Mechanisms and efficacy of metformin-mediated suppression of established experimental abdominal aortic aneurysms.

Objective: Metformin treatment attenuates experimental abdominal aortic aneurysm (AAA) formation, as well as reduces clinical AAA diameter enlargement in patients with diabetes. The mechanisms of metformin-mediated aneurysm suppression, and its efficacy in suppressing established experimental aneurysms, remain uncertain. Methods: Experimental AAAs were created in male C57BL/6J mice via intra-aortic infusion of porcine pancreatic elastase. Metformin alone (250 mg/kg), or metformin combined with the 5' AMP-activated protein kinase (AMPK) antagonist Compound C (10 mg/kg), were administered to respective mouse cohorts daily beginning 4 days following AAA induction. Further AAA cohorts received either the AMPK agonist AICA riboside (500 mg/kg) as positive, or vehicle (saline) as negative, controls. AAA progression in all groups was assessed via serial in vivo ultrasonography and histopathology at sacrifice. Cytokine-producing T cells and myeloid cellularity were determined by flow cytometric analyses. Results: Metformin limited established experimental AAA progression at 3 (-85%) and 10 (-68%) days following treatment initiation compared with saline control. Concurrent Compound C treatment reduced this effect by approximately 50%. In metformin-treated mice, reduced AAA progression was associated with relative elastin preservation, smooth muscle cell preservation, and reduced mural leukocyte infiltration and neoangiogenesis compared with vehicle control group. Metformin also resulted in reduced interferon-γ-, but not interleukin-10 or -17, producing splenic T cells in aneurysmal mice. Additionally, metformin therapy increased circulating and splenic inflammatory monocytes (CD11b+Ly-6Chigh), but not neutrophils (CD11b+Ly-6G+), with no effect on respective bone marrow cell populations. Conclusions: Metformin treatment suppresses existing experimental AAA progression in part via AMPK agonist activity, limiting interferon-γ-producing T cell differentiation while enhancing circulating and splenic inflammatory monocyte retention.

Bispecific sigma-1 receptor antagonism and mu-opioid receptor partial agonism: WLB-73502, an analgesic with improved efficacy and safety profile compared to strong opioids.

Opioids are the most effective painkillers, but their benefit-risk balance often hinder their therapeutic use. WLB-73502 is a dual, bispecific compound that binds sigma-1 (S1R) and mu-opioid (MOR) receptors. WLB-73502 is an antagonist at the S1R. It behaved as a partial MOR agonist at the G-protein pathway and produced no/unsignificant ß-arrestin-2 recruitment, thus demonstrating low intrinsic efficacy on MOR at both signalling pathways. Despite its partial MOR agonism, WLB-73502 exerted full antinociceptive efficacy, with potency superior to morphine and similar to oxycodone against nociceptive, inflammatory and osteoarthritis pain, and superior to both morphine and oxycodone against neuropathic pain. WLB-73502 crosses the blood-brain barrier and binds brain S1R and MOR to an extent consistent with its antinociceptive effect. Contrary to morphine and oxycodone, tolerance to its antinociceptive effect did not develop after repeated 4-week administration. Also, contrary to opioid comparators, WLB-73502 did not inhibit gastrointestinal transit or respiratory function in rats at doses inducing full efficacy, and it was devoid of proemetic effect (retching and vomiting) in ferrets at potentially effective doses. WLB-73502 benefits from its bivalent S1R antagonist and partial MOR agonist nature to provide an improved antinociceptive and safety profile respect to strong opioid therapy.

Implementation of a cloud-based electronic patient-reported outcome (ePRO) platform in patients with advanced cancer.

BACKGROUND: Patient reported outcomes (PROs) have been associated with improved symptom management and quality of life in patients with cancer. However, the implementation of PROs in an academic clinical practice has not been thoroughly described. Here we report on the execution, feasibility and healthcare utilization outcomes of an electronic PRO (ePRO) application for cancer patients at an academic medical center. METHODS: We conducted a randomized trial comparing an experimental ePRO arm to standard of care in patients with advanced cancer in the thoracic, gastrointestinal, and genitourinary oncology groups at Stanford Cancer Center from March 2018 to November 2019. We describe the pre-implementation, implementation, and post-implementation phases of the ePRO arm, technological barriers, electronic health record (EHR) integration, clinician burden, and patient data privacy and security. Feasibility was pre-specified to be at least 70% completion of all questionnaires. Acceptability was based on patient and clinician feedback. Ambulatory healthcare utilization was assessed by reviewing numbers of phone messages, electronic portal messages, and referrals for supportive care. RESULTS: Of 617 ePRO questionnaires sent to 72 patients, 445 (72%) were completed. Most clinicians (87.5%) and patients (93%) felt neutral or positive about the ePRO tool's ease of use. Exposure to ePRO did not cause a measurable change in ambulatory healthcare utilization, with a median of less than two phone messages and supportive care referrals, and 5-6 portal messages. CONCLUSIONS: Web-based ePRO tools for patients with advanced cancer are feasible and acceptable without increasing clinical burden. Key lessons include the importance of pilot testing, engagement of stakeholders at all levels, and the need for customization by disease group. Future directions for this work include completion of EHR integration, expansion to other centers, and development of integrated workflows for routine clinical practice.

Programa de soporte a los docentes de alumnos con TEA / Program of support to teachers of students with ASD

En el presente trabajo se describe un programa de soporte a los docentes de alumnos con Trastornos del Espectro Autista que se puso en marcha hace tres años en la zona de Granollers, Barcelona. Se organiza a partir de la presentación de casos y de las vicisitudes de su recorrido escolar y asistencial dentro de un grupo de trabajo en el que participan profesionales de las Escuelas Ordinaria y Especial, de los Equipos de Asesoramiento Psicopedagógico, del Centro de Desarrollo y Atención Precoz y del Centro de Salud Mental Infantil y Juvenil (AU)

The purpose of this paper is to describe a teacher support programme for Autism Spectrum Disorders launched three years ago in the area of Granollers, Barcelona. The paper is structured through case presentations and the vicissitudes of their school and care pathways in a working group involving professionals from Ordinary and Special Schools, from the Psychopedagogical Counselling Teams, the Development and Early Care Centre and the Mental Health Centre for Children and Adolescents (AU)

Pharmacokinetic dose proportionality between two strengths (12.5 mg and 25 mg) of doxylamine hydrogen succinate film-coated tablets in fasting state: a single-dose, randomized, two-period crossover study in healthy volunteers.

BACKGROUND: Doxylamine succinate, an ethanolamine-based antihistamine, is used in the short-term management of insomnia because of its sedative effects. No data on the dose proportionality of the pharmacokinetics of doxylamine are available, although this drug has been marketed in European countries for more than 50 years. OBJECTIVE: The objective of this study was to evaluate and compare the dose proportionality between two marketed strengths (12.5 mg and 25 mg) of doxylamine hydrogen succinate after a single oral dose administration under fasting conditions in healthy human subjects. STUDY DESIGN: This was a single-center, randomized, single dose, laboratory-blinded, two-period, two-sequence, crossover study. SETTING: The study was conducted in a phase I clinical unit. SUBJECTS AND METHODS: A single oral dose of doxylamine hydrogen succinate of 12.5 mg (equivalent to 8.7 mg of doxylamine base) or 25 mg (equivalent to 17.4 mg of doxylamine base) was administered to healthy volunteers under fasting conditions in each study period. The drug administrations were separated by a wash-out period of 7 calendar days. Blood samples were collected for up to 60 h post-dose, and plasma doxylamine levels were determined by an ultra high-performance liquid chromatography method with tandem mass spectrometry detection. Pharmacokinetic parameters were calculated using non-compartmental analysis. Dose proportionality was assessed based on the parameter area under the concentration-time curve (AUCt normalized). Safety was evaluated through assessment of adverse events, standard laboratory evaluations, vital signs and 12-lead electrocardiogram (ECG). RESULTS: In total, 12 healthy volunteers (3 male; 9 female) were included in the study. Mean maximum observed plasma concentration (Cmax) and area under the concentration-time curve from time zero to time t (AUCt ) of doxylamine hydrogen succinate 12.5 mg and 25 mg tablets increased linearly and dose-dependently [12.5 mg: mean Cmax 61.94 ng/mL, coefficient of variation (CV) 23.2%; mean AUCt 817.33 ng·h/mL, CV 27.4%; and 25 mg: mean Cmax 124.91 ng/mL, CV 18.7%; mean AUCt 1630.85 ng·h/mL, CV 22.8%]. Mean AUCt normalized was 815.43 ng·h/mL, CV 22.8% for 25 mg. The dose-normalized geometric mean ratio (%, 12.5 mg/25 mg) of AUCt was 98.92 (90% CI: 92.46, 105.83). The most common adverse event was somnolence. CONCLUSIONS: Exposure to doxylamine was proportional over the therapeutic dose range of 12.5-25 mg in healthy volunteers. Based on the results, a predictable and linear increase in systemic exposure can be expected. Doxylamine hydrogen succinate was safe and well tolerated.

Studies on toxic oil syndrome: development of an enzyme-linked immunosorbent assay for 3-(N-phenylamino)propane-1,2-diol in human urine.

The fatty acid esters of 3-(N-phenylamino)propane-1,2-diol (PAP) are biomarkers of toxic oil batches that caused toxic oil syndrome (TOS), an intoxication that caused over 400 deaths and affected 20,000 people in Spain in 1981. PAP esters are converted into PAP by human pancreatic lipase. The in vivo biotransformation of PAP in two mouse strains generated potentially toxic metabolites. Here we report an enzyme-linked immunosorbent assay (ELISA) for PAP detection incorporating antibodies generated using PAP-hapten derivatives 1 and 2. The immunizing haptens were designed to recognize the phenylamino and hydroxymethylene moieties of the PAP structure. The antisera raised against 1-HCH showed greater affinity for free PAP, as demonstrated in competitive experiments using either 1-BSA or 2-BSA as coating antigens. The developed ELISA detects PAP at a threshold of 130 µg L(-1) and can be used over a wide range of pH and ionic strength values. The assay can be applied to human urine samples, after a simple treatment method, with good recovery according to the correlation obtained when analyzing blind spiked urine samples.

Generation of quinoneimine intermediates in the bioactivation of 3-(N-phenylamino)alanine (PAA) by human liver microsomes: a potential link between eosinophilia-myalgia syndrome and toxic oil syndrome.

Eosinophilia-myalgia syndrome (EMS) was an intoxication episode that occurred in the US in 1989 and affected 1,500 people. EMS was associated with the ingestion of manufactured L-tryptophan, and 3-(N-phenylamino)alanine (PAA) was identified as one of the contaminants present in the L-tryptophan batches responsible for intoxication. In previous studies (Martínez-Cabot et al., Chem Res. Toxicol., in press), we have shown that the incubation of 3-(N-phenylamino)propane-1,2-diol (PAP), a toxic biomarker of the oil batches that caused Toxic Oil Syndrome in Spain, with human liver microsomes generates a reactive quinoneimine intermediate. The structural similarity between PAA and PAP led Mayeno and co-workers (Mayeno et al. (1995) Chem. Res. Toxicol. 8, 911-916) to hypothesize that both xenobiotics could be linked to a common etiologic agent. We thus set about to study the bioactivation of PAA by human liver microsomes. Under these conditions, PAA is converted to its 4'-hydroxy derivative, an unstable intermediate that is rapidly transformed into the final metabolites 4-aminophenol and formylglycine, which were identified in the incubations by GC/MS using the H2(18)O-labeled medium. We also provide evidence that 4-aminophenol and formylglycine are formed from a quinoneimine intermediate via a pathway similar to that demonstrated for PAP bioactivation. This quinoneimine, in the absence of nucleophiles in the incubation medium, could isomerize to give the corresponding imine, which could undergo hydrolysis to yield the aforementioned final products. These findings establish that EMS and TOS are linked by a common toxic metabolite (4-aminophenol) and that they may be further linked by the concomitant release of potentially hazardous carbonyl species.

[Neonatal screening of hemoglobinopathies and G6PD deficiency in Catalonia (Spain). Molecular study of sickle cell disease associated with alpha thalassemia and G6PD deficiency]. / Cribado neonatal de hemoglobinopatías y déficit de glucosa-6-fosfato deshidrogenasa (G6PD) en Cataluña. Estudio molecular de la anemia falciforme asociada a alfatalasemia y déficit de G6PD.

BACKGROUND AND OBJECTIVE: The prevalence of hemoglobinopathies and glucose-6-phosphate dehidrogenase (G6PD) deficiency in the Catalan neonatal population is increasing due to immigration. Coinheritance of more than a single RBC genetic defect is becoming more frequent and diagnostic pitfalls are also increasing. We intended to demonstrate the need to perform an early diagnosis of sickle cell disease (SCD) by means of neonatal screening, to establish the prevalence of SCD associated with alpha thalassemia and G6PD deficiency and to identify genotypes associated with sickle cell disease and G6PD deficiency. PATIENTS AND METHOD: 4,020 blood samples from newborns were screened. For the screening of hemoglobinopathies the high performance liquid chromatography method was used and for G6PD deficiency the fluorescent spot test was employed. We studied the association between betaS gene and alpha thalassaemia del-3.7 Kb. SCD and G6PD deficiency genotypes were established. RESULTS: Prevalence of SCD in population at risk was 1/475 newborns. Prevalence of G6PD deficiency in population at risk was 1/43, and in autochthonous population was 1/527 newborns. In all the cases, sickle hemoglobin was confirmed by ARMS (amplification refractory mutation system). Association between betaS gene and alpha thalassaemia del-3.7 Kb was found in 32.2% of the samples, and an association between betaS gene and G6PD deficiency was observed in 7% of the samples. CONCLUSIONS: This study confirms the high prevalence of SCD and G6PD deficiency in population at risk as well as their genetic and clinical heterogeneity. The study of genotype/phenotype relationships allows a better knowledge of molecular mechanism and is useful to establish suitable criteria of diagnosis.

In vitro bioactivation of 3-(N-phenylamino)propane-1,2-diol by human and rat liver microsomes and recombinant P450 enzymes. Implications for toxic oil syndrome.

Toxic oil syndrome (TOS) was a massive food-borne intoxication that occurred in Spain in 1981. Epidemiological studies imputed 3-( N-phenylamino)propane-1,2-diol (PAP) derivatives as the toxic agents. The in vitro bioactivation of PAP by rat and human liver microsomes was studied. In both cases, 3-[ N-(4'-hydroxyphenyl)amino]propane-1,2-diol ( 1) was detected as the main metabolite. Inhibition studies with pooled human liver microsomes in the presence and absence of P450-specific inhibitors suggest that 2C8 and 2E1 are the main enzymes involved in PAP bioactivation, followed by 3A4/5, 1A1/2, and 2C9. Incubations of PAP with 10 different recombinant P450 enzymes showed that 2C8, 2C9, 2C18, 2D6, and 2E1 catalyzed PAP 4'-hydroxylation. Incubations of phenol 1 with rat and human liver microsomes in the presence of GSH resulted in the formation of a glutathione conjugate of a quinoneimine metabolite derived from 1. In rat liver microsomes, P450 enzymes play a key role in the bioactivation of 1, whereas in human liver microsomes, autoxidation appears to be the major mechanism. The implications of these results for toxic oil syndrome are discussed.

Cribado neonatal de hemoglobinopatías y déficit de glucosa-6-fosfato deshidrogenasa (G6PD) en Cataluña. Estudio molecular de la anemia falciforme asociada a alfatalasemia y déficit de G6PD / Neonatal screening of hemoglobinopathies and G6PD deficiency in Catalonia (Spain). Molecular study of sickle cell disease associated with alpha thalassemia and G6PD deficiency

Fundamento y objetivo: Con los flujos inmigratorios se ha elevado la prevalencia de hemoglobinopatías y déficit de glucosa-6-fosfato deshidrogenasa (G6PD) en nuestra población. La probabilidad de encontrar en un individuo más de un defecto del eritrocito es elevada, lo que comporta una mayor heterogeneidad clínica y dificultades diagnósticas. El objetivo de este trabajo ha sido realizar el diagnóstico precoz de la anemia falciforme mediante cribado neonatal, analizar la prevalencia de herencia conjunta de alfatalasemia, déficit de G6PD y hemoglobina S e identificar los genotipos asociados. Pacientes y método: Se ha estudiado a 4.020 recién nacidos (RN) de población de riesgo y autóctona. El cribado neonatal de hemoglobinopatías se realizó mediante cromatografía líquida de alta resolución y el de déficit de G6PD mediante la técnica de la mancha fluorescente. Se analizó molecularmente la asociación entre el gen ßS y alfatalasemia con deleción ­3.7 Kb. Finalmente se estableció el genotipo de los casos de déficit de G6PD. Resultados: La prevalencia de anemia falciforme en población de riesgo fue de 1/475 RN, y la de déficit de G6PD, de 1/43 RN en población de riesgo y de 1/527 RN en población autóctona. La hemoglobina S se confirmó mediante ARMS (amplification refractory mutation system). La asociación entre el gen ßS y la alfatalasemia con deleción ­3.7 Kb fue de un 32,2%, y entre el gen ßS y el déficit de G6PD, de un 7%. Conclusiones: Se confirma la elevada prevalencia de la anemia falciforme y del déficit de G6PD en población de riesgo, así como la elevada heterogeneidad molecular de ambos defectos. El conocimiento de los genotipos asociados y su relación con la expresión clínica es de gran utilidad para establecer criterios adecuados de diagnóstico y pronóstico

Background and objective: The prevalence of hemoglobinopathies and glucose-6-phosphate dehidrogenase (G6PD) deficiency in the Catalan neonatal population is increasing due to immigration. Coinheritance of more than a single RBC genetic defect is becoming more frequent and diagnostic pitfalls are also increasing. We intended to demonstrate the need to perform an early diagnosis of sickle cell disease (SCD) by means of neonatal screening, to establish the prevalence of SCD associated with alpha thalassemia and G6PD deficiency and to identify genotypes associated with sickle cell disease and G6PD deficiency. Patients and method: 4,020 blood samples from newborns were screened. For the screening of hemoglobinopathies the high performance liquid chromatography method was used and for G6PD deficiency the fluorescent spot test was employed. We studied the association between ßS gene and alpha thalassaemia del-3.7 Kb. SCD and G6PD deficiency genotypes were established. Results: Prevalence of SCD in population at risk was 1/475 newborns. Prevalence of G6PD deficiency in population at risk was 1/43, and in autochthonous population was 1/527 newborns. In all the cases, sickle hemoglobin was confirmed by ARMS (amplification refractory mutation system). Association between ßS gene and alpha thalassaemia del-3.7 Kb was found in 32.2% of the samples, and an association between ßS gene and G6PD deficiency was observed in 7% of the samples. Conclusions: This study confirms the high prevalence of SCD and G6PD deficiency in population at risk as well as their genetic and clinical heterogeneity. The study of genotype/phenotype relationships allows a better knowledge of molecular mechanism and is useful to establish suitable criteria of diagnosis

Mal de Pott i abscés prevertebral i paravertebral en un nen de 23 mesos d’edat / Mal de pott y absceso prevertebral y paravertebral en un niño de 23 meses de edad / Pott disease and pre- and para-vertebral abscesses in a 23-month-old boy

La malaltia tuberculosa és tan antiga com l’espècie humana1 , i encara se’n continuen detectant casos en la població pediàtrica que viu a Catalunya. Sens dubte, l’important flux migratori dels darrers anys és un element amb un pes específic important en aquesta constatació, per bé que no pas l’únic. Es presenta el cas d’un nen de 23 mesos d’origen magribí, nascut a Catalunya, que consulta a Urgències per una coixesa a totes dues cames de set dies d’evolució, sense febre ni antecedent traumàtic. En l’exploració destacava una temperatura axil•lar de 37.5 °C. L’examen físic per aparells no va mostrar alteracions. Tant l’analítica com la punció lumbar realitzades van ser normals. La radiologia de tòrax i de malucs fou anodina i en la de columna dorsolumbar es detectà un pinçament de l’espai D-11/D-12 amb espondilòlisi i espondilolistesi. El PPD fou positiu (25 x 17 mm) i el Ziehl-Nielsen i el cultiu en medi Löwenstein d’aspirats gàstrics seriats i LCR, negatius. La ressonància magnètica nuclear mostrà un abscés prevertebral i paravertebral de D-08 a L-2 amb espondilòlisi i espondilolistesi de D-10 a D-12. Sota l’orientació diagnòstica de tuberculosi vertebral (mal de Pott) i abscés prevertebral i paravertebral s’inicià el tractament amb quatre fàrmacs tuberculostàtics. Amb la punció-aspiració es van obtenir 12 cc de càseum (Ziehl-Nielsen negatiu i Löwenstein positiu) i es col•locà una cotilla d’immobilització externa. Els estudis immunitaris i la serologia a VIH foren negatius i en l’estudi de contactes familiars destacava una pleuropneumònia tuberculosa en el pare, tuberculosi primària en la mare i infecció tuberculosa latent en el germà. L’evolució clínica fou favorable, i l’alta hospitalària s’aconseguí al cap de 32 dies. Als 10 mesos de l’ingrés deambula normalment i ha millorat la cifosi regional i local (AU)

A pesar de ser tan antigua como la especie humana 1 , se continúan detectando casos de enfermedad tuberculosa en la población pediátrica que vive en Catalunya. Sin duda, el importante flujo migratorio de los últimos años es un elemento con un importante peso específico en la causa de esta constatación, si bien no es el único. Se presenta el caso de un niño de 23 meses de origen magrebí, nacido en Catalunya, que consultó a Urgencias por presentar cojera de ambas piernas de siete días de evolución, sin fiebre ni antecedente traumático. En la exploración, destacaba una temperatura axilar de 37.5 °C. El examen físico por aparatos no mostró alteraciones. La analítica y la punción lumbar realizadas fueron normales. La radiología de tórax y caderas fue anodina y en la de columna dorso-lumbar se detectó pinzamiento del espacio D-11/D-12 con espondilolisis y espondilolistesis. El P.P.D. fue positivo (25 x 17 mm) y el Zhiel-Nielsen y el Löwenstein de aspirados gástricos seriados y LCR negativos. La resonancia magnética nuclear mostró un absceso prevertebral y paravertebral de D-08 a L-2 con espondilolisis y espondilolistesis de D-10 a D-12. Bajo la orientación diagnóstica de tuberculosis vertebral (mal de Pott) y absceso prevertebral y paravertebral, se inició tratamiento con cuatro fármacos según pauta. En la punción-aspiración se obtuvieron 12 cc de cáseum (Zhiel-Nielsen negativo y Löwenstein positivo) y se procedió a colocar corsé de inmovilización externo. Los estudios inmunitarios y la serología a VIH fueron negativos y en el estudio de contactos familiares destacó el hallazgo de una pleuroneumonía tuberculosa en el padre, tuberculosis primaria en la madre e infección tuberculosa en el hermano. La evolución clínica fue favorable, y recibió el alta del hospital a los 32 días. A los 10 meses del ingreso deambula normalmente con mejora evidente de la cifosis regional y local (AU)

Despite being described to be as old as humankind, pediatric cases of tuberculosis continue to be diagnosed in Catalonia. Many factors contribute to the persistence of this problem, including the increase in migratory flow documented in recent years. We present the case of a 23 month-old child of Maghribian descent, who presented with a 7-day history of progressive limpness. There was no recent history of trauma, and the child was afebrile. On physical examination, axillary temperature was 37.5o C, and examination by systems and organs was normal. Laboratory evaluation, including CSF, was normal. Chest and hips XRays were normal, but imaging of the thoracolumbar spine disclosed narrowing of the T11-T12 intervertebral space, with spondylolysis and spondylolystesis. PPD was positive (25 x 17 mm) and the Ziehl-Nielsen and Löwenstein stains of serial gastric aspirates and CSF were negative. MRI showed a pre- and para-vertebral abscess extending from T-8 through L-2, with spondylolysis and spondylolystesis of T-10 through T-12. A needle aspiration with drainage of 12 mL of caseum was performed. The material was negative for Ziehl-Nielsen and positive for Löwenstein stains. With the clinical diagnosis of vertebral tuberculosis (Pott disease) and prevertebral and paravertebral abscess, the patient was started with a 4-drug regimen, and was fitted for a trunk brace. Immune function studies were normal and HIV serology was negative, and contact evaluation revealed a tuberculous pleuropneumonia in the father, primary tuberculosis in the mother, and primary infection in the brother. Clinical course was favorable, and the patient was discharged from the inpatient unit after 32 days. Follow-up at 10 months from diagnosis shows normal walking and improvement in the regional and local kyphosis (AU)

Synthesis and stability studies of the glutathione and N-acetylcysteine adducts of an iminoquinone reactive intermediate generated in the biotransformation of 3-(N-phenylamino)propane-1,2-diol: implications for toxic oil syndrome.

Epidemiological studies have pointed to fatty acid mono- and diesters of 3-(N-phenylamino)propane-1,2-diol (PAP) as the biomarkers of the toxic oil batches that caused toxic oil syndrome (TOS), an intoxication episode that occurred in Spain in 1981, causing over 400 deaths and affecting more than 20000 people. The biotransformation of PAP administered intraperitoneally to two mouse strains produced potentially toxic metabolites. The identification of 3-(4'-hydroxyphenylamino)propane-1,2-diol among those metabolites was important because the compound can generate the quinoneimine intermediate 2. The potential toxicity of quinoneimines has been attributed primarily to their electrophilic character. Accordingly, the reactions of 2 with N-acetylcysteine, N-acetylcysteine methyl ester, and GSH were investigated. Quinoneimine 2 reacts with the N-acetylcysteine methyl ester to give the expected conjugate as a major product, accompanied by the corresponding bis and tris adducts. The monoadduct, when isolated in pure form, undergoes spontaneous oxidation to generate a new quinoneimine intermediate, which in turn rearranges and undergoes hydrolysis to afford the thiol adduct formally derived from the quinoneimine generated from p-aminophenol. The same overall pathway was observed for the reaction of 2 with N-acetylcysteine and GSH. Both thiol reagents reacted with the quinoneimine to give the corresponding adducts in which the addition took place at the ortho position with respect to the amino group. These conjugates were also unstable and ultimately afforded the corresponding adduct derived from p-aminophenol. The relevancy of these results to TOS, as well as their potential generalization for quinoneimines derived from other xenobiotics, is discussed herein.

Studies on toxic oil syndrome: stereoselective hydrolysis of 3-(phenylamino)propane-1,2-diol esters by human pancreatic lipase.

The ingestion of rapeseed oil batches denatured with aniline and illegally refined and distributed by street vendors was responsible for toxic oil syndrome (TOS), an intoxication episode that took place in Spain in 1981, causing over 400 deaths and affecting more than 20,000 people. Despite the intense research efforts carried out to date, the compounds responsible for that intoxication have not been elucidated. Nevertheless, epidemiological studies have pointed to fatty acid mono- and diesters of 3-phenylamino-1,2-propanediol (PAP) as the biomarkers of those toxic oil batches. The structure of these esters bears common features with that of triglycerides, which suggested that PAP esters could follow the route of lipids metabolism up to a certain extent. The incubation of racemic PAP dioleyl ester with human pancreatic lipase (hPL) led to the formation of the corresponding stereoisomeric monoesters bearing the oleyl residue at C-2, although a kinetic resolution in favor of the (S)-enantiomer was observed. These monoesters are unstable and in equilibrium with their corresponding regioisomers with the acyl residue at C-1, apparently without the intervention of the lipase. Finally, incubations of these latter monoesters with hPL led to the formation of the respective PAP enantiomers. Again, the kinetic resolution of this hydrolytic process favored the formation of the enantiomer with the (S)-configuration. Taken together, these results showed that PAP esters are substrates of hPL and that the two hydrolytic steps exhibit kinetic resolution in favor of the (S)-enantiomers.