Alkali metal⋯methyl short contacts in aluminates: more than agostic interactions.

Knowing the nature and strength of noncovalent interactions is key to enhancing the synthetic methods and catalytic processes in which they are involved. We present herein the synthesis and characterization of a novel aluminium sodium oximate compound, followed by a comprehensive computational study of the sodium⋯methyl interaction that appears in its crystal structure. Our experimental results have been compared to a large set of structural data retrieved from the Cambridge Structural Database in order to assess the main geometrical preferences of these interactions. Moreover, representative model systems have been studied at the DFT level and the topology of their electron density analysed by means of QTAIM. Although alkali metal⋯methyl short contacts have been traditionally considered as agostic interactions, we have demonstrated here that the physical origin of the attraction relies on the electron-rich carbon atom bound to aluminium and its interaction with the cation.

Ring-Opening Polymerization of L-Lactide Catalyzed by Potassium-Based Complexes: Mechanistic Studies.

Two non-toxic potassium compounds, 1 and 2, with a commercial oximate ligand have been prepared and fully spectroscopically characterized. Their activity as catalysts for the ring-opening polymerization (ROP) process of LLA has been studied, showing that they are extremely active and able to polymerize the monomer in a few minutes. For derivative 2, the presence of a crown ether in the potassium coordination sphere affects the nuclearity of the compound and consequently its solubility, with both aspects having an influence in the polymerization process. Detailed studies of the polymerization mechanism have been performed, and an unusual anionic mechanism was observed in absence of a co-initiator. Indeed, the monomer deprotonation generates a lactide enolate, which initiates the polymerization propagation. On the contrary, when a 1:1 ratio of cat:BnOH is used, a mixture of mechanisms is observed, the anionic mechanism and the activated monomer one, while from a cat:BnOH ratio of 1:2 and over, only the activated monomer mechanism is observed.

Hipertensión nocturna y eventos cardiovasculares en un hospital de la ciudad de Buenos Aires / Nocturnal Hypertension and Cardiovascular Events at a Buenos Aires City Hospital

RESUMEN Introducción: Nuestro objetivo fue determinar si la hipertensión arterial nocturna (HTAN) se asocia a eventos cardiovasculares o mortalidad en el seguimiento. Material y métodos: Estudio de cohorte retrospectiva que incluyó pacientes adultos que se realizaron una presurometría ambulatoria en un hospital de la ciudad de Buenos Aires, incorporados a un registro propio entre marzo de 2017 y julio de 2020, con seguimiento de hasta 36 meses de la presurometría índice. Se realizaron análisis uni y multivariados para identificar factores asociados. Resultados: De 522 sujetos, se incluyeron 494 en el análisis final. El 48% eran de sexo masculino y la edad promedio fue de 58,9 años. El 62% (n = 308) presentó HTAN. Se halló una mayor incidencia del punto final compuesto cardiovascular en este grupo en comparación con quienes no la presentaban, 10,4% vs 3,8% (p = 0,013). El análisis final por regresión de Cox multivariada demostró que la HTAN fue un predictor independiente de eventos cardiovasculares (HR = 3,9; IC 95% 1,56-9,81; p = 0,001), incluso independientemente de la HTA diurna y de los diferentes patrones circadianos de presión. Conclusión: En una cohorte contemporánea y de la ciudad de Buenos Aires, el patrón de HTAN se asoció con la aparición de desenlaces cardiovasculares. En base a estos hallazgos, se deben implementar medidas para incrementar su diagnóstico en nuestro medio.

ABSTRACT Background: Nocturnal Hypertension (NHT) has an impact on cardiovascular morbidity and mortality. Our aim was to evaluate the association between NHT and cardiovascular events. Methods: We carried out a retrospective cohort study including adults which had an ambulatory blood pressure monitoring test between March 2017 and July 2020 at a hospital in Buenos Aires City Argentina, with up to 36 months follow-up. Univariate and multivariate analyzes were performed to identify associated factors. Results: Four hundred and ninety four patients were included in the final analysis, 48% male, average age 58.9 years. Sixty two percent (n=308) presented NHT. A higher incidence of the cardiovascular composite endpoint was found in this group compared to those who did not present it, 10.4% vs 3.8% (p=0.013). In the final multivariate Cox regression analysis NHT was an independent predictor of cardiovascular events (HR=3.9; 95% CI 1.56-9.81; p=0.001), even independently of daytime HTN and the different circadian patterns of pressure. Conclusions: In this contemporary cohort from Buenos Aires, NHT was related to cardiovascular events incidence. Different measures should be taken to increase NHT awareness and diagnosis.

Ruminal effects of excessive dietary sulphur in feedlot cattle.

Sulphur (S) dietary excess can limit productive performance and increase polioencephalomalacia (PEM) incidence in feedlot cattle (FC). Sulphur excess ingested is transformed to hydrogen sulphide (H2 S) by sulfo-reducing ruminal bacteria (SRB), being high ruminal H2 S concentration responsible for aforementioned damages. As the ruminal mechanisms involved in H2 S concentrations increase have not been elucidated, this study aimed to evaluate the ruminal environment, and the association between ruminal H2 S and dissimilatory SRB (DSRB) concentration in FC experimentally subjected to S dietary excess. Twelve crossbred steers were randomly assigned to one of two dietary S levels (6 animals per treatment): low (LS, 0.19% S) and high (HS, 0.39% S obtained by sodium sulfate inclusion at 0.86%). The study lasted 38 days, and on days 0, 22 and 38, ruminal gas samples were taken to quantify H2 S concentration, and ruminal fluid to determine total bacteria, DSRB, protozoa, volatile fatty acid and ammonia nitrogen concentration. For ruminal H2 S concentration, S dietary × sampling day interaction was significant (p < 0.001), so that the greater concentration was observed on days 22 and 38 with the HS diet. The remaining ruminal parameters were not affected by dietary S level, and no significant correlation between H2 S and DSRB concentrations was observed. The ruminal adaptation that maximizes H2 S production in FC consuming S excess does not seem to be associated with biological or biochemical alterations, nor DSRB concentration changes. The microbial diversity and ruminal environment were resilient to the S excess evaluated, suggesting that 0.39% of dietary S achieved by 0.86% sodium sulfate addition, could be used without disturbances on digestion nor health of FC.

[Outbreak of bovine paralytic rabies in a disease-free region of Argentina]. / Brote de rabia paresiante bovina en la región libre de enfermedad en la Argentina.

We report an outbreak of bovine paralytic rabies in a feed lot in a disease-free area in southern Santa Fe, Argentina. Six of 122 unvaccinated steers died after showing neurological signs (morbimortality = 4.9%) for 24-72 hours, 40-75 days after being transported to the feed lot from a farm located in Formosa. Pathologic examination of the brain in 3 steers revealed gliosis, lymphoplasmacytic meningoencephalitis, and intracytoplasmic inclusion bodies in neurons, along with intralesional detection of the rabies virus antigen by immunohistochemistry in 2 cases. Rabies virus was confirmed by direct immunofluorescence in the brain, and further identified as variant 3a, typical of hematogenous bats, by inoculation in mice followed by indirect immunofluorescence. This represents the first communication of bovine paralytic rabies described in the Pampas plain in Argentina, and evidences that the transport of cattle from endemic to disease-free areas could represent a mechanism of dissemination of this communicable zoonotic disease.

[Assisted fertilization with at term pregnancies in two patients with severe rheumatoid arthritis while in treatment with etanercept.] / Embarazos a término por fertilización asistida en dos pacientes con artritis reumatoidea severa en tratamiento con etanercept.

Introduction: There are numerous reports of patients with rheumatoid arthritis (RA) who became pregnant while on treatment with etanercept. In spite of being formally contraindicated during pregnancy and lactation its discontinuation in cases of women with severe RA is no longer recommended since an increase in congenital malformations nor perinatal complications has not been reported. There are few data on the success or failure of pregnancies achieved by assisted fertilization in patients with RA treated with etanercept. Methods: Two cases of severe RA under etanercept treatment and assisted fertilization are described. Results: After 4 failed attempts both patients became pregnant. They finally arrived at term without obstetric or perinatal complications. No congenital malformations nor infectious complications of the newborns occurred. Conclusion: The risk-benefit profile of etanercept in severe RA patients has been changing with postmarketing surveillance. If there is clinical indication, the benefit of not stopping etanercept during assited fertilization and pregnancy should be .evaluated.

Introducción: Existen numerosos reportes de pacientes con artritis reumatoidea (AR) que quedaron embarazadas mientras se encontraban en tratamiento con etanercept. Si bien se encuentra formalmente contraindicado durante embarazo y lactancia, su suspensión en casos de mujeres con AR severa ya no se aconseja debido a que no se ha reportado un aumento de malformaciones congénitas ni de complicaciones perinatales. Existen pocos datos acerca del éxito o fracaso de embarazos logrados por fertilización asistida en pacientes con AR en tratamiento con etanercept. Métodos: Se describen dos casos clínicos de pacientes con AR severa en tratamiento con etanercept que realizaron técnicas de fertilización in vitro. Resultados: Tras 4 intentos fallidos, ambas pacientes cursaron embarazos sin complicaciones obstétricas ni perinatales y no se registraron malformaciones congénitas ni complicaciones infectológicas en los recién nacidos. Conclusión: El perfil riesgo-beneficio de etanercept en pacientes con AR severa ha ido cambiando con la farmacovigilancia poscomercialización. Si existe indicación clínica, debe evaluarse el beneficio de no suspenderlo en el curso de tratamientos de fertilización asistida y embarazo.