Nerve Regeneration after a Nerve Graft in a Rat Model: The Effectiveness of Fibrin Glue.

BACKGROUND: Simulating the post-traumatic continuity defect of small human peripheral nerves, we compared the effectiveness of fibrin glue with neurorrhaphy for nerve gap restoration. METHODS: In twenty-four male Wistar rats, a fifteen mm defect in one sciatic nerve only was made and immediately repaired with an inverted polarity autograft. According to the used technique, rats were divided into Group A (Control), using traditional neurorrhaphy, and Group B (Study), using fibrine glue sealing; in total, 50% of rats were sacrificed at 16 weeks and 50% at 21 weeks. Before sacrifice, an assessment of motor function was done through Walking Track Analysis and an electroneurophysiological evaluation. After sacrifice, selected muscle mass indexes and the histology of the regenerated nerves were assessed. All data were evaluated by Student's t test for unpaired data. RESULTS: No significant differences were found between the two groups, with only the exception of a relative improvement in the tibialis anterior muscle's number of motor units in the study group. CONCLUSION: Despite the fact that the use of fibrin glue as a nerve sealant is not superior in terms of functional recovery, its effectiveness is comparable to that of microsurgical repair. Hence, the faster and technically easier glueing technique could deserve broader clinical application.

Evidence of Excited-State Vibrational Mode Governing the Photorelaxation of a Charge-Transfer Complex.

Modern, nonlinear, time-resolved spectroscopic techniques have opened new doors for investigating the intriguing but complex world of photoinduced ultrafast out-of-equilibrium phenomena and charge dynamics. The interaction between light and matter introduces an additional dimension, where the complex interplay between electronic and vibrational dynamics needs the most advanced theoretical-computational protocols to be fully understood on the molecular scale. In this study, we showcase the capabilities of ab initio molecular dynamics simulation integrated with a multiresolution wavelet protocol to carefully investigate the excited-state relaxation dynamics in a noncovalent complex involving tetramethylbenzene (TMB) and tetracyanoquinodimethane (TCNQ) undergoing charge transfer (CT) upon photoexcitation. Our protocol provides an accurate description that facilitates a direct comparison between transient vibrational analysis and time-resolved spectroscopic signals. This molecular level perspective enhances our understanding of photorelaxation processes confined in the adiabatic regime and offers an improved interpretation of vibrational spectra. Furthermore, it enables the quantification of anharmonic vibrational couplings between high- and low-frequency modes, specifically the TCNQ "rocking" and "bending" modes. Additionally, it identifies the primary vibrational mode that governs the adiabaticity between the ground state and the CT state. This comprehensive understanding of photorelaxation processes holds significant importance in the rational design and precise control of more efficient photovoltaic and sensor devices.

Tuning ultrafast time-evolution of photo-induced charge-transfer states: A real-time electronic dynamics study in substituted indenotetracene derivatives.

Photo-induced charge transfer (CT) states are pivotal in many technological and biological processes. A deeper knowledge of such states is mandatory for modeling the charge migration dynamics. Real-time time-dependent density functional theory (RT-TD-DFT) electronic dynamics simulations are employed to explicitly observe the electronic density time-evolution upon photo-excitation. Asymmetrically substituted indenotetracene molecules, given their potential application as n-type semiconductors in organic photovoltaic materials, are here investigated. Effects of substituents with different electron-donating characters are analyzed in terms of the overall electronic energy spacing and resulting ultrafast CT dynamics through linear response (LR-)TD-DFT and RT-TD-DFT based approaches. The combination of the computational techniques here employed provided direct access to the electronic density reorganization in time and to its spatial and rational representation in terms of molecular orbital occupation time evolution. Such results can be exploited to design peculiar directional charge dynamics, crucial when photoactive materials are used for light-harvesting applications.

Latissimus Dorsi Flap and Thoracodorsal Artery Perforator Flap with Immediate Fat Transfer (LIFT and TIFT): A Retrospective Study about Total Breast Reconstruction in High-Risk Patients.

INTRODUCTION: Microsurgical breast reconstruction has become popular over the past twenty years and allows a tailor-tuck approach to each patient. However, smoking or coagulation disorders may switch surgeon's choice towards alternative options. When facing these risk factors, we performed pedicled latissimus dorsi (LD) flap and thoracodorsal artery perforator (TDAP) flap reconstruction with immediate fat transfer (LIFT and TIFT), achieving satisfactory surgical outcomes. Hence, we aim to present our seven-years case-series and discuss our decisional algorithm. MATERIALS AND METHODS: Thirty smoker women and seven women affected by coagulation disorder (n = 37) respectively had LIFT and TIFT surgery and were retrospectively evaluated. Patients' demographics and outcomes were recorded and compared. RESULTS: LIFT patients received higher volumes of immediate fat grafting compared to TIFT patients (p < 0.05), which required additional lipofilling to provide adequate volume amount, since the TDAP flap was not immediately grafted. However, the additional lipofilling procedures and fat volume were similar (p > 0.05). Flap survival reached 100%, and flap necrosis or loss did not occur. Few minor complications were evidenced in the LIFT group only (p > 0.05). CONCLUSION: Based on our experience, we support the reliability of pedicled LD and TDAP flaps with immediate fat transfer in breast reconstruction as valuable alternative to microsurgery in smokers (LIFT) and patients with coagulation disorders (TIFT). However, the results of our study are not conclusive since still must be clarified the role of the smoking and coagulation disorders in microsurgery and the real benefit of a non-microsurgical procedure. LEVEL OF EVIDENCE IV: Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

An Expedited Route to Optical and Electronic Properties at Finite Temperature via Unsupervised Learning.

Electronic properties and absorption spectra are the grounds to investigate molecular electronic states and their interactions with the environment. Modeling and computations are required for the molecular understanding and design strategies of photo-active materials and sensors. However, the interpretation of such properties demands expensive computations and dealing with the interplay of electronic excited states with the conformational freedom of the chromophores in complex matrices (i.e., solvents, biomolecules, crystals) at finite temperature. Computational protocols combining time dependent density functional theory and ab initio molecular dynamics (MD) have become very powerful in this field, although they require still a large number of computations for a detailed reproduction of electronic properties, such as band shapes. Besides the ongoing research in more traditional computational chemistry fields, data analysis and machine learning methods have been increasingly employed as complementary approaches for efficient data exploration, prediction and model development, starting from the data resulting from MD simulations and electronic structure calculations. In this work, dataset reduction capabilities by unsupervised clustering techniques applied to MD trajectories are proposed and tested for the ab initio modeling of electronic absorption spectra of two challenging case studies: a non-covalent charge-transfer dimer and a ruthenium complex in solution at room temperature. The K-medoids clustering technique is applied and is proven to be able to reduce by ∼100 times the total cost of excited state calculations on an MD sampling with no loss in the accuracy and it also provides an easier understanding of the representative structures (medoids) to be analyzed on the molecular scale.

Electronic and Vibrational Manifold of Tetracyanoethylene-Chloronaphthalene Charge Transfer Complex in Solution: Insights from TD-DFT and Ab Initio Molecular Dynamics.

The interplay between light absorption and the molecular environment has a central role in the observed photophysics of a wide range of photoinduced chemical and biological phenomena. The understanding of the interplay between vibrational and electronic transitions is the focus of this work, since it can provide a rationale to tune the optical properties of charge transfer (CT) materials used for technological applications. A clear description of these processes poses a nontrivial challenge from both the theoretical and experimental points of view, where the main issue is how to accurately describe and probe drastic changes in the electronic structure and the ultrafast molecular relaxation and dynamics. In this work we focused on the intermolecular CT reaction that occurs upon photon absorption in a π-stacked model system in dichloromethane solution, in which the 1-chloronaphthalene (1ClN) acts as the electron donor and tetracyanoethylene (TCNE) is the electron acceptor. Density functional theory calculations have been carried out to characterize both the ground-state properties and more importantly the low-lying CT electronic transition, and excellent agreement with recently available experimental results [Mathies, R. A.; et al. J. Phys. Chem. A 2018, 122 (14), 3594] was obtained. The minima of the ground state and first singlet excited state have been accurately characterized in terms of spatial arrangements and vibrational Raman frequencies, and the CT natures of the first two low-lying electronic transitions in the absorption spectra have been addressed and clarified too. Finally, by modeling the possible coordination sites of the TCNE electron acceptor with respect to monovalent ions (Na+, K+) in an implicit solution of acetonitrile, we find that TCNE can accommodate a counterion in two different arrangements, parallel and orthogonal to the C═C axis, leading to the formation of a contact ion pair. The nature of the counterion and its relative position entail structural modifications of the TCNE radical anion, mainly the central C═C and C≡N bonds, compared to the isolated case. An important red shift of the C═C stretching frequency was observed when the counterion is orthogonal to the double bond, to a greater extent for Na+. On the contrary, in the second case, where the counterion ion lies along the internuclear C═C axis, we find that K+ polarizes the electron density of the double bond more, resulting in a greater red shift than with Na+.

Interference of Polydatin/Resveratrol in the ACE2:Spike Recognition during COVID-19 Infection. A Focus on Their Potential Mechanism of Action through Computational and Biochemical Assays.

In the search for new therapeutic strategies to contrast SARS-CoV-2, we here studied the interaction of polydatin (PD) and resveratrol (RESV)-two natural stilbene polyphenols with manifold, well known biological activities-with Spike, the viral protein essential for virus entry into host cells, and ACE2, the angiotensin-converting enzyme present on the surface of multiple cell types (including respiratory epithelial cells) which is the main host receptor for Spike binding. Molecular Docking simulations evidenced that both compounds can bind Spike, ACE2 and the ACE2:Spike complex with good affinity, although the interaction of PD appears stronger than that of RESV on all the investigated targets. Preliminary biochemical assays revealed a significant inhibitory activity of the ACE2:Spike recognition with a dose-response effect only in the case of PD.

Exploring the Franck-Condon region of a photoexcited charge transfer complex in solution to interpret femtosecond stimulated Raman spectroscopy: excited state electronic structure methods to unveil non-radiative pathways.

We present electronic structure methods to unveil the non-radiative pathways of photoinduced charge transfer (CT) reactions that play a main role in photophysics and light harvesting technologies. A prototypical π-stacked molecular complex consisting of an electron donor (1-chloronaphthalene, 1ClN) and an electron acceptor (tetracyanoethylene, TCNE) was investigated in dichloromethane solution for this purpose. The characterization of TCNE:π:1ClN in both its equilibrium ground and photoinduced low-lying CT electronic states was performed by using a reliable and accurate theoretical-computational methodology exploiting ab initio molecular dynamics simulations. The structural and vibrational time evolution of key vibrational modes is found to be in excellent agreement with femtosecond stimulated Raman spectroscopy experiments [R. A. Mathies et al., J. Phys. Chem. A, 2018, 122, 14, 3594], unveiling a correlation between vibrational fingerprints and electronic properties. The evaluation of nonadiabatic coupling matrix elements along generalized normal modes has made possible the interpretation on the molecular scale of the activation of nonradiative relaxation pathways towards the ground electronic state. In particular, two low frequency vibrational modes such as the out of plane bending and dimer breathing and the TCNE central C[double bond, length as m-dash]C stretching play a prominent role in relaxation phenomena from the electronic CT state to the ground state one.

A Not Obvious Correlation Between the Structure of Green Fluorescent Protein Chromophore Pocket and Hydrogen Bond Dynamics: A Choreography From ab initio Molecular Dynamics.

The Green Fluorescent Protein (GFP) is a widely studied chemical system both for its large amount of applications and the complexity of the excited state proton transfer responsible of the change in the protonation state of the chromophore. A detailed investigation on the structure of the chromophore environment and the influence of chromophore form (either neutral or anionic) on it is of crucial importance to understand how these factors could potentially influence the protein function. In this study, we perform a detailed computational investigation based on the analysis of ab-initio molecular dynamics simulations, to disentangle the main structural quantities determining the fine balance in the chromophore environment. We found that specific hydrogen bonds interactions directly involving the chromophore (or not), are correlated to quantities, such as the volume of the cavity in which the chromophore is embedded and that it is importantly affected by the chromophore protonation state. The cross-correlation analysis performed on some of these hydrogen bonds and the cavity volume, demonstrates a direct correlation among them and we also identified the ones specifically involved in this correlation. We also found that specific interactions among residues far in the space are correlated, demonstrating the complexity of the chromophore environment and that many structural quantities have to be taken into account to properly describe and understand the main factors tuning the active site of the protein. From an overall evaluation of the results obtained in this work, it is shown that the residues which a priori are perceived to be spectators play instead an important role in both influencing the chromophore environment (cavity volume) and its dynamics (cross-correlations among spatially distant residues).

An electron density based analysis to establish the electronic adiabaticity of proton coupled electron transfer reactions.

Electrons and protons are the main actors in play in proton coupled electron transfer (PCET) reactions, which are fundamental in many biological (i.e., photosynthesis and enzymatic reactions) and electrochemical processes. The mechanism, energetics and kinetics of PCET reactions are strongly controlled by the coupling between the transferred electrons and protons. Concerted PCET reactions are classified according to the electronical adiabaticity degree of the process. To discriminate among different mechanisms, we propose a new analysis based on the use of electron density based indexes. We choose, as test case, the 3-Methylphenoxyl/phenol system in two different conformations to show how the proposed analysis is a suitable tool to discriminate between the different degree of adiabaticity of PCET processes. The very low computational cost of this procedure is extremely promising to analyze and provide evidences of PCET mechanisms ruling the reactivity of many biological and catalytic systems.

Unveiling anharmonic coupling by means of excited state ab initio dynamics: application to diarylethene photoreactivity.

In this work, excited state ab initio molecular dynamics together with a time resolved vibrational analysis is employed to shed light on the vibrational photoinduced dynamics of a well-known diarylethene molecule experiencing a ring opening reaction upon electronic excitation. The photoreactivity of diarylethenes is recognized to be controlled by a non-adiabatic intersection point between the ground and the first excited state surfaces. The computation of an energy scan, along a suitable reaction coordinate, allows us to identify the region of potential energy surfaces in which the ground (S0) and the first excited (S1) state are well separated. The adiabatic sampling of that region in S1 shows that in the first 3 picoseconds, the central CC bond, which is subject to break, oscillates in an antiphase with respect to the energy gap ΔE(S1 - S0). A multiresolution analysis based on the wavelet transform was then applied to the structural parameters extracted from the excited state dynamics. The wavelet maps show characteristic oscillations of the frequencies, mainly CC stretching and CCC bending localized on the central 4-ring moiety. Moreover, we have identified the main frequency (methyl wagging motion) involved in the modulation of these oscillations. The anharmonic coupling within a group of vibrational modes was therefore highlighted, in good agreement with experimental evidence. For the first time, a quantitative analysis of time resolved signals from a wavelet transform/ab initio molecular dynamics approach was performed.

Thoracic spinal cord injury without radiologic abnormality in a pediatric patient case report.

Spinal Cord Injury Without Radiologic Abnormality (SCIWORA) accounts for up to 19% of spinal cord related lesions in pediatric population, mostly comprising the cervical spine. A 2-year-old patient is presented, who suffered a motor-vehicle accident. After being admitted, neither X-Ray nor spinal TC scan showed any structural abnormalities. Neurological examination showed complete sensory and motor loss under T7 as well as bladder and bowel dysfunction. Magnetic resonance imaging (MRI) showed spinal cord lesion extending from T7 to T10. The patient was treated with external immobilization and physical therapy. Thoracic SCIWORA is an uncommon diagnosis that should be considered in pediatric patients who suffer spinal trauma. Spinal cord MRI has proven to be the most accurate modality for diagnosis.

[Comparative analysis of Grade I vs Grade II intracranial Meningiomas in a retrospective series of 63 patients]. / Análisis comparativo de meningiomas cerebrales Grado I vs Grado II en una serie retrospectiva de 63 pacientes operados.

OBJECTIVE: We aimed to demonstrate the differences between grade I and II (OMS classification) of intracranial meningiomas. We evaluate their location, Simpson resection grade, re-operations rate, adjuvant treatment and patient outcomes. METHODS: We conduct a retrospective review of Sixty- three clinical records of patients who were diagnosed with meningiomas grade I and II (OMS) between 2009-2015 and received surgical treatment at our Hospital. We evaluated different variables such as age, sex, histological type, Simpson grade resection, location, symptoms, radiotherapy, follow-up, mortality rate and patient outcome. The main aim was to establish the differences between these intracranial tumors. RESULTS: A total of sixty-three patients diagnosed with meningiomas and received surgical treatment; fifty-one were grade I and thirteen with grade II. There were no differences in the rate between man and women. The average age for both types of meningiomas was 57 years old. The typical meningiomas were located in 55% of the cases outside the cranial base vs. 91.6% of the atypical meningiomas (P = 0.03). Typical meningioma had a Simpson resection grade of I, II and III in 74.5% against 58.3% of the atypical (P = 0.2). The atypical meningioma in 33% had more than one-stage surgery vs. 9.8% of the typical (P = 0.03). The patients with a typical meningioma showed a good outcome in 86.2% vs. 53.8 of the grade II (P = 0, 01). The typical meningiomas showed a good outcome in 82.2% of the cases vs. 53.8% of the atypical. The grade II meningiomas received adjuvant treatment in 33.3%, while the grade I only 1.9%. CONCLUSIONS: The atypical intracranial meningiomas have a worse outcome compared with the typical kind and a higher incidence of re-operations. These tumors have a preference for a location outside the cranial base. Concluding that the location could be a risk factor.

Irinotecan, oxaliplatin plus bolus 5-fluorouracil and low dose folinic acid every 2 weeks: a feasibility study in metastatic colorectal cancer patients.

OBJECTIVES: Irinotecan or oxaliplatin combined with 5-fluorouracil (5-FU) +/- folinic acid (FA) has changed the treatment standards for metastatic colorectal cancer (CRC). The oxaliplatin and irinotecan combination has reported consistent activity. The purpose of this phase II study was to assess the efficacy and safety of the simultaneous administration of a triple chemotherapy combination of oxaliplatin, irinotecan, 5-FU bolus, and FA. MATERIALS AND METHODS: Eligible patients had metastatic CRC with no prior oxaliplatin or irinotecan-based chemotherapy. Treatment consisted of oxaliplatin 85 mg/m2 followed by irinotecan 150 mg/m2, repeated every 15 days, with 5-FU 500 mg/m2 bolus and FA 20 mg/m2 on days 1, 8, and 15. An early amendment suppressed the day 8 5-FU/FA. RESULTS: Twenty-six eligible treated patients receiving 253 doses were assessed for toxicity. Myelosuppression was the most frequent toxicity; grade 3 to 4 neutropenia and febrile neutropenia occurred in 50% and 15% of patients, respectively. The treatment schedule modification, omitting the 5-FU dosing on day 8, considerably improved treatment compliance, reducing the incidence of febrile neutropenia, diarrhea, and asthenia. Among the 25 patients evaluable for efficacy, 10 had objective responses including 1 complete response (CR) (4%) and 9 partial responses (PR) (36%), giving an overall response rate of 40%. Median time to progression was 6.20 months [95% confidence interval (CI), 5.44-6.96]. Median overall survival was 12.95 months. CONCLUSIONS: The administration of a triple combination produced promising objective responses with acceptable toxicity but does not seem to produce an evident benefit in time-related parameters.