Long Term Follow-Up Observation in Small Choroidal Melanocytic Tumors.

BACKGROUND: The purpose of this study is to analyze the long-term evolution of patients with small choroidal melanocytic tumors (SCMTs) undergoing observation, and to assess their rate of transformation into melanomas and survival. METHODS: A retrospective single-cohort study of patients with SCMTs (1-3 mm in height and 5-10 mm in base) diagnosed from January 1992 to February 2023 was carried out, with observation as the initial treatment. The main criterion for a transformation into melanoma is considered to be an increase in size of more than 1 mm in height and/or more than 1 mm in base measured on an ultrasound/retinography, recorded in two consecutive visits separated by one to three months. RESULTS: 243 patients were included with a mean age of 65.3 years and a mean follow-up of 7.9 years (6 months-27.9 years); 27 patients showed tumor growth. The probabilities of growth at 5, 10, and 15 years are 10%, 14%, and 17%, respectively. Regarding survival, 22 patients died and only 3 deaths were due to melanoma metastasis. Survival rates at 5 and 10 years are 99% and 97%. CONCLUSIONS: Observation is a viable therapeutic option for SCMTs, avoiding the side effects of treatment, considering the majority of these tumors do not progress to melanoma. With close monitoring, patients can be treated promptly upon detecting a transformation. Additionally, the findings confirm that small melanocytic tumors can lead to metastatic disease, albeit at a low rate.

Unilateral alacrimia as a presenting symptom of Meckel's cave tumour.

Meckel's cave tumour, a rare benign tumour originating from the Schwann cells surrounding the trigeminal nerve within the Meckel's cave region, can present with a variety of clinical manifestations. We report a case of a 44-year-old male patient who presented with symptoms of tear deficiency, including dryness, ocular discomfort, and blurred vision. Diagnostic evaluation revealed the presence of a Meckel's cave tumour harming the trigeminal nerve, leading to alacrimia. This case highlights the association between Meckel's cave tumour and tear deficiency disorders.

Comparación de desempeño de algoritmos para el diagnóstico de sífilis / Performance comparison of algorithms for the diagnosis of syphilis / Comparação de desempenho de algoritmos para o diagnóstico da sífilis

Resumen La sífilis es una de las infecciones de transmisión sexual con mayor incidencia en la Argentina. Para su diagnóstico, el Ministerio de Salud de la Nación avala distintos algoritmos, entre ellos, el algoritmo tradicional y el reverso. En el algoritmo tradicional, la VDRL constituye la prueba de screening y los resultados positivos se confirman con la prueba treponémica de aglutinación de partículas (TPPA). El algoritmo reverso con un test rápido, avalado más recientemente, consiste en la realización de un test rápido treponémico como screening y posterior VDRL en las muestras que resulten positivas. Se realizó una comparación entre ambos algoritmos para evaluar si era factible y conveniente la implementación del algoritmo reverso con un test rápido en el laboratorio del H.I.G.A. Dr. Oscar Alende. El objetivo fue determinar la concordancia entre el algoritmo tradicional, utilizado actualmente en la institución (VDRL seguido por TPPA), y el nuevo algoritmo propuesto (test rápido treponémico Alere Determine Syphilis TP seguido por VDRL-USR). Para ello se realizó un estudio prospectivo de desempeño de métodos cualitativos. Se realizó VDRL-USR, TPPA y test rápido Alere Determine Syphilis TP en muestras de 580 pacientes, de los cuales 558 cumplieron con los criterios de inclusión. Se obtuvieron 51 muestras con resultados positivos y 507 con resultados negativos para el diagnóstico de sífilis por ambos algoritmos, con un porcentaje de concordancia global del 100%, lo cual indica que podría reemplazarse el algoritmo tradicional por el reverso en aquellas situaciones que lo requieran en la población estudiada.

Abstract Syphilis is one of the sexually transmitted infections with the highest incidence in Argentina. For its diagnosis, the Ministry of Health of the Nation endorses different algorithms, among them, the traditional algorithm and the reverse. In the traditional algorithm, VDRL constitutes the screening test and positive results are confirmed with particle agglutination assay TPPA. The reverse algorithm with rapid test, endorsed more recently, consists of performing a rapid treponemal test as screening and subsequent VDRL in the samples that are positive. A comparison was made between both algorithms to evaluate if the implementation of the reverse algorithm with rapid test in Dr. Oscar Alende Hospital would be feasible and convenient. The objective of this work was to determine the concordance between the traditional algorithm, currently used in the institution (VDRL followed by TPPA), and the new algorithm proposed (rapid treponemal test Alere Determine Syphilis TP followed by VDRL-USR). For that purpose, a prospective study of the performance of qualitative methods was carried out. VDRL-USR, TPPA and Alere Determine Syphilis TP Rapid Test were performed on samples from 580 patients, of which 558 met the inclusion criteria. A total of 51 samples with positive results and 507 with negative results for the diagnosis of syphilis were obtained by both algorithms, with an overall concordance percentage of 100%, which indicates that the traditional algorithm could be replaced by the reverse in those situations that require it in the studied population.

Resumo A sífilis é uma das infecções sexualmente transmissíveis com maior incidência na Argentina. Para o seu diagnóstico, o Ministério da Saúde da Nação endossa diversos algoritmos, incluindo o algoritmo tradicional e o reverso. No algoritmo tradicional, o VDRL constitui o teste de triagem e os resultados positivos são confirmados com o teste treponêmico de aglutinação de partículas (TPPA). O algoritmo reverso com teste rápido, endossado mais recentemente, consiste na realização de um teste rápido treponêmico como triagem e posterior VDRL nas amostras positivas. Foi feita uma comparação entre os dois algoritmos para avaliar se a implementação do algoritmo reverso com um teste rápido no laboratório H.I.G.A. Dr. Óscar Alende era viável e conveniente. O objetivo foi determinar a concordância entre o algoritmo tradicional, atualmente utilizado na instituição (VDRL seguido de TPPA), e o novo algoritmo proposto (teste rápido treponêmico Alere Determine Syphilis TP seguido de VDRL-USR). Para tanto, foi realizado um estudo prospectivo de desempenho de métodos qualitativos. O VDRL- -USR, o TPPA e o teste rápido Alere Determine Syphilis TP foram realizados em amostras de 580 pacientes, dos quais 558 preencheram os critérios de inclusão. Foram obtidas 51 amostras com resultados positivos e 507 com resultados negativos para o diagnóstico de sífilis por ambos os algoritmos, com um percentual de concordância global de 100%, o que indica que o algoritmo tradicional poderia ser substituído pelo reverso nas situações que o exigissem na população estudada.

Fibrosis Management Algorithm in Secondary Liposculpture.

BACKGROUND: Liposuction is considered one of the most common procedures in plastic surgery. However, major postoperative complications such as visceral injury, fluid overload, and necrotizing fasciitis still occur. Likewise, minor complications such as ecchymosis, seromas, infections, and contour irregularities that do not threaten the life of the patient do generate significant dissatisfaction. Current evidence regarding the management of fibrosis after previous liposuction remains limited. OBJECTIVES: The objective of this article is to standardize a management algorithm based on the extensive experience and successful results of the primary author (G.M.). METHODS: Patients who underwent secondary liposculpture between August 2022 and May 2023 were evaluated prospectively. Inclusion criteria comprised females between 18 and 60 years old, nonsmokers, with a BMI < 35 kg/m2 and a history of previous body contouring surgeries. Identification of the patient's skin condition and subcutaneous lesions in the adipose tissue were obtained in detail. Statistical analysis of preoperative and postoperative medical photographs was also performed with the Fiji Biological image analyzer. RESULTS: Photographic analysis of preoperative and postoperative photographs showed a statistically significant difference between the areas affected by fibrosis (P < .001). The most frequent clinical findings were depressions in 99% of the females (74), followed by soft nodules in 95% (70), hard nodules in 81% (61), adhesions in 47% (35), and finally cutaneous bursas in 4%. CONCLUSIONS: Our classification system and management algorithm for fibrosis and contour irregularities is a safe and reliable tool. Results were objectively verified, yielding statistically significant outcomes.

Filamentous actin destabilization by H2O2 favors DnmA aggregation, with crucial roles of cysteines 450 and 776 in mitochondrial and peroxisomal division in Aspergillus nidulans.

IMPORTANCE: Mitochondria constitute major sources of H2O2 and other reactive oxygen species in eukaryotic cells. The division of these organelles is crucial for multiple processes in cell biology and relies on highly regulated mechano-GTPases that are oligomerization dependent and belong to the dynamin-related protein family, like A. nidulans DnmA. Our previous work demonstrated that H2O2 induces mitochondrial constriction, division, and remodeling of the outer membrane. Here, we show that H2O2 also induces a DnmA aggregation consistent with higher-order oligomerization and its recruitment to mitochondria. The study of this response uncovered that H2O2 induces the depolymerization and reorganization of actin as well as the critical role that cysteines 450 and 776 play in DnmA function. Our results provide new insights into the mechanisms of reactive oxygen species cell signaling and how they can regulate the dynamics of the actin cytoskeleton and the division of mitochondria and peroxisomes.

Prevalent coinfection and associated factors for Hepatitis B, Hepatitis C, and Human Immunodeficiency Virus in patients submitted to renal replacement therapy: A cross-sectional study of 21 dialysis units in the State of Mexico.

BACKGROUND: Chronic kidney disease (CKD) predispose to viral coinfections in patients submitted to renal replacement therapy (RRT); nevertheless, few reports have been performed to elucidate the current epidemiology within this population in Mexico. AIM: To estimate the prevalence of HBV, HCV, and HIV coinfection and to explore factors associated with prevalent coinfection in patients living with renal failure undergoing to RRT. METHODS: A multicenter cross-sectional recruitment across 21 units at the Mexican Institute of Social Security (IMSS) at the State of Mexico was performed during 2019. A standardized clinical questionnaire was performed to elucidate individual and relatives-related conditions. A treatment facility questionnaire was applied to the chief responsible of each unit to explore treatment facility variables. Serological testing, clinical, biochemical, and anthropometrical parameters were extracted from clinical records. RESULT: In 1,304 patients (57.5% male, mean age 45.5 (SD: 15.6) years, and 95.8% in hemodialysis), the prevalence of any viral coinfection was 3.14% (95% CI: 2.32%-4.23%). The highest viral coinfection prevalence were for HCV, HBV, and HIV, in which men and subjects diagnosed after 2010's had the highest rates. We identify that being submitted to peritoneal dialysis, being treated in a surrogated dialysis center and living with a close relative with prior hepatitis coinfection were associated factors for any viral coinfection. CONCLUSION: In patients submitted to RRT, the prevalence of viral coinfection remains high compared with general population. Screening strategies, medical awareness and targeted public healthcare policies should prioritize better care practices within patients submitted to RRT in Mexico.

In-Office Superior Laryngeal Nerve Block for Paralaryngeal Pain and Odynophonia.

OBJECTIVES: Pain localized to the thyrohyoid region may be due to neuralgia of the superior laryngeal nerve (SLN), inflammation of the thyrohyoid complex, or a voice disorder. We present outcomes of treatment of paralaryngeal pain and odynophonia with SLN block. STUDY DESIGN: Retrospective Review. METHODS: A retrospective chart review of patients undergoing in-office SLN block for paralaryngeal pain between 2015 and 2018 at two tertiary care centers was conducted. Patient demographics, indications, and response to treatment were analyzed. RESULTS: Thirty-eight patients underwent blockade of the internal branch of the SLN for paralaryngeal pain, with 10 excluded for incomplete medical records. Eighty-two percent (23/28) reported an improvement in their symptoms. Patients underwent an average of 2.5 blocks (SD = 1.88, range 1-8), with 10 patients (36%) undergoing a single procedure. Of the 18 patients who underwent multiple blocks, nine had eventual cessation of symptoms (50%) compared to resolution in 6/10 undergoing a single injection. Eleven patients (39%) noted odynophonia related to vocal effort, and all of these patients had improvement in or resolution of their symptoms and were more likely to improve compared to those without odynophonia (P = .006). Of the four patients who had a vocal process granuloma (VPG) at presentation, three had complete resolution of the lesion at follow-up. CONCLUSION: In-office SLN block is effective in the treatment of paralaryngeal pain. It may be used as an adjunct in the treatment of vocal process granulomas, as well as voice disorders where odynophonia is a prominent symptom. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:401-405, 2022.

Detección de SARS-CoV-2 en contactos estrechos asintomáticos de casos confirmados por diagnóstico molecular, provincia de Buenos Aires, Argentina / Detection of SARS-CoV-2 in asymptomatic close contacts of cases confirmed by molecular diagnosis, Buenos Aires province, Argentina

Resumen La detección de SARS-CoV-2 y su implicancia en el diagnóstico de COVID-19 han sido muy debatidas en la pandemia. El objetivo de este estudio fue evaluar el costo/beneficio de la detección de SARS-CoV-2 en contactos estrechos asintomáticos (CE) mediante el uso de distintas pruebas de diagnóstico molecular. Se estudiaron 51 CE de personas con diagnóstico de SARS-CoV-2 confirmado por RTqPCR, clasificadas por el umbral de ciclos (Ct) (<20, entre 20 y 30 y >30) en hospitales públicos de la provincia de Buenos Aires. Del total de contactos estudiados el 15,7% resultó confirmado para SARS-CoV-2; no hubo contactos positivos de casos con Ct>30. La cantidad de contactos positivos de casos con Ct<20 fue significativamente mayor que la de casos con Ct>20. Las muestras con Ct<20 se asociaron a una carga viral estimada de entre uno a cuatro órdenes de magnitud de diferencia con los rangos de Ct>20. Un 13,7% de contactos positivos fueron casos con Ct<20. De las muestras positivas confirmadas por PCR, correspondientes a la semana epidemiológica 1 de 2021 (SE1), sólo un 19,35% correspondían a muestras con Ct<20 y un 50,7% con Ct entre 20 y 30. Estos datos muestran un incremento de sólo un 3,7% de casos detectados. El esfuerzo por parte del sistema de salud pública para esta estrategia, con bajo poder predictivo, puede tener un efecto negativo para el cumplimiento del aislamiento de los contactos y podría generar una demora en los resultados de los casos sospechosos, sin aportar significativamente en el control de la pandemia.

Abstract The detection of SARS-CoV-2 and its implication in the diagnosis of COVID-19 have been highly debated in the pandemic. The objective of this study was to evaluate the cost/benefit of detecting SARS-CoV-2 in asymptomatic close contacts (CC) using different molecular diagnostic tests. A total of 51 CC of people with a diagnosis of SARS-CoV-2 confirmed by RTqPCR, classified by the cycle threshold (Ct) (<20, between 20 and 30 and >30), were studied in public hospitals in the Province of Buenos Aires. Of the total contacts studied, 15.7% were confirmed for SARS-CoV-2; there were no positive contacts of cases with Ct>30 positive. The number of positive contacts of cases with Ct<20 was significantly higher than that of cases with Ct>20. Samples with Ct<20 were associated with an estimated viral load of one to four orders of magnitude difference with Ct ranges >20. A total of 13.7% of positive close contacts were from cases with Ct<20. When studying positive samples with confirmed diagnosis by PCR, corresponding to 1 epidemiological week of 2021 (EW1), only 19.35% corresponded to samples with Ct<20 and 50.7% with Ct between 20 and 30. From these data it is shown that with the CC test only 3.7% of the cases were detected. The effort by the public health system for this strategy, with low predictive power, may have a negative effect on the fulfillment of the isolation of contacts and could generate a delay in the results of suspected cases, without contributing significantly to controlling the pandemic.

Resumo A detecção do SARS-CoV-2 e seu envolvimento no diagnóstico da COVID-19 têm sido muito discutidos durante a pandemia. O objetivo desse estudo foi avaliar a relação custo/benefício na detecção de SARSCoV- 2 em casos de contatos próximos assintomático (CP), por meio do uso de diferentes testes de diagnóstico molecular. Foram estudados 51 casos de CP de pessoas com diagnóstico de SARS-CoV-2 confirmado pelo RTqPCR, sendo classificados pelo limiar de ciclos (Ct) (<20, entre 20 e 30 e >30), em hospitais públicos da província de Buenos Aires. Do total de contatos estudados, 15,7% foram confirmados para SARS-CoV-2, não houve contatos positivos de casos com Ct>30. O número de contatos positivos de casos com Ct<20, foi significativamente maior que os casos com Ct>20. As amostras com Ct<20 foram associadas a uma carga viral estimada de uma a quatro ordens de magnitude de diferença com os intervalos de Ct>20. Dos casos positivos, 13,7% foram com Ct<20. Das amostras positivas confirmadas por PCR, correspondentes à semana epidemiológica 1 de 2021 (SE1), apenas 19,35% correspondiam a amostras com Ct>20 e 50,7% com Ct entre 20 e 30. Esses dados mostram incremento de apenas 3,7% de casos detectados. O esforço por parte do sistema de saúde pública para essa estratégia, com baixo poder preditivo, pode ter um efeito negativo no cumprimento do isolamento dos contatos e poderia gerar uma demora nos resultados dos casos suspeitos, sem contribuir significativamente para o controle da pandemia.

Amyloid Oligomers: A Joint Experimental/Computational Perspective on Alzheimer's Disease, Parkinson's Disease, Type II Diabetes, and Amyotrophic Lateral Sclerosis.

Protein misfolding and aggregation is observed in many amyloidogenic diseases affecting either the central nervous system or a variety of peripheral tissues. Structural and dynamic characterization of all species along the pathways from monomers to fibrils is challenging by experimental and computational means because they involve intrinsically disordered proteins in most diseases. Yet understanding how amyloid species become toxic is the challenge in developing a treatment for these diseases. Here we review what computer, in vitro, in vivo, and pharmacological experiments tell us about the accumulation and deposition of the oligomers of the (Aß, tau), α-synuclein, IAPP, and superoxide dismutase 1 proteins, which have been the mainstream concept underlying Alzheimer's disease (AD), Parkinson's disease (PD), type II diabetes (T2D), and amyotrophic lateral sclerosis (ALS) research, respectively, for many years.

Treatment of Vocal Fold Polyps with In-Office Potassium Titanyl Phosphate (KTP) Laser Ablation in Professional Singers.

Vocal fold polyp (VFP) is an exophytic gelatinous lesion with an atrophic epithelium. After behavioral and conservative management, phonomicrosurgery is the treatment of choice for VFPs with excellent outcomes in terms of lesion resolution and postoperative vocal function. Office-based potassium titanyl phosphate (KTP) laser ablation is a new treatment modality for VFPs but its efficacy for professional singers has yet to be validated. Reported is a consecutive series of six professional singers (with seven episodes of VFP) who, based on patient and provider preference, underwent in-office KTP laser ablation of VFP. Two polyps required two ablation procedures; otherwise, a single treatment was successful in resolution of VFP at a mean resolution time of 44 days. Singing voice handicap index 10 improved from a mean of 30.8 (range 4-40) to 6.0 (range 0-22). All patients resumed their professional singing careers without vocal limitations. Posttreatment videos were reviewed by three blinded fellowship trained laryngologists, who were not able to accurately predict the laterality of the polyp (52% correct, p = 0.99).

Impact of Fiberoptic Endoscopic Evaluation of Swallowing Outcomes and Dysphagia Management in Neurodegenerative Diseases.

OBJECTIVES/HYPOTHESIS: To determine the incidence of abnormal fiberoptic endoscopic evaluation of swallowing (FEES) findings in patients with progressive neurologic disorders and identify the most commonly implemented dysphagia management strategies. STUDY DESIGN: Retrospective Review. METHODS: A retrospective review was performed of patients with neurodegenerative disease who underwent FEES at a tertiary-care center between 2008 and 2019. Patient demographics, diagnosis, and Eating Assessment Tool-10 (EAT-10) scores were recorded. Rates of penetration, aspiration, and functional change in management (FCIM) to include dietary modifications, home exercises, swallow therapy, surgical intervention (injection augmentation or esophageal dilation), or alternative means of nutrition (i.e., percutaneous enteral gastrostomy [PEG] tube) were calculated. RESULTS: Two hundred nine FEES assessments were performed in 178 patients with a mean age of 64.8 years (standard deviation = ±14). The most common diagnoses were amyotrophic lateral sclerosis (32%) followed by Parkinson's disease or Parkinsonism (26%). FEES demonstrated penetration in 72.5% of patients and aspiration in 14.6%. Mean EAT-10 scores differed between patients with aspiration versus penetration versus normal FEES (24.7 vs. 14.9 vs. 13.9, respectively, P < .001). An FCIM was recommended in 88% of patients and most commonly included self-directed modifications (43%). Overall, 4.5% of patients underwent surgical intervention. A PEG tube was recommended for either supplemental or sole form of nutrition in 19% of the entire cohort. CONCLUSIONS: Most patients with neurodegenerative diseases presenting with dysphagia demonstrated abnormal FEES findings necessitating an FCIM, suggesting early dysphagia evaluation may be warranted in this cohort. These findings correlate with worsened EAT-10 scores in patients with aspiration or penetration on FEES. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:726-730, 2021.

Correlation of Glottic Gap and Voice Impairment in Presbyphonia.

OBJECTIVE/HYPOTHESIS: The objective of this study was to investigate the glottic gap area as a significant marker for the severity of presbyphonia as it relates to patient-reported outcome measures (Voice Handicap Index-10 [VHI-10]) and stroboscopic findings. STUDY DESIGN: Retrospective case-control study conducted in an academic tertiary voice center. METHODS: Patients seen at a tertiary voice clinic who were diagnosed with presbyphonia without other organic laryngeal pathology from January 2014 to December 2017 were included. Clinical data and laryngeal videostroboscopy videos were collected. Still images at the point of vocal process approximation during adduction were captured, and the glottic gap area was measured using ImageJ. These were compared to a control cohort. Correlations were made using Wilcoxon rank sum test, Mann-Whitney U test, and Pearson correlation coefficients. RESULTS: Thirty-three patients were included. Inter-rater reliability of glottic area measurement was strong (intraclass correlation coefficient = 0.73, P < .001). Compared to controls, presbyphonia patients had a larger glottic gap area (P < .001) and greater open-phase quotient on laryngeal videostroboscopy (P < .001). Larger glottic gap area did not correlate with patient-reported vocal function as measured by VHI-10 (P = .79) and did not correlate with presence of secondary muscle tension dysphonia (P = .99). In the presbyphonia cohort, the glottic gap area did not correlate with age (P = .29). CONCLUSIONS: Glottic gap area at the point of vocal process approximation during phonation can be reliably measured. Patients with presbyphonia have a larger glottic gap area and greater open-phase quotient on stroboscopy, but these do not correlate with patient-reported voice impairment or the presence of secondary muscle tension dysphonia (MTD). These data suggest that dysphonia severity in presbyphonia is not fully explained by a glottic gap or secondary MTD alone. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:1594-1598, 2021.

Differing Progression to Posterior Glottic Stenosis in Autoimmune and Idiopathic Subglottic Stenosis.

OBJECTIVES/HYPOTHESIS: We sought to characterize rates of progression to posterior glottic stenosis (PGS) from autoimmune or idiopathic subglottic stenosis. STUDY DESIGN: This was a retrospective review. METHODS: Patients from a tertiary-care laryngology practice over a 10-year period with autoimmune or idiopathic subglottic stenosis (SGS) were included. Patients with a history of prolonged intubation or other causes of iatrogenic stenosis were excluded. PGS was confirmed on videostrobolaryngoscopy recordings by a fellowship-trained laryngologist. PGS type (1-4) was also recorded. Demographic information was recorded, and if applicable, autoimmune disease type was specified. Time until PGS was recorded along with the number of interventions. Chi-squared analysis was used to compare PGS in autoimmune and idiopathic SGS. RESULTS: A total of 77 patients were identified with autoimmune (32 patients) or idiopathic (45 patients) subglottic stenosis. Autoimmune pathologies included systemic lupus erythematosus, granulomatosis with polyangiitis (GPA), rheumatoid arthritis, relapsing polychondritis, and sarcoidosis, with GPA the most common (14/32). Patients with autoimmune SGS had a higher rate of PGS (10 of 32) compared to idiopathic subglottic stenosis (1 of 45) for an odds ratio of 20 (95% CI: 2.4-166.4, P = .006). Patients with idiopathic SGS were more likely to be female (all 45 compared to 29/32 autoimmune, P = .07) and older (mean 53 (range 29-75) compared to 46 (20-82), P = .02). CONCLUSIONS: In this large patient cohort, autoimmune SGS patients were found to have a higher likelihood of developing PGS compared to their idiopathic counterparts, suggesting that counseling for this progression may be warranted. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:1816-1820, 2021.

Exploring the folding process of human ßB2-crystallin using multiscale molecular dynamics and the Markov state model.

Adequate knowledge of protein conformations is crucial for understanding their function and their association properties with other proteins. The cataract disease is correlated with conformational changes in key proteins called crystallins. These changes are due to mutations or post-translational modifications that may lead to protein unfolding, and thus the formation of aggregate states. Human ßB2-crystallin (HßB2C) is found in high proportion in the eye lens, and its mutations are related to some cataracts. HßB2C also associates into dimers, tetramers, and other higher-order supramolecular complexes. However, it is the only protein of the ßγ-crystallin family that has been found in an extended conformation. Therefore, we hypothesize that the extended conformation is not energetically favourable and that HßB2C may adopt a closed (completely folded) conformation, similar to the other members of the ßγ-crystallin family. To corroborate this hypothesis, we performed extensive molecular dynamics simulations of HßB2C in its monomeric and dimeric conformations, using all-atom and coarse-grained scales. We employed Markov state model (MSM) analysis to characterize the conformational and kinetically relevant states in the folding process of monomeric HßB2C. The MSM analysis clearly shows that HßB2C adopts a completely folded structure, and this conformation is the most kinetically and energetically favourable one. In contrast, the extended conformations are kinetically unstable and energetically unfavourable. Our MSM analysis also reveals a key metastable state, which is particularly interesting because it is from this state that the folded state is reached. The folded state is stabilized by the formation of two salt bridges between the residue-pairs E74-R187 and R97-E166 and the two hydrophobic residue-pairs V59-L164 and V72-V151. Furthermore, free energy surface (FES) analysis revealed that the HßB2C dimer with both monomers in a closed conformation (face-en-face dimer) is energetically more stable than the domain-swapped dimer (crystallographic structure). The results presented in this report shed light on the molecular details of the folding mechanism of HßB2C in an aqueous environment and may contribute to interpreting different experimental findings. Finally, a detailed knowledge of HßB2C folding may be key to the rational design of potential molecules to treat cataract disease.

Postoperative Complications in Obese Patients After Tracheostomy.

OBJECTIVE: To determine the prevalence of varying classes of obesity in patients undergoing tracheostomy and the associated complication rates as compared with nonobese patients. STUDY DESIGN: A retrospective chart review was performed from 2012 to 2018 on all patients who underwent open tracheostomy by the Department of Otolaryngology-Head and Neck Surgery. SETTING: All tracheostomies were performed at a single tertiary care center. METHODS: Patients were classified by body mass index (BMI) according to the World Health Organization classification system: underweight (<18.5), normal-overweight (18.5-29.9), class I (30-34.9), class II (35-39.9), and class III (>40). Charts were reviewed for patient demographic information, Charlson Comorbidity Index score, surgical indication, operative time, tracheostomy tube type, and postoperative complications. RESULTS: A total of 387 patients (mean ± SD BMI, 31.3 ± 14.2) were identified per the inclusion/exclusion criteria. Of patients with BMI >30 (n=153), 34.6% were categorized as obesity class I, 29.4% as class II, and 35.9% as class III. The most common indication for tracheostomy was malignancy in nonobese patients (41.5%) and respiratory failure for obese patients (58.2%). Operative time was significantly longer in obese patients, and most of these patients required an extended-length tracheostomy tube. Patients with a BMI >40 had higher rates of multiple postoperative complications or death (P = .009). Underweight patients also had a higher rate of complication than normal-overweight patients (P = .016). CONCLUSION: Class III and underweight patients had higher rates of postoperative complications, which should be taken into consideration during perioperative counseling.

Design, Synthesis and Evaluation of 2,4-Diaminoquinazoline Derivatives as Potential Tubulin Polymerization Inhibitors.

Microtubules are highly dynamic polymers composed of α- and ß-tubulin proteins that have been shown to be potential therapeutic targets for the development of anticancer drugs. Currently, a wide variety of chemically diverse agents that bind to ß-tubulin have been reported. Nocodazole (NZ) and colchicine (COL) are well-known tubulin-depolymerizing agents that have close binding sites in the ß-tubulin. In this study, we designed and synthesized a set of nine 2,4-diaminoquinazoline derivatives that could occupy both NZ and COL binding sites. The synthesized compounds were evaluated for their antiproliferative activities against five cancer cell lines (PC-3, HCT-15, MCF-7, MDA-MB-231, and SK-LU-1), a noncancerous one (COS-7), and peripheral blood mononuclear cells (PBMC). The effect of compounds 4 e and 4 i on tubulin organization and polymerization was analyzed on the SK-LU-1 cell line by indirect immunofluorescence, western blotting, and tubulin polymerization assays. Our results demonstrated that both compounds exert their antiproliferative activity by inhibiting tubulin polymerization. Finally, a possible binding pose of 4 i in the NZ/COL binding site was determined by using molecular docking and molecular dynamics (MD) approaches. To our knowledge, this is the first report of non-N-substituted 2,4-diaminoquinazoline derivatives with the ability to inhibit tubulin polymerization.

Disruption of TFIIH activities generates a stress gene expression response and reveals possible new targets against cancer.

Disruption of the enzymatic activities of the transcription factor TFIIH by the small molecules Triptolide (TPL) or THZ1 could be used against cancer. Here, we used the MCF10A-ErSrc oncogenesis model to compare the effect of TFIIH inhibitors between transformed cells and their progenitors. We report that tumour cells exhibited highly increased sensitivity to TPL or THZ1 and that the combination of both had a synergic effect. TPL affects the interaction between XPB and p52, causing a reduction in the levels of XPB, p52 and p8, but not other TFIIH subunits. RNA-Seq and RNAPII-ChIP-Seq experiments showed that although the levels of many transcripts were reduced, the levels of a significant number were increased after TPL treatment, with maintained or increased RNAPII promoter occupancy. A significant number of these genes encode for factors that have been related to tumour growth and metastasis, suggesting that transformed cells might rapidly develop resistance to TPL/THZ inhibitors. Some of these genes were also overexpressed in response to THZ1, of which depletion enhances the toxicity of TPL, and are possible new targets against cancer.

Conformational analysis by NMR and molecular dynamics of adamantane-doxorubicin prodrugs and their assemblies with ß-cyclodextrin: A focus on the design of platforms for controlled drug delivery.

Nanoscale design and construction of affinity-based drug delivery systems (ADDS) is an active research area with enormous potential for the improvement of cancer treatment. For the therapeutic load of these ADDS, a promising strategy is the design of pH-sensitive prodrugs based on the construction of conjugates between adamantane and doxorubicin (Ad-Dox), which stands out as an excellent model system to obtain novel supramolecular materials. Construction of these prodrugs involves a modification of three zones of doxorubicin which in principle does not affect the action mechanism: the carbonyl group C13 (hydrazone linker), the primary alcohol neighboring the carbonyl (ester linker) and the 3' amino group of daunosamine sugar (amide linker). These modifications are aimed to improve the efficacy and reduce the systemic toxicity of the drug chemotherapy by controlling its release in cancer cells. In this work, we performed 2D NMR experiments and molecular dynamics simulations to characterize the conformational changes of three constructed prodrugs. Our results demonstrated that ring A and the daunsamine sugar of the hydrazone and amide linkers conserve the half-chair state 9H8, while the ester linker disrupts this conformation. Our study also showed that the hydrazone-linked compound (Ad-h-Dox) does not modify the conformation of the original drug and maintains cytotoxic activity. Moreover, the inclusion complex (IC) of Ad-h-Dox with ß-cyclodextrin (ßCD) generated a highly soluble platform in water, whereas the ester-linked compound (Ad-e-Dox) causes the loss of biological activity. This study proves that Ad-h-Dox prodrug can be an optimum prodrug and act as a building block for a more complex drug transport system.

Evaluation of New Benzimidazole Derivatives as Cysticidal Agents: In Vitro, in Vivo and Docking Studies.

Based on our previous research on cysticidal drugs, we report the synthesis and evaluation of three new benzimidazole derivatives. In these compounds, the amido group was used as a bioisosteric replacement of the ester group. The molecular docking on ß-tubulin revealed that the derivatives interacted through hydrogen bonding with N165, E198 and V236. All compounds showed in vitro activity against Taenia crassiceps cysts. Among them, benzimidazole 3 was found to be the most potent of the series (EC50 0.86 µM). This compound also exhibited the highest probability of binding and the lowest binding free energy score and was therefore selected for in vivo evaluation. Results indicated that the efficacy of compound 3 was comparable to that of the reference drug, albendazole (50.39 vs. 47.16% parasite reduction). Animals treated with compound 3 seemed to tolerate this benzimidazole well, with no changes in behavior, or food and water consumption. These findings are consistent with the in silico prediction results, which indicated low toxicity risks. The pharmacokinetic study showed that the half-life and mean residence time (6.06 and 11.9 h, respectively) were long after oral administration. Together, these results indicate that this new benzimidazole derivative represents a promising structure with cysticidal activity.

[Asociación de la composición corporal total con la fuerza del tronco, el dolor y la discapacidad en pacientes con espondiloartrosis lumbar]. / The association of total body composition with trunk strength, pain and disability in patients with lumbar osteoarthritis.

INTRODUCCIÓN: Las alteraciones en la composición corporal total podrían influir sobre la fuerza, el dolor y la discapacidad en pacientes con espondiloartrosis lumbar. OBJETIVO: Analizar la asociación de la composición corporal total con la fuerza muscular del tronco, el dolor y la discapacidad en pacientes con espondiloartrosis lumbar. MÉTODO: Estudio piloto en mayores de 50 años con dolor crónico de espalda baja y espondiloartrosis lumbar. Se excluyeron pacientes con diabetes mellitus, depresión, ansiedad, artropatías inflamatorias, fracturas vertebrales, escoliosis, cirugías de columna, cardiopatías, hipertensión arterial, radiculopatía o claudicación neurogénica. Se recolectaron datos sobre tiempo de evolución, composición corporal (masa grasa y muscular total), fuerza del tronco (isocinesia), dolor (escala numérica verbal) y discapacidad (Roland Morris). Análisis estadístico con U de Mann-Whitney y correlaciones de Spearman. RESULTADOS: 27 pacientes (18 mujeres y 9 hombres) con edad de 58.59 ± 6.98 años. La masa muscular total se asoció con el dolor (rho: -0.63, p = 0.001) y con la fuerza del tronco (flexores rho: -0.42, p = 0.02; extensores rho: -0.50, p = 0.007), sin correlación con la discapacidad. No se encontró correlación de la masa grasa con ninguna de las variables. CONCLUSIÓN: La disminución de la masa muscular se asocia con el dolor, pero no con la discapacidad, en pacientes con espondiloartrosis lumbar. BACKGROUND: Variations in body composition among patients with lumbar osteoarthritis may influence pain and disability and muscle strength. OBJECTIVE: To analyze the relationship between body composition with pain, disability and muscle strength, in patients with lumbar osteoarthritis. METHODS: Pilot study in patients older than 50 years of age, with chronic low back pain and lumbar osteoarthritis, who agreed to participate through informed consent. We excluded patients with diabetes mellitus, depression, anxiety, inflammatory arthropathies, vertebral fractures, idiopathic scoliosis, spinal surgery, heart disease or hypertension, radiculopathy or neurogenic claudication. Data on evolution time, body composition (total body fat and muscle mass), trunk strength, pain (numerical rating scale), and disability (Roland Morris questionnaire) were collected. Mann-Whitney U-test and Spearman correlations were performed. RESULTS: 27 patients (18 women and 9 men) aged 58.59 ± 6.98 years. Negative correlations between muscle mass with pain (rho: −0.63, p = 0.001) and strength (flexors rho: −0.42, p = 0.02; extensors rho: −0.50, p = 0.007) were found, without correlation with disability. No correlations of fat mass with pain or disability were found. CONCLUSION: Decreased of muscle mass were associated with higher pain scores without influencing the disability in patients with lumbar osteoarthritis..