RESUMEN
Currently, the incorrect judgment of burn depth remains common even among experienced surgeons. Contributing to this problem are change in burn appearance throughout the first week requiring periodic evaluation until a confident diagnosis can be made. To overcome these issues, we investigated the feasibility of an artificial intelligence algorithm trained with multispectral images of burn injuries to predict burn depth rapidly and accurately, including burns of indeterminate depth. In a feasibility study, 406 multispectral images of burns were collected within 72 hours of injury and then serially for up to 7 days. Simultaneously, the subject's clinician indicated whether the burn was of indeterminate depth. The final depth of burned regions within images were agreed upon by a panel of burn practitioners using biopsies and 21-day healing assessments as reference standards. We compared three convolutional neural network architectures and an ensemble in their capability to automatically highlight areas of nonhealing burn regions within images. The top algorithm was the ensemble with 81% sensitivity, 100% specificity, and 97% positive predictive value (PPV). Its sensitivity and PPV were found to increase in a sigmoid shape during the first week postburn, with the inflection point at day 2.5. Additionally, when burns were labeled as indeterminate, the algorithm's sensitivity, specificity, PPV, and negative predictive value were: 70%, 100%, 97%, and 100%. These results suggest multispectral imaging combined with artificial intelligence is feasible for detecting nonhealing burn tissue and could play an important role in aiding the earlier diagnosis of indeterminate burns.
Asunto(s)
Inteligencia Artificial , Quemaduras , Humanos , Quemaduras/patología , Algoritmos , Cicatrización de Heridas , Redes Neurales de la Computación , Piel/patologíaRESUMEN
BACKGROUND: In the Posterior left pericardiotomy for the prevention of atrial fibrillation after cardiac surgery (PALACS) trial, posterior pericardiotomy was associated with a significant reduction in postoperative atrial fibrillation (POAF) after cardiac surgery. We aimed to investigate the mechanisms underlying this effect. METHODS: We included PALACS patients with available echocardiographic data (n = 387/420, 92%). We tested the hypotheses that the reduction in POAF with the intervention was associated with 1) a reduction in postoperative pericardial effusion and/or 2) an effect on left atrial size and function. Spline and multivariable logistic regression analyses were used. RESULTS: Most patients (n = 307, 79%) had postoperative pericardial effusions (anterior 68%, postero-lateral 51.9%). The incidence of postero-lateral effusion was significantly lower in patients undergoing pericardiotomy (37% vs 67%; P < .001). The median size of anterior effusion was comparable between patients with and without POAF (5.0 [IQR 3.0-7.0] vs 5.0 [IQR 3.0-7.5] mm; P = .42), but there was a nonsignificant trend towards larger postero-lateral effusion in the POAF group (5.0 [IQR 3.0-9.0] vs 4.0 [IQR 3.0-6.4] mm; P = .06). There was a non-linear association between postero-lateral effusion and POAF at a cut-off at 10 mm (OR 2.70; 95% CI 1.13, 6.47; P = .03) that was confirmed in multivariable analysis (OR 3.5, 95% CI 1.17, 10.58; P = 0.02). Left atrial dimension and function did not change significantly after posterior pericardiotomy. CONCLUSIONS: Reduction in postero-lateral pericardial effusion is a plausible mechanism for the effect of posterior pericardiotomy in reducing POAF. Measures to reduce postoperative pericardial effusion are a promising approach to prevent POAF.
Asunto(s)
Fibrilación Atrial , Procedimientos Quirúrgicos Cardíacos , Derrame Pericárdico , Humanos , Fibrilación Atrial/etiología , Fibrilación Atrial/prevención & control , Fibrilación Atrial/epidemiología , Pericardiectomía/efectos adversos , Pericardiectomía/métodos , Derrame Pericárdico/epidemiología , Derrame Pericárdico/etiología , Derrame Pericárdico/cirugía , Resultado del Tratamiento , Procedimientos Quirúrgicos Cardíacos/efectos adversos , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/prevención & controlRESUMEN
BACKGROUND: Although left ventricular assist device (LVAD) implantation is associated with improved heart failure survival, the impact of pre-implantation Impella support on outcomes is unknown. We undertook this study to evaluate the impact of preoperative Impella support on LVAD outcomes. METHODS: We conducted a retrospective review of all Heartmate 3 LVAD implants. Primary stratification was by the need for preoperative Impella support with the 5.0/5.5 device. Longitudinal survival was assessed by the Kaplan-Meier method. Multivariable Cox proportional hazards regression models were developed to evaluate mortality. Secondary outcomes included changes in laboratory values during Impella support. RESULTS: From 2017 to 2021, 87 patients underwent LVAD implantation. Sixteen were supported with a single inotrope, 36 with dual inotropes, 27 with Impella, and 3 with extracorporeal membrane oxygenation (ECMO). When stratified by the need for Impella, there was no difference in survival at 30-days (98.3 [88.2-99.8]% vs. 96.3 [76.5-99.5]%, p = .59), 1-year (91.0 [79.8-96.2] vs. 74.9 [51.7-88.2], p = .10), or at 2 years (87.9 [74.3-94.5] vs. 74.9 [51.7-88.2], p = .15). On multivariable modeling, the need for preoperative Impella was not associated with an increased hazard of 1-year (1.24 [0.23-6.73], p = .81) or 2-year mortality (1.05 [0.21-5.19], p = .95). After 7 (5-10) days of Impella support, recipient creatinine (p < .01), creatinine clearance (p = .02), and total bilirubin (p = .053) improved and lactic acidosis resolved (p < .01). CONCLUSIONS: Preoperative Impella support is not associated with increased short or long-term mortality but is associated with improved renal and hepatic function as well as total body perfusion before LVAD implantation.
Asunto(s)
Oxigenación por Membrana Extracorpórea , Insuficiencia Cardíaca , Corazón Auxiliar , Bilirrubina , Creatinina , Oxigenación por Membrana Extracorpórea/métodos , Insuficiencia Cardíaca/cirugía , Humanos , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
Although left ventricular assist device (LVAD) therapy is associated with improved survival, the impact of preoperative liver function on short-term outcomes is unclear. We conducted a retrospective review of all primary HeartMate 3 LVAD implants at a single center. Composite metrics of hepatic function including the model for end-stage liver disease (MELD), the MELD with sodium, and the MELD excluding international normalized ratio (MELD-XI) were evaluated. Receiver operator characteristic curves were compared to determine which equation was most predictive of 1-year survival. Primary stratification was based on MELD-XI tertiles. Secondary stratification was based on hypoalbuminemia (<3.0 mg/100 ml). A total of 94 patients underwent primary LVAD implantation from 2017 to 2022. MELD-XI and hypoalbuminemia were most associated with 1-year outcomes. When stratified by MELD tertiles, higher MELD was strongly associated with decreased 30 days (100.00% vs 100.00% vs 90.32%, p = 0.04), 1-year (93.00% vs 93.32% vs 69.79%, p = 0.01), and 2-year survival (93.00% vs 83.21% vs 69.79%, p = 0.04). In addition, while hypoalbuminemia was associated with similar 30 days (97.87% vs 95.74%, p = 0.56) survival, it was associated with a significant decrease in 1-year (92.93% vs 77.92%, p = 0.03) and 2-year survival (92.93% vs 68.89%, p <0.01). These results persisted on multivariable analysis for both MELD-XI score (p = 0.04) and hypoalbuminemia (p = 0.04). In conclusion, this is the first study to demonstrate that preoperative MELD-XI score and serum albumin levels are associated with short-term HeartMate 3 outcomes.
Asunto(s)
Enfermedad Hepática en Estado Terminal , Hipoalbuminemia , Enfermedad Hepática en Estado Terminal/complicaciones , Enfermedad Hepática en Estado Terminal/cirugía , Humanos , Hipoalbuminemia/epidemiología , Pronóstico , Estudios Retrospectivos , Albúmina Sérica , Índice de Severidad de la Enfermedad , SodioRESUMEN
BACKGROUND: Extracorporeal membrane oxygenation (ECMO) has been associated with acceptable short-term survival in patients with refractory respiratory failure secondary to coronavirus disease 2019 (COVID-19) pneumonia. Previous studies have demonstrated acceptable long-term outcomes in patients supported with ECMO for respiratory failure of other etiologies. However, long-term survival and functional outcomes in COVID ECMO patients remain unknown. METHODS: We conducted a retrospective review of all COVID patients requiring ECMO at our hospital. The primary outcomes measured were survival to discharge and contemporary survival. Secondary outcomes included two simple functional assessments: the ongoing need for oxygen supplementation and the ability to return to work. Survival was calculated using the Kaplan-Meier method. Hazard ratios were calculated using Cox hazards regression models. RESULTS: From 2020 to 2021, 48 COVID patients have been supported with ECMO at our hospital. Four patients remain on support and were excluded from further analysis. The average age was 47 ± 8 years, 34 (77%) were males, and the plurality (19, 43%) were Hispanic. Median duration of support was 23 (12-51) days. Median follow-up was 106 (29-226) days. Survival to discharge was 59%. Kaplan-Meier 180-day survival was 51%. Long-term survival conditioned on survival to discharge was 89%. In evaluating functional outcomes, the overwhelming majority of patients no longer required oxygen supplementation (74%), and most had returned to work (52%). CONCLUSION: In conclusion, COVID ECMO patients have acceptable intermediate-term survival with adequate functional recovery.
Asunto(s)
COVID-19 , Oxigenación por Membrana Extracorpórea , Insuficiencia Respiratoria , Adulto , COVID-19/terapia , Humanos , Masculino , Persona de Mediana Edad , Insuficiencia Respiratoria/etiología , Insuficiencia Respiratoria/terapia , Estudios Retrospectivos , SARS-CoV-2Asunto(s)
Procedimientos Quirúrgicos Cardíacos/economía , Educación de Postgrado en Medicina/economía , Administración Financiera/organización & administración , Internado y Residencia/economía , Cirugía Torácica/economía , Procedimientos Quirúrgicos Cardíacos/educación , Humanos , Cirugía Torácica/educaciónRESUMEN
Kinetoplastid parasites are model eukaryotes with a complex cell cycle that is highly regulated both spatially and temporally. In addition, diseases caused by these parasites continue to have a significant impact on human and animal health worldwide. While there have been advancements in chemotherapy for these diseases, there is a continual need for an arsenal of compounds that have robust anti-parasite activity with minimal impact on the human host. While investigating a series of 2,3-diphenyl-2,3-dihydro-4H-1,3-thiaza-4-one heterocycles with potential activity against these parasites, we found a pyridothiazinone that inhibits growth of the monoxenous parasite Crithidia fasciculata and two life cycle stages of Trypanosoma brucei. This inhibition is more pronounced in T. brucei and is associated with an unusual pre-abscission cell cycle arrest. Exploring the mode of action for these and related compounds in kinetoplastids may provide tools with which to explore cell cycle regulation in these important organisms.
Asunto(s)
Parásitos , Trypanosoma brucei brucei , Animales , Compuestos de Bifenilo , Crithidia fasciculata , Citocinesis , HumanosRESUMEN
BACKGROUND: Although the incidence of mitral valve (MV) surgery after previous open-heart surgery is increasing, there is no consensus regarding the optimal surgical approach. Reoperative MV surgery is most commonly performed via sternotomy (ST). We sought to determine whether minimally-invasive (MIS) reoperative MV surgery is safe and feasible. METHODS: All patients with a history of ST undergoing MV surgery with or without concomitant tricuspid or atrial fibrillation surgery at a single institution from 2007 to 2018 were retrospectively reviewed. ST and MIS approaches were compared using propensity-matched analysis. The coprimary endpoints were operative mortality and 1-year survival, and secondary endpoints were operative complications and length of stay. RESULTS: A total of 305 isolated MV reoperations were performed: 199 (65%) MIS and 106 (35%) ST. MIS patients were older than ST patients (71 [63, 76.5] vs. 66 [56, 72] years, p < .01), more likely to have undergone prior coronary artery bypass grafting (57% vs. 27%, p < .01), and less likely to have had prior valve surgery (55% vs. 78%, p < .01). In unmatched comparisons, operative mortality was significantly lower among MIS patients (3.0% vs. 8.5%, p = .04), but 1-year mortality was similar (14.4% vs. 15.6%, p = .8). After propensity matching, 88 pairs had excellent balance across baseline characteristics. Mortality was similar among MIS and ST patients at 30 days (3.4% vs. 8%, p = .19) and 1 year (15.9% vs. 16.5%, p = .9). RBC and fresh frozen plasma transfusions were significantly lower in the MIS group (p < .01). CONCLUSIONS: A minimally invasive approach is a safe alternative in patients with prior ST undergoing MV surgery.
Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Implantación de Prótesis de Válvulas Cardíacas , Humanos , Procedimientos Quirúrgicos Mínimamente Invasivos , Válvula Mitral/cirugía , Estudios Retrospectivos , Esternotomía , Resultado del TratamientoRESUMEN
BACKGROUND AND AIM OF STUDY: The convergent procedure (CVP) is a hybrid ablation technique via a subxiphoid incision that has recently emerged as a treatment option for non-paroxysmal atrial fibrillation (npAF). By combining endocardial and epicardial ablation into a simultaneous or staged procedure, the pulmonary vein and posterior left atrium can be isolated with transmural lesion sets while minimizing the risk of proarrhythmic gaps that are a known limitation with endocardial linear lesion sets. We reviewed the 12-month outcomes in patients who underwent CVP compared to those who underwent endocardial catheter ablation (CA) and surgical ablation (SA). METHODS: A literature search was conducted using the PubMed database for publications related to CVP. Selected studies included detailed 12-month follow-up of patients, patient characteristics, periprocedural complications, use of antiarrhythmic drugs (AADs), and monitoring method. RESULTS: Five studies with 340 patients who underwent CVP between January 2009 and March 2017 were selected for this review. A total of 8.5% of patients had paroxysmal AF (pAF), 42.2% had persistent AF (peAF), and 49.1% had long-standing persistent AF (lspAF). At 12 months, 81.9% of patients were in sinus rhythm, while 54.1% of patients were in sinus rhythm while not taking AADs. The overall complication rate was 10%. CONCLUSION: CVP had better 1-year efficacy in eliminating AF when compared to CA. However, SA, specifically the Cox Maze IV, had lower rates of AF recurrence in the npAF patient population. Despite its promising 1-year efficacy rates, the periprocedural complication rate for CVP was significantly higher than both CA and SA.
Asunto(s)
Técnicas de Ablación/métodos , Fibrilación Atrial/cirugía , Ablación por Catéter/métodos , Endocardio/cirugía , Pericardio/cirugía , Humanos , Recurrencia , Factores de Tiempo , Resultado del TratamientoRESUMEN
Left ventricular assist devices (LVADs) have improved clinical outcomes and quality of life for those with end-stage heart failure. However, the costs and risks associated with these devices necessitate appropriate patient selection. LVAD candidates are becoming increasingly more obese and there are conflicting reports regarding obesity's effect on outcomes. Hence, we sought to evaluate the impact of extreme obesity on clinical outcomes after LVAD placement. Consecutive LVAD implantation patients at our center from June 2008 to May 2016 were studied retrospectively. We compared patients with a body mass index (BMI) ≥40 kg/m2 (extremely obese) to those with BMI < 40 kg/m2 with respect to patient characteristics and surgical outcomes, including survival. 252 patients were included in this analysis, 30 (11.9%) of whom met the definition of extreme obesity. We found that patients with extreme obesity were significantly younger (47[33, 57] vs. 60[52, 67] years, P < 0.001) with fewer prior sternotomies (16.7% vs. 36.0%, P = 0.04). They had higher rates of pump thrombosis (30% vs. 9.0%, P = 0.003) and stage 2/3 acute kidney injury (46.7% vs. 27.0%, P = 0.003), but there were no differences in 30-day or 1-year survival, even after adjusting for age and clinical factors. Extreme obesity does not appear to place LVAD implantation patients at a higher risk for mortality compared to those who are not extremely obese; however, extreme obesity was associated with an increased risk of pump thrombosis, suggesting that these patients may require additional care to reduce the need for urgent device exchange.
Asunto(s)
Insuficiencia Cardíaca/cirugía , Corazón Auxiliar , Obesidad Mórbida/complicaciones , Complicaciones Posoperatorias/epidemiología , Implantación de Prótesis/efectos adversos , Adulto , Anciano , Índice de Masa Corporal , Femenino , Ventrículos Cardíacos/cirugía , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/etiología , Implantación de Prótesis/métodos , Calidad de Vida , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
Mitochondria are central organelles in cellular metabolism. Their structure is highly dynamic, allowing them to adapt to different energy requirements, to be partitioned during cell division, and to maintain functionality. Mitochondrial dynamics, including membrane fusion and fission reactions, are well studied in yeast and mammals but it is not known if these processes are conserved throughout eukaryotic evolution. Kinetoplastid parasites are some of the earliest-diverging eukaryotes to retain a mitochondrion. Each cell has only a single mitochondrial organelle, making them an interesting model for the role of dynamics in controlling mitochondrial architecture. We have investigated the mitochondrial division cycle in the kinetoplastid Crithidia fasciculata. The majority of mitochondrial biogenesis occurs during the G1 phase of the cell cycle, and the mitochondrion is divided symmetrically in a process coincident with cytokinesis. Live cell imaging revealed that the mitochondrion is highly dynamic, with frequent changes in the topology of the branched network. These remodeling reactions include tubule fission, fusion, and sliding, as well as new tubule formation. We hypothesize that the function of this dynamic remodeling is to homogenize mitochondrial contents and to facilitate rapid transport of mitochondria-encoded gene products from the area containing the mitochondrial nucleoid to other parts of the organelle.
Asunto(s)
Crithidia fasciculata/metabolismo , Fase G1/fisiología , Mitocondrias/metabolismo , Dinámicas Mitocondriales/fisiología , Crithidia fasciculata/citologíaRESUMEN
Self-assembled peptide-based hydrogels are emerging materials that have been exploited for wound healing, drug delivery, tissue engineering, and other applications. In comparison to synthetic polymer hydrogels, supramolecular peptide-based gels have advantages in biocompatibility, biodegradability, and ease of synthesis and modification. Modification of the emergent viscoelasticity of peptide hydrogels in a stimulus responsive fashion is a longstanding goal in the development of next-generation materials. In an effort to selectively modulate hydrogel viscoelasticity, we report herein a method to enhance the elasticity of ß-sheet peptide hydrogels using specific molecular recognition events between functionalized hydrogel fibrils and biomolecules. Two distinct biomolecular recognition strategies are demonstrated: oligonucleotide Watson-Crick duplex formation between peptide nucleic acid (PNA) modified fibrils with a bridging oligonucleotide and protein-ligand recognition between mannose modified fibrils with concanavalin A. These methods to modulate hydrogel elasticity should be broadly adaptable in the context of these materials to a wide variety of molecular recognition partners.
Asunto(s)
Materiales Biocompatibles/química , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Ácidos Nucleicos de Péptidos/química , Péptidos/química , Materiales Biocompatibles/síntesis química , Sistemas de Liberación de Medicamentos , Elasticidad , Humanos , Hidrogel de Polietilenoglicol-Dimetacrilato/síntesis química , Ácidos Nucleicos de Péptidos/síntesis química , Péptidos/síntesis química , Polímeros/síntesis química , Polímeros/química , Ingeniería de TejidosRESUMEN
The display of functional proteins on self-assembled peptide nanofibrils is challenging since the steric bulk of proteins attached to simple self-assembling peptides often impedes incorporation into nanofibrils. Herein is described a split-protein strategy to tether functional proteins to preassembled peptide nanofibrils. In this strategy, a short affinity motif peptide derived from a split protein system is appended to a self-assembly motif (the amphipathic Ac-(FKFE)2-NH2 peptide) to form an affinity-assembly fusion peptide. The small size of the affinity motif allows the affinity-assembly fusion peptide to be readily incorporated into peptide nanofibrils that display the affinity motif when the affinity-assembly peptide is coassembled with Ac-(FKFE)2-NH2. Introduction of the split-protein that is complementary to the affinity motif to the assembled nanofibrils results in efficient, multivalent attachment of functional proteins to the peptide nanofibrils. This strategy is demonstrated with two split-protein systems, ribonuclease S' (RNase S') and split green fluorescent protein (GFP).
Asunto(s)
Proteínas Fluorescentes Verdes/química , Nanofibras/química , Péptidos/química , Ribonucleasas/química , Sustancias Macromoleculares/síntesis química , Sustancias Macromoleculares/química , Modelos Moleculares , Tamaño de la Partícula , Péptidos/síntesis químicaRESUMEN
Excitotoxicity was originally postulated to be a late stage side effect of Alzheimer׳s disease (AD)-related neurodegeneration, however more recent studies indicate that it may occur early in AD and contribute to the neurodegenerative process. Tau and amyloid beta (Aß), the main components of neurofibrillary tangles (NFTs) and amyloid plaques, have been implicated in cooperatively and independently facilitating excitotoxicity. Our study investigated the roles of tau and Aß in AD-related excitotoxicity. In vivo studies showed that tau knockout (tau(-/-)) mice were significantly protected from seizures and hippocampal superoxide production induced with the glutamate analog, kainic acid (KA). We hypothesized that tau accomplished this by facilitating KA-induced Ca(2+) influx into neurons, however lentiviral tau knockdown failed to ameliorate KA-induced Ca(2+) influx into primary rat cortical neurons. We further investigated if tau cooperated with Aß to facilitate KA-induced Ca(2+) influx. While Aß biphasically modulated the KA-induced Cacyt(2+) responses, tau knockdown continued to have no effect. Therefore, tau facilitates KA-induced seizures and superoxide production in a manner that does not involve facilitation of Ca(2+) influx through KA receptors (KAR). On the other hand, acute pretreatment with Aß (10 min) enhanced KA-induced Ca(2+) influx, while chronic Aß (24 h) significantly reduced it, regardless of tau knockdown. Given previously published connections between Aß, group 1 metabotropic glutamate receptors (mGluRs), and KAR regulation, we hypothesized that Aß modulates KAR via a G-protein coupled receptor pathway mediated by group 1 mGluRs. We found that Aß did not activate group 1 mGluRs and inhibition of these receptors did not reverse Aß modulation of KA-induced Ca(2+) influx. Therefore, Aß biphasically regulates KAR via a mechanism that does not involve group 1mGluR activation.
Asunto(s)
Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/toxicidad , Corteza Cerebral/metabolismo , Convulsiones/metabolismo , Proteínas tau/metabolismo , Enfermedad de Alzheimer/complicaciones , Péptidos beta-Amiloides/metabolismo , Animales , Calcio/metabolismo , Corteza Cerebral/efectos de los fármacos , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Ácido Kaínico/administración & dosificación , Ratones , Ratones Noqueados , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Ratas , Especies Reactivas de Oxígeno/metabolismo , Receptores de Ácido Kaínico/agonistas , Receptores de Ácido Kaínico/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Convulsiones/inducido químicamente , Convulsiones/etiología , Superóxidos/metabolismo , Proteínas tau/genéticaRESUMEN
Cationic amyloid fibrils, including the Semen Enhancer of Virus Infection (SEVI), have recently been described in human semen. Simple methods for quantitating these fibrils are needed to improve our understanding of their biological function. We performed high-throughput screening to identify molecules that bind SEVI, and identified a small molecule (8E2), that fluoresced brightly in the presence of SEVI and other cationic fibrils. 8E2 bound SEVI with almost 40-fold greater affinity than thioflavin-T, and could efficiently detect high molecular weight fibrils in human seminal fluid.
Asunto(s)
Amiloide/análisis , Semen/química , Cationes/análisis , Humanos , Estructura Molecular , Espectrometría de FluorescenciaRESUMEN
We used CDK4/hTERT-immortalized normal human bronchial epithelial cells (HBEC) from several individuals to study lung cancer pathogenesis by introducing combinations of common lung cancer oncogenic changes (p53, KRAS, and MYC) and followed the stepwise transformation of HBECs to full malignancy. This model showed that: (i) the combination of five genetic alterations (CDK4, hTERT, sh-p53, KRAS(V12), and c-MYC) is sufficient for full tumorigenic conversion of HBECs; (ii) genetically identical clones of transformed HBECs exhibit pronounced differences in tumor growth, histology, and differentiation; (iii) HBECs from different individuals vary in their sensitivity to transformation by these oncogenic manipulations; (iv) high levels of KRAS(V12) are required for full malignant transformation of HBECs, however, prior loss of p53 function is required to prevent oncogene-induced senescence; (v) overexpression of c-MYC greatly enhances malignancy but only in the context of sh-p53+KRAS(V12); (vi) growth of parental HBECs in serum-containing medium induces differentiation, whereas growth of oncogenically manipulated HBECs in serum increases in vivo tumorigenicity, decreases tumor latency, produces more undifferentiated tumors, and induces epithelial-to-mesenchymal transition (EMT); (vii) oncogenic transformation of HBECs leads to increased sensitivity to standard chemotherapy doublets; (viii) an mRNA signature derived by comparing tumorigenic versus nontumorigenic clones was predictive of outcome in patients with lung cancer. Collectively, our findings show that this HBEC model system can be used to study the effect of oncogenic mutations, their expression levels, and serum-derived environmental effects in malignant transformation, while also providing clinically translatable applications such as development of prognostic signatures and drug response phenotypes.
Asunto(s)
Bronquios/patología , Carcinogénesis/patología , Células Epiteliales/metabolismo , Células Epiteliales/patología , Animales , Carcinogénesis/genética , Diferenciación Celular , Línea Celular Tumoral , Proliferación Celular , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/patología , Senescencia Celular , Transición Epitelial-Mesenquimal , Femenino , Técnicas de Silenciamiento del Gen , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Ratones , Ratones Endogámicos NOD , Modelos Biológicos , Proteínas Mutantes/metabolismo , Adhesión en Parafina , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteínas Proto-Oncogénicas p21(ras) , Fijación del Tejido , Proteína p53 Supresora de Tumor/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto , Proteínas ras/metabolismoRESUMEN
Amphipathic peptides composed of alternating hydrophobic and hydrophilic amino acids self-assemble into amyloid-inspired, ß-sheet nanoribbon fibrils. Herein, we report a new fibril type that is formed from equimolar mixtures of enantiomeric amphipathic peptides (L- and D-(FKFE)(2)). Spectroscopic analysis indicates that these peptides do not self-sort and assemble into enantiomeric fibrils composed of all-l and all-d peptides, but rather coassemble into fibrils that contain alternating L- and D-peptides in a "rippled ß-sheet" orientation. Isothermal titration calorimetry indicates an enthalpic advantage for rippled ß-sheet coassembly compared to self-sorted ß-sheet assembly of enantiomeric peptides.
Asunto(s)
Amiloide/química , Péptidos/química , Secuencia de Aminoácidos , Aminoácidos/química , Amiloide/ultraestructura , Interacciones Hidrofóbicas e Hidrofílicas , Modelos Moleculares , Datos de Secuencia Molecular , Estructura Secundaria de Proteína , Espectrofotometría InfrarrojaRESUMEN
Amyloid fibrils contained in semen, known as SEVI, or semen-derived enhancer of viral infection, have been shown to increase the infectivity of HIV dramatically. However, previous work with these fibrils has suggested that extensive time and nonphysiologic levels of agitation are necessary to induce amyloid formation from the precursor peptide (a proteolytic cleavage product of prostatic acid phosphatase, PAP(248-286)). Here, we show that fibril formation by PAP(248-286) is accelerated dramatically in the presence of seminal plasma (SP) and that agitation is not required for fibrillization in this setting. Analysis of the effects of specific SP components on fibril formation by PAP(248-286) revealed that this effect is primarily due to the anionic buffer components of SP (notably inorganic phosphate and sodium bicarbonate). Divalent cations present in SP had little effect on the kinetics of fibril formation, but physiologic levels of Zn(2+) strongly protected SEVI fibrils from degradation by seminal proteases. Taken together, these data suggest that in the in vivo environment, PAP(248-286) is likely to form fibrils efficiently, thus providing an explanation for the presence of SEVI in human semen.
Asunto(s)
Amiloide/química , VIH-1/patogenicidad , Fragmentos de Péptidos/química , Multimerización de Proteína , Proteínas Tirosina Fosfatasas/química , Semen/química , Amiloide/metabolismo , Amiloide/ultraestructura , Tampones (Química) , Línea Celular , Infecciones por VIH/virología , Humanos , Cinética , Fragmentos de Péptidos/fisiología , Péptido Hidrolasas/química , Estabilidad Proteica , Proteínas Tirosina Fosfatasas/fisiología , Proteolisis , Semen/metabolismo , Zinc/químicaRESUMEN
Semen-derived enhancer of viral infection (SEVI), an amyloid fibril formed from a cationic peptide fragment of prostatic acidic phosphatase (PAP), dramatically enhances the infectivity of human immunodeficiency virus type 1 (HIV-1). Insoluble, sedimentable fibrils contribute to SEVI-mediated enhancement of virus infection. However, the SEVI-forming PAP(248-286) peptide is able to produce infection-enhancing structures much more quickly than it forms amyloid fibrils. This suggests that soluble supramolecular assemblies may enhance HIV-1 infection. To address this question, non-SEVI amyloid-like fibrils were derived from general amphipathic peptides of sequence Ac-K(n)(XKXE)(2)-NH(2). These cationic peptides efficiently self-assembled to form soluble, fibril-like structures that were, in some cases, able to enhance HIV-1 infection even more efficiently than SEVI. Experiments were also performed to determine whether agents that efficiently shield the charged surface of SEVI fibrils block SEVI-mediated infection-enhancement. To do this, we generated self-assembling anionic peptides of sequence Ac-E(n)(XKXE)(2)-NH(2). One of these peptides completely abrogated SEVI-mediated enhancement of HIV-1 infection, without altering HIV-1 infectivity in the absence of SEVI. Collectively, these data suggest that soluble SEVI assemblies may mediate infection-enhancement, and that anionic peptide supramolecular assemblies have the potential to act as anti-SEVI microbicides.
Asunto(s)
VIH-1/efectos de los fármacos , VIH-1/patogenicidad , Péptidos/metabolismo , Péptidos/farmacología , Secuencia de Aminoácidos , Línea Celular , Modelos Moleculares , Datos de Secuencia Molecular , Péptidos/química , Estructura Secundaria de Proteína , SolubilidadRESUMEN
Although several thousand patients are diagnosed with sarcoma annually in the United States, metastases to the heart are very uncommon. In this case report, an overall low frequency cancer presents masquerading with common cardiac symptomology. This case illustrates the importance for detailed diagnostic cardiac evaluations and heightened suspicion by physicians to consider metastatic disease to the heart in cancer patients with cardiovascular complications. Also discussed is a review of surgical and chemotherapeutic options for this problem.