Dynamics of Single-Chain Nanoparticles under Crowding: A Neutron Spin Echo Study.

We present a neutron spin echo (NSE) investigation to examine the impact of macromolecular crowding on the dynamics of single-chain nanoparticles (SCNPs), serving as synthetic models for biomacromolecules with flexibility and internal degrees of freedom, such as intrinsically disordered proteins (IDPs). In particular, we studied the dynamics of a medium-size poly(methyl methacrylate) (PMMA)-based SCNP (33 kDa) in solutions with low- (10 kDa) and high- (100 kDa) molecular weight analogous deuterated PMMA linear crowders. The dynamic structure factors of the SCNPs in dilute solution show certain degrees of freedom, yet the analysis in terms of the Zimm model reveals high internal friction that effectively stiffens the chain-a phenomenon also observed for IDPs. Under crowding conditions, the internal dynamics remains essentially unchanged, but the center-of-mass diffusion slows down. The effective viscosity felt by the SCNPs at the timescales probed by NSE is lower than the macroscopic viscosity of the crowder solution, and it does not depend significantly on the molecular weight.

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.

Microscopic Evidence for the Topological Transition in Model Vitrimers.

In addition to the glass transition, vitrimers undergo a topological transition from viscoelastic liquid to viscoelastic solid behavior when the network rearrangements facilitated by dynamic bond exchange reactions freeze. The microscopic observation of this transition is elusive. Model polyisoprene vitrimers based on imine dynamic covalent bonds were synthesized by reaction of α,ω-dialdehyde-functionalized polyisoprenes and a tris(2-aminoethyl)amine. In these dynamic networks nanophase separation of polymer and reactive groups leads to the emergence of a relevant length scale characteristic for the network structure. We exploited the scattering sensitivity to structural features at different length scales to determine how dynamical and topological arrests affect correlations at segmental and network levels. Chains expand obeying the same expansion coefficient throughout the entire viscoelastic region, i.e., both in the elastomeric regime and in the liquid regime. The onset of liquid-like behavior is only apparent at the mesoscale, where the scattering reveals the reorganization of the network triggered by bond exchange events. The such determined "microscopic" topological transition temperature is compared with the outcome of "conventional" methods, namely viscosimetry and differential scanning calorimetry. We show that using proper thermal (aging-like) protocols, this transition is also nicely revealed by the latter.

Cardiac Laterality: Surgical Results of Right Atrial Isomerism.

Right atrial isomerism (RAI) is a complex entity with varying diagnostic and treatment outcomes due to its rarity. Treatment options range from palliative to corrective surgeries, resulting in heterogeneous outcomes. The aim of this study was to analyze the results obtained after cardiac surgery in patients with RAI. A retrospective study was conducted, including patients diagnosed with RAI who underwent cardiac surgery. Their follow-up was from 1 January 2010 to 31 March 2020. Demographic characteristics and perioperative conditions were described. Thirty-eight patients were included, the median age was 4 years (IQR 2-9.2) and 57.9% were men. The main diagnoses were atrioventricular canal (63.2%) and pulmonary stenosis (55.3%). The most common surgical procedures were modified Blalock-Taussig shunt (65.8%) and total cavopulmonary connection with an extracardiac conduit fenestrated without cardiopulmonary bypass (15.9%). We did not find any factors associated with negative outcomes in these patients. The overall survival was 86.8%, with a better outcome in those who did not require reintubation (log rank, p < 0.01). The survival of RAI was similar to other centers. Individuals with RAI should be evaluated rigorously to determine an adequate repair strategy, considering high morbidity and mortality.

Structure of Single-Chain Nanoparticles under Crowding Conditions: A Random Phase Approximation Approach.

The conformation of poly(methyl methacrylate) (PMMA)-based single-chain nanoparticles (SCNPs) and their corresponding linear precursors in the presence of deuterated linear PMMA in deuterated dimethylformamide (DMF) solutions has been studied by small-angle neutron scattering (SANS). The SANS profiles were analyzed in terms of a three-component random phase approximation (RPA) model. The RPA approach described well the scattering profiles in dilute and crowded solutions. Considering all the contributions of the RPA leads to an accurate estimation of the single chain form factor parameters and the Flory-Huggins interaction parameter between PMMA and DMF. The value of the latter in the dilute regime indicates that the precursors and the SCNPs are in good solvent conditions, while in crowding conditions, the polymer becomes less soluble.

The Debye's model for the dielectric relaxation of liquid water and the role of cross-dipolar correlations. A MD-simulations study.

By means of massive (more than 1.2 · 106 molecules) molecular dynamics simulations at 300 K we have disentangled self- and cross-dipolar contributions to the dielectric relaxation of liquid water that cannot be experimentally resolved. We have demonstrated that cross dipolar correlations are of paramount importance. They amount for almost a 60% of the total dielectric amplitude. The corresponding relaxation function is a one-step Debye-like function with a characteristic time, τcross, of the order of the phenomenological Debye time, τD. In contrast, the relaxation function corresponding to the self-contribution is rather complex and contains a fast decay related to dipolar librations and a second relaxation step that can be well described by two exponentials: a low-amplitude fast process (τ0 = 0.31 ps) and a main slow process (τself = 5.4 ps) that fully randomizes the dipolar orientation. In addition to dipolar relaxation functions, we have also calculated scattering-like magnitudes characterizing translation and rotation of water molecules. Although these processes can be considered as "jump" processes in the short time range, at the time scale of about τD-τcross, at which the cross-dipolar correlations decay to zero, the observed behavior cannot be distinguished from that corresponding to uncoupled Brownian translational and rotational diffusion. We propose that this is the reason why the Debye model, which does not consider intermolecular dipolar interactions, seems to work at time t ≳ τD.

Abordaje terapéutico de cardiopatías congénitas en el síndrome de Down / Congenital heart disease in Down's syndrome

Resumen Antecedentes: El síndrome de Down es la anomalía cromosómica más frecuente y se asocia con defectos cardiacos congénitos, elementos clínicos de una alta morbilidad y mortalidad infantil. Objetivo: Describir los desenlaces clínicos de los pacientes con síndrome de Down sometidos a cirugía e intervencionismo como tratamiento de las cardiopatías congénitas en esta institución. Material y métodos: Estudio retrospectivo que incluyó pacientes menores de 18 años con síndrome de Down y patología cardiaca asociada durante los últimos 10 años. Las variables estudiadas fueron: peso, talla, sexo, edad, tipo de cardiopatía, procedimiento correctivo, tiempo de estancia intrahospitalaria y en unidad de terapia intensiva, morbilidad y mortalidad. Resultados: 368 pacientes pediátricos fueron llevados a corrección quirúrgica o intervencionista, de los cuales 197 (54%) pertenecían al sexo femenino, la mediana de edad fue de 24 meses (rango intercuartílico [RIQ]: 14-48) en el grupo quirúrgico y de 36 meses (RIQ: 17-85) en el intervencionista. Las cardiopatías congénitas más frecuentes fueron: persistencia del conducto arterioso (31%), comunicación interventricular (28%), canal atrioventricular (CAV) (20%), comunicación interauricular (16%) y tetralogía de Fallot con el 4% respectivamente. La estancia hospitalaria fue de 9 días (RIQ: 7-15) en el grupo quirúrgico y de 3 días (RIQ: 2-5) en el hemodinámico. Las morbilidades fueron infección postoperatoria en 30 pacientes (14%) y en 19 pacientes (9%) bloqueo atrioventricular completo. La mortalidad global incluyendo tanto el quirúrgico como el intervencionista fue del 2%. Conclusiones: Los resultados terapéuticos, quirúrgicos e intervencionistas, en los niños con síndrome de Down y cardiopatías congénitas han mejorado en forma muy satisfactoria. Es de destacar la menor prevalencia del CAV en la población mexicana. Es indispensable realizar evaluación cardiológica a los niños con síndrome de Down y aquellos con cardiopatías congénitas llevarlos a corrección de manera oportuna para favorecer la sobrevida y calidad de vida.

Abstract Background: Down syndrome is the most common chromosomal abnormality, it is associated with a wide variety of congenital heart defects, being considered as clinical elements of high infant morbidity and mortality. Objective: To describe the clinical outcomes of patients with Down syndrome undergoing surgery and interventionism as treatment for congenital heart disease at this Institution. Material and methods: 368 patients with Down syndrome and associated congenital heart disease were diagnosed. The variables studied were weight, stature, sex, age, type of heart disease, corrective procedure, length of stay in the hospital and intensive care unit, morbidity and mortality. Results: 368 pediatric patients underwent surgical or interventional correction. Of which 197 (54%) were female, the median age was 24 months (interquartile range [IQR]: 14-48) in the surgical group and 36 months (IQR: 17-85) in the interventional group. The most frequent congenital heart diseases were: PCA (31%), IVC (28%), CAV (20%), ASD (16%) and tetralogy of Fallot with 4% respectively. Hospital stay was 9 days (IQR: 7-15) in the surgical group and 3 days (IQR: 2-5) in the hemodynamic group. Morbidities were postoperative infection in 30 patients (14%) and complete atrioventricular block in 19 patients (9%). Overall mortality including both surgical and interventional was 2%. Conclusions: The therapeutic, surgical and interventional results in children with Down syndrome and congenital heart disease have improved very satisfactorily. The lower prevalence of the atrioventricular canal in the Mexican population is noteworthy. It is essential to carry out a cardiological evaluation of children with Down syndrome and those with congenital heart disease to correct them in a timely manner to promote survival and quality of life.

Pulmonary arterial hypertension in children with congenital heart disease: a deeper look into the role of endothelial progenitor cells and circulating endothelial cells to assess disease severity.

Endothelial progenitor cells and circulating endothelial cells have been proposed as useful markers of severity and disease progression in certain vascular diseases, including pulmonary arterial hypertension. Our study focused on evaluating the levels of circulating endothelial progenitor cells and circulating endothelial cells in patients with congenital left-to-right shunts and pulmonary hypertension undergoing definitive repair. Endothelial progenitor cells (identified by simultaneous co-expression of CD45dim, CD34 + and KDR2 + surface antibodies) and circulating endothelial cells (identified by simultaneous co-expression of inherent antibodies CD45-, CD31+, CD146 + and CD105+) were prospectively measured in seventy-four children (including children with Down syndrome), median age six years (2.75-10), with clinically significant left-to-right shunts undergoing transcatheter or surgical repair and compared to thirty healthy controls. Endothelial progenitor cells and, particularly, circulating endothelial cells were significantly higher in children with heart disease and pulmonary arterial hypertension when compared to controls. Endothelial progenitor cells showed significant correlation with pulmonary vascular resistance index when measured both systemically (r = 0.259; p = 0.026) and in the superior vena cava (r = 0.302; p = 0.009). Children with Down syndrome showed a stronger correlation between systemic cellularity and pulmonary vascular resistance index (r = 0.829; p = 0.002). Endothelial progenitor cells were reduced along their transit through the lung, whereas circulating endothelial cells did not suffer any modification across the pulmonary circulation. In children with yet to be repaired left-to-right shunts, endothelial progenitor cells and circulating endothelial cell counts are increased compared to healthy subjects.

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.

Collective dynamics and self-motions in the van der Waals liquid tetrahydrofuran from meso- to inter-molecular scales disentangled by neutron spectroscopy with polarization analysis.

By using time-of-flight neutron spectroscopy with polarization analysis, we have separated coherent and incoherent contributions to the scattering of deuterated tetrahydrofuran in a wide scattering vector (Q)-range from meso- to inter-molecular length scales. The results are compared with those recently reported for water to address the influence of the nature of inter-molecular interactions (van der Waals vs hydrogen bond) on the dynamics. The phenomenology found is qualitatively similar in both systems. Both collective and self-scattering functions are satisfactorily described in terms of a convolution model that considers vibrations, diffusion, and a Q-independent mode. We observe a crossover in the structural relaxation from being dominated by the Q-independent mode at the mesoscale to being dominated by diffusion at inter-molecular length scales. The characteristic time of the Q-independent mode is the same for collective and self-motions and, contrary to water, faster and with a lower activation energy (≈1.4 Kcal/mol) than the structural relaxation time at inter-molecular length scales. This follows the macroscopic viscosity behavior. The collective diffusive time is well described by the de Gennes narrowing relation proposed for simple monoatomic liquids in a wide Q-range entering the intermediate length scales, in contraposition to the case of water.

Replacement of Obstructed Right Ventricle to Pulmonary Artery Conduits: The Modified Peel Operation.

Reconstruction of the right outflow tract with extracardiac conduits has made complete repair of complex cardiac malformations possible. However, reoperation is usually required for a right ventricle-to-pulmonary artery conduit obstruction. We describe a modified peel operation, where the sides and posterior half of the previously placed conduit are preserved, and a prosthetic roof is placed over the conduit remnant. This has been our current technique to manage conduit obstructions. It is a safe operation and to teach residents. This review aims to convey the technical details of each step of this technique.

Microscopic versus Macroscopic Glass Transitions and Relevant Length Scales in Mixtures of Industrial Interest.

We have combined X-ray diffraction, neutron diffraction with polarization analysis, small-angle neutron scattering (SANS), neutron elastic fixed window scans (EFWS), and differential scanning calorimetry (DSC) to investigate polymeric blends of industrial interest composed by isotopically labeled styrene-butadiene rubber (SBR) and polystyrene (PS) oligomers of size smaller than the Kuhn length. The EFWS are sensitive to the onset of liquid-like motions across the calorimetric glass transition, allowing the selective determination of the "microscopic" effective glass transitions of the components. These are compared with the "macroscopic" counterparts disentangled by the analysis of the DSC results in terms of a model based on the effects of thermally driven concentration fluctuations and self-concentration. At the microscopic level, the mixtures are dynamically heterogeneous for blends with intermediate concentrations or rich in PS, while the sample with highest content of the fast SBR component looks as dynamically homogeneous. Moreover, the combination of SANS and DSC has allowed determining the relevant length scale for the α-relaxation through its loss of equilibrium to be ≈30 Å. This is compared with the different characteristic length scales that can be identified in these complex mixtures from structural, thermodynamical, and dynamical points of view because of the combined approach followed. We also discuss the sources of the non-Gaussian effects observed for the atomic displacements and the applicability of a Lindemann-like criterion in these materials.

Epigenetic Evaluation of the TBX20 Gene and Environmental Risk Factors in Mexican Paediatric Patients with Congenital Septal Defects.

The TBX20 gene has a key role during cardiogenesis, and it has been related to epigenetic mechanisms in congenital heart disease (CHD). The purpose of this study was to assess the association between DNA methylation status and congenital septal defects. The DNA methylation of seven CpG sites in the TBX20 gene promoter was analyzed through pyrosequencing as a quantitative method in 48 patients with congenital septal defects and 104 individuals with patent ductus arteriosus (PDA). The average methylation was higher in patients than in PDA (p < 0.001). High methylation levels were associated with a higher risk of congenital septal defects (OR = 4.59, 95% CI = 1.57-13.44, p = 0.005). The ROC curve analysis indicated that methylation of the TBX20 gene could be considered a risk marker for congenital septal defects (AUC = 0.682; 95% CI = 0.58-0.77; p < 0.001). The analysis of environmental risk factors in patients with septal defects and PDA showed an association between the consumption of vitamins (OR = 0.10; 95% CI = 0.01-0.98; p = 0.048) and maternal infections (OR = 3.10; 95% CI = 1.26-7.60; p = 0.013). These results suggest that differences in DNA methylation of the TBX20 gene can be associated with septal defects.

[Congenital heart disease in Down's syndrome]. / Abordaje terapéutico de cardiopatías congénitas en el síndrome de Down.

Background: Down syndrome is the most common chromosomal abnormality, it is associated with a wide variety of congenital heart defects, being considered as clinical elements of high infant morbidity and mortality. Objective. Objective: To describe the clinical outcomes of patients with Down syndrome undergoing surgery and interventionism as treatment for congenital heart disease at this Institution. Material and methods: 368 patients with Down syndrome and associated congenital heart disease were diagnosed. The variables studied were weight, stature, sex, age, type of heart disease, corrective procedure, length of stay in the hospital and intensive care unit, morbidity and mortality. Results: 368 pediatric patients underwent surgical or interventional correction. Of which 197 (54%) were female, the median age was 24 months (interquartile range [IQR]: 14-48) in the surgical group and 36 months (IQR: 17-85) in the interventional group. The most frequent congenital heart diseases were: PCA (31%), IVC (28%), CAV (20%), ASD (16%) and tetralogy of Fallot with 4% respectively. Hospital stay was 9 days (IQR: 7-15) in the surgical group and 3 days (IQR: 2-5) in the hemodynamic group. Morbidities were postoperative infection in 30 patients (14%) and complete atrioventricular block in 19 patients (9%). Overall mortality including both surgical and interventional was 2%. Conclusions: The therapeutic, surgical and interventional results in children with Down syndrome and congenital heart disease have improved very satisfactorily. The lower prevalence of the atrioventricular canal in the Mexican population is noteworthy. It is essential to carry out a cardiological evaluation of children with Down syndrome and those with congenital heart disease to correct them in a timely manner to promote survival and quality of life.

Antecedentes: El síndrome de Down es la anomalía cromosómica más frecuente y se asocia con defectos cardiacos congénitos, elementos clínicos de una alta morbilidad y mortalidad infantil. Objetivo: Describir los desenlaces clínicos de los pacientes con síndrome de Down sometidos a cirugía e intervencionismo como tratamiento de las cardiopatías congénitas en esta institución. Material y métodos: Estudio retrospectivo que incluyó pacientes menores de 18 años con síndrome de Down y patología cardiaca asociada durante los últimos 10 años. Las variables estudiadas fueron: peso, talla, sexo, edad, tipo de cardiopatía, procedimiento correctivo, tiempo de estancia intrahospitalaria y en unidad de terapia intensiva, morbilidad y mortalidad. Resultados: 368 pacientes pediátricos fueron llevados a corrección quirúrgica o intervencionista, de los cuales 197 (54%) pertenecían al sexo femenino, la mediana de edad fue de 24 meses (rango intercuartílico [RIQ]: 14-48) en el grupo quirúrgico y de 36 meses (RIQ: 17-85) en el intervencionista. Las cardiopatías congénitas más frecuentes fueron: persistencia del conducto arterioso (31%), comunicación interventricular (28%), canal atrioventricular (CAV) (20%), comunicación interauricular (16%) y tetralogía de Fallot con el 4% respectivamente. La estancia hospitalaria fue de 9 días (RIQ: 7-15) en el grupo quirúrgico y de 3 días (RIQ: 2-5) en el hemodinámico. Las morbilidades fueron infección postoperatoria en30 pacientes (14%) y en 19 pacientes (9%) bloqueo atrioventricular completo. La mortalidad global incluyendo tanto el quirúrgico como el intervencionista fue del 2%. Conclusiones: Los resultados terapéuticos, quirúrgicos e intervencionistas, enlos niños con síndrome de Down y cardiopatías congénitas han mejorado en forma muy satisfactoria. Es de destacar lamenor prevalencia del CAV en la población mexicana. Es indispensable realizar evaluación cardiológica a los niños consíndrome de Down y aquellos con cardiopatías congénitas llevarlos a corrección de manera oportuna para favorecer la sobrevida y calidad de vida.

Prenatal Diagnosis and Outcome of Intrapericardial Teratoma: Report of Two Clinical Scenarios.

Intrapericardial teratoma is a rare tumor composed of tissue from the three germ cell layers with a rapid growth that may cause severe hemodynamic complications due to compressive effects. We present two clinical cases: the first case had severe fetal heart failure with fatal outcome, and the second underwent surgical treatment during the immediate postnatal period with a favorable evolution. Although teratomas are histologically benign tumors, rapid growth can cause serious hemodynamic complications. The importance of prenatal diagnosis is to allow appropriate monitoring of tumor growth and establish a prompt therapeutic plan. Opportune surgical treatment can prevent death and improve the prognosis of these patients.

Neat Protein Single-Chain Nanoparticles from Partially Denatured BSA.

The main challenge for the preparation of protein single-chain nanoparticles (SCNPs) is the natural complexity of these macromolecules. Herein, we report the suitable conditions to produce "neat" bovine serum albumin (BSA) single-chain nanoparticles (SCNPs) from partially denatured BSA, which involves denaturation in urea and intramolecular cross-linking below the overlap concentration. We use two disuccinimide ester linkers containing three and six methylene spacer groups: disuccinimidyl glutarate (DSG) and disuccinimidyl suberate (DSS), respectively. Remarkably, the degree of internal cross-linking can be followed simply and efficiently via 1H NMR spectroscopy. The associated structural changes-as probed by small-angle neutron scattering (SANS)-reveal that the denatured protein has a random-like coil conformation, which progressively shrinks with the addition of DSG or DSS, thus allowing for size control of the BSA-SCNPs with radii of gyration down to 5.4 nm. The longer cross-linker exhibits slightly more efficiency in chain compaction with a somewhat stronger size reduction but similar reactivity at a given cross-linker concentration. This reliable method is applicable to a wide range of compact proteins since most proteins have appropriate reactive amino acids and denature in urea. Critically, this work paves the way to the synthesis of "neat", biodegradable protein SCNPs for a range of applications including nanomedicine.

Surgical outcomes among children with bicuspid aortic valve: 17 years of experience in a single center. First report in Mexico.

PURPOSE: To evaluate the clinical and surgical outcomes among children with bicuspid aortic valve who underwent cardiac surgery. METHODS: This observational and retrospective study included patients with a diagnosis of bicuspid aortic valve who underwent cardiac surgery between January 1, 2003, and March 31, 2020. Demographic characteristics and perioperative conditions were described. RESULTS: One hundred and sixteen patients were included, with a mean age of 12.4 ± 4.2 years; 63.2% were male. The most frequent diagnosis was congenital aortic stenosis (23.5%), followed by connective tissue disorders (16%). Mechanical aortic prostheses were used in 87.7% of cases, with a mean size of 21 ± 2.6 mm. The main factors associated with mortality were valve prosthesis dysfunction (odds ratio [OR]: 12.44; 95% confidence interval [CI]: 1.05-147.48; p = .04) and reoperation (OR: 24.29; 95% CI: 1.03-570.08; p = .04). The overall survival was 87.9%, with better outcomes among those who did not undergo reoperation (Log Rank, p = .01). CONCLUSIONS: Outcomes after aortic valve replacement in children with bicuspid aortic valve are excellent in the short and long term, regardless of using mechanical or biological prostheses.