Exploring kidney biopsy findings in congenital heart diseases: Insights beyond cyanotic nephropathy.

BACKGROUND: The association between congenital heart disease and chronic kidney disease is well known. Various mechanisms of kidney damage associated with congenital heart disease have been established. The etiology of kidneydisease has commonly been considered to be secondary to focal segmental glomerulosclerosis (FSGS), however, this has only been demonstrated in case reports and not in observational or clinical trials. AIM: To identify baseline and clinical characteristics, as well as the findings in kidney biopsies of patients with congenital heart disease in our hospital. METHODS: This is a retrospective observational study conducted at the Nephrology Department of the National Institute of Cardiology "Ignacio Chávez". All patients over 16 years old who underwent percutaneous kidney biopsy from January 2000 to January 2023 with congenital heart disease were included in the study. RESULTS: Ten patients with congenital heart disease and kidney biopsy were found. The average age was 29.00 years ± 15.87 years with pre-biopsy proteinuria of 6193 mg/24 h ± 6165 mg/24 h. The most common congenital heart disease was Fallot's tetralogy with 2 cases (20%) and ventricular septal defect with 2 (20%) cases. Among the 10 cases, one case of IgA nephropathy and one case of membranoproliferative glomerulonephritis associated with immune complexes were found, receiving specific treatment after histopathological diagnosis, delaying the initiation of kidney replacement therapy. Among remaining 8 cases (80%), one case of FSGS with perihilar variety was found, while the other 7 cases were non-specific FSGS. CONCLUSION: Determining the cause of chronic kidney disease can help in delaying the need for kidney replacement therapy. In 2 out of 10 patients in our study, interventions were performed, and initiation of kidney replacement therapy was delayed. Prospective studies are needed to determine the usefulness of kidney biopsy in patients with congenital heart disease.

Breaking a Molecular Scaling Relationship Using an Iron-Iron Fused Porphyrin Electrocatalyst for Oxygen Reduction.

The design of efficient electrocatalysts is limited by scaling relationships governing trade-offs between thermodynamic and kinetic performance metrics. This ″iron law″ of electrocatalysis arises from synthetic design strategies, where structural alterations to a catalyst must balance nucleophilic versus electrophilic character. Efforts to circumvent this fundamental impasse have focused on bioinspired applications of extended coordination spheres and charged sites proximal to a catalytic center. Herein, we report evidence for breaking a molecular scaling relationship involving electrocatalysis of the oxygen reduction reaction (ORR) by leveraging ligand design. We achieve this using a binuclear catalyst (a diiron porphyrin), featuring a macrocyclic ligand with extended electronic conjugation. This ligand motif delocalizes electrons across the molecular scaffold, improving the catalyst's nucleophilic and electrophilic character. As a result, our binuclear catalyst exhibits low overpotential and high catalytic turnover frequency, breaking the traditional trade-off between these two metrics.

[Circulatory support with venovenous ECMO in a patient with reperfusion pulmonary edema after pulmonary artery thromboendarterectomy]. / Soporte circulatorio con ECMO venovenoso en paciente con síndrome de reperfusión pulmonar secundario a tromboendarterectomía arterial pulmonar.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a subtype of pulmonary hypertension characterized by the obstruction of pulmonary arteries secondary to chronic thromboembolism. Pulmonary thromboendarterectomy surgery (PTE) is the main treatment for patients with CTEPH, as it removes the chronic thrombi from the pulmonary arteries. Pulmonary reperfusion syndrome is a common complication of the surgery, which involves the development of pulmonary edema in the area where blood perfusion improves after the surgery. The incidence of this syndrome varies from 8 to 91% depending on the criteria used for diagnosis, and it is one of the most serious complications of pulmonary thromboendarterectomy. In such cases, circulatory support with extracorporeal membrane oxygenation (ECMO) has become a valuable therapeutic modality. We present the case of a 60-year-old woman with a history of acute pulmonary embolism due to deep vein thrombosis of the right pelvic limb who was diagnosed later with CTEPH who was admitted for scheduled surgical treatment involving bilateral PTE. However, during the immediate postoperative period, she developed cardiogenic shock and refractory hypoxemia secondary to pulmonary reperfusion syndrome following the surgical procedure. As a result, she required veno-venous ECMO circulatory support for 6 days, leading to resolution of the pulmonary condition and clinical improvement.

La hipertensión pulmonar tromboembólica crónica (HPTEC) es un subtipo de hipertensión pulmonar caracterizada por la obstrucción de las arterias pulmonares secundaria a tromboembolias crónicas. La cirugía de tromboendarterectomía pulmonar (TEAP) es el tratamiento principal para los pacientes con HPTEC, elimina los trombos crónicos de las arterias pulmonares. El síndrome de reperfusión pulmonar es una complicación común de la cirugía, se trata del desarrollo de edema pulmonar en el área en la que la perfusión sanguínea mejora después de la cirugía. La incidencia del síndrome varía del 8 al 91% según los criterios utilizados para diagnosticarlo y es una de las complicaciones más graves de la tromboendarterectomía pulmonar. En tales casos, el soporte circulatorio con oxigenación por membrana extracorpórea (ECMO) se ha convertido en una valiosa modalidad terapéutica. Presentamos el caso de una paciente de 60 años de edad con antecedente de tromboembolia pulmonar aguda secundaria a trombosis venosa profunda de miembro pélvico derecho a quien durante el seguimiento se realizó el diagnóstico de HPTEC e ingresó de manera programada para tratamiento quirúrgico con realización de TEAP bilateral, sin embargo durante el posquirúrgico inmediato presentó choque cardiogénico e hipoxemia refractaria secundarios a síndrome de reperfusión pulmonar, por lo cual requirió soporte circulatorio con ECMO venovenosa durante seis días, con resolución del cuadro pulmonar y mejoría clínica.

The fourth COVID-19 vaccine dose increased the neutralizing antibody response against the SARS-CoV-2 Omicron (B.1.1.529) variant in a diverse Brazilian population.

IMPORTANCE: Several additional COVID-19 vaccine doses were administered in the Brazilian population to prevent the disease caused by the B.1.1.529 (Omicron) variant. The efficacy of a third dose as a booster is already well described. However, it is important to clarify the humoral immune response gain induced by a fourth dose. In this study, we evaluate the effect of the fourth COVID-19 vaccine dose in a diverse Brazilian population, considering a real-life context. Our study reveals that the fourth dose of the COVID-19 vaccine increased the neutralizing antibody response against SARS-CoV-2 Omicron and significantly contributed in the reduction of the disease caused by this variant.

New species of Protomicrocotyle (Monogenea: Protomicrocotylidae), and new information on P. mirabilis, parasites of Caranx spp. from Veracruz, México.

During a study of the helminth parasites of carangid fish of the Gulf of Mexico, Protomicrocotyle mirabilis and a new member of that genus were found. The aim of the present study is to provide new morphological and sequences of 28s rDNA and CO1 mtDNA for P. mirabilis and describe the new species. Between 2005-2022, 73 specimens of Caranx spp. were purchased from local fishermen of the littoral waters of the Gulf of Mexico. Protomicrocotyle veracruzensis sp. nov. is most similar to P. mirabilis than to P. ivoriensis, the only members of the genus known from the Greater Atlantic Ocean Basin. Protomicrocotyle veracruzensis sp. nov. can be distinguished from those two species by the arrangement and number of testes. Measurement data on the haptoral armature for the new species is provided and the potential value and need for comparative data from these structures of other members of the genus is discussed. The results of the molecular analysis and the morphometric analysis of 91 characters confirmed that this new species belongs to Protomicrocotyle.

Clinical Characteristics and Outcomes in Adults With Moderate-to-Severe Complexity Congenital Heart Disease Undergoing Palliation or Surgical Repair.

Background: Congenital heart disease (CHD) survival rate has improved dramatically due to advances in diagnostic and therapeutic techniques. However, concerning the unrepaired CHD population of moderate and severe complexity, the data regarding risk predictors and surgical outcomes are scarce. Our aim was to describe the surgical results and predictors of in-hospital outcomes in adult patients with moderate-to-severe complexity CHD that were not repaired in childhood. Methods: We conducted a retrospective cohort study that included 49 adult patients with moderate-to-complex CHD who were treated in a single medical centre. Clinical and echocardiographic variables were obtained on admission, after surgical procedures and during follow-up. Results: Most of the patients were female (66%). Left ventricular ejection fraction and right ventricular outflow tract fractional shortening were within the normal range. The median pulmonary artery systolic pressure was 37 (27-55) mm Hg. The median time was 118 (80-181) minutes for extracorporeal circulation and 76 (49-121) minutes for aortic cross-clamping. The most frequent complication was postoperative complete atrioventricular block (12.2%). In-hospital survival rate was 87.7%. The development of low cardiac output syndrome with predominant right ventricle failure in the postoperative period was the most important predictor of in-hospital death (P = 0.03). Conclusions: Deciding to treat adults with CHD is challenging in moderate and severe unrepaired cases. Adequate clinical, functional, and imaging evaluation is essential to determine each patient's suitability for surgical management and to achieve the best clinical outcome for this population.

Contexte: Grâce aux avancées réalisées en matière de techniques diagnostiques et thérapeutiques, la survie des patients atteints d'une cardiopathie congénitale s'est considérablement améliorée. Cependant, en ce qui concerne les personnes atteintes d'une cardiopathie congénitale non corrigée présentant une complexité modérée ou extrême, les données portant sur les facteurs de risque prédictifs ainsi que sur les résultats chirurgicaux sont rares. Notre objectif était de décrire les résultats chirurgicaux ainsi que les facteurs prédictifs des résultats obtenus en milieu hospitalier chez les patients adultes atteints d'une cardiopathie congénitale présentant une complexité modérée ou extrême qui n'a pas été corrigée pendant l'enfance. Méthodologie: Nous avons mené une étude de cohorte rétrospective comprenant 49 patients adultes atteints d'une cardiopathie congénitale modérée ou complexe qui ont reçu leurs traitements dans un seul centre médical. Les variables cliniques et échocardiographiques ont été obtenues au moment de l'admission, après les interventions chirurgicales et pendant la période de suivi. Résultats: Les patients étaient en majorité des femmes (66 %). La fraction d'éjection du ventricule gauche ainsi que la fraction de raccourcissement de la voie d'éjection ventriculaire droite sont demeurées dans les limites de la normale. La pression systolique médiane de l'artère pulmonaire a été de 37 mmHg (27-55 mmHg). Le temps médian écoulé pour la circulation extracorporelle a été de 118 minutes (80-181 minutes) et pour le clampage de la crosse aortique, de 76 minutes (49-121 minutes). Le bloc auriculo-ventriculaire postopératoire complet a été la complication la plus fréquente (12,2 %). Le taux de survie en milieu hospitalier a été de 87,7 %. Le développement du syndrome du faible débit cardiaque accompagné d'une insuffisance prédominante du ventricule droit durant la période postopératoire a constitué le principal facteur prédictif de décès à l'hôpital (p = 0,03). Conclusion: Il est difficile de traiter les adultes qui présentent une cardiopathie congénitale modérée ou sévère non corrigée. Il est essentiel que les évaluations cliniques, fonctionnelles et par imagerie soient réalisées de façon adéquate pour déterminer si une prise en charge chirurgicale convient aux patients et pour garantir les meilleurs résultats cliniques chez ces derniers.

Acute respiratory distress syndrome in patients with COVID-19 vs. Non-COVID-19: clinical characteristics and outcomes in a tertiary care setting in Mexico City.

BACKGROUND: Acute Respiratory Distress Syndrome (ARDS) due tocoronavirus disease (COVID-19) infection has a unique phenotype generating a growing need to determine the existing differences that can alter existing evidence-based management strategies for ARDS. RESEARCH QUESTION: What differences does the clinical profile of patients with ARDS due to COVID 19 and Non-COVID 19 have? STUDY DESIGN AND METHODS: We conducted a comparative, observational, retrospective study in the Intensive Care Unit (ICU)of a third-level hospital in Mexico City, from March 2020 through March 2022. Clinical, echocardiographic, and laboratory variables were compared between patients with ARDS due to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and those due to other etiologies. RESULTS: We enrolled 140 patients with a diagnosis of ARDS. The study group of COVID-19 etiology were younger males, higher body mass index, progressed to organ dysfunction, required more frequently renal replacement therapy, and higher SOFA score. There was no difference in rates of right ventricular dysfunction. INTERPRETATION: COVID-19 ARDS exhibit much greater severity that led to higher admission and mortality rates, whilst being younger and less comorbid.

Assessing the venous system: Correlation of mean systemic filling pressure with the venous excess ultrasound grading system in cardiac surgery.

BACKGROUND: Evaluation of the venous system has long been underestimated as an important component of the circulatory system. As systemic venous pressure increases, the perfusion pressure to the tissues is compromised. During initial resuscitation in cardiac surgery, excessive fluid administration is associated with increased morbidity and mortality. METHODS: We conducted a cross-sectional study of 60 consecutive adult patients who underwent cardiac surgery and in whom it was possible to obtain the venous excess ultrasound (VExUS) grading system and mean systemic filling pressure (Pmsf) in the postoperative period upon admission, at 24 and 48 h. We then determined the correlation between VExUS grading and Pmsf. RESULTS: On admission, patients with VExUS grading 0 predominated, with a progressive increase in venous congestion and an increase in Pmsf over the course of the first 48 h. There was a strong positive correlation between VExUS grading and the invasive measurement of Pmsf at 24 and 48 h after arrival. The presence of grade 2 or grade 3 venous congestion in the postoperative period poses an increased risk of developing acute kidney injury. CONCLUSION: The VExUS grading system indicates a high degree of systemic venous congestion in the first 48 h of the postoperative period after cardiac surgery and correlates with the Pmsf, which is the best surrogate of stressed circulatory volume.

Hypertrophic cardiomyopathy in the systemic right ventricle in a patient with congenitally corrected transposition of the great arteries: A case report.

Congenitally corrected transposition of the great arteries is a rare clinical entity, which usually presents during adulthood with associated defects; atrioventricular block, heart failure, systemic valve failure, and arrhythmias usually complicate the clinical course. Even rarer is associated hypertrophic cardiomyopathy, which complicates the disease course and clinical decision-making. Herein, we present a patient with this condition who underwent heart transplantation, with adequate clinical resolution.

Usefulness of the velocity-time integral of the left ventricular outflow tract variability index to predict fluid responsiveness in patients undergoing cardiac surgery.

BACKGROUND: Haemodynamic monitoring of patients after cardiac surgery using echocardiographic evaluation of fluid responsiveness is both challenging and increasingly popular. We evaluated fluid responsiveness in the first hours after surgery by determining the variability of the velocity-time integral of the left ventricular outflow tract (VTI-LVOT). METHODS: We conducted a cross-sectional study of 50 consecutive adult patients who underwent cardiac surgery and in whom it was possible to obtain VTI-LVOT measurements. We then determined the variability and correlations with our pulse pressure variation (PPV) measurements to predict fluid responsiveness. RESULTS: A strong positive correlation was seen between the VTI-LVOT variability index absolute values and PPV for predicting fluid responsiveness in the first hours after cardiac surgery. We also found that the VTI-LVOT variability index has high specificity and a high positive likelihood ratio compared with the gold standard using a cut-off point of ≥ 12%. CONCLUSIONS: The VTI-LVOT variability index is a valuable tool for determining fluid responsiveness during the first 6 postoperative hours in patients undergoing cardiac surgery.

Senotherapeutic peptide treatment reduces biological age and senescence burden in human skin models.

Cellular senescence is known to play a role in age-related skin function deterioration which potentially influences longevity. Here, a two-step phenotypic screening was performed to identify senotherapeutic peptides, leading to the identification of Peptide (Pep) 14. Pep 14 effectively decreased human dermal fibroblast senescence burden induced by Hutchinson-Gilford Progeria Syndrome (HGPS), chronological aging, ultraviolet-B radiation (UVB), and etoposide treatment, without inducing significant toxicity. Pep 14 functions via modulation of PP2A, an understudied holoenzyme that promotes genomic stability and is involved in DNA repair and senescence pathways. At the single-cell level, Pep 14 modulates genes that prevent senescence progression by arresting the cell cycle and enhancing DNA repair, which consequently reduce the number of cells progressing to late senescence. When applied on aged ex vivo skin, Pep 14 promoted a healthy skin phenotype with structural and molecular resemblance to young ex vivo skin, decreased the expression of senescence markers, including SASP, and reduced the DNA methylation age. In summary, this work shows the safe reduction of the biological age of ex vivo human skins by a senomorphic peptide.

The third vaccine dose significantly reduces susceptibility to the B.1.1.529 (Omicron) SARS-CoV-2 variant.

The main coronavirus disease 2019 (COVID-19) vaccine formulations used today are mainly based on the wild-type severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein as an antigen. However, new virus variants capable of escaping neutralization activity of serum antibodies elicited in vaccinated individuals have emerged. The Omicron (B.1.1.529) variant caused epidemics in regions of the world in which most of the population has been vaccinated. In this study, we aimed to understand what determines individual's susceptibility to Omicron in a scenario of extensive vaccination. For that purpose, we collected nasopharynx swab (n = 286) and blood samples (n = 239) from flu-like symptomatic patients, as well as their vaccination history against COVID-19. We computed the data regarding vaccine history, COVID-19 diagnosis, COVID-19 serology, and viral genome sequencing to evaluate their impact on the number of infections. As main results, we showed that vaccination in general did not reduce the number of individuals infected by Omicron, even with an increased immune response found among vaccinated, noninfected individuals. Nonetheless, we found that individuals who received the third vaccine dose showed significantly reduced susceptibility to Omicron infections. A relevant evidence that support this finding was the higher virus neutralization capacity of serum samples of most patients who received the third vaccine dose. In summary, this study shows that boosting immune responses after a third vaccine dose reduces susceptibility to COVID-19 caused by the Omicron variant. Results presented in this study are useful for future formulations of COVID-19 vaccination policies.

In vitro and in vivo toxicity assessment of the senotherapeutic Peptide 14.

Senotherapeutic molecules decrease cellular senescence burden, constituting promising approaches to combat the accumulation of senescent cells observed in chronological aging and age-related diseases. Numerous molecules have displayed senotherapeutic potential, but toxicity has been frequently observed. Recently, a new senotherapeutic compound, Peptide 14, was developed to modulate cellular senescence in the skin. In order to assess the potential toxic and genotoxic effects of the peptide, we observed the viability of human primary dermal fibroblasts and epidermal keratinocytes with Peptide 14 treatment, and show that it is mostly non-toxic in concentrations up to 100 µM. Cancer lines were also used to investigate its potential of modulating proliferation. Different concentrations of the peptide promoted a discrete reduction in the proliferation of cancerous cells of the MeWo and HeLa lineages. In full-thickness human skin equivalents, topically formulated Peptide 14 also failed to exert any significant irritation, nor cellular toxicity when added to the culture media. Genotoxic assays including the Ames, micronucleus, and karyotyping tests also indicate the safety of the peptide. Finally, the irritative potential of the peptide was assessed in human subjects in a repeated insult patch test executed using 1 mM peptide. No visible skin reactions were observed in any of the 54 participants. Taken together, the present data support that Peptide 14 is a senotherapeutic molecule with a positive safety profile as tested with cruelty-free models, justifying further studies involving the peptide.

Stent en una fístula sistémico-pulmonar de Blalock-Taussig modificada en un adulto paliado con atresia tricúspide con estenosis infundibular pulmonar crítica / Stenting of a modified Blalock-Taussig shunt in an adult with palliated tricuspid atresia and critical pulmonary stenosis

Resumen: Los adultos con cardiopatía congénita compleja, con fisiología univentricular y flujo pulmonar disminuido, constituyen un reto terapéutico. Muchos de ellos reciben tratamiento paliativo con fístula sistémico-pulmonar desde la etapa pediátrica. Dicha fístula puede presentar oclusión o estenosis y ocasionar deterioro de la capacidad funcional y clínica. Colocar una nueva fístula sistémico-pulmonar a través de una cirugía se considera de alto riesgo, por lo que el uso de stents a través de cateterismo cardíaco surge como una opción que ha tenido buenos resultados. Se describe el caso de un adulto con atresia tricúspide con fístula sistémico-pulmonar en la etapa pediátrica, quien acudió al servicio de urgencias por deterioro de su clase funcional y desaturación en aire ambiente de hasta un 64%; en la tomografía cardíaca se evidenció estenosis del tercio distal de la fístula sistémico-pulmonar, por lo que se decidió colocar, mediante cateterismo cardíaco intervencionista, dos stents (Express LD vascular 6 x 37 mm y 6 x 27 mm), luego de lo cual la saturación sistémica fue del 75%, por lo que se consideró exitosa la colocación de los dispositivos. La oclusión de estas fístulas es una complicación habitual, que genera disminución de la perfusión pulmonar con los subsecuentes síntomas respiratorios, disminución de la saturación y la oxigenación, cianosis y acidosis metabólica, y puede generar un evento que amenaza la vida si se presenta de manera aguda. La recanalización transcatéter de una fístula sistémico-pulmonar con stent es una alternativa adecuada para evitar un riesgo quirúrgico y arroja resultados óptimos.

Abstract: Adults with complex congenital heart disease with univentricular physiology and decreased in the pulmonary flow constitute a therapeutic challenge, many of these patients are palliated with modified Blalock-Taussig shunt (mBTS). The mBTS can develop occlusion or stenosis over time with deterioration of functional class and poor exercise tolerance. Dysfunction of a mBTS is a life-threatening situation requiring urgent therapy. A new surgical palliation is a high-risk procedure, so stenting a mBTS can be an alternative. We report a 29-year-old female with tricuspid atresia and pulmonary infundibular stenosis palliated with mBTS with progressive cyanosis (oxygen saturation of 54%) and dyspnea; computed tomography revealed a stenosed mBTS, and an interventional percutaneous approach was made. The stenting of the mBTS was made with two stents (Express LD vascular 6 x 37 mm and 6 x 27 mm). Oxygen saturation post-procedure increase to 70-75%. Occlusion of these shunts are a common major complication, leading to a decrease in pulmonary perfusion with subsequent respiratory symptoms, low saturation and oxygenation, cyanosis, metabolic acidosis and can generate a life-threatening event if it occurs acutely. Stent implantation into a previous mBTS through cardiac catheterization can be an alternative to shunt operation in patients with cyanotic congenital heart disease having a good long-term results.

Molecular-Modified Photocathodes for Applications in Artificial Photosynthesis and Solar-to-Fuel Technologies.

Nature offers inspiration for developing technologies that integrate the capture, conversion, and storage of solar energy. In this review article, we highlight principles of natural photosynthesis and artificial photosynthesis, drawing comparisons between solar energy transduction in biology and emerging solar-to-fuel technologies. Key features of the biological approach include use of earth-abundant elements and molecular interfaces for driving photoinduced charge separation reactions that power chemical transformations at global scales. For the artificial systems described in this review, emphasis is placed on advancements involving hybrid photocathodes that power fuel-forming reactions using molecular catalysts interfaced with visible-light-absorbing semiconductors.

Evaluating the Immediate Impact of Graphic Messages for Vaping Prevention among Black and Latino Adolescents: A Randomized Controlled Trial.

The purpose of this pilot study was to assess the immediate impact of vaping prevention graphic messages on the susceptibility to future vaping among Black and Latino adolescents (ages 12 to 17). Graphic messages (available in English and Spanish) were developed using participatory research procedures with Black and Latino adolescents. Recruitment was conducted by a team of diverse, bilingual (English and Spanish), trained recruiters. Participants (n = 362) were randomized in a 1:1:1:1 schema to receive one of four graphic messages (health rewards, financial rewards, autonomy, and social norms). Overall, all graphic messages but one showed a slight decrease in the number of participants susceptible to future vaping, though none of these differences was statistically significant. The graphic message on health rewards decreased the number of participants susceptible to future vaping the most (55.7% vs. 50%, at pre- vs. post-viewing, p = 0.125), followed by the graphic messages on social norms and autonomy (55.1% vs. 52.8%, p = 0.687; 55.4% vs. 52.2%, p = 0.435; respectively). The graphic message on financial rewards increased the number of participants susceptible to future vaping slightly (52.7% vs. 53.8%, p = 1.00). Future research is needed to evaluate susceptibility to future vaping before and after exposure to different and/or repeated vaping prevention graphic messages.

Managing the Redox Potential of PCET in Grotthuss-Type Proton Wires.

Expanding proton-coupled electron transfer to multiproton translocations (MPCET) provides a bioinspired mechanism to transport protons away from the redox site. This expansion has been accomplished by separating the initial phenolic proton donor from the pyridine-based terminal proton acceptor by a Grotthuss-type proton wire made up of concatenated benzimidazoles that form a hydrogen-bonded network. However, it was found that the midpoint potential of the phenol oxidation that launched the Grotthuss-type proton translocations is a function of the number of benzimidazoles in the hydrogen-bonded network; it becomes less positive (i.e., a weaker oxidant) as the number of bridging benzimidazoles increases. Herein, we report a strategy to maintain the high redox potential necessary for oxidative processes relevant to artificial photosynthesis, e.g., water oxidation and long-range MPCET processes for managing protons. The integrated structural and functional roles of the benzimidazole-based bridge provide sites for substitution of the benzimidazoles with electron-withdrawing groups (e.g., trifluoromethyl groups). Such substitution increases the midpoint potential of the phenoxyl radical/phenol couple so that proton translocations over ∼11 Å become thermodynamically comparable to that of an unsubstituted system where one proton is transferred over ∼2.5 Å. The extended, substituted system maintains the hydrogen-bonded network; infrared spectroelectrochemistry confirms reversible proton translocations from the phenol to the pyridyl terminal proton acceptor upon oxidation and reduction. Theory supports the change in driving force with added electron-withdrawing groups and provides insight into the role of electron density and electrostatic potential in MPCET processes associated with these Grotthuss-type proton translocations.

Focused Transesophageal Echocardiography in Critical Care: The COVID-19 Pandemic.

Background: The use of transesophageal echocardiography (TEE) is controversial in patients with COVID-19. The aim of this case series was to demonstrate the usefulness of transesophageal echocardiography in acute cardiovascular care settings in patients with COVID-19 infection. Materials and Methods: We enrolled 13 patients with confirmed SARS-CoV-2 infection admitted to the critical care unit of our center from April 1, 2020, to July 30, 2020, in which transesophageal echocardiography was performed. TOE was performed by three cardiologists with training in echocardiography. Results: The main indication was suspected infective endocarditis in four cases, venovenous extracorporeal membrane oxygenation cannulation in four cases, suspected prosthetic mitral valve dysfunction in two patients, suspected pulmonary embolism in two patients, and acute right ventricular dysfunction and prone position ventilation in one patient. The final diagnosis was confirmed in 11 patients and discarded in 2 patients. None of the operators result infected. Conclusions: TOE is safe in the context of COVID-19 infection; it must be performed in well-selected cases and in a targeted manner.

Concerted Electron-Nuclear Motion in Proton-Coupled Electron Transfer-Driven Grotthuss-Type Proton Translocation.

Photoinduced proton-coupled electron transfer and long-range two-proton transport via a Grotthuss-type mechanism are investigated in a biomimetic construct. The ultrafast, nonequilibrium dynamics are assessed via two-dimensional electronic vibrational spectroscopy, in concert with electrochemical and computational techniques. A low-frequency mode is identified experimentally and found to promote double proton and electron transfer, supported by recent theoretical simulations of a similar but abbreviated (non-photoactive) system. Excitation frequency peak evolution and center line slope dynamics show direct evidence of strongly coupled nuclear and electronic degrees of freedom, from which we can conclude that the double proton and electron transfer processes are concerted (up to an uncertainty of 24 fs). The nonequilibrium pathway from the photoexcited Franck-Condon region to the E2PT state is characterized by an ∼110 fs time scale. This study and the tools presented herein constitute a new window into hot charge transfer processes involving an electron and multiple protons.