that obscure the prognosis of patients. This review does not include reconstruction modalities after lesion resection, but the emphasis is placed on the great functional impact they produce. Surgical treatment in the early stages is the most important when talking about prognosis and emphasizing it; systemic oncological management of advanced stages is not so deep.

Two Novel Variants in YARS2 Gene Are Responsible for an Extended MLASA Phenotype with Pancreatic Insufficiency.

Pathogenic variants in the mitochondrial tyrosyl-tRNA synthetase gene (YARS2) were associated with myopathy, lactic acidosis, and sideroblastic anemia (MLASA). However, patients can present mitochondrial myopathy, with exercise intolerance and muscle weakness, leading from mild to lethal phenotypes. Genes implicated in mtDNA replication were studied by Next Generation Sequencing (NGS) and whole exome sequence with the TruSeq Rapid Exome kit (Illumina, San Diego, CA, USA). Mitochondrial protein translation was studied following the Sasarman and Shoubridge protocol and oxygen consumption rates with Agilent Seahorse XF24 Analyzer Mitostress Test, (Agilent, Santa Clara, CA, USA). We report two siblings with two novel compound heterozygous pathogenic variants in YARS2 gene: a single nucleotide deletion in exon 1, c.314delG (p.(Gly105Alafs*4)), which creates a premature stop codon in the amino acid 109, and a single nucleotide change in exon 5 c.1391T>C (p.(Ile464Thr)), that cause a missense variant in amino acid 464. We demonstrate the pathogenicity of these new variants associated with reduced YARS2 mRNA transcript, reduced mitochondrial protein translation and dysfunctional organelle function. These pathogenic variants are responsible for late onset MLASA, herein accompanied by pancreatic insufficiency, observed in both brothers, clinically considered as Pearson's syndrome. Molecular study of YARS2 gene should be considered in patients presenting Pearson's syndrome characteristics and MLASA related phenotypes.

Chromosome Number, Ploidy Level, and Nuclear DNA Content in 23 Species of Echeveria (Crassulaceae).

Echeveria is a polyploid genus with a wide diversity of species and morphologies. The number of species registered for Echeveria is approximately 170; many of them are native to Mexico. This genus is of special interest in cytogenetic research because it has a variety of chromosome numbers and ploidy levels. Additionally, there are no studies concerning nuclear DNA content and the extent of endopolyploidy. This work aims to investigate the cytogenetic characteristics of 23 species of Echeveria collected in 9 states of Mexico, analyzing 2n chromosome numbers, ploidy level, nuclear DNA content, and endopolyploidy levels. Chromosome numbers were obtained from root tips. DNA content was obtained from the leaf parenchyma, which was processed according to the two-step protocol with Otto solutions and propidium iodide as fluorochrome, and then analyzed by flow cytometry. From the 23 species of Echeveria analyzed, 16 species lacked previous reports of 2n chromosome numbers. The 2n chromosome numbers found and analyzed in this research for Echeveria species ranged from 24 to 270. The range of 2C nuclear DNA amounts ranged from 1.26 pg in E. catorce to 7.70 pg in E. roseiflora, while the 1C values were 616 Mbp and 753 Mbp, respectively, for the same species. However, differences in the level of endopolyploidy nuclei were found, corresponding to 4 endocycles (8C, 16C, 32C and 64C) in E. olivacea, E. catorce, E. juarezensis and E. perezcalixii. In contrast, E. longiflora presented 3 endocycles (8C, 16C and 32C) and E. roseiflora presented 2 endocycles (8C and 16C). It has been suggested that polyploidization and diploidization processes, together with the presence of endopolyploidy, allowed Echeveria species to adapt and colonize new adverse environments.

Methylation of the central transcriptional regulator KLF4 by PRMT5 is required for DNA end resection and recombination.

Cell fitness and survival upon exposure to DNA damage depends on the repair of DNA lesions. Interestingly, cellular identity does affect and finetunes such response, although the molecular basis of such differences between tissues and cell types is not well understood. Thus, a possibility is that DNA repair itself is controlled by the mechanisms that govern cell identity. Here we show that the KLF4, involved in cellular homeostasis, proliferation, cell reprogramming and cancer development, directly regulates resection and homologous recombination proficiency. Indeed, resection efficiency follows KLF4 protein levels, i.e. decreases upon KLF4 downregulation and increases when is overexpressed. Moreover, KLF4 role in resection requires its methylation by the methyl-transferase PRMT5. Thus, PRMT5 depletion not only mimics KLF4 downregulation, but also showed an epistatic genetic relationship. Our data support a model in which the methylation of KLF4 by PRMT5 is a priming event required to license DNA resection and homologous recombination.

[Cardiovascular risk factors in climacteric]. / Factores de riesgo cardiovascular en el climaterio.

BACKGROUND: Ischemic heart disease is the second leading killer of women in Mexico, regardless of age group. The incidence of cardiovascular events increases after menopause, and depend on the prevalence and accumulation of risk factors. OBJECTIVE: To determine the prevalence of cardiovascular risk factors in a population of Mexican women who receive care in a menopause clinic. METHODS: Cross-sectional study included 308 women. Sociodemographic characteristics were collected, and background somatometric-family inherited cardiovascular risk factors, biochemical variables: blood glucose and lipid profile. Women were classified into two groups: pre-and postmenopause, the latter being subdivided according to time since menopause: less than three years and more than three years. RESULTS: Two hundred six (66.7%) women had inherited a positive family history. We identified 123 (39.9%) in premenopausal, mean age 46.4 +/- 3.2 years and 185 (60.1%) postmenopausal with a mean age of 50.5 +/- 3.2. We found no differences in blood pressure and blood glucose somatometric features. The levels of total cholesterol (TC) and cholesterol of low density lipoprotein (LDL-C) were significantly higher in the group of postmenopausal women. It was noted that total cholesterol and triglycerides increased with age regardless of hormonal status. Hypercholesterolemia was detected in 41.5% of premenopausal patients and in 51.4% of postmenopausal women. More than half of the population studied had three or more cardiovascular risk factors. CONCLUSIONS: There is a high prevalence of cardiovascular risk factors in Mexican women present from pre-menopause. The major modifiable: sedentary lifestyle, dyslipidaemia and overweight.

Novel human metapneumovirus with a 180-nucleotide duplication in the G gene.

AIM: To describe the circulation, genetic diversity and clinical features of human metapneumovirus (HMPV) in pediatric patients that attended the Hospital Universitari Vall d'Hebron, Spain from 2014 to 2016. MATERIALS & METHODS: Partial G gene was sequenced from laboratory-confirmed HMPV respiratory specimens for subsequent phylogenetic analysis. RESULTS: A total of 121 different samples were HMPV laboratory-confirmed out of 6658 specimens received. The highest circulation was from February to April, with a prevalence of 3%. Different genetic groups within both genotypes were detected at variable levels. A 180-nucleotide duplication was first characterized within the G gene in nine cases, mostly related to lower respiratory-tract infection. CONCLUSION: This study reported on the circulation of a novel HMPV with a 180-nucleotide duplication in the G gene, but no clinical changes in related cases were observed. Their prevalence increased during the last season suggesting changes in viral features.

[Position paper on the results of Symplicity HTN-3 trial. Grupo de estudio de la hipertensión arterial resistente]. / Declaración ante los resultados del ensayo clínico Symplicity HTN 3. Grupo de estudio de la hipertensión arterial resistente.

Renal artery denervation has shown to be an effective treatment for resistant hypertension. Symplicity HTN 1 and 2 trials showed in small and uncontrolled groups, significant systolic blood pressure reductions down to 30 mm Hg. Symplicity HTN-3, a double blind, randomized, placebo controlled clinical trial shaded this initial enthusiasm. Surprisingly, their results showed that renal denervation has a similar effect to placebo. Pre-specified subgroup analysis showed that non-black race individuals, younger than 65 years and with normal renal function, had a statistically significant systolic blood pressure decrease. This manuscript critically appraises the Symplicity HTN-3 trial, proposing possible explanations for the results. Also declares our group position and future actions regarding renal denervation.

Integration of an intensified charge-coupled device (ICCD) camera for accurate spectroscopic measurements.

Intensified charge-coupled devices (ICCD) are used in a great variety of spectroscopic applications, some of them requiring high sensitivity and spectral resolution. The setup, configuration, and featuring of these cameras are fundamental issues in order to acquire high quality spectra. In this work a critical assessment of these detectors is performed and the specific configuration, the optical alignment, featuring, and the dark and shot noise are described and analyzed. Spatial response of the detector usually shows a significant lack of spatial homogeneity and a map of interferences may appear in certain ranges of wavelengths, which damages the quality of the recorded spectra. In this work the spectral resolution and the spatial and spectral sensitivity are also studied. The analysis of the dark current reveals the existence of a smooth but clear spatial dependence. As a final conclusion, the spectra registered with the spectrometer equipped with our ICCD camera allow us to explore and measure accurately spectral line shapes emitted by pulsed plasmas in the visible range and particularly in the ultraviolet (UV) range.

Percutaneous coronary intervention in octogenarian patients / Intervención coronaria percutánea en pacientes octogenarios

Abstract: Introduction: Octogenarian patients are usually excluded from studies in which the effectiveness of percutaneous coronary intervention (PCI) is compared. Objective: Our aim is to compare this procedure among octogenarians and those younger; in addition to comparing the radial access (RA) and femoral access (FA) in patients older than 80 years. Material and methods: This is a retrospective, observational, comparative, longitudinal, single-center study. Patients who have been referred for PCI, from 2010 to 2016 in Monterrey, Nuevo Leon, Mexico were included. The groups were divided into the octogenarians group (OG) and a group of younger than 80 years (YG). Results: A total of 1,282 patients were collected, of whom 92 were of the OG and 1,190 were of the YG. The FA was the most used. Similar levels of radiation time (RT), radiation dose (DR), and amount of administered contrast medium (CM), vascular complications (VC) and mortality between the two groups were found. However, the OG had more length of hospital stay (LHS). Comparing the FA against RA in the OG there were no differences in RT, RD, amount of CM, VC, death and LHS. Conclusion: The results are similar between the two groups, with a greater tendency to more LHS in the OG. There were not significant differences between the RA and FA in the OG, except that LHS in the FA.

Resumen: Introducción: Los pacientes octogenarios son usualmente excluidos de los estudios en los cuales se compara la efectividad de las intervenciones coronarias percutáneas. Objetivo: Nuestro objetivo es comparar este procedimiento entre los pacientes octogenarios y aquéllos más jóvenes; además se compara el abordaje radial y el abordaje femoral en los pacientes octogenarios. Material y métodos: Éste es un estudio retrospectivo, observacional, comparativo, longitudinal, unicéntrico. Se realizó con aquellos pacientes que se refirieron para realización de un intervencionismo coronario percutáneo, en Monterrey, Nuevo León, México del 2010 al 2016. Los grupos se dividieron en el grupo de pacientes octogenarios y el grupo de pacientes menores de 80 años. Resultados: Se recabó un total de 1,282 pacientes, de los cuales 92 eran pacientes octogenarios, mientras que 1,190 fueron más jóvenes. En ambos el abordaje femoral fue el más utilizado. Se encontraron valores similares de dosis de radiación, tiempo de radiación, cantidad de contraste administrado, complicaciones vasculares y mortalidad entre los dos grupos. Sin embargo, los pacientes octogenarios tuvieron más días de estancia hospitalaria. Al comparar el abordaje femoral y el radial en octogenarios no se encontraron diferencias en dosis de radiación, tiempo de radiación, cantidad de medio de contraste, complicaciones vasculares, muerte y días de estancia hospitalaria. Conclusiones: Los resultados fueron similares entre ambos grupos de edad, con una mayor tendencia de estancia hospitalaria en octogenarios. No se encontraron diferencias significativas entre ambos abordajes en pacientes octogenarios, a excepción de mayores días de estancia hospitalaria en el abordaje femoral.

Dobutamine versus levosimendan for patients with acute decompensated heart failure / Dobutamina versus levosimendán en pacientes con insuficiencia cardiaca agudizada

Introduction: Heart failure remains a highly frequent cause of hospitalization; with a high morbidity and mortality. Objectives: The aim of this study is to compare the 30-day in hospital survival of patients treated with Levosimendan vs. Dobutamine in acute decompensated heart failure. Secondary aims will be to compare the measurement of LVEF before and after inotropic and length of hospital stay. Material and methods: Observational, descriptive, retrospective study. All adult patients were admitted to the Hospital Christus Muguerza Alta Especialidad, with acute decompensated heart failure diagnosis and have required inotropic support in the period January 2013 to September 2015 were collected. Results: 83 patients were included, however only 38 met the inclusion criteria. Of the 38 patients 20 (53%) were prescribed levosimendan and 18 (47%) dobutamine. The average age in both groups was 62.2 years (± 15.6) of levosimendan versus dobutamine 78.8 years (± 10.6) (p = 0.0005). Survival at 30 days was 100% in levosimendan versus 77.8% in dobutamine (p = 0.0274). In days of hospital stay it was 9.3 days (± 5.1) levosimendan and 13.8 days (± 6.5) in dobutamine (p = 0.02). postinotropic LVEF change was 18.3% (± 6.2) levosimendan versus 18.7% (± 9.9) dobutamine (p = 0.88). Conclusions: The use of dobutamine leads to a lower survival to 30 days, in addition to longer hospital stay. However no difference in LVEF values ​​at admission or inotropic post.

Introducción: La insuficiencia cardiaca agudizada continúa siendo una causa altamente frecuente de hospitalización con una gran morbimortalidad. Objetivos: El objetivo primario es comparar la sobrevida a 30 días de los pacientes tratados con levosimendán versus dobutamina en insuficiencia cardiaca agudizada. Como objetivo secundario será comparar la determinación de la FEVI pre- y post-inotrópico y días de estancia hospitalaria. Material y métodos: Estudio observacional, descriptivo, retrospectivo. Se recabaron todos los pacientes adultos que hayan ingresado en el Hospital Christus Muguerza Alta Especialidad, con diagnóstico de insuficiencia cardiaca agudizada y que hayan requerido el apoyo de inotrópicos, en el periodo comprendido de enero de 2013 a septiembre de 2015. Resultados: Se documentaron 83 pacientes con diagnóstico de insuficiencia cardiaca agudizada, de los cuales sólo 38 cumplieron con los criterios de inclusión. De los 38 pacientes a 20 (53%) se les indicó levosimendán y a 18 (47%) dobutamina. La media de edad en ambos grupos fue de 62.2 años (±15.6) de levosimendán versus 78.8 años de dobutamina (±10.6) (p = 0.0005). La supervivencia a 30 días fue de 77.8% en dobutamina versus 100% levosimendán (p = 0.0274). En días de estancia hospitalaria fue de 9.3 días (± 5.1) en levosimendán y de 13.8 días (± 6.5) en dobutamina (p = 0.02). El cambio FEVI postinotrópico fue de 18.3% (± 6.2) levosimendán versus 18.7% (± 9.9) dobutamina (p = 0.88). Conclusiones: El uso de Dobutamina conlleva a una menor sobrevida a 30 días, además de tener mayor estancia hospitalaria. Sin embargo no hay diferencia en los valores de FEVI al ingreso ni postinotrópico.

Declaración ante los resultados del ensayo clínico Symplicity HTN 3. Grupo de estudio de la hipertensión arterial resistente / Position paper on the results of Symplicity HTN-3 trial. Grupo de estudio de la hipertensión arterial resistente

La denervación de las arterias renales ha sido una alternativa para el tratamiento de la hipertensión arterial resistente. Los estudios Symplicity HTN 1 y 2 mostraron en grupos pequeños y no controlados disminuciones de la presión sistólica hasta de 30 mm Hg. Este entusiasmo ha sido opacado por el estudio Symplicity HTN 3, ensayo clínico aleatorizado y controlado con un procedimiento placebo. Sorprendentemente, los resultados sugirieron que la denervación renal tuvo un efecto similar al del placebo, aunque en el análisis de subgrupos preespecificados los pacientes que no eran de raza negra, los menores de 65 años y los que tenían función renal normal tuvieron una reducción de la presión arterial sistólica estadísticamente significativa. Esta es una evaluación crítica de los resultados del Symplicity HTN 3 y propone posibles explicaciones para estos. Además, declara la postura de nuestro grupo y las acciones futuras.

Renal artery denervation has shown to be an effective treatment for resistant hypertension. Symplicity HTN 1 and 2 trials showed in small and uncontrolled groups, significant systolic blood pressure reductions down to 30 mm Hg. Symplicity HTN-3, a double blind, randomized, placebo controlled clinical trial shaded this initial enthusiasm. Surprisingly, their results showed that renal denervation has a similar effect to placebo. Pre-specified subgroup analysis showed that non-black race individuals, younger than 65 years and with normal renal function, had a statistically significant systolic blood pressure decrease. This manuscript critically appraises the Symplicity HTN-3 trial, proposing possible explanations for the results. Also declares our group position and future actions regarding renal denervation.

Part per trillion determination of atrazine in natural water samples by a surface plasmon resonance immunosensor.

A new immunoassay for continuously monitoring atrazine in water has been developed. It uses a portable biosensor platform based on surface plasmon resonance (SPR) technology. This immunoassay is based on the binding inhibition format with purified polyclonal antibodies, with the analyte derivative covalently immobilized on a gold sensor surface. An alkanethiol self-assembled monolayer (SAM) was formed on the gold-coated sensor surface in order to obtain a reusable sensing surface. The low detection limit for the optimized assay, calculated as the concentration that produces a 10% decrease in the blank signal, is 20 ng/L. A complete assay cycle, including regeneration, is accomplished in 25 min. Additionally, a study of the matrix effects of different types of wastewater was performed. All measurements were carried out with the SPR sensor system (beta-SPR) commercialised by the company Sensia, S.L. (Spain). The small size and low response time of the beta-SPR platform would allow it to be used in real contaminated locations. The immunosensor was evaluated and validated by measuring the atrazine content of 26 natural samples collected from Ebro River. Solid-phase extraction followed by gas chromatography coupled to mass spectrometric detection (SPE-GC-MS) was used to validate the new immunoassay.

Evaluation of a newly developed enzyme-linked immunosorbent assay for determination of linear alkyl benzenesulfonates in wastewater treatment plants.

A recently developed enzyme-linked immunosorbent assay (ELISA) for the determination of linear alkyl benzenesulfonates (LAS) and long chain sulfophenyl carboxylates (SPCs) has been evaluated for its application in wastewater control analysis. This ELISA based on the use of polyclonal antibodies in an indirect format shows an IC50 of 28.1 +/- 3.2 microg L(-1) and a limit of detection (LOD) of 1.8 +/- 0.6 microg L(-1) in buffer. The assay uses antibodies raised through a pseudoheterologous immunization strategy using an equimolar mixture of two immunogens, N-(4-alkylphenyl)sulfonyl-3-aminopropanoic acid covalently coupled to keyhole limped hemocyanin (SFA-KLH) and sulfophenyl carboxylate 13C13 coupled to KLH (13C13-SPC-KLH). The immunizing haptens have been designed to address recognition versus two different epitopes of the LAS molecule. To assess the performance of this immunoassay in complex real samples, a cross reactivity study was carried out, and the possible interference of other surfactants commonly detected in wastewater, including nonylphenol ethoxylates (NPEOs), nonylphenol (NP), octylphenol (OP), and coconut fatty acid diethanol amides (CDEA), have been evaluated. Additionally, a study of the matrix effects of different types of wastewater was achieved. This ELISA has been evaluated and validated by measuring the LAS content of 22 samples collected from the influents and the effluents of six wastewater treatment plants (WWTP) located in Catalonia, Spain. A solid-phase extraction followed by liquid chromatography coupled to mass spectrometry detection (SPE-LC-MS) has been used as a validation method of the new ELISA test.