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1.
Nat Immunol ; 17(8): 922-9, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27270400

RESUMEN

Deficiency in mevalonate kinase (MVK) causes systemic inflammation. However, the molecular mechanisms linking the mevalonate pathway to inflammation remain obscure. Geranylgeranyl pyrophosphate, a non-sterol intermediate of the mevalonate pathway, is the substrate for protein geranylgeranylation, a protein post-translational modification that is catalyzed by protein geranylgeranyl transferase I (GGTase I). Pyrin is an innate immune sensor that forms an active inflammasome in response to bacterial toxins. Mutations in MEFV (encoding human PYRIN) result in autoinflammatory familial Mediterranean fever syndrome. We found that protein geranylgeranylation enabled Toll-like receptor (TLR)-induced activation of phosphatidylinositol-3-OH kinase (PI(3)K) by promoting the interaction between the small GTPase Kras and the PI(3)K catalytic subunit p110δ. Macrophages that were deficient in GGTase I or p110δ exhibited constitutive release of interleukin 1ß that was dependent on MEFV but independent of the NLRP3, AIM2 and NLRC4 inflammasomes. In the absence of protein geranylgeranylation, compromised PI(3)K activity allows an unchecked TLR-induced inflammatory responses and constitutive activation of the Pyrin inflammasome.


Asunto(s)
Transferasas Alquil y Aril/metabolismo , Fiebre Mediterránea Familiar/metabolismo , Inflamasomas/metabolismo , Macrófagos/fisiología , Mutación/genética , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Pirina/genética , Transferasas Alquil y Aril/genética , Animales , Células Cultivadas , Fiebre Mediterránea Familiar/genética , Humanos , Inmunidad Innata , Interleucina-1beta/metabolismo , Ratones Endogámicos C57BL , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Fosfotransferasas (Aceptor de Grupo Alcohol)/genética , Fosfatos de Poliisoprenilo/metabolismo , Procesamiento Proteico-Postraduccional , Transducción de Señal , Receptores Toll-Like/metabolismo
2.
Proc Natl Acad Sci U S A ; 120(4): e2208536120, 2023 01 24.
Artículo en Inglés | MEDLINE | ID: mdl-36656858

RESUMEN

Actin cytoskeleton force generation, sensing, and adaptation are dictated by the bending and twisting mechanics of filaments. Here, we use magnetic tweezers and microfluidics to twist and pull individual actin filaments and evaluate their response to applied loads. Twisted filaments bend and dissipate torsional strain by adopting a supercoiled plectoneme. Pulling prevents plectoneme formation, which causes twisted filaments to sever. Analysis over a range of twisting and pulling forces and direct visualization of filament and single subunit twisting fluctuations yield an actin filament torsional persistence length of ~10 µm, similar to the bending persistence length. Filament severing by cofilin is driven by local twist strain at boundaries between bare and decorated segments and is accelerated by low pN pulling forces. This work explains how contractile forces generated by myosin motors accelerate filament severing by cofilin and establishes a role for filament twisting in the regulation of actin filament stability and assembly dynamics.


Asunto(s)
Citoesqueleto de Actina , Citoesqueleto , Citoesqueleto de Actina/metabolismo , Citoesqueleto/metabolismo , Factores Despolimerizantes de la Actina/metabolismo , Miosinas/metabolismo , Unión Proteica , Actinas/metabolismo
3.
Proc Natl Acad Sci U S A ; 119(7)2022 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-35135883

RESUMEN

How can exactly six SNARE complexes be assembled under each synaptic vesicle? Here we report cryo-EM crystal structures of the core domain of Munc13, the key chaperone that initiates SNAREpin assembly. The functional core of Munc13, consisting of C1-C2B-MUN-C2C (Munc13C) spontaneously crystallizes between phosphatidylserine-rich bilayers in two distinct conformations, each in a radically different oligomeric state. In the open conformation (state 1), Munc13C forms upright trimers that link the two bilayers, separating them by ∼21 nm. In the closed conformation, six copies of Munc13C interact to form a lateral hexamer elevated ∼14 nm above the bilayer. Open and closed conformations differ only by a rigid body rotation around a flexible hinge, which when performed cooperatively assembles Munc13 into a lateral hexamer (state 2) in which the key SNARE assembly-activating site of Munc13 is autoinhibited by its neighbor. We propose that each Munc13 in the lateral hexamer ultimately assembles a single SNAREpin, explaining how only and exactly six SNARE complexes are templated. We suggest that state 1 and state 2 may represent two successive states in the synaptic vesicle supply chain leading to "primed" ready-release vesicles in which SNAREpins are clamped and ready to release (state 3).


Asunto(s)
Proteínas del Tejido Nervioso/química , Proteínas del Tejido Nervioso/metabolismo , Regulación de la Expresión Génica , Células HEK293 , Humanos , Modelos Moleculares , Proteínas del Tejido Nervioso/genética , Conformación Proteica
4.
Cell ; 136(1): 110-22, 2009 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-19135893

RESUMEN

Segregation of nonexchange chromosomes during Drosophila melanogaster meiosis requires the proper function of NOD, a nonmotile kinesin-10. We have determined the X-ray crystal structure of the NOD catalytic domain in the ADP- and AMPPNP-bound states. These structures reveal an alternate conformation of the microtubule binding region as well as a nucleotide-sensitive relay of hydrogen bonds at the active site. Additionally, a cryo-electron microscopy reconstruction of the nucleotide-free microtubule-NOD complex shows an atypical binding orientation. Thermodynamic studies show that NOD binds tightly to microtubules in the nucleotide-free state, yet other nucleotide states, including AMPPNP, are weakened. Our pre-steady-state kinetic analysis demonstrates that NOD interaction with microtubules occurs slowly with weak activation of ADP product release. Upon rapid substrate binding, NOD detaches from the microtubule prior to the rate-limiting step of ATP hydrolysis, which is also atypical for a kinesin. We propose a model for NOD's microtubule plus-end tracking that drives chromosome movement.


Asunto(s)
Cromosomas/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/citología , Proteínas de Microtúbulos/metabolismo , Microtúbulos/metabolismo , Nucleótidos de Adenina/química , Adenosina Trifosfatasas/metabolismo , Animales , Drosophila melanogaster/metabolismo , Cinesinas , Meiosis , Microtúbulos/química
5.
BMC Genomics ; 24(1): 520, 2023 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-37667205

RESUMEN

BACKGROUND: Symbiotic nitrogen fixation differs among Bradyrhizobium japonicum strains. Soybean inoculated with USDA123 has a lower yield than strains known to have high nitrogen fixation efficiency, such as USDA110. In the main soybean-producing area in the Midwest of the United States, USDA123 has a high nodule incidence in field-grown soybean and is competitive but inefficient in nitrogen fixation. In this study, a high-throughput system was developed to characterize nodule number among 1,321 Glycine max and 69 Glycine soja accessions single inoculated with USDA110 and USDA123. RESULTS: Seventy-three G. max accessions with significantly different nodule number of USDA110 and USDA123 were identified. After double inoculating 35 of the 73 accessions, it was observed that PI189939, PI317335, PI324187B, PI548461, PI562373, and PI628961 were occupied by USDA110 and double-strain nodules but not by USDA123 nodules alone. PI567624 was only occupied by USDA110 nodules, and PI507429 restricted all strains. Analysis showed that 35 loci were associated with nodule number in G. max when inoculated with strain USDA110 and 35 loci with USDA123. Twenty-three loci were identified in G. soja when inoculated with strain USDA110 and 34 with USDA123. Only four loci were common across two treatments, and each locus could only explain 0.8 to 1.5% of phenotypic variation. CONCLUSIONS: High-throughput phenotyping systems to characterize nodule number and occupancy were developed, and soybean germplasm restricting rhizobium strain USDA123 but preferring USDA110 was identified. The larger number of minor effects and a small few common loci controlling the nodule number indicated trait genetic complexity and strain-dependent nodulation restriction. The information from the present study will add to the development of cultivars that limit USDA123, thereby increasing nitrogen fixation efficiency and productivity.


Asunto(s)
Fabaceae , Rhizobium , Glycine max/genética , Citoplasma , Variación Genética
6.
Breast Cancer Res ; 25(1): 24, 2023 03 07.
Artículo en Inglés | MEDLINE | ID: mdl-36882838

RESUMEN

BACKGROUND: Higher circulating prolactin has been associated with increased breast cancer risk. Prolactin binding to the prolactin receptor (PRLR) can activate the transcription factor STAT5, thus, we examined the association between plasma prolactin and breast cancer risk by tumor expression of PRLR, STAT5, and the upstream kinase JAK2. METHODS: Using data from 745 cases and 2454 matched controls in the Nurses' Health Study, we conducted polytomous logistic regression to examine the association between prolactin (> 11 ng/mL vs. ≤ 11 ng/mL) measured within 10 years of diagnosis and breast cancer risk by PRLR (nuclear [N], cytoplasmic [C]), phosphorylated STAT5 (pSTAT5; N, C), and phosphorylated JAK2 (pJAK2; C) tumor expression. Analyses were conducted separately in premenopausal (n = 168 cases, 765 controls) and postmenopausal women (n = 577 cases, 1689 controls). RESULTS: In premenopausal women, prolactin levels > 11 ng/mL were positively associated with risk of tumors positive for pSTAT5-N (OR 2.30, 95% CI 1.02-5.22) and pSTAT5-C (OR 1.64, 95% CI 1.01-2.65), but not tumors that were negative for these markers (OR 0.98, 95% CI 0.65-1.46 and OR 0.73, 95% CI 0.43-1.25; p-heterogeneity = 0.06 and 0.02, respectively). This was stronger when tumors were positive for both pSTAT5-N and pSTAT5-C (OR 2.88, 95% CI 1.14-7.25). No association was observed for PRLR or pJAK2 (positive or negative) and breast cancer risk among premenopausal women. Among postmenopausal women, plasma prolactin levels were positively associated with breast cancer risk irrespective of PRLR, pSTAT5, or pJAK2 expression (all p-heterogeneity ≥ 0.21). CONCLUSION: We did not observe clear differences in the association between plasma prolactin and breast cancer risk by tumor expression of PRLR or pJAK2, although associations for premenopausal women were observed for pSTAT5 positive tumors only. While additional studies are needed, this suggests that prolactin may act on human breast tumor development through alternative pathways.


Asunto(s)
Neoplasias de la Mama , Prolactina , Femenino , Humanos , Neoplasias de la Mama/epidemiología , Prolactina/sangre , Factor de Transcripción STAT5
7.
J Pediatr ; 262: 113621, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37473990

RESUMEN

OBJECTIVE: To characterize the psychological well-being, everyday functioning, and autonomy of emerging adults with congenital heart disease (CHD) and explore how they relate to the executive function (EF) deficits commonly observed in this population. STUDY DESIGN: Questionnaires assessing psychological well-being (encompassing psychosocial functioning and resilience), EF, and age-appropriate indicators of everyday function and autonomy (eg, housing, education, employment, relationship status) were completed by participants with CHD (16-26 years) who underwent open-heart surgery during infancy and age- and sex-matched controls. RESULTS: A total of 58 emerging adults with CHD and 57 controls participated in this study. Mean scores on the resilience and psychosocial functioning questionnaires were not significantly different between CHD and control participants. Emerging adults with CHD also did not differ from controls in terms of holding a driver's license, involvement in a romantic relationship, or current employment status. Multiple linear regression identified that better EF was associated with better psychological well-being. CONCLUSIONS: This study supports the need for systematic screening for EF deficits during adolescence and early adulthood to promote optimal well-being in this population. Further research is required to continue to document the everyday experiences of adolescents and young adults with CHD to identify protective factors associated with a successful and satisfying transition to adult life.


Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Cardiopatías Congénitas , Adolescente , Adulto Joven , Humanos , Adulto , Bienestar Psicológico , Cardiopatías Congénitas/complicaciones , Función Ejecutiva
8.
BMC Nephrol ; 24(1): 18, 2023 01 19.
Artículo en Inglés | MEDLINE | ID: mdl-36658531

RESUMEN

BACKGROUND: Hyperkalemia (HK) is a barrier to optimization of renin-angiotensin-aldosterone system inhibitor (RAASi) therapy in heart failure (HF) and chronic kidney disease (CKD). We investigated cardiorenal risk associated with changes in RAASi regimen after an episode of HK in patients with HF and/or CKD. METHODS: This observational study utilized data from hospital records, claims, and health registers from the US (Optum's de-identified Market Clarity Data) and Japan (Medical Data Vision). Included patients had an index episode of HK between July 2019 and September 2021 (US), or May 2020 and September 2021 (Japan), with prior diagnosis of HF or CKD (stage 3 or 4), and RAASi use. Risk of a cardiorenal composite outcome (HF emergency visit, HF hospitalization, or progression to end-stage kidney disease) was determined in patients who discontinued RAASi, down-titrated their dose by > 25%, or maintained or up-titrated their dose following the HK episode. RESULTS: A total of 15,488 and 6020 patients were included from the US and Japan, respectively. Prior to the episode of HK, 59% (US) and 27% (Japan) of patients had achieved > 50% target RAASi dose. Following the episode of HK, 33% (US) and 32% (Japan) of patients did not fill a new RAASi prescription. Risk of the cardiorenal outcome at 6 months was higher in patients who discontinued or down-titrated versus maintained or up-titrated RAASi treatment both in the US (17.5, 18.3, and 10.6%; p <  0.001) and in Japan (19.7, 20.0, and 15.1%; p <  0.001). CONCLUSION: HK-related RAASi discontinuation or down-titration was associated with higher risk of cardiorenal events versus maintained or up-titrated RAASi.


Asunto(s)
Inhibidores de la Enzima Convertidora de Angiotensina , Insuficiencia Cardíaca , Hiperpotasemia , Insuficiencia Renal Crónica , Humanos , Aldosterona , Inhibidores de la Enzima Convertidora de Angiotensina/efectos adversos , Antihipertensivos/uso terapéutico , Inhibidores Enzimáticos/uso terapéutico , Insuficiencia Cardíaca/complicaciones , Insuficiencia Cardíaca/tratamiento farmacológico , Hiperpotasemia/inducido químicamente , Hiperpotasemia/tratamiento farmacológico , Potasio/uso terapéutico , Insuficiencia Renal Crónica/complicaciones , Insuficiencia Renal Crónica/tratamiento farmacológico , Sistema Renina-Angiotensina
9.
Proc Natl Acad Sci U S A ; 117(29): 16976-16984, 2020 07 21.
Artículo en Inglés | MEDLINE | ID: mdl-32636254

RESUMEN

Microtubules are tubular polymers with essential roles in numerous cellular activities. Structures of microtubules have been captured at increasing resolution by cryo-EM. However, dynamic properties of the microtubule are key to its function, and this behavior has proved difficult to characterize at a structural level due to limitations in existing structure determination methods. We developed a high-resolution cryo-EM refinement method that divides an imaged microtubule into its constituent protofilaments, enabling deviations from helicity and other sources of heterogeneity to be quantified and corrected for at the single-subunit level. We demonstrate that this method improves the resolution of microtubule 3D reconstructions and substantially reduces anisotropic blurring artifacts, compared with methods that utilize helical symmetry averaging. Moreover, we identified an unexpected, discrete behavior of the m-loop, which mediates lateral interactions between neighboring protofilaments and acts as a flexible hinge between them. The hinge angle adopts preferred values corresponding to distinct conformations of the m-loop that are incompatible with helical symmetry. These hinge angles fluctuate in a stochastic manner, and perfectly cylindrical microtubule conformations are thus energetically and entropically penalized. The hinge angle can diverge further from helical symmetry at the microtubule seam, generating a subpopulation of highly distorted microtubules. However, the seam-distorted subpopulation disappears in the presence of Taxol, a microtubule stabilizing agent. These observations provide clues into the structural origins of microtubule flexibility and dynamics and highlight the role of structural polymorphism in defining microtubule behavior.


Asunto(s)
Microtúbulos/ultraestructura , Animales , Bovinos , Microscopía por Crioelectrón , Microtúbulos/química , Simulación de Dinámica Molecular
10.
Proc Natl Acad Sci U S A ; 117(3): 1478-1484, 2020 01 21.
Artículo en Inglés | MEDLINE | ID: mdl-31900364

RESUMEN

Members of the cofilin/ADF family of proteins sever actin filaments, increasing the number of filament ends available for polymerization or depolymerization. Cofilin binds actin filaments with positive cooperativity, forming clusters of contiguously bound cofilin along the filament lattice. Filament severing occurs preferentially at boundaries between bare and cofilin-decorated (cofilactin) segments and is biased at 1 side of a cluster. A molecular understanding of cooperative binding and filament severing has been impeded by a lack of structural data describing boundaries. Here, we apply methods for analyzing filament cryo-electron microscopy (cryo-EM) data at the single subunit level to directly investigate the structure of boundaries within partially decorated cofilactin filaments. Subnanometer resolution maps of isolated, bound cofilin molecules and an actin-cofilactin boundary indicate that cofilin-induced actin conformational changes are local and limited to subunits directly contacting bound cofilin. An isolated, bound cofilin compromises longitudinal filament contacts of 1 protofilament, consistent with a single cofilin having filament-severing activity. An individual, bound phosphomimetic (S3D) cofilin with weak severing activity adopts a unique binding mode that does not perturb actin structure. Cofilin clusters disrupt both protofilaments, consistent with a higher severing activity at boundaries compared to single cofilin. Comparison of these structures indicates that this disruption is substantially greater at pointed end sides of cofilactin clusters than at the barbed end. These structures, with the distribution of bound cofilin clusters, suggest that maximum binding cooperativity is achieved when 2 cofilins occupy adjacent sites. These results reveal the structural origins of cooperative cofilin binding and actin filament severing.


Asunto(s)
Citoesqueleto de Actina/química , Factores Despolimerizantes de la Actina/química , Citoesqueleto de Actina/metabolismo , Factores Despolimerizantes de la Actina/metabolismo , Animales , Sitios de Unión , Microscopía por Crioelectrón , Humanos , Fosforilación , Unión Proteica , Conejos
11.
Sensors (Basel) ; 23(11)2023 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-37300083

RESUMEN

Agriculture is a major consumer of freshwater and is often associated with low water productivity. To prevent drought, farmers tend to over-irrigate, putting a strain on the ever-depleting groundwater resources. To improve modern agricultural techniques and conserve water, quick and accurate estimates of soil water content (SWC) should be made, and irrigation timed correctly in order to optimize crop yield and water use. In this study, soil samples common to the Maltese Islands having different clay, sand, and silt contents were, primarily, investigated to: (a) deduce whether the dielectric constant can be considered as a viable indicator of the SWC for the soils of Malta; (b) determine how soil compaction affects the dielectric constant measurements; and (c) to create calibration curves to directly relate the dielectric constant and the SWC for two different soil types of low and high density. The measurements, which were carried out in the X-band, were facilitated by an experimental setup comprising a two-port Vector Network Analyzer (VNA) connected to a rectangular waveguide system. From data analysis, it was found that for each soil investigated, the dielectric constant increases notably with an increase in both density and SWC. Our findings are expected to aid in future numerical analysis and simulations aimed at developing low-cost, minimally invasive Microwave (MW) systems for localized SWC sensing, and hence, in agricultural water conservation. However, it should be noted that a statistically significant relationship between soil texture and the dielectric constant could not be determined at this stage.


Asunto(s)
Agua Subterránea , Suelo , Agricultura , Arcilla , Agua/análisis
12.
Sensors (Basel) ; 23(14)2023 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-37514884

RESUMEN

In microwave hyperthermia tumor therapy, electromagnetic waves focus energy on the tumor to elevate the temperature above its normal levels with minimal injury to the surrounding healthy tissue. Microwave hyperthermia applicator design is important for the effectiveness of the therapy and the feasibility of real-time application. In this study, the potential of using fractal octagonal ring antenna elements as a dipole antenna array and as a connected array at 2.45 GHz for breast tumor hyperthermia application was investigated. Microwave hyperthermia treatment models consisting of different fractal octagonal ring antenna array designs and a breast phantom are simulated in COMSOL Multiphysics to obtain the field distributions. The antenna excitation phases and magnitudes are optimized using the global particle swarm algorithm to selectively increase the specific absorption rate at the target region while minimizing hot spots in other regions within the breast. Specific absorption rate distributions, obtained inside the phantom, are analyzed for each proposed microwave hyperthermia applicator design. The dipole fractal octagonal ring antenna arrays are comparatively assessed for three different designs: circular, linear, and Cross-array. The 16-antenna dipole array performance was superior for all three 1-layer applicator designs, and no distinct difference was found between 16-antenna circular, linear, or cross arrays. Two-layer dipole arrays have better performance in the deep-tissue targets than one-layer arrays. The performance of the connected array with a higher number of layers exceeds the performance of the dipole arrays in the superficial regions, while they are comparable for deep regions of the breast. The 1-layer 12-antenna circular FORA dipole array feasibility as a microwave hyperthermia applicator was experimentally shown.

13.
Int J Mol Sci ; 24(14)2023 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-37511584

RESUMEN

Survivin (BIRC5) is a tumor-associated antigen (TAA) overexpressed in various tumors but present at low to undetectable levels in normal tissue. Survivin is known to have a high expression in breast cancer (e.g., Ductal Carcinoma in situ (DCIS) and triple negative breast cancer). Previous studies have not compared survivin expression levels in DCIS tumor samples to levels in adjacent, normal breast tissue from the same patient. To ensure the effective use of survivin as a target for T cell immunotherapy of breast cancer, it is essential to ascertain the varying levels of survivin expression between DCIS tumor tissue samples and the adjacent normal breast tissue taken from the same patient simultaneously. Next-generation sequencing of RNA (RNA-seq) in normal breast tissue and tumor breast tissue from five women presenting with DCIS for lumpectomy was used to identify sequence variation and expression levels of survivin. The identity of both tumor and adjacent normal tissue samples were corroborated by histopathology. Survivin was overexpressed in human breast tissue tumor samples relative to the corresponding adjacent human normal breast tissue. Wild-type survivin transcripts were the predominant species identified in all tumor tissue sequenced. This study demonstrates upregulated expression of wild type survivin in DCIS tumor tissue versus normal breast tissue taken from the same patient at the same time, and provides evidence that developing selective cytotoxic T lymphocyte (CTL) immunotherapy for DCIS targeting survivin warrants further study.


Asunto(s)
Neoplasias de la Mama , Carcinoma Ductal de Mama , Carcinoma Intraductal no Infiltrante , Femenino , Humanos , Neoplasias de la Mama/genética , Neoplasias de la Mama/terapia , Neoplasias de la Mama/metabolismo , Survivin/genética , Carcinoma Intraductal no Infiltrante/metabolismo , Proteínas Inhibidoras de la Apoptosis/genética , Proteínas Inhibidoras de la Apoptosis/metabolismo , Mama/metabolismo , Carcinoma Ductal de Mama/patología
14.
J Biol Chem ; 296: 100337, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33508320

RESUMEN

Members of the ADF/cofilin family of regulatory proteins bind actin filaments cooperatively, locally change actin subunit conformation and orientation, and sever filaments at "boundaries" between bare and cofilin-occupied segments. A cluster of bound cofilin introduces two distinct classes of boundaries due to the intrinsic polarity of actin filaments, one at the "pointed" end side and the other at the "barbed" end-side of the cluster; severing occurs more readily at the pointed end side of the cluster ("fast-severing" boundary) than the barbed end side ("slow-severing" boundary). A recent electron-cryomicroscopy (cryo-EM) model of the slow-severing boundary revealed structural "defects" at the interface that potentially contribute to severing. However, the structure of the fast-severing boundary remains uncertain. Here, we use extensive molecular dynamics simulations to produce atomic resolution models of both severing boundaries. Our equilibrated simulation model of the slow-severing boundary is consistent with the cryo-EM structural model. Simulations indicate that actin subunits at both boundaries adopt structures intermediate between those of bare and cofilin-bound actin subunits. These "intermediate" states have compromised intersubunit contacts, but those at the slow-severing boundary are stabilized by cofilin bridging interactions, accounting for its lower fragmentation probability. Simulations where cofilin proteins are removed from cofilactin filaments favor a mechanism in which a cluster of two contiguously bound cofilins is needed to fully stabilize the cofilactin conformation, promote cooperative binding interactions, and accelerate filament severing. Together, these studies provide a molecular-scale foundation for developing coarse-grained and theoretical descriptions of cofilin-mediated actin filament severing.


Asunto(s)
Factores Despolimerizantes de la Actina/metabolismo , Actinas/metabolismo , Citoesqueleto de Actina/química , Citoesqueleto de Actina/metabolismo , Factores Despolimerizantes de la Actina/química , Actinas/química , Animales , Pollos , Humanos , Simulación de Dinámica Molecular , Conformación Proteica , Subunidades de Proteína/química , Subunidades de Proteína/metabolismo , Conejos
15.
N Engl J Med ; 380(19): 1825-1833, 2019 05 09.
Artículo en Inglés | MEDLINE | ID: mdl-30883047

RESUMEN

BACKGROUND: Ticagrelor is an oral P2Y12 inhibitor that is used with aspirin to reduce the risk of ischemic events among patients with acute coronary syndromes or previous myocardial infarction. Spontaneous major bleeding and bleeding associated with urgent invasive procedures are concerns with ticagrelor, as with other antiplatelet drugs. The antiplatelet effects of ticagrelor cannot be reversed with platelet transfusion. A rapid-acting reversal agent would be useful. METHODS: In this randomized, double-blind, placebo-controlled, phase 1 trial, we evaluated intravenous PB2452, a monoclonal antibody fragment that binds ticagrelor with high affinity, as a ticagrelor reversal agent. We assessed platelet function in healthy volunteers before and after 48 hours of ticagrelor pretreatment and again after the administration of PB2452 or placebo. Platelet function was assessed with the use of light transmission aggregometry, a point-of-care P2Y12 platelet-reactivity test, and a vasodilator-stimulated phosphoprotein assay. RESULTS: Of the 64 volunteers who underwent randomization, 48 were assigned to receive PB2452 and 16 to receive placebo. After 48 hours of ticagrelor pretreatment, platelet aggregation was suppressed by approximately 80%. PB2452 administered as an initial intravenous bolus followed by a prolonged infusion (8, 12, or 16 hours) was associated with a significantly greater increase in platelet function than placebo, as measured by multiple assays. Ticagrelor reversal occurred within 5 minutes after the initiation of PB2452 and was sustained for more than 20 hours (P<0.001 after Bonferroni adjustment across all time points for all assays). There was no evidence of a rebound in platelet activity after drug cessation. Adverse events related to the trial drug were limited mainly to issues involving the infusion site. CONCLUSIONS: In healthy volunteers, the administration of PB2452, a specific reversal agent for ticagrelor, provided immediate and sustained reversal of the antiplatelet effects of ticagrelor, as measured by multiple assays. (Funded by PhaseBio Pharmaceuticals; ClinicalTrials.gov number, NCT03492385.).


Asunto(s)
Anticuerpos Neutralizantes/uso terapéutico , Plaquetas/efectos de los fármacos , Coagulantes/uso terapéutico , Inhibidores de Agregación Plaquetaria , Ticagrelor/antagonistas & inhibidores , Adulto , Anticuerpos Neutralizantes/efectos adversos , Plaquetas/fisiología , Anticuerpos ampliamente neutralizantes , Coagulantes/efectos adversos , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Femenino , Voluntarios Sanos , Humanos , Infusiones Intravenosas , Masculino , Ticagrelor/efectos adversos , Ticagrelor/uso terapéutico
16.
Hum Brain Mapp ; 43(11): 3545-3558, 2022 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-35411995

RESUMEN

Brain injury and dysmaturation is common in fetuses and neonates with congenital heart disease (CHD) and is hypothesized to result in persistent myelination deficits. This study aimed to quantify and compare myelin content in vivo between youth born with CHD and healthy controls. Youth aged 16 to 24 years born with CHD and healthy age- and sex-matched controls underwent brain magnetic resonance imaging including multicomponent driven equilibrium single pulse observation of T1 and T2 (mcDESPOT). Average myelin water fraction (MWF) values for 33 white matter tracts, as well as a summary measure of average white matter MWF, the White Matter Myelination Index, were calculated and compared between groups. Tract-average MWF was lower throughout the corpus callosum and in many bilateral association tracts and left hemispheric projection tracts in youth with CHD (N = 44) as compared to controls (N = 45). The White Matter Myelination Index was also lower in the CHD group. As such, this study provides specific evidence of widespread myelination deficits in youth with CHD, likely representing a long-lasting consequence of early-life brain dysmaturation in this population. This deficient myelination may underlie the frequent neurodevelopmental impairments experienced by CHD survivors and could eventually serve as a biomarker of neuropsychological function.


Asunto(s)
Cardiopatías Congénitas , Sustancia Blanca , Adolescente , Encéfalo/diagnóstico por imagen , Cardiopatías Congénitas/diagnóstico por imagen , Humanos , Recién Nacido , Imagen por Resonancia Magnética/métodos , Vaina de Mielina , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología
17.
AJR Am J Roentgenol ; 218(6): 940-952, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-34612682

RESUMEN

The introduction of immunotherapy with immune-checkpoint inhibitors (ICIs) has revolutionized cancer treatment paradigms. Since FDA approval of the first ICI in 2011, multiple additional ICIs have been approved and granted marketing authorization, and many promising agents are in early clinical adoption. Due to the distinctive biologic mechanisms of ICIs, the patterns of tumor response and progression seen with immunotherapy differ from those observed with cytotoxic chemothera-pies. With increasing clinical adoption of immunotherapy, it is critical for radiologists to recognize different response patterns and common pitfalls to avoid misinterpretation of imaging studies or prompt premature cessation of potentially effective treatment. This review provides an overview of ICIs and their mechanisms of action and discusses anatomic and metabolic immune-related response assessment methods, typical and atypical patterns of immunotherapy response (including pseudoprogression, hyperprogression, dissociated response, and durable response), and common imaging features of immune-related adverse events. Future multicenter trials are needed to validate the proposed immune-related response criteria and identify the functional imaging markers of early treatment response and survival.


Asunto(s)
Inmunoterapia , Neoplasias , Humanos , Inhibidores de Puntos de Control Inmunológico , Inmunoterapia/efectos adversos , Inflamación , Neoplasias/diagnóstico por imagen , Neoplasias/tratamiento farmacológico , Criterios de Evaluación de Respuesta en Tumores Sólidos
18.
J Immunol ; 205(11): 3191-3204, 2020 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-33148717

RESUMEN

IL-10 is a potent anti-inflammatory cytokine capable of suppressing a number of proinflammatory signals associated with intestinal inflammatory diseases, such as ulcerative colitis and Crohn's disease. Clinical use of human IL-10 (hIL-10) has been limited by anemia and thrombocytopenia following systemic injection, side effects that might be eliminated by a gut-restricted distribution. We have identified a transcytosis pathway used by cholix, an exotoxin secreted by nonpandemic forms of the intestinal pathogen Vibrio cholerae A nontoxic fragment of the first 386 aa of cholix was genetically fused to hIL-10 to produce recombinant AMT-101. In vitro and in vivo characterization of AMT-101 showed it to efficiently cross healthy human intestinal epithelium (SMI-100) by a vesicular transcytosis process, activate hIL-10 receptors in an engineered U2OS osteosarcoma cell line, and increase cellular phospho-STAT3 levels in J774.2 mouse macrophage cells. AMT-101 was taken up by inflamed intestinal mucosa and activated pSTAT3 in the lamina propria with limited systemic distribution. AMT-101 administered to healthy mice by oral gavage or to cynomolgus monkeys (nonhuman primates) by colonic spray increased circulating levels of IL-1R antagonist (IL-1Ra). Oral gavage of AMT-101 in two mouse models of induced colitis prevented associated pathological events and plasma cytokine changes. Overall, these studies suggest that AMT-101 can efficiently overcome the epithelial barrier to focus biologically active IL-10 to the intestinal lamina propria.


Asunto(s)
Colitis/metabolismo , Interleucina-10/metabolismo , Mucosa Intestinal/metabolismo , Animales , Células Cultivadas , Colon/metabolismo , Enfermedad de Crohn/metabolismo , Citocinas/metabolismo , Femenino , Humanos , Inflamación/metabolismo , Macaca fascicularis , Macrófagos/metabolismo , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones SCID , Membrana Mucosa/metabolismo , Ratas , Ratas Wistar , Transcitosis/fisiología
19.
Can J Anaesth ; 69(4): 494-503, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35014000

RESUMEN

PURPOSE: Noise in the operating room (OR) is common and associated with negative effects on anesthesiologists, surgeons, and patient outcomes. Induction of anesthesia is among the loudest perioperative periods. Despite its critical nature, there is little data on noise levels during induction, associated patient and anesthesiologist satisfaction, and the effects of noise reduction strategies. METHODS: We conducted a two-part prospective interventional quality improvement project on the care of adult patients receiving general anesthesia for elective noncardiac surgery. For part A, we measured average and peak noise (dB[A]) levels during anesthesia induction in N = 100 cases and administered a satisfaction questionnaire to anesthesiologists. We then applied a multidisciplinary educational program to OR personnel on active noise reduction strategies and subsequently collected data during N = 109 cases in a post-intervention phase. For part B, we administered satisfaction questionnaires to N = 100 patients pre- vs postintervention, respectively. RESULTS: Median [interquartile range] noise levels throughout induction were 66.0 [62.5-68.6] dB(A) preintervention vs 63.5 [60.1-65.4] dB[A] post-intervention (Hodges-Lehmann estimator of the difference, - 2.7 dB[A]; 95% confidence interval [CI], - 4.0 to - 1.5; P < 0.001). Peak noise levels during induction were 87.3 [84.0-90.5] dB(A) preintervention and 86.2 [81.8-89.3] dB(A) postintervention (Hodges-Lehmann estimator of the difference, - 1.8 dB[A]; 95% CI, - 3.3 to - 0.3; P = 0.02). Noise-related anesthesiologist satisfaction postintervention was significantly improved in multiple domains, including assessment of noise having distracted anesthesiologists. Patient satisfaction was high pre-intervention and did not significantly improve further. CONCLUSION: In this quality improvement project, average noise levels during induction of anesthesia, anesthesiologist satisfaction, and anesthesiologists' perceived ability to perform were improved following a multidisciplinary educational program on noise reduction in the OR. STUDY REGISTRATION: www. CLINICALTRIALS: gov (NCT04204785); registered 19 December 2019.


RéSUMé: OBJECTIF: Le bruit en salle d'opération (SOP) est fréquent et associé à des effets négatifs sur les anesthésiologistes, les chirurgiens et les issues des patients. L'induction de l'anesthésie est l'une des périodes périopératoires les plus bruyantes. Malgré sa nature critique, il existe peu de données sur les niveaux sonores pendant l'induction, la satisfaction des patients et des anesthésiologistes qui y est reliée, et les effets des stratégies de réduction du bruit. MéTHODE: Nous avons mené un projet prospectif et interventionnel, en deux parties, d'amélioration de la qualité sur les soins aux patients adultes recevant une anesthésie générale pour une chirurgie non cardiaque non urgente. Dans le cadre de la première partie A, nous avons mesuré les niveaux de bruit moyen et maximaux (dB[A]) pendant l'induction de l'anesthésie dans n = 100 cas et administré un questionnaire de satisfaction aux anesthésiologistes. Nous avons ensuite appliqué un programme de formation multidisciplinaire au personnel de la salle d'opération sur les stratégies de réduction active du bruit et avons ensuite recueilli des données pour n = 109 cas dans une phase post-intervention. Pour la deuxième partie B, nous avons administré des questionnaires de satisfaction à n = 100 patients pré- vs post-intervention, respectivement. RéSULTATS: Les niveaux de bruit médians [écart interquartile] tout au long de l'induction étaient de 66,0 [62,5­68,6] dB(A) avant l'intervention vs 63,5 [60,1­65,4] dB[A] après l'intervention (estimateur de Hodges-Lehmann, − 2,7 dB[A]; intervalle de confiance [IC] 95 %, − 4,0 à − 1,5; P < 0,001). Les niveaux maximaux de bruit pendant l'induction étaient de 87,3 [84,0­90,5] dB(A) avant l'intervention et de 86,2 [81,8­89,3] dB(A) après l'intervention (estimateur de Hodges-Lehmann, − 1,8 dB[A]; IC 95 %, − 3,3 à − 0,3; P = 0,02). La satisfaction des anesthésiologistes par rapport au bruit après l'intervention a été considérablement améliorée dans de nombreux domaines, y compris l'évaluation du bruit ayant distrait les anesthésiologistes. La satisfaction des patients était élevée avant l'intervention et ne s'est pas améliorée de manière significative. CONCLUSION: Dans ce projet d'amélioration de la qualité, les niveaux de bruit moyens lors de l'induction de l'anesthésie, la satisfaction des anesthésiologistes et la capacité perçue des anesthésiologistes à réaliser leurs tâches ont été améliorés à la suite d'un programme de formation multidisciplinaire sur la réduction du bruit en salle d'opération. ENREGISTREMENT DE L'éTUDE: www.ClinicalTrials.gov (NCT04204785); enregistrée le 19 décembre 2019.


Asunto(s)
Anestesiología , Quirófanos , Adulto , Anestesia General , Humanos , Estudios Prospectivos , Mejoramiento de la Calidad
20.
Sensors (Basel) ; 22(10)2022 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-35632302

RESUMEN

Electromagnetic thermal therapies for cancer treatment, such as microwave hyperthermia, aim to heat up a targeted tumour site to temperatures within 40 and 44 °C. Computational simulations used to investigate such heating systems employ the Pennes' bioheat equation to model the heat exchange within the tissue, which accounts for several tissue properties: density, specific heat capacity, thermal conductivity, metabolic heat generation rate, and blood perfusion rate. We present a review of these thermal and physiological properties relevant for hyperthermia treatments of breast including fibroglandular breast, fatty breast, and breast tumours. The data included in this review were obtained from both experimental measurement studies and estimated properties of human breast tissues. The latter were used in computational studies of breast thermal treatments. The measurement methods, where available, are discussed together with the estimations and approximations considered for values where measurements were unavailable. The review concludes that measurement data for the thermal and physiological properties of breast and tumour tissue are limited. Fibroglandular and fatty breast tissue properties are often approximated from those of generic muscle or fat tissue. Tumour tissue properties are mostly obtained from approximating equations or assumed to be the same as those of glandular tissue. We also present a set of reliable data, which can be used for more accurate modelling and simulation studies to better treat breast cancer using thermal therapies.


Asunto(s)
Neoplasias de la Mama , Hipertermia Inducida , Regulación de la Temperatura Corporal , Neoplasias de la Mama/terapia , Simulación por Computador , Femenino , Humanos , Hipertermia Inducida/métodos , Conductividad Térmica
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