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1.
Surg Clin North Am ; 104(4): 891-908, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38944507

RESUMEN

Pancreatic neuroendocrine tumors (PNETs) arise from neuroendocrine cells and are a rare class of heterogenous tumors with increasing incidence. The diagnosis, staging, treatment, and prognosis of PNETs depend heavily on identifying the histologic features and biological mechanisms. Here, the authors provide an overview of the diagnostic workup (biomarkers and imaging), grade, and staging of PNETs. The authors also explore associated genetic mutations and molecular pathways and describe updated guidelines on surgical and systemic treatment modalities.


Asunto(s)
Tumores Neuroendocrinos , Neoplasias Pancreáticas , Humanos , Neoplasias Pancreáticas/cirugía , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/patología , Tumores Neuroendocrinos/cirugía , Tumores Neuroendocrinos/diagnóstico , Tumores Neuroendocrinos/patología , Estadificación de Neoplasias , Pancreatectomía/métodos , Pronóstico
2.
Nutrients ; 16(3)2024 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-38337615

RESUMEN

Atherosclerosis and resulting cardiovascular disease are the leading causes of death in the US. Hyperhomocysteinemia (HHcy), or the accumulation of the intermediate amino acid homocysteine, is an independent risk factor for atherosclerosis, but the intricate biological processes mediating this effect remain elusive. Several factors regulate homocysteine levels, including the activity of several enzymes and adequate levels of their coenzymes, including pyridoxal phosphate (vitamin B6), folate (vitamin B9), and methylcobalamin (vitamin B12). To better understand the biological influence of HHcy on the development and progression of atherosclerosis, apolipoprotein-E-deficient (apoE-/- mice), a model for human atherosclerosis, were fed a hyperhomocysteinemic diet (low in methyl donors and B vitamins) (HHD) or a control diet (CD). After eight weeks, the plasma, aorta, and liver were collected to quantify methylation metabolites, while plasma was also used for a broad targeted metabolomic analysis. Aortic plaque burden in the brachiocephalic artery (BCA) was quantified via 14T magnetic resonance imaging (MRI). A severe accumulation of plasma and hepatic homocysteine and an increased BCA plaque burden were observed, thus confirming the atherogenic effect of the HHD. Moreover, a decreased methylation capacity in the plasma and aorta, indirectly assessed by the ratio of S-adenosylmethionine to S-adenosylhomocysteine (SAM:SAH) was detected in HHD mice together with a 172-fold increase in aortic cystathionine levels, indicating increased flux through the transsulfuration pathway. Betaine and its metabolic precursor, choline, were significantly decreased in the livers of HHD mice versus CD mice. Widespread changes in the plasma metabolome of HHD mice versus CD animals were detected, including alterations in acylcarnitines, amino acids, bile acids, ceramides, sphingomyelins, triacylglycerol levels, and several indicators of dysfunctional lipid metabolism. This study confirms the relevance of severe HHcy in the progression of vascular plaque and suggests novel metabolic pathways implicated in the pathophysiology of atherosclerosis.


Asunto(s)
Aterosclerosis , Hiperhomocisteinemia , Ratones , Animales , Humanos , Aterosclerosis/metabolismo , Dieta , S-Adenosilmetionina/metabolismo , Ácido Fólico/efectos adversos , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Metaboloma , Homocisteína/metabolismo , Apolipoproteínas/metabolismo
3.
RSC Med Chem ; 14(10): 2035-2047, 2023 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-37859710

RESUMEN

The phosphatidylinositol 5-phosphate 4-kinases (PI5P4Ks) are therapeutic targets for diseases such as cancer, neurodegeneration and immunological disorders as they are key components in regulating cell signalling pathways. In an effort to make probe molecules available for further exploring these targets, we have previously reported PI5P4Kα-selective and PI5P4Kγ-selective ligands. Herein we report the rational design of PI5P4Kα/γ dual inhibitors, using knowledge gained during the development of selective inhibitors for these proteins. ARUK2007145 (39) is disclosed as a potent, cell-active probe molecule with ADMET properties amenable to conducting experiments in cells.

4.
Cancers (Basel) ; 15(15)2023 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-37568572

RESUMEN

Pancreatic neuroendocrine neoplasms (pNENs) are a heterogeneous group of tumors derived from multiple neuroendocrine origin cell subtypes. Incidence rates for pNENs have steadily risen over the last decade, and outcomes continue to vary widely due to inability to properly screen. These tumors encompass a wide range of functional and non-functional subtypes, with their rarity and slow growth making therapeutic development difficult as most clinically used therapeutics are derived from retrospective analyses. Improved molecular understanding of these cancers has increased our knowledge of the tumor biology for pNENs. Despite these advances in our understanding of pNENs, there remains a dearth of models for further investigation. In this review, we will cover the current field of pNEN models, which include established cell lines, animal models such as mice and zebrafish, and three-dimensional (3D) cell models, and compare their uses in modeling various disease aspects. While no study model is a complete representation of pNEN biology, each has advantages which allow for new scientific understanding of these rare tumors. Future efforts and advancements in technology will continue to create new options in modeling these cancers.

5.
Artículo en Inglés | MEDLINE | ID: mdl-37297548

RESUMEN

The speciation of volatile organic compounds (VOCs) emitted from personal care products (PCPs) is complex and contributes to poor air quality and health risks to users via the inhalation exposure pathway. Detailed VOC emission profiles were generated for 26 sunscreen products; consequently, variability was observed between products, even though they were all designed for the same purpose. Some were found to contain fragrance compounds not labelled on their ingredients list. Five contaminant VOCs were identified (benzene, toluene, ethylbenzene, o-xylene, and p-xylene); headspace sampling of an additional 18 randomly selected products indicated that ethanol originating from fossil petroleum was a potential source. The gas phase emission rates of the VOCs were quantified for 15 of the most commonly emitted species using SIFT-MS. A wide range of emission rates were observed between the products. Usage estimates were made based on the recommended dose per body surface area, for which the total mass of VOCs emitted from one full-body application dose was in the range of 1.49 × 103-4.52 × 103 mg and 1.35 × 102-4.11 × 102 mg for facial application (men aged 16+; children aged 2-4). Depending on age and sex, an estimated 9.8-30 mg of ethanol is inhaled from one facial application of sunscreen.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Compuestos Orgánicos Volátiles , Humanos , Masculino , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Monitoreo del Ambiente , Etanol , Exposición por Inhalación , Protectores Solares , Compuestos Orgánicos Volátiles/análisis , Femenino , Preescolar , Adolescente
6.
RSC Med Chem ; 14(5): 934-946, 2023 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-37252102

RESUMEN

The phosphatidylinositol 5-phosphate 4-kinases (PI5P4Ks) play a central role in regulating cell signalling pathways and, as such, have become therapeutic targets for diseases such as cancer, neurodegeneration and immunological disorders. Many of the PI5P4Kα inhibitors that have been reported to date have suffered from poor selectivity and/or potency and the availability of better tool molecules would facilitate biological exploration. Herein we report a novel PI5P4Kα inhibitor chemotype that was identified through virtual screening. The series was optimised to deliver ARUK2002821 (36), a potent PI5P4Kα inhibitor (pIC50 = 8.0) which is selective vs. other PI5P4K isoforms and has broad selectivity against lipid and protein kinases. ADMET and target engagement data are provided for this tool molecule and others in the series, as well as an X-ray structure of 36 solved in complex with its PI5P4Kα target.

7.
Environ Sci Technol ; 57(21): 8026-8034, 2023 05 30.
Artículo en Inglés | MEDLINE | ID: mdl-37191998

RESUMEN

There are widespread policy assumptions that the phase-out of gasoline and diesel internal combustion engines will over time lead to much reduced emissions of Volatile Organic Compounds (VOCs) from road transport and related fuels. However, the use of real-world emissions measurements from a new mobile air quality monitoring station demonstrated a large underestimation of alcohol-based species in road transport emissions inventories. Scaling of industry sales statistics enabled the discrepancy to be attributed to the use of ancillary solvent products such as screenwash and deicer which are not included in internationally applied vehicle emission methodologies. A fleet average nonfuel nonexhaust VOC emission factor of 58 ± 39 mg veh-1 km-1 was calculated for the missing source, which is greater than the total of all VOCs emitted from vehicle exhausts and their associated evaporative fuel losses. These emissions are independent of the vehicle energy/propulsion system and therefore applicable to all road vehicle types including those with battery-electric powertrains. In contrast to predictions, vehicle VOC emissions may actually increase given a predicted growth in total vehicle kilometers driven in a future electrified fleet and will undergo a complete VOC respeciation due to the source change.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Compuestos Orgánicos Volátiles , Contaminantes Atmosféricos/análisis , Compuestos Orgánicos Volátiles/análisis , Emisiones de Vehículos/análisis , Contaminación del Aire/análisis , Gasolina/análisis
8.
Environ Sci Process Impacts ; 25(4): 805-817, 2023 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-36883522

RESUMEN

Plug-in fragrance diffusers are one of myriad volatile organic compound-containing consumer products that are commonly found in homes. The perturbing effects of using a commercial diffuser indoors were evaluated using a study group of 60 homes in Ashford, UK. Air samples were taken over 3 day periods with the diffuser switched on and in a parallel set of control homes where it was off. At least four measurements were taken in each home using vacuum-release into 6 L silica-coated canisters and with >40 VOCs quantified using gas chromatography with FID and MS (GC-FID-QMS). Occupants self-reported their use of other VOC-containing products. The variability between homes was very high with the 72 hour sum of all measured VOCs ranging between 30 and >5000 µg m-3, dominated by n/i-butane, propane, and ethanol. For those homes in the lowest quartile of air exchange rate (identified using CO2 and TVOC sensors as proxies) the use of a diffuser led to a statistically significant increase (p-value < 0.02) in the summed concentration of detectable fragrance VOCs and some individual species, e.g. alpha pinene rising from a median of 9 µg m-3 to 15 µg m-3 (p-value < 0.02). The observed increments were broadly in line with model-calculated estimates based on fragrance weight loss, room sizes and air exchange rates.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire Interior , Compuestos Orgánicos Volátiles , Humanos , Compuestos Orgánicos Volátiles/análisis , Monitoreo del Ambiente/métodos , Contaminación del Aire Interior/análisis , Contaminantes Atmosféricos/análisis , Odorantes/análisis
9.
J Med Chem ; 66(1): 804-821, 2023 01 12.
Artículo en Inglés | MEDLINE | ID: mdl-36516442

RESUMEN

Owing to their central role in regulating cell signaling pathways, the phosphatidylinositol 5-phosphate 4-kinases (PI5P4Ks) are attractive therapeutic targets in diseases such as cancer, neurodegeneration, and immunological disorders. Until now, tool molecules for these kinases have been either limited in potency or isoform selectivity, which has hampered further investigation of biology and drug development. Herein we describe the virtual screening workflow which identified a series of thienylpyrimidines as PI5P4Kγ-selective inhibitors, as well as the medicinal chemistry optimization of this chemotype, to provide potent and selective tool molecules for further use. In vivo pharmacokinetics data are presented for exemplar tool molecules, along with an X-ray structure for ARUK2001607 (15) in complex with PI5P4Kγ, along with its selectivity data against >150 kinases and a Cerep safety panel.


Asunto(s)
Neoplasias , Transducción de Señal , Humanos , Isoformas de Proteínas , Encéfalo , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/química
10.
Am J Health Syst Pharm ; 80(Suppl 3): S119-S122, 2023 08 18.
Artículo en Inglés | MEDLINE | ID: mdl-36566506

RESUMEN

PURPOSE: Standardized processes to order and prepare medications can decrease the potential for error and provider uncertainty. Our health system utilizes a standard concentration policy, smart infusion pumps, and the electronic health record (EHR) to catalog, order, and deliver intravenous medications. A need for a more proactive and formalized process to ensure medication listings are harmonized between these 3 resources was identified. Standardizing these resources can reduce confusion, reduce time spent in pharmacy operations and nursing workflow, and may improve patient safety. The purpose of this quality improvement project was to compare and resolve inconsistencies between these 3 sources and to create a new process to assure uniformity in a complex work environment. SUMMARY: An audit-style comparison and evaluation of entries for continuous infusions within the standard concentration policy, the pump library, and the EHR was conducted. All continuous infusion entries within any one of these 3 sources were included. Key exclusion criteria included pediatric and neonatal infusions, intermittent infusions, and infusions in procedural areas. We compared the policy, the pump library, and the EHR to identify, document, and resolve discrepancies in medication name, concentration, rate, and volume; fluid restriction concentration; and upper and lower pump limits. A new method to ensure proactive continuity and consistent updates to the 3 sources was implemented into existing operational workflows. We recommended a total of 82 updates to policy (n = 48), the pump library (n = 30), and the EHR (n = 4) out of 187 continuous infusion entries. CONCLUSION: Standardizing infusion resources will reduce confusion, and improve pharmacy operations, nursing workflow, and patient safety.


Asunto(s)
Registros Electrónicos de Salud , Bombas de Infusión , Recién Nacido , Humanos , Niño , Centros Médicos Académicos , Administración Intravenosa , Políticas
11.
J Med Chem ; 65(4): 3359-3370, 2022 02 24.
Artículo en Inglés | MEDLINE | ID: mdl-35148092

RESUMEN

Phosphatidylinositol 5-phosphate 4-kinases (PI5P4Ks) are emerging as attractive therapeutic targets in diseases, such as cancer, immunological disorders, and neurodegeneration, owing to their central role in regulating cell signaling pathways that are either dysfunctional or can be modulated to promote cell survival. Different modes of binding may enhance inhibitor selectivity and reduce off-target effects in cells. Here, we describe efforts to improve the physicochemical properties of the selective PI5P4Kγ inhibitor, NIH-12848 (1). These improvements enabled the demonstration that this chemotype engages PI5P4Kγ in intact cells and that compounds from this series do not inhibit PI5P4Kα or PI5P4Kß. Furthermore, the first X-ray structure of PI5P4Kγ bound to an inhibitor has been determined with this chemotype, confirming an allosteric binding mode. An exemplar from this chemical series adopted two distinct modes of inhibition, including through binding to a putative lipid interaction site which is 18 Å from the ATP pocket.


Asunto(s)
Adenosina Trifosfato/metabolismo , Fosfotransferasas (Aceptor de Grupo Alcohol)/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacología , Quinazolinas/síntesis química , Quinazolinas/farmacología , Tiofenos/síntesis química , Tiofenos/farmacología , Regulación Alostérica/efectos de los fármacos , Unión Competitiva , Cristalografía por Rayos X , Humanos , Modelos Moleculares , Simulación del Acoplamiento Molecular , Fosfotransferasas (Aceptor de Grupo Alcohol)/química , Especificidad por Sustrato
12.
Indoor Air ; 32(1): e12948, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34816489

RESUMEN

Volatile organic compound (VOC) emissions from personal care products (PCPs) contribute to poor indoor air quality. Exposure to indoor VOCs is typically determined through ambient concentration measurements; however, for some PCPs the proximity of use to the nose and mouth may lead to disproportionately large inhaled doses. In this paper, we quantify emission factors for six common PCP ingredient VOCs (ethanol, 2-propanol, benzyl alcohol, 1,3-butanediol, t-butyl alcohol, and the grouping of monoterpenes as limonene) from 16 facial day-moisturizers using headspace analysis and selected ion flow-tube mass spectrometry. A wide range of emissions rates were observed across the range of products tested (e.g., ethanol 3.3-6.9 × 102  µg s-1  g[product]-1 , limonene 1.3 × 10-1 -4.1 × 10-1  µg s-1  g[product]-1 ). We use a mannequin head with reconstructed nose and mouth airways to sample VOCs from facial application at typical respiration volumes. A single facial application of moisturizer can lead to a much larger inhaled VOC dose than would be inhaled from typical indoor ambient air over 24 h (e.g., limonene up to ~×16 greater via facial application, ethanol up to ~×300). Emissions from facially applied PCPs typically decayed to background concentrations over periods ranging from 5 to 150 min.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire Interior , Cosméticos , Compuestos Orgánicos Volátiles , Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/análisis , Cosméticos/análisis , Monitoreo del Ambiente/métodos , Compuestos Orgánicos Volátiles/análisis
14.
PLoS One ; 16(3): e0248292, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33690647

RESUMEN

Low oxygen and mechanical loading may play roles in regulating the fibrocartilaginous phenotype of the human inner meniscus, but their combination in engineered tissues remains unstudied. Here, we investigated how continuous low oxygen ("hypoxia") combined with dynamic compression would affect the fibrocartilaginous "inner meniscus-like" matrix-forming phenotype of human meniscus fibrochondrocytes (MFCs) in a porous type I collagen scaffold. Freshly-seeded MFC scaffolds were cultured for 4 weeks in either 3 or 20% O2 or pre-cultured for 2 weeks in 3% O2 and then dynamically compressed for 2 weeks (10% strain, 1 Hz, 1 h/day, 5 days/week), all with or without TGF-ß3 supplementation. TGF-ß3 supplementation was found necessary to induce matrix formation by MFCs in the collagen scaffold regardless of oxygen tension and application of the dynamic compression loading regime. Neither hypoxia under static culture nor hypoxia combined with dynamic compression had significant effects on expression of specific protein and mRNA markers for the fibrocartilaginous matrix-forming phenotype. Mechanical properties significantly increased over the two-week loading period but were not different between static and dynamic-loaded tissues after the loading period. These findings indicate that 3% O2 applied immediately after scaffold seeding and dynamic compression to 10% strain do not affect the fibrocartilaginous matrix-forming phenotype of human MFCs in this type I collagen scaffold. It is possible that a delayed hypoxia treatment and an optimized pre-culture period and loading regime combination would have led to different outcomes.


Asunto(s)
Condrocitos , Matriz Extracelular/metabolismo , Menisco , Estrés Mecánico , Ingeniería de Tejidos , Adulto , Hipoxia de la Célula , Células Cultivadas , Condrocitos/citología , Condrocitos/metabolismo , Humanos , Masculino , Menisco/citología , Menisco/metabolismo
15.
JCO Precis Oncol ; 5: 1588-1602, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34994648

RESUMEN

PURPOSE: Clinical utility of up-front multigene panel testing (MGPT) is directly related to the frequency of pathogenic variants (PVs) in the population screened and how genetic findings can be used to guide treatment decision making and cancer prevention efforts. The benefit of MGPT for many common malignancies remains to be determined. In this study, we evaluated up-front MGPT in unselected patients with endometrial cancer (EC) to determine the frequency of PVs in cancer susceptibility genes. METHODS: Patients with EC were prospectively enrolled at nine Ohio institutions from October 1, 2017, to December 31, 2020. Nine hundred and sixty-one patients with newly diagnosed EC underwent clinical germline MGPT for 47 cancer susceptibility genes. In addition to estimating the prevalence of germline PVs, the number of individuals identified with Lynch syndrome (LS) was compared between MGPT and tumor-based screening. RESULTS: Likely pathogenic variants or PVs were identified in 97 of 961 women (10.1%). LS was diagnosed in 29 of 961 patients (3%; 95% CI, 2.1 to 4.3), with PVs in PMS2 most frequent. MGPT revealed nine patients with LS in addition to the 20 identified through routine tumor-based screening. BRCA1 and BRCA2 PVs were found in 1% (10 of 961; 95% CI, 0.6 to 1.9) of patients and that group was significantly enriched for type II ECs. CONCLUSION: This prospective, multicenter study revealed potentially actionable germline variants in 10% of unselected women with newly diagnosed EC, supporting the use of up-front MGPT for all EC patients. The discovery that BRCA1 or BRCA2 heterozygotes frequently had type II cancers points to therapeutic opportunities for women with aggressive histologic EC subtypes.


Asunto(s)
Neoplasias Endometriales/genética , Predisposición Genética a la Enfermedad , Pruebas Genéticas/métodos , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Genes BRCA1 , Genes BRCA2 , Humanos , Persona de Mediana Edad , Estudios Prospectivos
16.
ACS Med Chem Lett ; 11(8): 1539-1547, 2020 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-32832021

RESUMEN

Bifunctional molecules known as PROTACs simultaneously bind an E3 ligase and a protein of interest to direct ubiquitination and clearance of that protein, and they have emerged in the past decade as an exciting new paradigm in drug discovery. In order to investigate the permeability and properties of these large molecules, we synthesized two panels of PROTAC molecules, constructed from a range of protein-target ligands, linkers, and E3 ligase ligands. The androgen receptor, which is a well-studied protein in the PROTAC field was used as a model system. The physicochemical properties and permeability of PROTACs are discussed.

17.
Sci Rep ; 9(1): 17115, 2019 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-31723212

RESUMEN

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

18.
Front Oncol ; 9: 1067, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31681600

RESUMEN

Uterine cervix or vaginal cancers have inherent overactivity of ribonucleotide reductase (RNR), making these cancers rational targets for therapy based on interruption of cisplatin-radiotherapy-induced DNA damage repair. We conducted a pilot, open-label randomized phase II trial to evaluate the efficacy and safety of cisplatin-radiotherapy with or without triapine, a small molecule with RNR-inhibitory activity, in patients with advanced-stage uterine cervix or vaginal cancers (NCT01835171), as a lead in to a randomized phase III study (NCT02466971). A total of 26 women were randomly assigned to receive 6 weeks of daily radiotherapy followed by brachytherapy (80 Gy) and once-weekly cisplatin (40 mg m-2)-with or without three-times weekly intravenous triapine (25 mg m-2)-in one 56-days cycle. Primary end points were metabolic complete response by positron emission tomography and safety. Additional end points included the rate of clinical response, rate of methemoglobinemia, and progression-free survival. The addition of triapine to cisplatin-radiotherapy improved the rate of metabolic complete response from 69 to 92% (P = 0.32) and raised the 3-year progression-free survival estimate from 77 to 92% (hazard ratio for progression, 0.30; P = 0.27). The most frequent grade 3 or 4 adverse events in either treatment group included reversible leukopenia, neutropenia, fatigue, or electrolyte abnormalities. No significant differences were seen between the two groups in the rate of adverse events. Symptomatic methemoglobinemia was not encountered after triapine infusion. In conclusion, the addition of triapine to cisplatin-radiotherapy improved the rate of metabolic complete response in patients with advanced-stage uterine cervix or vaginal cancers without significant toxicity. A phase III trial adequately powered to evaluate progression-free and overall survival is underway (NCT02466971).

19.
Bioorg Med Chem Lett ; 29(20): 126611, 2019 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-31447084

RESUMEN

A series of novel allosteric antagonists of the GLP-1 receptor (GLP-1R), exemplified by HTL26119, are described. SBDD approaches were employed to identify HTL26119, exploiting structural understanding of the allosteric binding site of the closely related Glucagon receptor (GCGR) (Jazayeri et al., 2016) and the homology relationships between GCGR and GLP-1R. The region around residue C3476.36b of the GLP-1R receptor represents a key difference from GCGR and was targeted for selectivity for GLP-1R.


Asunto(s)
Receptor del Péptido 1 Similar al Glucagón/antagonistas & inhibidores , Compuestos Heterocíclicos/química , Regulación Alostérica/efectos de los fármacos , Sitio Alostérico , Secuencia de Aminoácidos , Diseño de Fármacos , Simulación del Acoplamiento Molecular , Estructura Molecular , Unión Proteica , Receptores de Glucagón/antagonistas & inhibidores , Transducción de Señal , Relación Estructura-Actividad
20.
ACS Appl Mater Interfaces ; 11(36): 33323-33335, 2019 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-31464413

RESUMEN

An ex vivo heart perfusion device preserves the donor heart in a warm beating state during transfer between extraction and implantation surgeries. One of the current challenges includes the use of rigid and noncompliant plastic tubes, which causes injuries to the heart at the junction between the tissue and the tube. The compliant and rapidly strain-stiffening mechanical property that generates a "J-shaped" stress-strain behavior is necessary for producing the Windkessel effect, which ensures continuous flow of blood through the aorta. In this study, we mimic the J-shaped and anisotropic stress-strain behavior of human aorta in synthetic elastomers to replace the problematic noncompliant plastic tube. First, we assess the mechanical properties of human (n = 1) and porcine aorta (n = 14) to quantify the nonlinear and anisotropic behavior under uniaxial tensile stress from five different regions of the aorta. Second, fabric-reinforced elastomer composites were prepared by reinforcing silicone elastomers with embedded fabrics in a trilayer geometry. The knitted structures of the fabric provide strain-stiffening as well as anisotropic mechanical properties of the resulting composite in a deterministic manner. By optimizing the combination between different elastomers and fabrics, the resulting composites matched the J-shaped and anisotropic stress-strain behavior of natural human and porcine aorta. Finally, improved analytical constitutive models based on Gent's and Mooney-Rivlin's constitutive model (to describe the elastomer matrix) combined with Holzapfel-Gasser-Ogden's model (to represent the stiffer fabrics) were developed to describe the J-shaped behavior of the natural aortas and the fabric-reinforced composites. We anticipate that the suggested fabric-reinforced silicone elastomer composite design concept can be used to develop complex soft biomaterials, as well as in emerging engineering fields such as soft robotics and microfluidics, where the Windkessel effect can be useful in regulating the flow of fluids.


Asunto(s)
Aorta/fisiología , Elastómeros/farmacología , Estrés Mecánico , Animales , Anisotropía , Aorta/efectos de los fármacos , Fenómenos Biomecánicos , Femenino , Humanos , Porcinos , Resistencia a la Tracción
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