Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 46
Filtrar
1.
Pharmaceuticals (Basel) ; 17(7)2024 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-39065809

RESUMEN

Many routes may lead to the transition from a healthy to a diseased phenotype. However, there are not so many routes to travel in the opposite direction; that is, therapy for different diseases. The following pressing question thus remains: what are the pathogenic routes and how can be they counteracted for therapeutic purposes? Human cells contain >500 protein kinases and nearly 200 protein phosphatases, acting on thousands of proteins, including cell growth factors. We herein discuss neurotrophins with pathogenic or metabotrophic abilities, particularly brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), pro-NGF, neurotrophin-3 (NT-3), and their receptor Trk (tyrosine receptor kinase; pronounced "track"). Indeed, we introduced the word trackins, standing for Trk-targeting drugs, that play an agonistic or antagonistic role in the function of TrkBBDNF, TrkCNT-3, TrkANGF, and TrkApro-NGF receptors. Based on our own published results, supported by those of other authors, we aim to update and enlarge our trackins concept, focusing on (1) agonistic trackins as possible drugs for (1a) neurotrophin-deficiency cardiometabolic disorders (hypertension, atherosclerosis, type 2 diabetes mellitus, metabolic syndrome, obesity, diabetic erectile dysfunction and atrial fibrillation) and (1b) neurodegenerative diseases (Alzheimer's disease, Parkinson's disease, and multiple sclerosis), and (2) antagonistic trackins, particularly TrkANGF inhibitors for prostate and breast cancer, pain, and arrhythmogenic right-ventricular dysplasia. Altogether, the druggability of TrkANGF, TrkApro-NGF, TrkBBDNF, and TrkCNT-3 receptors via trackins requires a further translational pursuit. This could provide rewards for our patients.

2.
Molecules ; 27(3)2022 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-35164015

RESUMEN

As a result of our study on the interaction between the octahydrotriborate anion with nucleophiles (Nu = THF, Ph3P, Ph2P-(CH2)2-PPh2 (dppe), Ph3As, Et3N, PhNH2, C5H5N, CH3CN, Ph2CHCN)) in the presence of a wide range of Lewis acids (Ti(IV), Hf(IV), Zr(IV), Al, Cu(I), Zn, Mn(II), Co(II) halides and iodine), a number of substituted derivatives of the octahydrotriborate anion [B3H7Nu] are obtained. It is found that the use of TiCl4, AlCl3, ZrCl4, HfCl4, CuCl and iodine leads to the highest product yields. In this case, it is most likely that the reaction proceeds through the formation of an intermediate [B3H7-HMXnx], which was detected by NMR spectroscopy. The structures of [Ph3P·B3H7] and [PhNH2·B3H7] were determined by X-ray diffraction.

3.
Molecules ; 26(12)2021 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-34207280

RESUMEN

The interaction of hafnium(IV) salts (oxide-dichloride, chloride, and bromide) with nitrilotriacetic acid (NTA), diethylenetriamminepentaacetic acid (DTPA), 1,2-diaminocyclohexanetetraacetic acid (CDTA), 1,3-dipropylmino-2-hydroxy N,N,N',N'-tetraacetic acid (dpta), and N-(2-hydroxyethyl)ethylenediamine triacetic acid (HEDTA) has been studied. The corresponding complexes Na2[Hf(NTA)2]·3H2O (1), Na[HfDTPA]·3H2O (2), [HfCDTA(H2O)2] (3), and Na[Hf2(dpta)2]·7.5H2O·0.5C2H5OH (4) have been isolated and characterized and their structures have been determined by single crystal X-ray diffraction. Biological studies of [HfCDTA(H2O)2] have shown that in 5% glucose solution this complex has low toxicity and good contrasting ability.

4.
Artículo en Inglés | MEDLINE | ID: mdl-32998629

RESUMEN

The results of neuropsychological tests may be distorted by patients who exaggerate cognitive deficits. Eighty-three patients with cognitive deficit [Amnestic Mild Cognitive Impairment (aMCI), n = 53; Alzheimer's disease (AD) dementia, n = 30], 44 healthy older adults (HA), and 30 simulators of AD (s-AD) underwent comprehensive neuropsychological assessment. Receiver Operating Characteristic (ROC) analysis revealed high specificity but low sensitivity of the Delayed Matching to Sample Task (DMS48) in differentiating s-AD from AD dementia (87 and 53%, respectively) and from aMCI (96 and 57%). The sensitivity was considerably increased by using the DMS48/Rey Auditory Verbal Learning Test (RAVLT) ratio (specificity and sensitivity 93% and 93% for AD dementia and 96% and 80% for aMCI). The DMS48 differentiates s-AD from both aMCI and AD dementia with high specificity but low sensitivity. Its predictive value greatly increased when evaluated together with the RAVLT.


Asunto(s)
Enfermedad de Alzheimer , Trastornos del Conocimiento , Disfunción Cognitiva , Anciano , Enfermedad de Alzheimer/diagnóstico , Disfunción Cognitiva/diagnóstico , Humanos , Simulación de Enfermedad/diagnóstico , Pruebas Neuropsicológicas
5.
Genome Biol ; 19(1): 87, 2018 07 17.
Artículo en Inglés | MEDLINE | ID: mdl-30012220

RESUMEN

BACKGROUND: Genome-wide association studies conducted on QRS duration, an electrocardiographic measurement associated with heart failure and sudden cardiac death, have led to novel biological insights into cardiac function. However, the variants identified fall predominantly in non-coding regions and their underlying mechanisms remain unclear. RESULTS: Here, we identify putative functional coding variation associated with changes in the QRS interval duration by combining Illumina HumanExome BeadChip genotype data from 77,898 participants of European ancestry and 7695 of African descent in our discovery cohort, followed by replication in 111,874 individuals of European ancestry from the UK Biobank and deCODE cohorts. We identify ten novel loci, seven within coding regions, including ADAMTS6, significantly associated with QRS duration in gene-based analyses. ADAMTS6 encodes a secreted metalloprotease of currently unknown function. In vitro validation analysis shows that the QRS-associated variants lead to impaired ADAMTS6 secretion and loss-of function analysis in mice demonstrates a previously unappreciated role for ADAMTS6 in connexin 43 gap junction expression, which is essential for myocardial conduction. CONCLUSIONS: Our approach identifies novel coding and non-coding variants underlying ventricular depolarization and provides a possible mechanism for the ADAMTS6-associated conduction changes.


Asunto(s)
Proteínas ADAMTS/genética , Conexina 43/genética , Exoma , Sitios Genéticos , Sistema de Conducción Cardíaco/metabolismo , Miocardio/metabolismo , Animales , Población Negra , Electrocardiografía , Femenino , Expresión Génica , Perfilación de la Expresión Génica , Estudio de Asociación del Genoma Completo , Sistema de Conducción Cardíaco/fisiopatología , Humanos , Masculino , Ratones , Persona de Mediana Edad , Miocardio/patología , Sistemas de Lectura Abierta , Polimorfismo de Nucleótido Simple , Población Blanca , Secuenciación del Exoma
6.
Nat Genet ; 49(7): 1152-1159, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28530678

RESUMEN

Congenital heart disease (CHD) affects up to 1% of live births. Although a genetic etiology is indicated by an increased recurrence risk, sporadic occurrence suggests that CHD genetics is complex. Here, we show that hypoplastic left heart syndrome (HLHS), a severe CHD, is multigenic and genetically heterogeneous. Using mouse forward genetics, we report what is, to our knowledge, the first isolation of HLHS mutant mice and identification of genes causing HLHS. Mutations from seven HLHS mouse lines showed multigenic enrichment in ten human chromosome regions linked to HLHS. Mutations in Sap130 and Pcdha9, genes not previously associated with CHD, were validated by CRISPR-Cas9 genome editing in mice as being digenic causes of HLHS. We also identified one subject with HLHS with SAP130 and PCDHA13 mutations. Mouse and zebrafish modeling showed that Sap130 mediates left ventricular hypoplasia, whereas Pcdha9 increases penetrance of aortic valve abnormalities, both signature HLHS defects. These findings show that HLHS can arise genetically in a combinatorial fashion, thus providing a new paradigm for the complex genetics of CHD.


Asunto(s)
Heterogeneidad Genética , Síndrome del Corazón Izquierdo Hipoplásico/genética , Secuencia de Aminoácidos , Animales , Aorta/embriología , Sistemas CRISPR-Cas , Mapeo Cromosómico , Cromosomas Humanos/genética , Modelos Animales de Enfermedad , Exoma , Femenino , Edición Génica , Técnicas de Inactivación de Genes , Ventrículos Cardíacos/embriología , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Mutantes , Mutación , Mutación Missense , Miocitos Cardíacos/patología , Penetrancia , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Obstrucción del Flujo Ventricular Externo/genética , Pez Cebra/genética
7.
Artículo en Inglés | MEDLINE | ID: mdl-28159874

RESUMEN

A central role for cilia in congenital heart disease (CHD) was recently identified in a large-scale mouse mutagenesis screen. Although the screen was phenotype-driven, the majority of genes recovered were cilia-related, suggesting that cilia play a central role in CHD pathogenesis. This partly reflects the role of cilia as a hub for cell signaling pathways regulating cardiovascular development. Consistent with this, many cilia-transduced cell signaling genes were also recovered, and genes regulating vesicular trafficking, a pathway essential for ciliogenesis and cell signaling. Interestingly, among CHD-cilia genes recovered, some regulate left-right patterning, indicating cardiac left-right asymmetry disturbance may play significant roles in CHD pathogenesis. Clinically, CHD patients show a high prevalence of ciliary dysfunction and show enrichment for de novo mutations in cilia-related pathways. Combined with the mouse findings, this would suggest CHD may be a new class of ciliopathy.


Asunto(s)
Cilios/fisiología , Ciliopatías/complicaciones , Cardiopatías Congénitas/etiología , Animales , Humanos
8.
Nat Genet ; 47(11): 1260-3, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26437028

RESUMEN

Heterotaxy results from a failure to establish normal left-right asymmetry early in embryonic development. By whole-exome sequencing, whole-genome sequencing and high-throughput cohort resequencing, we identified recessive mutations in MMP21 (encoding matrix metallopeptidase 21) in nine index cases with heterotaxy. In addition, Mmp21-mutant mice and mmp21-morphant zebrafish displayed heterotaxy and abnormal cardiac looping, respectively, suggesting a new role for extracellular matrix remodeling in the establishment of laterality in vertebrates.


Asunto(s)
Tipificación del Cuerpo/genética , Síndrome de Heterotaxia/genética , Metaloproteinasas de la Matriz Secretadas/genética , Mutación Puntual , Vertebrados/genética , Animales , Embrión no Mamífero/embriología , Embrión no Mamífero/metabolismo , Salud de la Familia , Femenino , Regulación del Desarrollo de la Expresión Génica , Genes Recesivos , Corazón/embriología , Cardiopatías Congénitas/genética , Humanos , Hibridación in Situ , Masculino , Ratones , Linaje , Análisis de Secuencia de ADN/métodos , Pez Cebra/embriología , Pez Cebra/genética , Proteínas de Pez Cebra/genética
9.
Am J Med Genet A ; 167A(9): 2188-96, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25914204

RESUMEN

Ciliopathies such as cranioectodermal dysplasia, Sensenbrenner syndrome, short-rib polydactyly, and Jeune syndrome are associated with respiratory complications arising from rib cage dysplasia. While such ciliopathies have been demonstrated to involve primary cilia defects, we show motile cilia dysfunction in the airway of a patient diagnosed with cranioectodermal dysplasia. While this patient had mild thoracic dystrophy not requiring surgical treatment, there was nevertheless newborn respiratory distress, restrictive airway disease with possible obstructive airway involvement, repeated respiratory infections, and atelectasis. High-resolution videomicroscopy of nasal epithelial biopsy showed immotile/dyskinetic cilia and nasal nitric oxide was reduced, both of which are characteristics of primary ciliary dyskinesia, a sinopulmonary disease associated with mucociliary clearance defects due to motile cilia dysfunction in the airway. Exome sequencing analysis of this patient identified compound heterozygous mutations in WDR35, but no mutations in any of the 30 known primary ciliary dyskinesia genes or other cilia-related genes. Given that WDR35 is only known to be required for primary cilia function, we carried out WDR35 siRNA knockdown in human respiratory epithelia to assess the role of WDR35 in motile cilia function. This showed WDR35 deficiency disrupted ciliogenesis in the airway, indicating WDR35 is also required for formation of motile cilia. Together, these findings suggest patients with WDR35 mutations have an airway mucociliary clearance defect masked by their restrictive airway disease.


Asunto(s)
Huesos/anomalías , Cilios/genética , Craneosinostosis/genética , Displasia Ectodérmica/genética , Enfermedades Respiratorias/genética , Niño , Proteínas del Citoesqueleto , Proteínas Hedgehog , Heterocigoto , Humanos , Péptidos y Proteínas de Señalización Intracelular , Masculino , Mutación/genética , Proteínas/genética
10.
Nature ; 521(7553): 520-4, 2015 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-25807483

RESUMEN

Congenital heart disease (CHD) is the most prevalent birth defect, affecting nearly 1% of live births; the incidence of CHD is up to tenfold higher in human fetuses. A genetic contribution is strongly suggested by the association of CHD with chromosome abnormalities and high recurrence risk. Here we report findings from a recessive forward genetic screen in fetal mice, showing that cilia and cilia-transduced cell signalling have important roles in the pathogenesis of CHD. The cilium is an evolutionarily conserved organelle projecting from the cell surface with essential roles in diverse cellular processes. Using echocardiography, we ultrasound scanned 87,355 chemically mutagenized C57BL/6J fetal mice and recovered 218 CHD mouse models. Whole-exome sequencing identified 91 recessive CHD mutations in 61 genes. This included 34 cilia-related genes, 16 genes involved in cilia-transduced cell signalling, and 10 genes regulating vesicular trafficking, a pathway important for ciliogenesis and cell signalling. Surprisingly, many CHD genes encoded interacting proteins, suggesting that an interactome protein network may provide a larger genomic context for CHD pathogenesis. These findings provide novel insights into the potential Mendelian genetic contribution to CHD in the fetal population, a segment of the human population not well studied. We note that the pathways identified show overlap with CHD candidate genes recovered in CHD patients, suggesting that they may have relevance to the more complex genetics of CHD overall. These CHD mouse models and >8,000 incidental mutations have been sperm archived, creating a rich public resource for human disease modelling.


Asunto(s)
Cilios/patología , Cardiopatías Congénitas/genética , Cardiopatías Congénitas/patología , Animales , Cilios/diagnóstico por imagen , Cilios/genética , Cilios/fisiología , Análisis Mutacional de ADN , Electrocardiografía , Exoma/genética , Genes Recesivos , Pruebas Genéticas , Cardiopatías Congénitas/diagnóstico por imagen , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Mutación/genética , Transducción de Señal , Ultrasonografía
11.
Nat Commun ; 6: 6023, 2015 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-25599650

RESUMEN

The ciliary kinase NEK8 plays a critical role in situs determination and cystic kidney disease, yet its exact function remains unknown. In this study, we identify ANKS6 as a target and activator of NEK8. ANKS6 requires NEK8 for localizing to the ciliary inversin compartment (IC) and activates NEK8 by binding to its kinase domain. Here we demonstrate the functional importance of this interaction through the analysis of two novel mouse mutations, Anks6(Streaker) and Nek8(Roc). Both display heterotaxy, cardiopulmonary malformations and cystic kidneys, a syndrome also characteristic of mutations in Invs and Nphp3, the other known components of the IC. The Anks6(Strkr) mutation decreases ANKS6 interaction with NEK8, precluding NEK8 activation. The Nek8(Roc) mutation inactivates NEK8 kinase function while preserving ANKS6 localization to the IC. Together, these data reveal the crucial role of NEK8 kinase activation within the IC, promoting proper left-right patterning, cardiopulmonary development and renal morphogenesis.


Asunto(s)
Tipificación del Cuerpo/fisiología , Proteínas Portadoras/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Animales , Western Blotting , Tipificación del Cuerpo/genética , Proteínas Portadoras/genética , Línea Celular , Femenino , Humanos , Cinesinas/genética , Cinesinas/metabolismo , Masculino , Ratones , Morfogénesis/genética , Morfogénesis/fisiología , Mutación , Quinasas Relacionadas con NIMA , Proteínas Nucleares/genética , Proteínas Serina-Treonina Quinasas/genética , Ratas , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
12.
Am J Hum Genet ; 95(3): 257-74, 2014 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-25192045

RESUMEN

A diverse family of cytoskeletal dynein motors powers various cellular transport systems, including axonemal dyneins generating the force for ciliary and flagellar beating essential to movement of extracellular fluids and of cells through fluid. Multisubunit outer dynein arm (ODA) motor complexes, produced and preassembled in the cytosol, are transported to the ciliary or flagellar compartment and anchored into the axonemal microtubular scaffold via the ODA docking complex (ODA-DC) system. In humans, defects in ODA assembly are the major cause of primary ciliary dyskinesia (PCD), an inherited disorder of ciliary and flagellar dysmotility characterized by chronic upper and lower respiratory infections and defects in laterality. Here, by combined high-throughput mapping and sequencing, we identified CCDC151 loss-of-function mutations in five affected individuals from three independent families whose cilia showed a complete loss of ODAs and severely impaired ciliary beating. Consistent with the laterality defects observed in these individuals, we found Ccdc151 expressed in vertebrate left-right organizers. Homozygous zebrafish ccdc151(ts272a) and mouse Ccdc151(Snbl) mutants display a spectrum of situs defects associated with complex heart defects. We demonstrate that CCDC151 encodes an axonemal coiled coil protein, mutations in which abolish assembly of CCDC151 into respiratory cilia and cause a failure in axonemal assembly of the ODA component DNAH5 and the ODA-DC-associated components CCDC114 and ARMC4. CCDC151-deficient zebrafish, planaria, and mice also display ciliary dysmotility accompanied by ODA loss. Furthermore, CCDC151 coimmunoprecipitates CCDC114 and thus appears to be a highly evolutionarily conserved ODA-DC-related protein involved in mediating assembly of both ODAs and their axonemal docking machinery onto ciliary microtubules.


Asunto(s)
Dineínas Axonemales/metabolismo , Cilios/patología , Síndrome de Kartagener/genética , Proteínas Asociadas a Microtúbulos/fisiología , Mutación/genética , Animales , Dineínas Axonemales/genética , Axonema/genética , Células Cultivadas , Cilios/metabolismo , Embrión de Mamíferos/citología , Embrión de Mamíferos/metabolismo , Exoma/genética , Femenino , Técnica del Anticuerpo Fluorescente , Humanos , Immunoblotting , Inmunoprecipitación , Hibridación in Situ , Síndrome de Kartagener/metabolismo , Síndrome de Kartagener/patología , Masculino , Ratones , Ratones Noqueados , Proteínas Asociadas a Microtúbulos/genética , Proteínas Asociadas a Microtúbulos/metabolismo , Linaje , Fenotipo , Técnicas del Sistema de Dos Híbridos , Pez Cebra/genética , Pez Cebra/crecimiento & desarrollo , Pez Cebra/metabolismo
13.
Birth Defects Res C Embryo Today ; 102(2): 115-25, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24975753

RESUMEN

Structural birth defect (SBD) is a major cause of morbidity and mortality in the newborn period. Although the etiology of SBD is diverse, a wide spectrum of SBD associated with ciliopathies points to the cilium as having a central role in the pathogenesis of SBDs. Ciliopathies are human diseases arising from disruption of cilia structure and/or function. They are associated with developmental anomalies in one or more organ systems and can involve defects in motile cilia, such as those in the airway epithelia or from defects in nonmotile (primary cilia) that have sensory and cell signaling function. Availability of low cost next generation sequencing has allowed for explosion of new knowledge in genetic etiology of ciliopathies. This has led to the appreciation that many genes are shared in common between otherwise clinically distinct ciliopathies. Further insights into the relevance of the cilium in SBD has come from recovery of pathogenic mutations in cilia-related genes from many large-scale mouse forward genetic screens with differing developmental phenotyping focus. Our mouse mutagenesis screen for congenital heart disease (CHD) using noninvasive fetal echocardiography has yielded a marked enrichment for pathogenic mutations in genes required for motile or primary cilia function. These novel mutant mouse models will be invaluable for modeling human ciliopathies and further interrogating the role of the cilium in the pathogenesis of SBD and CHD. Overall, these findings suggest a central role for the cilium in the pathogenesis of a wide spectrum of developmental anomalies associated with CHD and SBDs.


Asunto(s)
Cilios/patología , Anomalías Congénitas/genética , Modelos Animales de Enfermedad , Animales , Encéfalo/anomalías , Anomalías Congénitas/patología , Discinesias/genética , Discinesias/patología , Cardiopatías Congénitas/genética , Cardiopatías Congénitas/patología , Secuenciación de Nucleótidos de Alto Rendimiento , Ratones , Mutación , Orgánulos/patología , Transducción de Señal
14.
J Phys Chem A ; 117(49): 13138-50, 2013 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-24200215

RESUMEN

Interaction of [Cu2B10H10] with 2,2'-bipyridine (bipy) afforded a novel binuclear discrete complex of the [Cu2(bipy)2B10H10] composition. Two copper(I) atoms coordinate a bridge boron cage through an apical edge and a triangular BBB face situated at its opposite apical vertices to form four 3c2e (CuHB) and one 2c2e Cu-B bonds. The charge density model was obtained by density functional theory calculations of isolated molecule and crystal. The resultant densities were analyzed using the quantum theory of atoms in molecules (QTAIM) and electron localizability indicator (ELI-D). The geometry and the topological parameters of copper(I) coordination environment were found to be sensitive to crystal-field effect. An annulus of flat electron density ρ(r) and small ∇(2)ρ(r) is formed at dianion faces. As a result, some of the expected B-B, Cu-B, or Cu-H bond critical points are absent. The topological instability in the region of multicentered bonds is observed. The Cu-B bonding was found to be presumably electrostatic in nature, which could be the reason of topological isomerism for copper(I) decaborates. The results show that an unambiguous real-space criterion for multicentered bonding between transition metals and polyhedral boron anions is not yet given. The molecular graph for this class of compounds does not provide a definitive picture of the chemical boding and can be complemented with other descriptors, such as virial graphs and the ELI-D distribution.

15.
J Bacteriol ; 194(17): 4642-51, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22753061

RESUMEN

Cyclic dimeric GMP (c-di-GMP) regulates numerous processes in Gram-negative bacteria, yet little is known about its role in Gram-positive bacteria. Here we characterize two c-di-GMP phosphodiesterases from the filamentous high-GC Gram-positive actinobacterium Streptomyces coelicolor, involved in controlling colony morphology and development. A transposon mutation in one of the two phosphodiesterase genes, SCO0928, hereby designated rmdA (regulator of morphology and development A), resulted in decreased levels of spore-specific gray pigment and a delay in spore formation. The RmdA protein contains GGDEF-EAL domains arranged in tandem and possesses c-di-GMP phosphodiesterase activity, as is evident from in vitro enzymatic assays using the purified protein. RmdA contains a PAS9 domain and is a hemoprotein. Inactivation of another GGDEF-EAL-encoding gene, SCO5495, designated rmdB, resulted in a phenotype identical to that of the rmdA mutant. Purified soluble fragment of RmdB devoid of transmembrane domains also possesses c-di-GMP phosphodiesterase activity. The rmdA rmdB double mutant has a bald phenotype and is impaired in aerial mycelium formation. This suggests that RmdA and RmdB functions are additive and at least partially overlapping. The rmdA and rmdB mutations likely result in increased local pools of intracellular c-di-GMP, because intracellular c-di-GMP levels in the single mutants did not differ significantly from those of the wild type, whereas in the double rmdA rmdB mutant, c-di-GMP levels were 3-fold higher than those in the wild type. This study highlights the importance of c-di-GMP-dependent signaling in actinomycete colony morphology and development and identifies two c-di-GMP phosphodiesterases controlling these processes.


Asunto(s)
GMP Cíclico/análogos & derivados , Hidrolasas Diéster Fosfóricas/metabolismo , Streptomyces coelicolor/genética , Streptomyces coelicolor/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , GMP Cíclico/metabolismo , Elementos Transponibles de ADN , Regulación Bacteriana de la Expresión Génica , Mutación , Hidrolasas Diéster Fosfóricas/genética , Esporas Bacterianas/genética , Esporas Bacterianas/metabolismo , Streptomyces coelicolor/citología , Streptomyces coelicolor/crecimiento & desarrollo
16.
Environ Sci Technol ; 45(23): 9837-56, 2011 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-21988187

RESUMEN

Carbon nanotubes (CNTs) are currently incorporated into various consumer products, and numerous new applications and products containing CNTs are expected in the future. The potential for negative effects caused by CNT release into the environment is a prominent concern and numerous research projects have investigated possible environmental release pathways, fate, and toxicity. However, this expanding body of literature has not yet been systematically reviewed. Our objective is to critically review this literature to identify emerging trends as well as persistent knowledge gaps on these topics. Specifically, we examine the release of CNTs from polymeric products, removal in wastewater treatment systems, transport through surface and subsurface media, aggregation behaviors, interactions with soil and sediment particles, potential transformations and degradation, and their potential ecotoxicity in soil, sediment, and aquatic ecosystems. One major limitation in the current literature is quantifying CNT masses in relevant media (polymers, tissues, soils, and sediments). Important new directions include developing mechanistic models for CNT release from composites and understanding CNT transport in more complex and environmentally realistic systems such as heteroaggregation with natural colloids and transport of nanoparticles in a range of soils.


Asunto(s)
Ecología/métodos , Monitoreo del Ambiente/métodos , Nanotubos de Carbono/análisis
17.
Environ Sci Technol ; 45(22): 9765-75, 2011 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-21950836

RESUMEN

Nanoparticles possess unique physical, electrical, and chemical properties which make them attractive for use in a wide range of consumer products. Through their manufacturing, usage, and eventual disposal, nanoparticles are expected to ultimately be released to the environment after which point they may pose environmental and human health risks. One critical component of understanding and modeling those potential risks is their transport in the subsurface environment. This study investigates the mobility of one important nanoparticle (multi-walled carbon nanotubes or MWCNTs) through porous media, and makes the first measurements on the impact of mean collector grain size (d(50)) on MWCNT retention. Results from one-dimensional column experiments conducted under various physical and chemical conditions coupled with results of numerical modeling assessed the suitability of traditional transport models to predict MWCNT mobility. Findings suggest that a dual deposition model coupled with site blocking greatly improves model fits compared to traditional colloid filtration theory. Of particular note is that the MWCNTs traveled through porous media ranging in size from fine sand to silt resulting in normalized concentrations of MWCNTs in the effluent in excess of 60% of the influent concentration.


Asunto(s)
Nanotubos de Carbono/química , Modelos Químicos , Movimiento (Física) , Tamaño de la Partícula , Porosidad , Dióxido de Silicio/química
18.
Folia Med (Plovdiv) ; 53(4): 42-6, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-22708473

RESUMEN

OBJECTIVE: To study the relative share of asymptomatic forms of Hepatitis A in family reservoirs of infection with different hygienic conditions. MATERIALS AND METHODS: Asymptomatic forms were identified by detecting anti-HAV IgM using ELISA. Two types of households: with poor hygiene and with good hygiene, were studied. The study was designed as case-control. A group of Hepatitis A contact children attending day nurseries and kindergartens was also included in the study. RESULTS: The relative share of asymptomatic forms of HAV infection in poor hygiene households was 58.62%, while in those with good hygiene it was 41.57%. The comparison using Fisher's exact test yielded OR = 1.99 and 95% CI (P < 0.05). Asymptomatic forms were found in 7.75% of the investigated contacts among children attending day nurseries and kindergartens. CONCLUSION: Asymptomatic forms of hepatitis A are very common which makes them epidemiologically quite significant as many of the cases remain unrecognized and later become focal points of new cases of the disease. Poor hygiene conditions are likely to cause more asymptomatic forms. The high relative share of asymptomatic forms found in the households supports the need for immunoprophylaxis of the contacts.


Asunto(s)
Hepatitis A/epidemiología , Bulgaria/epidemiología , Niño , Preescolar , Familia , Femenino , Hepatitis A/etiología , Humanos , Higiene , Lactante , Masculino
19.
JAMA ; 273(10): 808-12, 1995 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-7532241

RESUMEN

OBJECTIVE: To develop a set of minimum clinical guidelines for use by primary care physicians in the evaluation and management of patients with hyperthyroidism and hypothyroidism. PARTICIPANTS: Guidelines were developed by a nine-member ad hoc Standards of Care Committee of the American Thyroid Association (the authors of this article). The participants were selected by the committee chair and the president of the American Thyroid Association on the basis of their clinical experience. The committee members represented different geographic areas within the United States, in order to take into account different practice styles. EVIDENCE: Guidelines were developed on the basis of expert opinion of the participants, as well as on available published information. CONSENSUS PROCESS: Input was obtained from all of the participants, each of whom wrote an initial section of the document. A complete draft document was then written by three participants (P.A.S., D.S.C., and E.G.L.) and resubmitted to the entire committee for revision. The revised document was then submitted to the entire membership of the American Thyroid Association for written comments, which were then reviewed (mainly by P.A.S., D.S.C., and E.G.L.). Many of the suggestions of the American Thyroid Association members were incorporated into the final draft, which was then approved by the Executive Council of the American Thyroid Association. The entire process, from initial drafts to final approval, took approximately 18 months. CONCLUSIONS: A set of minimum clinical guidelines for the diagnosis and treatment of hyperthyroidism and hypothyroidism were developed by consensus of a group of experienced thyroidologists. The guidelines are intended to be used by physicians in their care of patients with thyroid disorders, with the expectation that more effective care can be provided, and at a cost savings.


Asunto(s)
Hipertiroidismo/terapia , Hipotiroidismo/terapia , Antitiroideos/uso terapéutico , Medicina Familiar y Comunitaria/normas , Humanos , Hipertiroidismo/diagnóstico , Hipotiroidismo/diagnóstico , Radioisótopos de Yodo/uso terapéutico , Guías de Práctica Clínica como Asunto , Pruebas de Función de la Tiroides , Hormonas Tiroideas/uso terapéutico , Tiroidectomía
20.
Enzyme Microb Technol ; 14(3): 203-8, 1992 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-1372509

RESUMEN

Adherent cells can be cultivated in a stirred-tank bioreactor by attaching to microcarriers. Macroporous microcarriers, with their intraparticle space and surface area for cell growth, can potentially support a higher cell concentration than conventional microcarriers, which support cell growth only on the external surface. Chinese hamster ovary (CHO) cells and green monkey kidney (Vero) cells were cultivated on macroporous microcarriers, Cultispher-G. Cells attached to the microcarriers at a slow rate and grew to a high density. Thin sections of the microcarriers demonstrate that cells were initially on the exterior of the microcarriers and migrated into the interior as cell concentration increased. Vero cells cultivated on these microcarriers were successfully used for the production of vesicular stomatitis virus (VSV).


Asunto(s)
Técnicas de Cultivo/métodos , Animales , Células CHO , Adhesión Celular , División Celular , Cricetinae , Técnicas de Cultivo/instrumentación , Fluoresceínas , Colorantes Fluorescentes , Cinética , Perfusión/instrumentación , Perfusión/métodos , Coloración y Etiquetado , Células Vero
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA