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1.
Nature ; 595(7869): 730-734, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-34290403

RESUMEN

Hepatocellular carcinoma (HCC)-the most common form of liver cancer-is an aggressive malignancy with few effective treatment options1. Lenvatinib is a small-molecule inhibitor of multiple receptor tyrosine kinases that is used for the treatment of patients with advanced HCC, but this drug has only limited clinical benefit2. Here, using a kinome-centred CRISPR-Cas9 genetic screen, we show that inhibition of epidermal growth factor receptor (EGFR) is synthetic lethal with lenvatinib in liver cancer. The combination of the EGFR inhibitor gefitinib and lenvatinib displays potent anti-proliferative effects in vitro in liver cancer cell lines that express EGFR and in vivo in xenografted liver cancer cell lines, immunocompetent mouse models and patient-derived HCC tumours in mice. Mechanistically, inhibition of fibroblast growth factor receptor (FGFR)  by lenvatinib treatment leads to feedback activation of the EGFR-PAK2-ERK5 signalling axis, which is blocked by EGFR inhibition. Treatment of 12 patients with advanced HCC who were unresponsive to lenvatinib treatment with the combination of lenvatinib plus gefitinib (trial identifier NCT04642547) resulted in meaningful clinical responses. The combination therapy identified here may represent a promising strategy for the approximately 50% of patients with advanced HCC who have high levels of EGFR.


Asunto(s)
Antineoplásicos/farmacología , Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/metabolismo , Compuestos de Fenilurea/farmacología , Quinolinas/farmacología , Animales , Carcinoma Hepatocelular/tratamiento farmacológico , Línea Celular Tumoral , Resistencia a Antineoplásicos , Receptores ErbB/antagonistas & inhibidores , Receptores ErbB/metabolismo , Femenino , Gefitinib/farmacología , Humanos , Neoplasias Hepáticas/tratamiento farmacológico , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Receptores de Factores de Crecimiento de Fibroblastos , Transducción de Señal , Ensayos Antitumor por Modelo de Xenoinjerto
2.
Proc Natl Acad Sci U S A ; 121(9): e2319492121, 2024 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-38377196

RESUMEN

The Kirsten rat sarcoma viral oncogene homologue KRAS is among the most commonly mutated oncogenes in human cancers, thus representing an attractive target for precision oncology. The approval for clinical use of the first selective inhibitors of G12C mutant KRAS therefore holds great promise for cancer treatment. However, despite initial encouraging clinical results, the overall survival benefit that patients experience following treatment with these inhibitors has been disappointing to date, pointing toward the need to develop more powerful combination therapies. Here, we show that responsiveness to KRASG12C and pan-RAS inhibitors in KRAS-mutant lung and colon cancer cells is limited by feedback activation of the parallel MAP2K4-JNK-JUN pathway. Activation of this pathway leads to elevated expression of receptor tyrosine kinases that reactivate KRAS and its downstream effectors in the presence of drug. We find that the combination of sotorasib, a drug targeting KRASG12C, and the MAP2K4 inhibitor HRX-0233 prevents this feedback activation and is highly synergistic in a panel of KRASG12C-mutant lung and colon cancer cells. Moreover, combining HRX-0233 and sotorasib is well-tolerated and resulted in durable tumor shrinkage in mouse xenografts of human lung cancer cells, suggesting a therapeutic strategy for KRAS-driven cancers.


Asunto(s)
Antineoplásicos , Neoplasias del Colon , Neoplasias Pulmonares , Humanos , Animales , Ratones , Proteínas Proto-Oncogénicas p21(ras)/genética , Medicina de Precisión , Antineoplásicos/farmacología , Oncogenes , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/genética , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , Mutación , MAP Quinasa Quinasa 4
3.
EMBO Rep ; 25(5): 2220-2238, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38600345

RESUMEN

Perturbation of protein phosphorylation represents an attractive approach to cancer treatment. Besides kinase inhibitors, protein phosphatase inhibitors have been shown to have anti-cancer activity. A prime example is the small molecule LB-100, an inhibitor of protein phosphatases 2A/5 (PP2A/PP5), enzymes that affect cellular physiology. LB-100 has proven effective in pre-clinical models in combination with immunotherapy, but the molecular underpinnings of this synergy remain understood poorly. We report here a sensitivity of the mRNA splicing machinery to phosphorylation changes in response to LB-100 in colorectal adenocarcinoma. We observe enrichment for differentially phosphorylated sites within cancer-critical splicing nodes of U2 snRNP, SRSF and hnRNP proteins. Altered phosphorylation endows LB-100-treated colorectal adenocarcinoma cells with differential splicing patterns. In PP2A-inhibited cells, over 1000 events of exon skipping and intron retention affect regulators of genomic integrity. Finally, we show that LB-100-evoked alternative splicing leads to neoantigens that are presented by MHC class 1 at the cell surface. Our findings provide a potential explanation for the pre-clinical and clinical observations that LB-100 sensitizes cancer cells to immune checkpoint blockade.


Asunto(s)
Neoplasias del Colon , Empalme del ARN , Humanos , Neoplasias del Colon/genética , Neoplasias del Colon/inmunología , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/metabolismo , Empalme del ARN/efectos de los fármacos , Fosforilación , Línea Celular Tumoral , ARN Mensajero/genética , ARN Mensajero/metabolismo , Empalme Alternativo , Antígenos de Neoplasias/metabolismo , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/inmunología , Factores de Empalme Serina-Arginina/metabolismo , Factores de Empalme Serina-Arginina/genética , Proteína Fosfatasa 2/metabolismo , Inhibidores Enzimáticos/farmacología
4.
J Biol Chem ; 292(34): 14176-14187, 2017 08 25.
Artículo en Inglés | MEDLINE | ID: mdl-28663370

RESUMEN

Mitochondrial oxidation of nutrients is tightly regulated in response to the cellular environment and changes in energy demands. In vitro studies evaluating the mitochondrial capacity of oxidizing different substrates are important for understanding metabolic shifts in physiological adaptations and pathological conditions, but may be influenced by the nutrients present in the culture medium or by the utilization of endogenous stores. One such influence is exemplified by the Crabtree effect (the glucose-mediated inhibition of mitochondrial respiration) as most in vitro experiments are performed in glucose-containing media. Here, using high-resolution respirometry, we evaluated the oxidation of endogenous or exogenous substrates by cell lines harboring different metabolic profiles. We found that a 1-h deprivation of the main energetic nutrients is an appropriate strategy to abolish interference of endogenous or undesirable exogenous substrates with the cellular capacity of oxidizing specific substrates, namely glutamine, pyruvate, glucose, or palmitate, in mitochondria. This approach primed mitochondria to immediately increase their oxygen consumption after the addition of the exogenous nutrients. All starved cells could oxidize exogenous glutamine, whereas the capacity for oxidizing palmitate was limited to human hepatocarcinoma Huh7 cells and to C2C12 mouse myoblasts that differentiated into myotubes. In the presence of exogenous glucose, starvation decreased the Crabtree effect in Huh7 and C2C12 cells and abrogated it in mouse neuroblastoma N2A cells. Interestingly, the fact that the Crabtree effect was observed only for mitochondrial basal respiration but not for the maximum respiratory capacity suggests it is not caused by a direct effect on the electron transport system.


Asunto(s)
Metabolismo Energético , Regulación Enzimológica de la Expresión Génica , Mitocondrias Hepáticas/metabolismo , Mitocondrias Musculares/metabolismo , Mitocondrias/metabolismo , Estrés Oxidativo , Animales , Línea Celular , Línea Celular Tumoral , Flavoproteínas Transportadoras de Electrones/metabolismo , Glucosa/metabolismo , Glutamina/metabolismo , Humanos , Cinética , Ratones , Mitocondrias/enzimología , Mitocondrias Hepáticas/enzimología , Mitocondrias Musculares/enzimología , Especificidad de Órganos , Oxidación-Reducción , Fosforilación Oxidativa , Ácido Palmítico/metabolismo , Ácido Pirúvico/metabolismo
5.
Microsc Microanal ; 23(5): 1061-1066, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28849754

RESUMEN

In the development of dry self-lubricating composites, not only solid lubricant particle size and distribution are important, but also the correct selection of the solid lubricant characteristics, which should be stable, i.e. not reactive, during the whole processing. In this work, Fe+9 vol% h-BN composites were produced by uniaxial cold compaction and sintering, for which a reaction between h-BN and iron was detected after sintering at 1,150°C. The reaction phase was characterized by optical and scanning electron microscopy and identified by X-ray diffraction and energy-dispersive X-ray spectroscopy. The newly formed phase had high hardness when compared with the iron matrix. The resulting composites presented a high friction coefficient and high wear.

6.
Rev Gaucha Enferm ; 35(4): 79-85, 2014 Dec.
Artículo en Portugués | MEDLINE | ID: mdl-25842784

RESUMEN

The objective of this study was to perceive the death-dying process from the perspective of nursing students. This is an exploratory, descriptive and qualitative research study. Data were collected between June and July 2013, from three focus groups with six nursing students at a University Center located in the central region of Rio Grande do Sul, Brazil. The meetings were organized with an approach to increase discussions about the death-dying process from the perspective of the complex thinking. Data were analyzed by means of the Strategic Focal Analysis, and three categories were created: Death: a process of rupture or continuity?; Recognizing weaknesses in the undergraduate educational process; and Outlining strategies to broaden academic discussions. It is possible to conclude that the death/dying process is minimally discussed in undergraduate courses, and when it is discussed, it happens in a fragmented and disjunctive manner, without integrating it into the human living process. Descriptors: Death. Education, nursing. Attitude to death.


Asunto(s)
Actitud Frente a la Muerte , Bachillerato en Enfermería , Estudiantes de Enfermería/psicología , Humanos
7.
Cancer Cell ; 42(6): 919-922, 2024 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-38788721

RESUMEN

Most targeted cancer drugs inhibit the oncogenic signals to which cancer cells are addicted. We discuss here a counterintuitive approach to cancer therapy, which consists of deliberate overactivation of the oncogenic signals to overload the stress responses of cancer cells. We discuss why such overactivation of oncogenic signaling, combined with perturbation of the stress response pathways, can be potentially effective in killing cancer cells, aiming to inspire further discussion and consideration.


Asunto(s)
Neoplasias , Transducción de Señal , Humanos , Neoplasias/tratamiento farmacológico , Neoplasias/genética , Neoplasias/metabolismo , Transducción de Señal/efectos de los fármacos , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Animales , Oncogenes , Terapia Molecular Dirigida/métodos
8.
Mol Oncol ; 2024 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-38932511

RESUMEN

Immune checkpoint blockade has emerged as a potent new tool in the war on cancer. However, only a subset of cancer patients benefit from this therapeutic modality, sparking a search for combination therapies to increase the fraction of responding patients. We argue here that inhibition of protein phosphatase 2A (PP2A) is a promising approach to increase responses to immune checkpoint blockade and other therapies that rely on the presence of tumor-reactive T cells. Inhibition of PP2A increases neoantigen expression on tumor cells, activates the cGAS/STING pathway, suppresses regulatory T cells, and increases cytotoxic T cell activation. In preclinical models, inhibition of PP2A synergizes with immune checkpoint blockade and emerging evidence indicates that patients who have tumors with mutations in PP2A respond better to immune checkpoint blockade. Therefore, inhibition of PP2A activity may be an effective way to sensitize cancer cells to immune checkpoint blockade and cell-based therapies using tumor-reactive T cells.

9.
Int J Biol Macromol ; 254(Pt 3): 127813, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37935293

RESUMEN

The scarcity of nonrenewable resources and the increase in environmental pollution have intensified the search for materials that exhibit specific characteristics and are nontoxic, renewable, and sustainable. Thus, the objective of this work was to produce natural polyphenol adhesives reinforced with rice husk and its ash to increase the mechanical resistance and moisture resistance of the glue line in wood bonded joints. Polyphenols were extracted from the bark of Stryphnodendron adstringens (Mart.) Coville (barbatimão). Adhesives were produced with a 50 % solid and 50 % liquid composition. Rice husk and husk ash underwent X-ray fluorescence analysis (XRF). Adhesives and reinforcement material were characterized by Fourier transform infrared (FTIR) and thermogravimetric analyses (TGA). The adhesives were glued in a mechanical press in specimens made of Pinus elliottii, which were subjected to shear testing of the wet and dry glue line. As a result, the chemical components present in rice husk and its ash positively influenced the properties of the adhesives. The mechanical glue line shear test showed that the adhesive reinforced with rice husk ash did not show a statistically significant difference. However, natural adhesives based on polyphenols from barbatimão strengthened with rice husk and ash showed improved properties, demonstrating how much it pays to use the residue of rice production to reinforce the matrix of tannin adhesives. Thus, it can be determined that reinforcement with rice husk and ash is efficient in improving some properties of natural adhesives based on polyphenols.


Asunto(s)
Oryza , Árboles , Oryza/química , Brasil , Corteza de la Planta/química , Polifenoles/análisis , Ecosistema
10.
Int J Biol Macromol ; 274(Pt 2): 133349, 2024 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-38925179

RESUMEN

New routes for biomass valorization have been developing by the scientific community. The aim of this work was developing a novel OrganoCat-based protocol and deeply understand the structure of the obtained lignins. Microwave-assisted OrganoCat-based process was performed using a biphasic system (ethyl acetate and oxalic acid or HCl) at mild conditions. OrganoCat-based lignins (OCLs) were characterized by compositional analysis, FTIR, 1H, 13C, 1H13C HSQC, 31P NMR, TGA and GPC. The solubility of OCLs in different organic solvents and their antioxidant capacity against DPPH were investigated. The spectroscopic analyses showed that OCLs have high residual extractives and the lignin motifs were preserved. OCLs have presented lower thermal stability than MWL, but showed great antioxidant activities and high solubility in a wide range of organic solvents. A novel biorefinery protocol yielded coconut shell lignins with peculiar structural and compositional features and several technological applications through an eco-friendly, sustainable and relatively low-cost biphasic pulping process.

11.
Carbohydr Polym ; 329: 121802, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38286526

RESUMEN

Multivariate models were developed to classify cellulose nanofibril (CNF) fibrillation by a quality index from near infrared (NIR) spectra. Commercial pulps of Eucalyptus spp. were used to produce cellulose nanofibrils by means of a fibrillator mill. After each of the five passes through the mill, samples were collected and analyzed for energy consumption and fiber classification. As a standard, pulps were oxidized with TEMPO reagent followed by a single pass through the mill to compare the resulting quality of CNFs produced by each method. NIR spectra of CNFs were associated with quality indices determined by conventional laboratory analyses that included morphology, turbidity, mechanical properties, X-ray diffraction and quality index measurements. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were applied to the spectral and experimental data. Fibrillator milling to obtain CNFs was efficient and resulted in gel formation following the third pass through the mill. NIR spectroscopy combined with PLS-DA was used successfully to create a model to classify quality of CNFs with 96 % certainty in 3 wt% solutions. These findings suggest that NIR spectroscopy holds promise for estimating CNF quality in suspension, particularly in real-time industrial applications where reliable estimates are crucial.


Asunto(s)
Eucalyptus , Nanofibras , Celulosa/química , Espectroscopía Infrarroja Corta/métodos , Eucalyptus/química , Carbohidratos , Difracción de Rayos X , Nanofibras/química
12.
J Dev Orig Health Dis ; 15: e9, 2024 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-38721989

RESUMEN

Sodium overload during childhood impairs baroreflex sensitivity and increases arterial blood pressure and heart rate in adulthood; these effects persist even after high-salt diet (HSD) withdrawal. However, the literature lacks details on the effects of HSD during postnatal phases on cardiac ischemia/reperfusion responses in adulthood. The current study aimed to elucidate the impact of HSD during infancy adolescence on isolated heart function and cardiac ischemia/reperfusion responses in adulthood. Male 21-day-old Wistar rats were treated for 60 days with hypertonic saline solution (NaCl; 0.3M; experimental group) or tap water (control group). Subsequently, both groups were maintained on a normal sodium diet for 30 days. Subsequently, the rats were euthanized, and their hearts were isolated and perfused according to the Langendorff technique. After 30 min of the basal period, the hearts were subjected to 20 min of anoxia, followed by 20 min of reperfusion. The basal contractile function was unaffected by HSD. However, HSD elevated the left ventricular end-diastolic pressure during reperfusion (23.1 ± 5.2 mmHg vs. 11.6 ± 1.4 mmHg; p < 0.05) and increased ectopic incidence period during reperfusion (208.8 ± 32.9s vs. 75.0 ± 7.8s; p < 0.05). In conclusion, sodium overload compromises cardiac function after reperfusion events, diminishes ventricular relaxation, and increases the severity of arrhythmias, suggesting a possible arrhythmogenic effect of HSD in the postnatal phases.


Asunto(s)
Arritmias Cardíacas , Daño por Reperfusión Miocárdica , Ratas Wistar , Animales , Ratas , Arritmias Cardíacas/etiología , Arritmias Cardíacas/fisiopatología , Masculino , Daño por Reperfusión Miocárdica/etiología , Daño por Reperfusión Miocárdica/fisiopatología , Diástole/fisiología , Cloruro de Sodio Dietético/efectos adversos , Frecuencia Cardíaca/fisiología
13.
Cancer Discov ; 14(7): 1276-1301, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38533987

RESUMEN

Cancer homeostasis depends on a balance between activated oncogenic pathways driving tumorigenesis and engagement of stress response programs that counteract the inherent toxicity of such aberrant signaling. Although inhibition of oncogenic signaling pathways has been explored extensively, there is increasing evidence that overactivation of the same pathways can also disrupt cancer homeostasis and cause lethality. We show here that inhibition of protein phosphatase 2A (PP2A) hyperactivates multiple oncogenic pathways and engages stress responses in colon cancer cells. Genetic and compound screens identify combined inhibition of PP2A and WEE1 as synergistic in multiple cancer models by collapsing DNA replication and triggering premature mitosis followed by cell death. This combination also suppressed the growth of patient-derived tumors in vivo. Remarkably, acquired resistance to this drug combination suppressed the ability of colon cancer cells to form tumors in vivo. Our data suggest that paradoxical activation of oncogenic signaling can result in tumor-suppressive resistance. Significance: A therapy consisting of deliberate hyperactivation of oncogenic signaling combined with perturbation of the stress responses that result from this is very effective in animal models of colon cancer. Resistance to this therapy is associated with loss of oncogenic signaling and reduced oncogenic capacity, indicative of tumor-suppressive drug resistance.


Asunto(s)
Neoplasias del Colon , Proteína Fosfatasa 2 , Transducción de Señal , Humanos , Animales , Proteína Fosfatasa 2/metabolismo , Ratones , Línea Celular Tumoral , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/metabolismo , Neoplasias del Colon/patología , Neoplasias del Colon/genética , Ensayos Antitumor por Modelo de Xenoinjerto , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/antagonistas & inhibidores , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Proteínas Tirosina Quinasas/metabolismo , Resistencia a Antineoplásicos , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Replicación del ADN
14.
Int J Biol Macromol ; 243: 125279, 2023 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-37301348

RESUMEN

This study aimed to evaluate the influence of the addition of the cationic surfactant cetyltrimethylammonium bromide (CTAB) in microfibrillated cellulose (MFC/CNFs) suspensions submitted to different pretreatments to produce redispersible spray-dried (SD) MFC/CNFs. Suspensions pretreated with 5 % and 10 % sodium silicate and oxidized with 2,2,6,6,-tetramethylpiperidinyl-1-oxyl (TEMPO) were modified with CTAB surfactant and subsequently dried by SD. The SD-MFC/CNFs aggregates were redispersed by ultrasound to produce cellulosic films by the casting method. In summary, the results demonstrated that the addition of CTAB surfactant to the TEMPO-oxidized suspension was critical to achieving the most effective redispersion. The experimental results obtained using micrographs, optical (UV-Vis), mechanical, water vapor barrier properties, and the quality index confirmed that the addition of CTAB to the TEMPO-oxidized suspension favored the redispersion of spray-dried aggregates, development of cellulosic films with attractive properties, offering possibilities for the elaboration of new products, for example, in the production of bionanocomposites with higher mechanical performance. This research brings interesting insights into the redispersion and application of SD-MFC/CNFs aggregates, strengthening the commercialization of MFC/CNFs for industrial use.


Asunto(s)
Biopelículas , Celulosa , Suspensiones , Cetrimonio
15.
Oper Neurosurg (Hagerstown) ; 25(6): e361-e362, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37350587

RESUMEN

INDICATIONS CORRIDOR AND LIMITS OF EXPOSURE: This approach is intended for tumors centered in the jugular foramen with extensions between intracranial and extracranial spaces, possible spread to the middle ear, and variable bony destruction. 1,2. ANATOMIC ESSENTIALS NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT: Jugular foramen paragangliomas are complex lesions that usually invade and fill related venous structures. They present complex relationships with skull base neurovascular structures as internal carotid artery, lower cranial nerves (CNs), middle ear, and mastoid segment of facial nerve. In this way, it is essential to perform an adequate preoperative vascular study to evaluate sinus patency and the tumor blood supply, besides a computed tomography scan to depict bone erosion. ESSENTIAL STEPS OF THE PROCEDURE: Mastoidectomy through an infralabyrinthine route up to open the lateral border of jugular foramen, allowing exposure from the sigmoid sinus to internal jugular vein. Skeletonization of facial canal without exposure of facial nerve is performed and opening of facial recess to give access to the middle ear in way of a fallopian bridge technique. 2-10. PITFALLS/AVOIDANCE OF COMPLICATIONS: If there is preoperative preservation of lower CN function, it is important to not remove the anteromedial wall of the internal jugular vein and jugular bulb. In addition, facial nerve should be exposed just in case of preoperative facial palsy to decompress or reconstruct the nerve. VARIANTS AND INDICATIONS FOR THEIR USE: Variations are related mainly with temporal bone drilling depending on the extensions of the lesion, its source of blood supply, and preoperative preservation of CN function.Informed consent was obtained from the patient for the procedure and publication of his image.Anatomy images were used with permission from:• Ceccato GHW, Candido DNC, and Borba LAB. Infratemporal fossa approach to the jugular foramen. In: Borba LAB and de Oliveira JG. Microsurgical and Endoscopic Approaches to the Skull Base. Thieme Medical Publishers. 2021.• Ceccato GHW, Candido DNC, de Oliveira JG, and Borba LAB. Microsurgical Anatomy of the Jugular Foramen. In: Borba LAB and de Oliveira JG. Microsurgical and Endoscopic Approaches to the Skull Base. Thieme Medical Publishers. 2021.


Asunto(s)
Tumor del Glomo Yugular , Foramina Yugular , Humanos , Foramina Yugular/diagnóstico por imagen , Foramina Yugular/cirugía , Base del Cráneo/diagnóstico por imagen , Base del Cráneo/cirugía , Base del Cráneo/anatomía & histología , Tumor del Glomo Yugular/cirugía , Hueso Temporal/diagnóstico por imagen , Hueso Temporal/cirugía , Nervios Craneales
16.
Int J Biol Macromol ; 235: 123850, 2023 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-36863677

RESUMEN

In this work, nanofibrillated cellulose (NFC) was extracted from cactus Cereus jamacaru DC. (mandacaru) for nanopaper production. The technique adopted includes alkaline treatment, bleaching, and grinding treatment. The NFC was characterized according to its properties and scored based on a quality index. Particle homogeneity, turbidity, and microstructure of the suspensions were evaluated. Correspondingly, the optical and physical-mechanical properties of the nanopapers were investigated. The chemical constituents of the material were analyzed. The sedimentation test and the zeta potential analyzed the stability of the NFC suspension. The morphological investigation was performed using environmental scanning electron microscopy (ESEM) and transmission electron microscopy (TEM). X-ray diffraction (XRD) analysis revealed that Mandacaru NFC has high crystallinity. Thermogravimetric analysis (TGA) and mechanical analysis were also used and revealed good thermal stability and good mechanical properties of the material. Therefore, the application of mandacaru is interesting in sectors such as packaging and electronic device development, as well as in composite materials. Given its score of 72 points on a quality index, this material was presented as an attractive, facile, and innovative source for obtaining NFC.


Asunto(s)
Celulosa , Nanofibras , Celulosa/química , Nanofibras/química
17.
Environ Sci Pollut Res Int ; 30(2): 4934-4948, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-35978240

RESUMEN

Specific kinds of enzymes have been used as an eco-friendly pre-treatment for mechanical extraction of cellulose nanofibrils (CNFs) from vegetal pulps. Another well-established pre-treatment is the 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)-mediated oxidation, which has gained considerable attention. Pre-treatments assist in fiber swelling, facilitating mechanical fibrillation, and reducing energy consumption; however, some of these methods are extremely expensive. This work aimed to evaluate the influence of enzymatic pre-treatment with endoglucanase on the energy consumption during mechanical fibrillation of cellulose pulps. Bleached pulps from Eucalyptus sp. and Pinus sp. were pre-treated with endoglucanase enzyme compared to TEMPO-meditated oxidation. Average diameters of CNFs pre-treated with enzymes were close to that found for TEMPO-oxidized nanofibrils (TOCNFs). Results showed that enzymatic pre-treatment did not significantly modify the pulp chemical and morphological characteristics with efficient stabilization of the CNFs suspension at higher supernatant turbidity. Energy consumption of pulps treated with endoglucanase enzymes was lower than that shown by pulps treated with TEMPO, reaching up to 58% of energy savings. The enzyme studied in the pulp treatment showed high efficiency in reducing energy consumption during mechanical fibrillation and production of films with high mechanical quality, being an eco-friendly option for pulp treatment.


Asunto(s)
Celulasa , Celulosa , Oxidación-Reducción , Compuestos de Sodio , Ácido Hipocloroso
18.
Environ Sci Pollut Res Int ; 30(29): 74426-74440, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37209330

RESUMEN

Vegetable tannins are excellent options to produce adhesives for the panel industry since they have the capacity to reduce formaldehyde emissions and are derived from renewable sources. They also allow for the possibility of increasing the resistance of the glue line through the use of natural reinforcements such as cellulose nanofibrils. Condensed tannins, polyphenols isolated from tree bark, are widely studied for the production of natural adhesives as an alternative to commercial synthetic adhesives. So, the purpose of our research is to show a natural adhesive alternative for wood bonding. Therefore, the objective of the study was to evaluate the quality of tannin adhesives of different species reinforced with different nanofibrils and thus predict which adhesive is the most promising at different concentrations of reinforcement and with different types of polyphenols. To meet this objective, polyphenols were extracted from the bark, nanofibrils were obtained, and both processes followed the current standards. Then, the adhesives were produced, their properties were characterized, and they were chemically analyzed via Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). A mechanical shear analysis of the glue line was also performed. According to the results, the addition of cellulose nanofibrils affected the physical properties of the adhesives, mostly the content of solids and the gel time. In the FTIR spectra, the OH band of the 5% Pinus and 5% Eucalyptus (EUC) TEMPO in the barbatimao adhesive and the 5% EUC of the cumate red adhesive were reduced, possibly due to their higher moisture resistance. Mechanical tests of the glue line showed that barbatimao with 5% Pinus and cumate red with 5% EUC performed best in the dry and wet shear tests. The control was the best-performing sample in the test of the commercial adhesives. The cellulose nanofibrils used as reinforcement did not change the thermal resistance of the adhesives. Therefore, the addition of cellulose nanofibrils to these tannins is an interesting means of increasing the mechanical strength, as occurred in commercial adhesive with 5% EUC. Thus, the physical and mechanical properties of tannin adhesives were better with reinforcement, making it possible to expand the use of these adhesives in the panel industry. At the industrial level, it is important to replace synthetic products with natural ones. Besides environmental and health issues, there is the question of the value of petroleum-based products, which have been widely studied so that they can be replaced.


Asunto(s)
Polifenoles , Madera , Polifenoles/análisis , Madera/química , Adhesivos/química , Celulosa/química , Taninos/química
19.
Front Psychiatry ; 14: 1173635, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37143780

RESUMEN

Post-partum depression (PPD) with varying clinical manifestations affecting new parents remains underdiagnosed and poorly treated. This minireview revisits the pharmacotherapy, and relevant etiological basis, capable of advancing preclinical research frameworks. Maternal tasks accompanied by numerous behavioral readouts demand modeling different paradigms that reflect the complex and heterogenous nature of PPD. Hence, effective PPD-like characterization in animals towards the discovery of pharmacological intervention demands research that deepens our understanding of the roles of hormonal and non-hormonal components and mediators of this psychiatric disorder.

20.
Cien Saude Colet ; 28(7): 2025-2034, 2023 Jul.
Artículo en Portugués, Inglés | MEDLINE | ID: mdl-37436316

RESUMEN

Osteoporosis is a systemic disease characterized by a reduction in bone mineral density. The dissemination of knowledge about the disease can be a viable alternative for promoting preventive behavior and self-care. This study sought to identify the main characteristics of bone health programs for older persons. We conducted an integrative review, searching for studies published between 2011 and 2022 in the CAPES periodicals database, Web of Science, PubMed, and Google Scholar using English descriptors. A total of 10,093 studies were retrieved, seven of which were selected after applying the inclusion criteria. The findings show that bone health education programs aim to empower older people by increasing knowledge about the disease and raising awareness about calcium and vitamin D intake, osteoporosis medications, and the importance of changing habits and exercise. Programs generally consist of group or individual meetings, with sessions lasting 50 to 60 minutes. Class sizes may be limited or unrestricted. Follow-up during the educational process was also found to be important. Tailoring topics to the reality and interests of participants appears to be another positive way of promoting the adoption of self-care practices.


A osteoporose é uma doença sistêmica caracterizada pela redução da densidade mineral óssea. A difusão do conhecimento sobre à doença, pode ser uma alternativa viável para atitudes preventivas e de autocuidado. Dessa forma, esse artigo procura identificar como são os programas sobre saúde óssea para idosos. Trata-se de uma revisão integrativa de estudos publicados entre 2011 e 2022 nas bases de dados Periódicos Capes, Web of Science, PubMed e Google Scholar em inglês. Foram encontrados 10.093 estudos, sendo selecionados 7 depois dos critérios de inclusão. Foi possível verificar que os programas de educação para saúde óssea possuem o objetivo de empoderar o idoso pelo aumento do conhecimento sobre a doença, conscientizar sobre o consumo de cálcio e vitamina D ou de medicamentos para osteoporose, mudanças de hábitos e a prática de exercícios físicos. Os programas geralmente são realizados com reuniões em grupo ou individualizados, com sessões de 50 a 60 minutos, podendo ou não, delimitar o número de indivíduos em cada uma delas. Nota-se que acompanhar a evolução do processo educativo também é importante. A contextualização dos temas junto a realidade e interesse dos idosos, parece ser outra forma positiva para despertar atitudes de autocuidado.


Asunto(s)
Osteoporosis , Humanos , Anciano , Anciano de 80 o más Años , Osteoporosis/prevención & control , Educación en Salud , Calcio de la Dieta , Densidad Ósea , Ejercicio Físico
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