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1.
Artículo en Inglés | MEDLINE | ID: mdl-38421044

RESUMEN

CONTEXT: Thyroid-stimulating hormone (or thyrotropin) receptor (TSHR) could be a selective target for small molecule ligands to treat thyroid cancer (TC). OBJECTIVE: We report a novel, orally efficacious ligand for TSHR that exhibits proliferation inhibitory activity against human TC in vitro and in vivo, and inhibition of metastasis in vivo. DESIGN: A35 (NCATS-SM4420; NCGC00241808) was selected from a sub-library of >200 TSHR ligands. Cell proliferation assays including BrdU incorporation and WST-1, along with molecular docking studies were done. In vivo activity of A35 was assessed in TC cell-derived xenograft (CDX) models with immunocompromised (NSG) mice. FFPE sections of tumor and lung tissues were observed for the extent of cell death and metastasis. RESULTS: A35 was shown to stimulate cAMP production in some cell types by activating TSHR but not in TC cells, MDA-T32 and MDA-T85. A35 inhibited proliferation of MDA-T32 & MDA-T85 in vitro and in vivo, and pulmonary metastasis of MDA-T85F1 in mice. In vitro, A35 inhibition of proliferation was reduced by a selective TSHR antagonist. Inhibition of CDX tumor growth without decreases in mouse weights and liver function showed A35 to be efficacious without apparent toxicity. Lastly, A35 reduced levels of Ki67 in the tumors and metastatic markers in lung tissues. CONCLUSION: We conclude that A35 is a TSHR-selective inhibitor of TC cell proliferation and metastasis, and suggest that A35 may be a promising lead drug candidate for the treatment of differentiated thyroid cancer in humans.

2.
Prehosp Emerg Care ; 28(2): 200-208, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-36730082

RESUMEN

OBJECTIVE: The objective of this study was to determine the effect of transitioning from direct laryngoscopy (DL) to video laryngoscopy (VL) on endotracheal intubation success overall and with enhanced precautions implemented during the COVID-19 pandemic. METHODS: We examined electronic transport records from Mayo Clinic Ambulance Service, a large advanced life support (ALS) provider serving rural, suburban, and urban areas in Minnesota and Wisconsin, USA. We determined the success of intubation attempts when using DL (March 10, 2018 to December 19, 2019), VL (December 20, 2019 to September 29, 2021), and VL with an enhanced COVID-19 guideline that restricted intubation to one attempt, performed by the most experienced clinician, who wore enhanced personal protective equipment (April 1 to December 18, 2020). Success rates at first attempt and after any attempt were assessed for association with type of laryngoscopy (VL vs DL) after adjusting for patient age group, patient weight, use of enhanced COVID-19 guideline, medical vs trauma patient, and ALS vs critical care clinician. A secondary analysis further adjusted for degree of glottic visualization. RESULTS: We identified 895 intubation attempts using DL and 893 intubation attempts using VL, which included 382 VL intubation attempts using the enhanced COVID-19 guideline. Success on first intubation attempt was 69.2% for encounters with DL, 82.9% overall with VL, and 83.2% with VL and enhanced COVID-19 protocols (DL vs overall VL: p < 0.001; COVID-19 vs non-COVID VL: p = 0.86). In multivariable analysis, use of VL was associate with higher odds of successful intubation on first attempt (odds ratio, 2.28; 95%CI, 1.73-3.01; p < 0.001) and on any attempt (odds ratio, 2.16; 95%CI, 1.58-2.96; p < 0.001) compared with DL. Inclusion of glottic visualization in the model resulted in a nonsignificant association between laryngoscopy type and successful first intubation (p = 0.41) and a significant association with the degree of glottic visualization (p < 0.001). CONCLUSIONS: VL is designed to improve glottic visualization. The use of VL by a large, U.S. multistate ALS ambulance service was associated with increased odds of successful first-pass and overall attempted intubation, which was mediated by better visualization of the glottis. COVID-19 protocols were not associated with success rates.


Asunto(s)
COVID-19 , Servicios Médicos de Urgencia , Laringoscopios , Humanos , COVID-19/epidemiología , Servicios Médicos de Urgencia/métodos , Intubación Intratraqueal/métodos , Laringoscopía/métodos , Pandemias , Grabación en Video
3.
Pediatr Dev Pathol ; 27(1): 67-76, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-37771167

RESUMEN

Lymphoma is the fourth most common tumor to display placental metastasis. This study aimed to report a case of high-grade lymphoma involving the placenta and review the literature on lymphomas metastatic to the placenta. A systematic review was performed following the PRISMA guidelines, using the keywords "lymphoma" AND "placenta." All case reports and case series on lymphoma infiltrating the placenta were collected. Eight cases from 7 studies, including the present case, were synthesized. The mean patient age is 29.5 years. The clinical presentation is non-specific. Hematologic derangements included cytopenias or cytoses, and elevated prothrombin time. The mean gestational age (GA) when a diagnosis of lymphoma was rendered is 27 weeks. Five cases presented with either lymphadenopathy or visceral masses on imaging. Four of these cases eventually led to maternal demise. The mean GA when the fetus was delivered is 31 3/4 weeks. Grossly, most placentas had non-specific findings. Leukemic infiltrates were mostly seen within intervillous spaces. Intravillous infiltrates were associated with high-grade lymphomas, resulting in either maternal demise or stillborn fetuses. This study suggests that the placenta has mechanisms to guard against malignancies; however, these defense mechanisms are not foolproof and may be breached by tumor cells.


Asunto(s)
Linfoma , Neoplasias , Enfermedades Placentarias , Embarazo , Femenino , Humanos , Adulto , Lactante , Placenta/patología , Enfermedades Placentarias/patología , Neoplasias/patología , Feto/patología , Linfoma/diagnóstico , Linfoma/patología
4.
Anesth Analg ; 2023 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-38009837

RESUMEN

Obesity is often considered a contraindication to extracorporeal membrane oxygenation (ECMO) candidacy due to technical challenges with vascular access, higher cardiac output requirements, and known associations between obesity and overall increased morbidity and mortality due to chronic health conditions. However, a growing body of literature suggests that ECMO may be as safe and efficacious in both obese and nonobese patients. This scoping review provides a synthesis of the available literature on the outcomes of obese patients supported with (1) venovenous (VV)-ECMO in acute respiratory distress syndrome (ARDS) not due to coronavirus disease 2019 (COVID-19), (2) VV-ECMO in ARDS due to COVID-19, (3) venoarterial (VA)-ECMO for all indications, and (4) studies combining data of patients supported with VA- and VV-ECMO. A librarian-assisted search was performed using 4 primary electronic medical databases (PubMed, Web of Science, Excerpta Medica database [Embase], and Cochrane Library) from January 2003 to March 2023. Articles that reported outcomes of obese patients requiring ECMO support were included. Two reviewers independently screened titles, abstracts, and full text of articles to determine eligibility. Data extraction was performed using customized fields established a priori within a systematic review software system. A total of 354 publications were imported for screening on titles and abstracts, and 30 studies were selected for full-text review. A total of 26 publications met the inclusion criteria: 7 on VV-ECMO support in non-COVID-19 ARDS patients, 6 on ECMO in COVID-19 ARDS patients, 8 in patients supported with VA-ECMO, and 5 combining both VA- and VV-ECMO data. Although the included studies are limited to retrospective analyses and display a heterogeneity in definitions of obesity and comparison groups, the currently available literature suggests that outcomes and complications of ECMO therapy are equivalent in obese patients as compared to nonobese patients. Hence, obesity as measured by body mass index alone should not be considered an exclusion criterion in the decision to initiate ECMO.

5.
Front Endocrinol (Lausanne) ; 13: 989626, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36246873

RESUMEN

Proximity ligation assay (PLA) is a methodology that permits detection of protein-protein closeness, that is, proteins that are within 40 nanometers of each other, in cells or tissues at endogenous protein levels or after exogenous overexpression. It detects the protein(s) with high sensitivity and specificity because it employs a DNA hybridization step followed by DNA amplification. PLA has been used successfully with many types of proteins. In this methods paper, we will describe the workings of PLA and provide examples of its use to study TSH/IGF-1 receptor crosstalk in Graves' orbital fibroblasts (GOFs) and TSH receptor homodimerization in primary cultures of human thyrocytes.


Asunto(s)
Receptor IGF Tipo 1 , Receptores de Tirotropina , ADN , Humanos , Receptor IGF Tipo 1/genética , Receptor IGF Tipo 1/metabolismo , Receptores de Tirotropina/genética , Receptores de Tirotropina/metabolismo , Glándula Tiroides/metabolismo , Tirotropina
6.
Endocrinology ; 163(12)2022 10 23.
Artículo en Inglés | MEDLINE | ID: mdl-36281035

RESUMEN

Regulation of thyroid cells by thyrotropin (TSH) and epidermal growth factor (EGF) has been known but different effects of these regulators on proliferation and differentiation have been reported. We studied these responses in primary cultures of human thyroid cells to determine whether TSH receptor (TSHR) signaling may involve EGF receptor (EGFR) transactivation. We confirm that EGF stimulates proliferation and de-differentiation whereas TSH causes differentiation in the absence of other growth factors. We show that TSH/TSHR transactivates EGFR and characterize it as follows: (1) TSH-induced upregulation of thyroid-specific genes is inhibited by 2 inhibitors of EGFR kinase activity, AG1478 and erlotinib; (2) the mechanism of transactivation is independent of an extracellular EGFR ligand by showing that 2 antibodies, cetuximab and panitumumab, that completely inhibited binding of EGFR ligands to EGFR had no effect on transactivation, and by demonstrating that no EGF was detected in media conditioned by thyrocytes incubated with TSH; (3) TSH/TSHR transactivation of EGFR is different than EGFR activation by EGF by showing that EGF led to rapid phosphorylation of EGFR whereas transactivation occurred in the absence of receptor phosphorylation; (4) EGF caused downregulation of EGFR whereas transactivation had no effect on EGFR level; (5) EGF and TSH stimulation converged on the protein kinase B (AKT) pathway, because TSH, like EGF, stimulated phosphorylation of AKT that was inhibited by EGFR inhibitors; and (6) TSH-induced upregulation of thyroid genes was inhibited by the AKT inhibitor MK2206. Thus, TSH/TSHR causes EGFR transactivation that is independent of extracellular EGFR ligand and in part mediates TSH regulation of thyroid hormone biosynthetic genes.


Asunto(s)
Factor de Crecimiento Epidérmico , Proteínas Proto-Oncogénicas c-akt , Humanos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Factor de Crecimiento Epidérmico/farmacología , Factor de Crecimiento Epidérmico/metabolismo , Activación Transcripcional , Cetuximab/metabolismo , Receptores de Tirotropina/metabolismo , Ligandos , Clorhidrato de Erlotinib , Panitumumab , Receptores ErbB/genética , Receptores ErbB/metabolismo , Fosforilación , Proliferación Celular , Tirotropina/farmacología , Tirotropina/metabolismo
7.
Artículo en Inglés | MEDLINE | ID: mdl-35206253

RESUMEN

This commentary, by three authors with an aggregate experience of more than a century in technology and health and safety studies concerning radiofrequency (RF) energy, asks what has been learned over the past 75 years of research on radiofrequency and health, focusing on technologies for exposure assessment and dosimetry. Research programs on health and safety of RF exposure began in the 1950s, initially motivated by occupational health concerns for military personnel, and later to address public concerns about exposures to RF energy from environmental sources and near-field exposures from RF transmitting devices such as mobile phones that are used near the body. While this research largely focused on the biological effects of RF energy, it also led to important improvements in exposure assessment and dosimetry. This work in the aggregate has made RF energy one of the best studied potential technological hazards and represents a productive response by large numbers of scientists and engineers, working in many countries and supported by diverse funding agencies, to the ever rapidly evolving uses of the electromagnetic spectrum. This review comments on present needs of the field, which include raising the quality of dosimetry in many RF bioeffects studies and developing improved exposure/dosimetric techniques for the higher microwave frequencies to be used by forthcoming communications technologies. At present, however, the major uncertainties in dosimetric modeling/exposure assessment are likely to be related to the inherent variability in real-world exposures, rather than imprecision in measurement technologies.


Asunto(s)
Teléfono Celular , Campos Electromagnéticos , Exposición a Riesgos Ambientales , Microondas , Ondas de Radio/efectos adversos , Radiometría
8.
Thyroid ; 32(1): 90-96, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34714162

RESUMEN

Background: The pathogenesis of Graves' hyperthyroidism (GH) and associated Graves' orbitopathy (GO) appears to involve stimulatory autoantibodies (thyrotropin receptor [TSHR]-stimulating antibodies [TSAbs]) that bind to and activate TSHRs on thyrocytes and orbital fibroblasts. In general, measurement of circulating TSHR antibodies by clinical assays correlates with the status of GH and GO. However, most clinical measurements of TSHR antibodies use competitive binding assays that do not distinguish between TSAbs and antibodies that bind to but do not activate TSHRs. Moreover, clinical assays for TSAbs measure stimulation of only one signaling pathway, the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway, in engineered cells that are not thyrocytes or orbital fibroblasts. We determined whether measuring TSAbs by a cAMP-PKA readout in engineered cells accurately reveals the efficacies of stimulation by these antibodies on thyrocytes and orbital fibroblasts. Methods: We measured TSAb stimulation of normal human thyrocytes and orbital fibroblasts from patients with GO in primary cultures in vitro. In thyrocytes, we measured secretion of thyroglobulin (TG) and in orbital fibroblasts secretion of hyaluronan (hyaluronic acid [HA]). We also measured stimulation of cAMP production in engineered TSHR-expressing cells in an assay similar to clinical assays. Furthermore, we determined whether there were differences in stimulation of thyrocytes and orbital fibroblasts by TSAbs from patients with GH alone versus from patients with GO understanding that patients with GO have accompanying GH. Results: We found a positive correlation between TSAb stimulation of cAMP production in engineered cells and TG secretion by thyrocytes as well as HA secretion by orbital fibroblasts. However, TSAbs from GH patients stimulated thyrocytes more effectively than TSAbs from GO patients, whereas TSAbs from GO patients were more effective in activating orbital fibroblasts than TSAbs from GH patients. Conclusions: Clinical assays of stimulation by TSAbs measuring activation of the cAMP-PKA pathway do correlate with stimulation of thyrocytes and orbital fibroblasts; however, they do not distinguish between TSAbs from GH and GO patients. In vitro, TSAbs exhibit selectivity in activating TSHRs since TSAbs from GO patients were more effective in stimulating orbital fibroblasts and TSAbs from GH patients were more effective in stimulating thyrocytes.


Asunto(s)
Autoanticuerpos/inmunología , Fibroblastos/inmunología , Oftalmopatía de Graves/complicaciones , Células Epiteliales Tiroideas/inmunología , Adulto , Autoanticuerpos/análisis , Femenino , Fibroblastos/metabolismo , Enfermedad de Graves/sangre , Enfermedad de Graves/inmunología , Oftalmopatía de Graves/sangre , Oftalmopatía de Graves/patología , Humanos , Masculino , Persona de Mediana Edad , Células Epiteliales Tiroideas/metabolismo , Tirotropina/metabolismo
9.
Cell Signal ; 90: 110212, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34896620

RESUMEN

The TSH receptor (TSHR) is the major regulator of thyroid hormone biosynthesis in human thyrocytes by regulating the transcription of a number of genes including thyroglobulin (TG) and thyroperoxidase (TPO). Until recently, it was thought that TSHR initiated signal transduction pathways only at the cell-surface and that internalization was primarily involved in TSHR desensitization and downregulation. Studies primarily in mouse cells showed that TSHR internalization regulates gene transcription at an intracellular site also. However, this has not been shown for genes involved in thyroid hormone biosynthesis in human thyrocytes. We used human thyrocytes in primary culture. In these cells, the dose-response to TSH for gene expression is biphasic with low doses upregulating gene expression and higher doses decreasing gene expression. We used two approaches to inhibit internalization. In the first, we used inhibitors of dynamins, dynasore and dyngo-4a. Pretreatment with dynasore or dyngo-4a markedly inhibited TSH upregulation of TG and TPO mRNAs, as well as TG secretion. In the second, we used knockdown of dynamin 2, which is the most abundant dynamin in human thyrocytes. We showed that dynamin 2 knockdown inhibited TSHR internalization and decreased the TSH-stimulated levels of TG and TPO mRNAs and proteins. Lastly, we showed that the level of the activatory transcription factor phosphorylated cAMP response element binding protein (pCREB) in the cell nuclei was reduced by 68% when internalization was inhibited. We conclude that upregulation of genes involved in thyroid hormone synthesis in human thyrocytes is, in part, dependent on internalization leading to nuclear localization of an activated transcription factor(s).


Asunto(s)
Yoduro Peroxidasa , Tiroglobulina , Animales , Humanos , Yoduro Peroxidasa/genética , Yoduro Peroxidasa/metabolismo , Ratones , Receptores de Tirotropina/genética , Receptores de Tirotropina/metabolismo , Tiroglobulina/genética , Tiroglobulina/metabolismo , Tirotropina/genética , Tirotropina/farmacología , Transcripción Genética
10.
J Clin Endocrinol Metab ; 107(4): e1653-e1660, 2022 03 24.
Artículo en Inglés | MEDLINE | ID: mdl-34788857

RESUMEN

CONTEXT: We previously presented evidence that TSH receptor (TSHR)-stimulating autoantibodies (TSAbs) bind to and activate TSHRs but do not bind to IGF1 receptors (IGF1Rs). Nevertheless, we showed that IGF1Rs were involved in thyroid eye disease (TED) pathogenesis because TSAbs activated crosstalk between TSHR and IGF1R. Teprotumumab, originally generated to inhibit IGF1 binding to IGF1R, was recently approved for the treatment of TED (Tepezza). OBJECTIVE: To investigate the role of TSHR/IGF1R crosstalk in teprotumumab treatment of TED. DESIGN: We used orbital fibroblasts from patients with TED (TEDOFs) and measured stimulated hyaluronan (HA) secretion as a measure of orbital fibroblast activation by TED immunoglobulins (TED-Igs) and monoclonal TSAb M22. We previously showed that M22, which does not bind to IGF1R, stimulated HA in a biphasic dose-response with the higher potency phase dependent on TSHR/IGF1R crosstalk and the lower potency phase independent of IGF1R. Stimulation by TED-Igs and M22 was measured in the absence or presence of teprotumumab biosimilar (Tepro) or K1-70, an antibody that inhibits TSHR. RESULTS: We show: (1) Tepro dose-dependently inhibits stimulation by TED-Igs; (2) Tepro does not bind to TSHRs; (3) Tepro inhibits IGF1R-dependent M22-induced HA production, which is mediated by TSHR/IGF1R crosstalk, but not IGF1R-independent M22 stimulation; and (4) ß-arrestin 1 knockdown, which blocks TSHR/IGF1R crosstalk and prevents Tepro inhibition of HA production by M22 and by a pool of TED-Igs. CONCLUSION: We conclude that Tepro inhibits HA production by TEDOFs by inhibiting TSHR/IGF1R crosstalk and suggest that inhibition of TSHR/IGF1R crosstalk is the mechanism of its action in treating TED.


Asunto(s)
Oftalmopatía de Graves , Anticuerpos Monoclonales Humanizados/farmacología , Anticuerpos Monoclonales Humanizados/uso terapéutico , Oftalmopatía de Graves/metabolismo , Humanos , Ácido Hialurónico/metabolismo , Receptor IGF Tipo 1/metabolismo , Receptores de Tirotropina , Tirotropina/farmacología
11.
Cancers (Basel) ; 13(24)2021 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-34945002

RESUMEN

BACKGROUND: Enzalutamide is part of the treatment regimen for metastatic castration-resistant prostate cancer (MCRPC). However, both intrinsic and acquired resistance to the drug remain substantial clinical quandaries. circRNAs, a novel type of non-coding RNA, have been identified in a number of cancers including prostate cancer and have been associated with cancer development and progression. circRNAs have shown great potential as clinically useful blood-based 'liquid biopsies' and as therapeutic targets in prostate cancer. The aim of this study was to examine the role of circRNA transcripts in enzalutamide-resistant prostate cancer cells and assess their utility as biomarkers. METHODS: An isogenic cell line model of enzalutamide resistance was subjected to circRNA microarray profiling. Several differentially expressed circRNAs, along with their putative parental genes were validated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). circRNAs of interest were stably overexpressed in the control cell line and drug sensitivity was assessed using an ELISA-based proliferation assay. The candidate circRNA, hsa_circ_0001275, was measured in patient plasma samples using RT-droplet digital PCR (RT-ddPCR). RESULTS: hsa_circ_0001275 and its parental gene, PLCL2, were significantly up-regulated in strongly resistant clones vs. control (p < 0.05). Overexpression of hsa_circ_0001275 in the control cell line resulted in increased resistance to enzalutamide (p < 0.05). While RT-ddPCR analysis of hsa_circ_0001275 expression in plasma samples of 44 clinical trial participants showed a trend that mirrored the stages of disease activity (as defined by PSA level), the association did not reach statistical significance. CONCLUSIONS: Our data suggest that increased levels of hsa_circ_0001275 contribute to enzalutamide resistance. hsa_circ_0001275 plasma expression showed a trend that mirrors the PSA level at specific disease time points, indicating that circRNAs mirror disease recurrence and burden and may be associated with enzalutamide resistance.

12.
Chemistry ; 27(68): 17240-17254, 2021 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-34608688

RESUMEN

We present a mechanistic study on the formation of an active ligand layer over Pd(111), turning the catalytic surface highly active and selective in partial hydrogenation of an α,ß-unsaturated aldehyde acrolein. Specifically, we investigate the chemical composition of a ligand layer consisting of allyl cyanide deposited on Pd(111) and its dynamic changes under the hydrogenation conditions. On pristine surface, allyl cyanide largely retains its chemical structure and forms a layer of molecular species with the CN bond oriented nearly parallel to the underlying metal. In the presence of hydrogen, the chemical composition of allyl cyanide strongly changes. At 100 K, allyl cyanide transforms to unsaturated imine species, containing the C=C and C=N double bonds. At increasing temperatures, these species undergo two competing reaction pathways. First, the C=C bond become hydrogenated and the stable N-butylimine species are produced. In the competing pathway, the unsaturated imine reacts with hydrogen to fully hydrogenate the imine group and produce butylamine. The latter species are unstable under the hydrogenation reaction conditions and desorb from the surface, while the N-butylimine adsorbates formed in the first reaction pathway remain adsorbed and act as an active ligand layer in selective hydrogenation of acrolein.

13.
Health Phys ; 121(3): 234-247, 2021 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-34261892

RESUMEN

ABSTRACT: Two major sets of exposure limits for radiofrequency (RF) radiation, those of the International Commission on Nonionizing Radiation Protection (ICNIRP 2020) and the Institute of Electrical and Electronics Engineers (IEEE C95.1-2019), have recently been revised and updated with significant changes in limits above 6 GHz through the millimeter wave (mm-wave) band (30-300 GHz). This review compares available data on thermal damage and pain from exposure to RF energy above 6 GHz with corresponding data from infrared energy and other heat sources and estimates safety factors that are incorporated in the IEEE and ICNIRP RF exposure limits. The benchmarks for damage are the same as used in ICNIRP IR limits: minimal epithelial damage to cornea and first-degree burn (erythema in skin observable within 48 h after exposure). The data suggest that limiting thermal hazard to skin is cutaneous pain for exposure durations less than ≈20 min and thermal damage for longer exposures. Limitations on available data and thermal models are noted. However, data on RF and IR thermal damage and pain thresholds show that exposures far above current ICNIRP and IEEE limits would be required to produce thermally hazardous effects. This review focuses exclusively on thermal hazards from RF exposures above 6 GHz to skin and the cornea, which are the most exposed tissues in the considered frequency range.


Asunto(s)
Protección Radiológica , Ondas de Radio , Córnea , Ondas de Radio/efectos adversos , Temperatura
14.
Angew Chem Int Ed Engl ; 60(30): 16349-16354, 2021 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-34008906

RESUMEN

We present a mechanistic study on the formation and dynamic changes of a ligand-based heterogeneous Pd catalyst for chemoselective hydrogenation of α,ß-unsaturated aldehyde acrolein. Deposition of allyl cyanide as a precursor of a ligand layer renders Pd highly active and close to 100 % selective toward propenol formation by promoting acrolein adsorption in a desired configuration via the C=O end. Employing a combination of real-space microscopic and in-operando spectroscopic surface-sensitive techniques, we show that an ordered active ligand layer is formed under operational conditions, consisting of stable N-butylimine species. In a competing process, unstable amine species evolve on the surface, which desorb in the course of the reaction. Obtained atomistic-level insights into the formation and dynamic evolution of the active ligand layer under operational conditions provide important input required for controlling chemoselectivity by purposeful surface functionalization.

15.
Polymers (Basel) ; 13(9)2021 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-33919258

RESUMEN

Incorporating nanofillers into elastomers leads to composites with an enormous potential regarding their properties. Unfortunately, nanofillers tend to form agglomerates inhibiting adequate filler dispersion. Therefore, different carbon nanotube (CNT) pretreatment methods were analyzed in this study to enhance the filler dispersion in polydimethylsiloxane (PDMS)/CNT-composites. By pre-dispersing CNTs in solvents an increase in electrical conductivity could be observed within the sequence of tetrahydrofuran (THF) > acetone > chloroform. Optimization of the pre-dispersion step results in an AC conductivity of 3.2 × 10-4 S/cm at 1 Hz and 0.5 wt.% of CNTs and the electrical percolation threshold is decreased to 0.1 wt.% of CNTs. Optimum parameters imply the use of an ultrasonic finger for 60 min in THF. However, solvent residues cause a softening effect deteriorating the mechanical performance of these composites. Concerning the pretreatment of CNTs by physical functionalization, the use of surfactants (sodium dodecylbenzenesulfonate (SDBS) and polyoxyethylene lauryl ether ("Brij35")) leads to no improvement, neither in electrical conductivity nor in mechanical properties. Chemical functionalization enhances the compatibility of PDMS and CNT but damages the carbon nanotubes due to the oxidation process so that the improvement in conductivity and reinforcement is superimposed by the CNT damage even for mild oxidation conditions.

17.
18.
Acta Medica Philippina ; : 467-472, 2021.
Artículo en Inglés | WPRIM (Pacífico Occidental) | ID: wpr-987794

RESUMEN

Objectives@#To determine the overall diagnostic yield of bronchoscopy-guided sampling methods in detecting lung cancer at the University of the Philippines, Philippine General Hospital. The diagnostic yield, equivalent to sensitivity, is defined as the number of bronchoscopic sampling or biopsy procedures with a diagnosis of malignancy divided by the total number of confirmed malignant cases. @*Methods@#This is a cross-sectional, retrospective sensitivity study involving bronchoscopy procedures from January 2014 to December 2018. Surgical Pathology and Cytology Reports of eligible cases were accessed through the institutional Laboratory Information System. Sensitive patient information was omitted, and each case was assigned a unique code. The overall diagnostic yield/sensitivity of bronchoscopy and the diagnostic yield/sensitivity of each technique were calculated. @*Results@#A total of 100 patients satisfied the inclusion and exclusion criteria. Primary lung malignancies are more common in males and the elderly. The most common primary lung cancer is adenocarcinoma (33%). Bronchoscopy, regardless of whether single or multiple techniques were used, has a diagnostic yield of 86% (CI: 77.6-92.1%). Of the individual techniques, those that obtain solid tissues (endobronchial and transbronchial biopsies; 88.2% [CI: 78.1-94.8%] and 80.0% [CI: 28.4-99.5%], respectively) have higher yields compared to techniques that obtain cytologic samples (bronchial washing and brushing; 54.2% [43.7-64.4%] and 70.1% [58.6-80%], respectively). @*Conclusion@#Bronchoscopy, as a diagnostic procedure for pulmonary malignancies, has relatively high sensitivity and may be used for lesions located centrally and can be inspected visually. A multidisciplinary approach to patient selection for bronchoscopy helps improve the utility of the various bronchoscopic techniques.


Asunto(s)
Neoplasias Pulmonares , Broncoscopía , Citodiagnóstico , Patología Quirúrgica
20.
Int J Mol Sci ; 21(18)2020 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-32911689

RESUMEN

In this review, we summarize the evidence against direct stimulation of insulin-like growth factor 1 receptors (IGF1Rs) by autoantibodies in Graves' orbitopathy (GO) pathogenesis. We describe a model of thyroid-stimulating hormone (TSH) receptor (TSHR)/IGF1R crosstalk and present evidence that observations indicating IGF1R's role in GO could be explained by this mechanism. We evaluate the evidence for and against IGF1R as a direct target of stimulating IGF1R antibodies (IGF1RAbs) and conclude that GO pathogenesis does not involve directly stimulating IGF1RAbs. We further conclude that the preponderance of evidence supports TSHR as the direct and only target of stimulating autoantibodies in GO and maintain that the TSHR should remain a major target for further development of a medical therapy for GO in concert with drugs that target TSHR/IGF1R crosstalk.


Asunto(s)
Oftalmopatía de Graves/patología , Receptor IGF Tipo 1/inmunología , Receptores de Tirotropina/metabolismo , Autoanticuerpos/inmunología , Oftalmopatía de Graves/inmunología , Humanos , Ácido Hialurónico/metabolismo , Receptor Cross-Talk/inmunología , Receptor IGF Tipo 1/metabolismo , Receptores de Somatomedina , Receptores de Tirotropina/inmunología
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