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1.
Proc Natl Acad Sci U S A ; 119(1)2022 01 04.
Artículo en Inglés | MEDLINE | ID: mdl-34934014

RESUMEN

Cyclic adenosine monophosphate (cAMP) is a pivotal second messenger with an essential role in neuronal function. cAMP synthesis by adenylyl cyclases (AC) is controlled by G protein-coupled receptor (GPCR) signaling systems. However, the network of molecular players involved in the process is incompletely defined. Here, we used CRISPR/Cas9-based screening to identify that members of the potassium channel tetradimerization domain (KCTD) family are major regulators of cAMP signaling. Focusing on striatal neurons, we show that the dominant isoform KCTD5 exerts its effects through an unusual mechanism that modulates the influx of Zn2+ via the Zip14 transporter to exert unique allosteric effects on AC. We further show that KCTD5 controls the amplitude and sensitivity of stimulatory GPCR inputs to cAMP production by Gßγ-mediated AC regulation. Finally, we report that KCTD5 haploinsufficiency in mice leads to motor deficits that can be reversed by chelating Zn2+ Together, our findings uncover KCTD proteins as major regulators of neuronal cAMP signaling via diverse mechanisms.


Asunto(s)
AMP Cíclico/metabolismo , Canales de Potasio/metabolismo , Transducción de Señal , Regulación Alostérica , Animales , Conducta Animal , Sistemas CRISPR-Cas , Proteínas de Transporte de Catión/metabolismo , Cuerpo Estriado/citología , Cuerpo Estriado/metabolismo , AMP Cíclico/biosíntesis , Humanos , Ratones , Neuronas/metabolismo , Receptores Acoplados a Proteínas G/metabolismo
2.
Soft Matter ; 20(20): 4152-4164, 2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38738858

RESUMEN

When a soft tube is inflated, it may sometimes show a bulge instability wherein a portion of the tube inflates much more than the rest. The bulge instability is well-understood for hyperelastic materials. We examine inflation of polyurethane tubes whose material behavior is not strictly hyperelastic. Upon inflating at constant rate, the tubes deform into a variety of shapes including irregular axisymmetric shapes with multiple localized bulges, a single axially-propagating bulge, or homogeneous cylindrical shapes. In all cases regardless of the inflation mode, the pressure first rises to a maximum, and then gradually reduces towards a plateau. We document numerous differences as compared to hyperelastic tubes. Most notably a pressure maximum can appear even without bulging, whereas for hyperelastic tubes, a pressure maximum is necessarily accompanied by bulging. Further, the decrease in pressure beyond the maximum occurs gradually over timescales as long as an hour, whereas bulging of hyperelastic tubes induces an instantaneous drop in pressure. We also observe permanent deformation upon deflation, a decrease in the pressure maximum during a subsequent second inflation, and more severe bulge localization at low inflation rates. Existing theory of hyperelastic tube inflation cannot capture the observed behaviors, even qualitatively. Finite element simulations suggest that many of the observations can be explained by viscoelasticity, specifically that a slow material response allows the pressure to remain high for long durations, which in turn allows growth of multiple bulges.

3.
Microb Ecol ; 86(2): 1082-1095, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36197502

RESUMEN

Poultry waste has been used as fertilizer to avoid soil degradation caused by the long-term application of chemical fertilizer. However, few studies have evaluated field conditions where livestock wastes have been used for extended periods of time. In this study, physicochemical parameters, metabarcoding of the 16S rRNA gene, and ecotoxicity indexes were used for the characterization of chicken manure and poultry litter to examine the effect of their application to agricultural soils for 10 years. Poultry wastes showed high concentrations of nutrients and increased electrical conductivity leading to phytotoxic effects on seeds. The bacterial communities were dominated by typical members of the gastrointestinal tract, noting the presence of pathogenic bacteria. Soils subjected to poultry manure applications showed statistically higher values of total and extractable phosphorous, increasing the risk of eutrophication. Moreover, while the soil bacterial community remained dominated by the ones related to the biogeochemical cycles of nutrients and plant growth promotion, losses of alpha diversity were observed on treated soils. Altogether, our work would contribute to understand the effects of common local agricultural practices and support the adoption of the waste treatment process in compliance with environmental sustainability guidelines.


Asunto(s)
Aves de Corral , Suelo , Animales , Suelo/química , Estiércol , Fertilizantes , ARN Ribosómico 16S/genética , Bacterias/genética , Variación Genética
4.
Nucleic Acids Res ; 49(11): 6114-6127, 2021 06 21.
Artículo en Inglés | MEDLINE | ID: mdl-34125895

RESUMEN

Dynamic DNA nanodevices represent powerful tools for the interrogation and manipulation of biological systems. Yet, implementation remains challenging due to nuclease degradation and other cellular factors. Use of l-DNA, the nuclease resistant enantiomer of native d-DNA, provides a promising solution. On this basis, we recently developed a strand displacement methodology, referred to as 'heterochiral' strand displacement, that enables robust l-DNA nanodevices to be sequence-specifically interfaced with endogenous d-nucleic acids. However, the underlying reaction - strand displacement from PNA-DNA heteroduplexes - remains poorly characterized, limiting design capabilities. Herein, we characterize the kinetics of strand displacement from PNA-DNA heteroduplexes and show that reaction rates can be predictably tuned based on several common design parameters, including toehold length and mismatches. Moreover, we investigate the impact of nucleic acid stereochemistry on reaction kinetics and thermodynamics, revealing important insights into the biophysical mechanisms of heterochiral strand displacement. Importantly, we show that strand displacement from PNA-DNA heteroduplexes is compatible with RNA inputs, the most common nucleic acid target for intracellular applications. Overall, this work greatly improves the understanding of heterochiral strand displacement reactions and will be useful in the rational design and optimization of l-DNA nanodevices that operate at the interface with biology.


Asunto(s)
ADN/química , Ácidos Nucleicos Heterodúplex/química , Ácidos Nucleicos de Péptidos/química , Cinética , ARN/química , Estereoisomerismo , Termodinámica
5.
J Manipulative Physiol Ther ; 45(7): 531-542, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-36517270

RESUMEN

OBJECTIVE: The purpose of this study was to determine the immediate effects of adding dry needling (DN) to thoracic spine manipulation and neck-specific exercise in individuals with neck pain. METHODS: Forty-two participants with neck pain were randomized to either the true (n = 21) or sham (n = 21) DN groups, receiving treatment on the initial visit and 2 to 3 days later. Outcomes were assessed on day 1, both at baseline and immediately after the initial treatment, at the second treatment 2 to 3 days later, and at the final visit 5 to 7 days after visit 2. Primary outcomes were Neck Disability Index (NDI) (0-50) and current pain via numeric pain rating scale (0-10). Secondary outcomes were cervical range of motion, pain pressure threshold, and global rating of change. RESULTS: Repeated measures analysis of covariance with baseline value as covariate revealed no significant difference in NDI scores at either follow-up time point with adjusted mean differences (95% confidence interval) of -0.11 (-2.70 to 2.48) and 0.31 (-1.96 to 2.57). There were no between-group differences in pain at any time point via Independent-Samples Median Test (P value range of .54-1.0). Secondary outcome measures were similarly not statistically different between groups except for immediate improvements in rotation to the side opposite of pain, which favored DN, with an adjusted mean difference (95% confidence interval) of 7.85 (3.54-12.15) degrees. CONCLUSION: The addition of DN to thoracic spinal manipulation and neck-specific exercise did not affect improvements in NDI score or numeric pain rating scale but showed an increase in cervical range of motion.


Asunto(s)
Punción Seca , Manipulación Espinal , Humanos , Adulto , Dolor de Cuello/terapia , Dimensión del Dolor , Vértebras Torácicas , Rango del Movimiento Articular
6.
J Proteome Res ; 20(9): 4318-4330, 2021 09 03.
Artículo en Inglés | MEDLINE | ID: mdl-34342229

RESUMEN

G-protein-coupled receptors (GPCRs) initiate intracellular signaling events through heterotrimeric G-protein α-subunits (Gα) and the ßγ-subunit dimer (Gßγ). In this study, we utilized mass spectrometry to identify novel regulators of Gßγ signaling in human cells. This prompted our characterization of KCTD2 and KCTD5, two related potassium channel tetramerization domain (KCTD) proteins that specifically recognize Gßγ. We demonstrated that these KCTD proteins are substrate adaptors for a multisubunit CUL3-RING ubiquitin ligase, in which a KCTD2-KCTD5 hetero-oligomer associates with CUL3 through KCTD5 subunits and recruits Gßγ through both KCTD proteins in response to G-protein activation. These KCTD proteins promote monoubiquitination of lysine-23 within Gß1/2in vitro and in HEK-293 cells. Depletion of these adaptors from cancer cell lines sharply impairs downstream signaling. Together, our studies suggest that a KCTD2-KCTD5-CUL3-RING E3 ligase recruits Gßγ in response to signaling, monoubiquitinates lysine-23 within Gß1/2, and regulates Gßγ effectors to modulate downstream signal transduction.


Asunto(s)
Proteínas de Unión al GTP Heterotriméricas , Ubiquitina-Proteína Ligasas , Proteínas Cullin/genética , Proteínas Cullin/metabolismo , Células HEK293 , Proteínas de Unión al GTP Heterotriméricas/genética , Humanos , Canales de Potasio , Transducción de Señal , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitinación
7.
Electrophoresis ; 42(6): 756-765, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33314164

RESUMEN

The first autosomal sequence-based allele (aka SNP-STR haplotype) frequency database for forensic massively parallel sequencing (MPS) has been published, thereby removing one of the remaining barriers to implementing MPS in casework. The database was developed using a specific set of flank trim sites. If different trim sites or different kits with different primers are used for casework, then SNP-STR haplotypes may be detected that do not have frequencies in the database. We describe a procedure to address calculation of match probabilities when casework samples are generated using an MPS kit with different trim sites than those present in the relevant population frequency database. The procedure provides a framework for comparison of any MPS kit or database combination while also accommodating comparison of MPS and CE profiles.


Asunto(s)
Reacción en Cadena de la Polimerasa , Alelos , Dermatoglifia del ADN , Genotipo , Secuenciación de Nucleótidos de Alto Rendimiento , Repeticiones de Microsatélite/genética , Polimorfismo de Nucleótido Simple
8.
Langmuir ; 37(17): 5213-5221, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33876937

RESUMEN

Electrochemical aptamer-based (E-AB) sensors are a technology capable of real-time monitoring of drug concentrations directly in the body. These sensors achieve their selectivity from surface-attached aptamers, which alter their conformation upon target binding, thereby causing a change in electron transfer kinetics between aptamer-bound redox reporters and the electrode surface. Because, in theory, aptamers can be selected for nearly any target of interest, E-AB sensors have far-reaching potential for diagnostic and biomedical applications. However, a remaining critical weakness in the platform lies in the time-dependent, spontaneous degradation of the bioelectronic interface. This progressive degradation-seen in part as a continuous drop in faradaic current from aptamer-attached redox reporters-limits the in vivo operational life of E-AB sensors to less than 12 h, prohibiting their long-term application for continuous molecular monitoring in humans. In this work, we study the effects of nuclease action on the signaling lifetime of E-AB sensors, to determine whether the progressive signal loss is caused by hydrolysis of DNA aptamers and thus the loss of signaling moieties from the sensor surface. We continuously interrogate sensors deployed in several undiluted biological fluids at 37 °C and inject nuclease to reach physiologically relevant concentrations. By employing both naturally occurring d-DNA and the nuclease-resistant enantiomer l-DNA, we determine that within the current lifespan of state-of-the-art E-AB sensors, nuclease hydrolysis is not the dominant cause of sensor signal loss under the conditions we tested. Instead, signal loss is driven primarily by the loss of monolayer elements-both blocking alkanethiol and aptamer monolayers-from the electrode surface. While use of l-DNA aptamers may extend the E-AB operational life in the long term, the critical issue of passive monolayer loss must be addressed before those effects can be seen.


Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Técnicas Electroquímicas , Electrodos , Humanos , Hidrólisis
9.
Clin Infect Dis ; 70(12): 2593-2598, 2020 06 10.
Artículo en Inglés | MEDLINE | ID: mdl-31403165

RESUMEN

BACKGROUND: Posaconazole tablets are well tolerated and efficacious in the prophylaxis and treatment of aspergillosis, mucormycosis, and other invasive fungal infections. There have been case reports of posaconazole-induced pseudohyperaldosteronism (PIPH); however, its occurrence and association with serum posaconazole drug levels have not previously been investigated. METHODS: In this single-center, retrospective, observational study, we examined the occurrence of PIPH in outpatients newly starting posaconazole and evaluated differences in serum posaconazole concentrations and clinical characteristics between those with and without this syndrome. RESULTS: Sixty-nine patients receiving posaconazole were included, of whom 16 (23.2%) met the definition of PIPH. Patients with PIPH were significantly older (61.1 vs 44.7 years, P = .007) and more frequently had hypertension prior to starting posaconazole (68.8% vs 32.1%, P = .009). Patients with PIPH had a significantly higher median serum posaconazole level than those without PIPH (3.0 vs 1.2 µg/mL, P ≤ .0001). There was a positive correlation between serum posaconazole levels and changes in systolic blood pressure (r = .37, P = .01), a negative correlation between serum posaconazole levels and changes in serum potassium (r = -.39, P = .006), and a positive correlation between serum posaconazole levels and serum 11-deoxycortisol (r = .69, P < .0001). CONCLUSIONS: Posaconazole is associated with secondary hypertension and hypokalemia, consistent with pseudohyperaldosteronism, and development is associated with higher serum posaconazole concentrations, older age, and baseline hypertension.


Asunto(s)
Antifúngicos , Infecciones Fúngicas Invasoras , Anciano , Antifúngicos/efectos adversos , Humanos , Infecciones Fúngicas Invasoras/tratamiento farmacológico , Estudios Retrospectivos , Triazoles/efectos adversos
10.
J Antimicrob Chemother ; 75(12): 3688-3693, 2020 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-32830274

RESUMEN

BACKGROUND: Posaconazole-induced pseudohyperaldosteronism (PIPH) has been associated with elevated posaconazole serum concentrations. Clinicians are faced with the difficult task of managing patients with PIPH while maintaining the efficacy of antifungal therapy. Commonly, modifications to posaconazole therapy are utilized in managing PIPH, including dosage reduction of posaconazole or switch to an alternative antifungal. OBJECTIVES: To characterize the management of patients diagnosed with PIPH and their response to various therapeutic interventions. METHODS: We retrospectively reviewed 20 consecutive adult patients diagnosed with PIPH. Patient data collected included blood pressure, electrolytes, endocrine laboratory values and posaconazole serum concentrations collected before and after therapeutic intervention. RESULTS: Of 20 patients included, 17 patients (85%) underwent therapeutic modification, with posaconazole dose reduction (n = 11) as the most common change. Other modifications included discontinuation (n = 3), switch to an alternative antifungal (n = 2) and addition of spironolactone (n = 1). Clinical improvement (decrease in systolic blood pressure and increase in serum potassium) was observed in 9 of 17 patients (52.9%). An average decrease in systolic blood pressure of 7.1 mmHg and increase in serum potassium of 0.22 mmol/L was observed following therapeutic modification. CONCLUSIONS: We report our experience with PIPH management, for which there is no universally effective strategy. We utilized a stepwise approach for management, starting with posaconazole dose reduction and repeat assessment of clinical and laboratory parameters. If resolution of PIPH is not achieved, an alternative triazole antifungal or the addition of an aldosterone antagonist are additional potential interventions. It is possible for PIPH to persist after therapeutic modification despite these interventions. Thus, early diagnosis and continuous monitoring is warranted.


Asunto(s)
Antifúngicos , Triazoles , Adulto , Antifúngicos/efectos adversos , Humanos , Estudios Retrospectivos , Triazoles/efectos adversos
11.
J Surg Res ; 246: 269-273, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31614324

RESUMEN

BACKGROUND: A structured family meeting (FM) is recommended within 72 h of admission for trauma patients with high risk of mortality or disability. Multidisciplinary FMs (MDFMs) may further facilitate decision-making. We hypothesized that FM within three hospital days (HDs) or MDFM would be associated with increased use of comfort measures. MATERIALS AND METHODS: We reviewed all adult trauma deaths at an academic level 1 trauma center from December 2014 to December 2017. Death in the first 24 h or on nonsurgical services were excluded. Demographics, injury characteristics, FM characteristics, and outcomes such as length of stay (LOS) were recorded. Early FM was defined as occurring within three HDs; MDFM required attendance by two or more specialty teams. RESULTS: A total of 177 patients were included. Median LOS was 6 d (interquartile range 4-12). FMs were documented in 166 patients (94%), with 57% occurring early. MDFM occurred in 49 (28%), but usually occurred later (median HD 5 and interquartile range 2-8). Early FM was associated with reduced LOS (5 versus 11 d, P < 0.001), ventilator days (4 versus 9 d, P < 0.001), and deaths during a code (1.2% versus 13.2%, P < 0.001). MDFM was associated with higher use of comfort measures (88% versus 68%, P < 0.05). Of patients who transitioned to comfort care status (n = 130, 73.4%), code status change occurred earlier if an early FM occurred (5 versus 13 d, P < 0.001). CONCLUSIONS: MDFM is associated with increased comfort care measures, whereas early FM is associated with reduced LOS, ventilator days, death during a code, and earlier comfort care transition.


Asunto(s)
Toma de Decisiones , Familia , Planificación de Atención al Paciente , Cuidado Terminal/organización & administración , Heridas y Lesiones/terapia , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Unidades de Cuidados Intensivos/organización & administración , Unidades de Cuidados Intensivos/estadística & datos numéricos , Tiempo de Internación/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Cuidados Paliativos/organización & administración , Cuidados Paliativos/estadística & datos numéricos , Transferencia de Pacientes/organización & administración , Transferencia de Pacientes/estadística & datos numéricos , Estudios Retrospectivos , Factores de Tiempo , Centros Traumatológicos/organización & administración , Centros Traumatológicos/estadística & datos numéricos , Índices de Gravedad del Trauma , Heridas y Lesiones/diagnóstico , Heridas y Lesiones/mortalidad
12.
Ecotoxicol Environ Saf ; 205: 111176, 2020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-32846301

RESUMEN

The effects of 17α-ethinylestradiol (EE2) on sex ratio, gonopodium morphology, and gonadal histology of C. decemmaculatus were assessed by a full-lifecycle exposure experiment. Newborn fish were waterborne exposed to 30, 100, and 300 ng EE2/L for 90 d, using 50 fish per treatment. Additionally, in December of 2016, a field survey was conducted on a C. decemmaculatus population inhabiting the Girado Creek downstream of the Chascomus city wastewater effluent discharge. After 90 d of exposure, EE2 was able to histologically skew the sex ratio toward females and inhibit the full gonopodium development since the lowest tested concentration (LOEC = 30 ng/L). At higher concentrations, EE2 was toxic, inducing mortality in a concentration-dependent fashion (90 d-LC50 = 109.9 ng/L) and altering the gonadal histoarchitecture, causing neither testes nor ovaries discernible histologically (LOEC = 100 ng/L). In addition, a novel response, perianal hyperpigmentation, was discovered been induced by the EE2 exposure in a concentration-dependent fashion (90 d-EC50 = 39.3 ng/L). A higher proportion of females and perianal hyperpigmentation were observed in wild fish collected from the Girado Creek. The major reached conclusions are: i) EE2 induce different effects on the sexual traits of C. decemmaculatus when exposed from early-life or adult stages. ii) The most sensitive effects observed in the laboratory occur in a creek receiving wastewater effluent. iii) The perianal hyperpigmentation comes-up as a promising biomarker of exposure to estrogenic compounds.


Asunto(s)
Ciprinodontiformes/crecimiento & desarrollo , Disruptores Endocrinos/toxicidad , Etinilestradiol/toxicidad , Gónadas/efectos de los fármacos , Hiperpigmentación/inducido químicamente , Contaminantes Químicos del Agua/toxicidad , Animales , Relación Dosis-Respuesta a Droga , Femenino , Gónadas/crecimiento & desarrollo , Gónadas/patología , Humanos , Estadios del Ciclo de Vida/efectos de los fármacos , Masculino , Ovario/efectos de los fármacos , Ovario/crecimiento & desarrollo , Ovario/patología , Fenotipo , Razón de Masculinidad , Testículo/efectos de los fármacos , Testículo/crecimiento & desarrollo , Testículo/patología
13.
Ecotoxicol Environ Saf ; 202: 110939, 2020 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-32800222

RESUMEN

Pulp and paper mill wastewater (PPMWW) contains high concentrations of recalcitrant compounds that cause toxicity to organisms. Advanced oxidation processes (AOPs) have the ability to degrade these compounds and reduce overall toxicity. Physicochemical characterization and Lactuca sativa toxicity test were conducted to compare the effectiveness of two post-treatments: UV/H2O2 and photo-Fenton. A comparison of four phytotoxicity indexes was carried out. PPMWW from a Brazilian treatment plant was characterized by high values of phenols, color, integrated spectral area (ISA), and chemical oxygen demand (COD), and caused significant inhibition to seedling development. The use of both post-treatments allowed the removal of over 75% of phenols, color, ISA, and COD. Although UV/H2O2 was more effective in removing phenols and ISA, photo-Fenton better reduced phytotoxicity. The most sensitive phytotoxicity indexes were RGIC0.8 and GIC80%, whereas SGC0, REC-0.25 and REC-0.50 better showed the effectiveness of the post-treatments. We suggest the combined use of two phytotoxicity indexes: one that evaluates the effects on seed germination and, another, on root elongation, e.g., SGC0 and RGIC0.8. Additionally, we recommend the use of ISA for monitoring programs of wastewater treatments because it is a cost-effective approach that allows narrowing down the search and identification of compounds present in complex mixtures.


Asunto(s)
Papel , Fenoles/toxicidad , Eliminación de Residuos Líquidos/métodos , Análisis de la Demanda Biológica de Oxígeno , Brasil , Color , Colorantes/toxicidad , Peróxido de Hidrógeno/química , Residuos Industriales/análisis , Oxidación-Reducción , Fenoles/análisis , Plantas/efectos de los fármacos , Aguas Residuales/química
14.
Chemistry ; 25(34): 7981-7990, 2019 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-30913332

RESUMEN

As chiral molecules, naturally occurring d-oligonucleotides have enantiomers, l-DNA and l-RNA, which are comprised of l-(deoxy)ribose sugars. These mirror-image oligonucleotides have the same physical and chemical properties as that of their native d-counterparts, yet are highly orthogonal to the stereospecific environment of biology. Consequently, l-oligonucleotides are resistant to nuclease degradation and many of the off-target interactions that plague traditional d-oligonucleotide-based technologies; thus making them ideal for biomedical applications. Despite a flurry of interest during the early 1990s, the inability of d- and l-oligonucleotides to form contiguous Watson-Crick base pairs with each other has ultimately led to the perception that l-oligonucleotides have only limited utility. Recently, however, scientists have begun to uncover novel strategies to harness the bio-orthogonality of l-oligonucleotides, while overcoming (and even exploiting) their inability to Watson-Crick base pair with the natural polymer. Herein, a brief history of l-oligonucleotide research is presented and emerging l-oligonucleotide-based technologies, as well as their applications in research and therapy, are presented.


Asunto(s)
Técnicas Biosensibles/métodos , ADN/química , Nanotecnología/métodos , Oligonucleótidos/química , ARN/química , Animales , Emparejamiento Base , Secuencia de Bases , Humanos , Nanoestructuras/química , Nanoestructuras/ultraestructura , Conformación de Ácido Nucleico , Ribosa/química , Estereoisomerismo
15.
Nature ; 500(7461): 237-41, 2013 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-23903661

RESUMEN

Cellular metabolism converts available nutrients into usable energy and biomass precursors. The process is regulated to facilitate efficient nutrient use and metabolic homeostasis. Feedback inhibition of the first committed step of a pathway by its final product is a classical means of controlling biosynthesis. In a canonical example, the first committed enzyme in the pyrimidine pathway in Escherichia coli is allosterically inhibited by cytidine triphosphate. The physiological consequences of disrupting this regulation, however, have not been previously explored. Here we identify an alternative regulatory strategy that enables precise control of pyrimidine pathway end-product levels, even in the presence of dysregulated biosynthetic flux. The mechanism involves cooperative feedback regulation of the near-terminal pathway enzyme uridine monophosphate kinase. Such feedback leads to build-up of the pathway intermediate uridine monophosphate, which is in turn degraded by a conserved phosphatase, here termed UmpH, with previously unknown physiological function. Such directed overflow metabolism allows homeostasis of uridine triphosphate and cytidine triphosphate levels at the expense of uracil excretion and slower growth during energy limitation. Disruption of the directed overflow regulatory mechanism impairs growth in pyrimidine-rich environments. Thus, pyrimidine homeostasis involves dual regulatory strategies, with classical feedback inhibition enhancing metabolic efficiency and directed overflow metabolism ensuring end-product homeostasis.


Asunto(s)
Escherichia coli/metabolismo , Homeostasis , Pirimidinas/metabolismo , Carbono/metabolismo , Escherichia coli/enzimología , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Regulación Enzimológica de la Expresión Génica , Genes Supresores , Nucleósido-Fosfato Quinasa/metabolismo , Pirimidinas/biosíntesis , Transferasas/genética , Transferasas/metabolismo , Uracilo/metabolismo , Uridina Monofosfato/metabolismo
16.
J Electrocardiol ; 57S: S1-S4, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31387696

RESUMEN

A new standard for electrocardiographic (ECG) medical equipment is currently in development by the ISO/IEC Joint Work Group 22 (JWG22) and is entitled "80601, part 2-86: Particular requirements for the basic safety and essential performance of electrocardiographs, including diagnostic equipment, monitoring equipment, ambulatory equipment, electrodes, cables, and leadwires". This new standard will replace the current set of IEC particular standards that pertain to ECG equipment, namely, 60601-2-25 (diagnostic electrocardiographs), 60601-2-27 (ECG patient monitors), and 60601-2-47 (Ambulatory ECG) and also incorporates AAMI standards EC12 (disposable electrodes), EC53 (ECG cables and leadwires), and EC57 (arrhythmia analysis performance reporting). This new ECG device standard will define basic safety and essential performance requirements and compliance testing methods for all types of ECG devices including both legacy types of ECG devices as well as new types of ECG devices. In addition to the general requirements, specific requirements and testing methods will apply exclusively to devices claiming to be used as a diagnostic electrocardiograph, an ECG patient monitor, and or an ambulatory ECG device. The primary goal of the work to develop this new ECG standard is to combine and harmonize the content of the existing set of 6 ECG standards. In addition, because many of these standards are quite mature, this work provides an opportunity to update the content to align requirements and testing methods with changes in ECG technology as well as changes in the clinical use of ECG and the emergence of new types of ECG devices. The changes under consideration and the progress of this work by ISO/IEC JWG22 is reviewed. Specific updates are highlighted, including requirements for defibrillation recovery, changes for ECG filtering technology, and changes to address advancement in implanted pacing technology.


Asunto(s)
Electrocardiografía Ambulatoria , Electrocardiografía , Arritmias Cardíacas , Electrodos , Diseño de Equipo , Humanos , Estándares de Referencia
17.
Am Heart J ; 200: 1-10, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29898835

RESUMEN

BACKGROUND: Automated measurements of electrocardiographic (ECG) intervals by current-generation digital electrocardiographs are critical to computer-based ECG diagnostic statements, to serial comparison of ECGs, and to epidemiological studies of ECG findings in populations. A previous study demonstrated generally small but often significant systematic differences among 4 algorithms widely used for automated ECG in the United States and that measurement differences could be related to the degree of abnormality of the underlying tracing. Since that publication, some algorithms have been adjusted, whereas other large manufacturers of automated ECGs have asked to participate in an extension of this comparison. METHODS: Seven widely used automated algorithms for computer-based interpretation participated in this blinded study of 800 digitized ECGs provided by the Cardiac Safety Research Consortium. All tracings were different from the study of 4 algorithms reported in 2014, and the selected population was heavily weighted toward groups with known effects on the QT interval: included were 200 normal subjects, 200 normal subjects receiving moxifloxacin as part of an active control arm of thorough QT studies, 200 subjects with genetically proved long QT syndrome type 1 (LQT1), and 200 subjects with genetically proved long QT syndrome Type 2 (LQT2). RESULTS: For the entire population of 800 subjects, pairwise differences between algorithms for each mean interval value were clinically small, even where statistically significant, ranging from 0.2 to 3.6milliseconds for the PR interval, 0.1 to 8.1milliseconds for QRS duration, and 0.1 to 9.3milliseconds for QT interval. The mean value of all paired differences among algorithms was higher in the long QT groups than in normals for both QRS duration and QT intervals. Differences in mean QRS duration ranged from 0.2 to 13.3milliseconds in the LQT1 subjects and from 0.2 to 11.0milliseconds in the LQT2 subjects. Differences in measured QT duration (not corrected for heart rate) ranged from 0.2 to 10.5milliseconds in the LQT1 subjects and from 0.9 to 12.8milliseconds in the LQT2 subjects. CONCLUSIONS: Among current-generation computer-based electrocardiographs, clinically small but statistically significant differences exist between ECG interval measurements by individual algorithms. Measurement differences between algorithms for QRS duration and for QT interval are larger in long QT interval subjects than in normal subjects. Comparisons of population study norms should be aware of small systematic differences in interval measurements due to different algorithm methodologies, within-individual interval measurement comparisons should use comparable methods, and further attempts to harmonize interval measurement methodologies are warranted.


Asunto(s)
Algoritmos , Electrocardiografía , Síndrome de QT Prolongado/diagnóstico , Síndrome de Romano-Ward/diagnóstico , Adulto , Precisión de la Medición Dimensional , Electrocardiografía/métodos , Electrocardiografía/normas , Femenino , Sistema de Conducción Cardíaco/diagnóstico por imagen , Humanos , Masculino , Evaluación de Resultado en la Atención de Salud , Distribución Aleatoria , Procesamiento de Señales Asistido por Computador
18.
PLoS Genet ; 11(6): e1005292, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26091241

RESUMEN

The Skp1-Cul1-F box complex (SCF) associates with any one of a number of F box proteins, which serve as substrate binding adaptors. The human F box protein ßTRCP directs the conjugation of ubiquitin to a variety of substrate proteins, leading to the destruction of the substrate by the proteasome. To identify ßTRCP substrates, we employed a recently-developed technique, called Ligase Trapping, wherein a ubiquitin ligase is fused to a ubiquitin-binding domain to "trap" ubiquitinated substrates. 88% of the candidate substrates that we examined were bona fide substrates, comprising twelve previously validated substrates, eleven new substrates and three false positives. One ßTRCP substrate, CReP, is a Protein Phosphatase 1 (PP1) specificity subunit that targets the translation initiation factor eIF2α to promote the removal of a stress-induced inhibitory phosphorylation and increase cap-dependent translation. We found that CReP is targeted by ßTRCP for degradation upon DNA damage. Using a stable CReP allele, we show that depletion of CReP is required for the full induction of eIF2α phosphorylation upon DNA damage, and contributes to keeping the levels of translation low as cells recover from DNA damage.


Asunto(s)
Daño del ADN , Proteína Fosfatasa 1/metabolismo , Proteínas con Repetición de beta-Transducina/metabolismo , Animales , Células HEK293 , Humanos , Ratones , Unión Proteica , Biosíntesis de Proteínas , Estabilidad Proteica
19.
J Electrocardiol ; 51(6S): S103-S105, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30098796

RESUMEN

The current set of IEC particular standards that pertain to electrocardiograph (ECG) devices, namely, 60601-2-25, 60601-2-27, and 60601-2-47, which define requirements and testing for the essential performance and basic safety of diagnostic ECG, ECG monitoring and ambulatory ECG systems, respectively. These standards have been harmonized with the corresponding AAMI standards, namely EC11, EC13 and EC38. Together these standards have been in existence for decades and have evolved separately even though the technology used in these three clinical applications is very similar. A work proposal was initiated in the ISO/IEC Joint Work Group 22 (JWG22), which over sees the revision of these standards, to update the standards by creating a single new hybrid standard. The goal of this work is a joint endeavor between ISO and IEC to combine the three separate particular standards that cover ECG device and to harmonize the similar requirements that are common across all three types of devices into one set of general requirements. The requirements that separate specific to meeting the intended use and essential performance for each of the 3 types of devices (diagnostic, patient monitoring, and ambulatory ECG recording) will continue to remain as separate requirements. Furthermore, manufactures of ECG devices have also been required to meet standards for disposable electrodes (AAMI EC12), ECG cables and leadwires (AAMI EC53), and arrhythmia analysis performance reporting (AAMI EC57). In addition to the primary goal, a secondary goal for the JW22 work is to also incorporate these three AAMI standards into the ECG hybrid standard. This paper describes the work being done and highlights key updates, and explains the rationale for approaches and changes being made. The Joint Work Group is currently in the process of updating the committee draft of the new hybrid standard before requesting comments from National Standard Committees participating in JWG22.


Asunto(s)
Electrocardiografía/instrumentación , Electrocardiografía/normas , Humanos , Cooperación Internacional , Estándares de Referencia
20.
J Electrocardiol ; 51(6S): S113-S115, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30078672

RESUMEN

Digital ECG is today a common practice but a universal format for its storage and exchange has never been widely implemented. The reason is linked on one side to the need of the manufacturing industry to (rightly) protect intellectual propriety and technology, but on the other to an inadequate effort of the research community to sufficiently enforce the use of digital ECG data. To some degree, and at least from a practical point of view, the problem is also linked to other factors, such as the need in some instances to protect patient-sensitive information, and whether digital exchanged data should also include annotations and measurements from an algorithm or by human intervention. As a result, after more than 30 years it is still common that the full ECG acquired information is not preserved, but only partially stored or saved as a PDF report. Paradoxically, the modern era of hospital information technology and the advent and large diffusion of electronic health record systems did not bring expected improvements: the process of digital ECG retrieval and management remains extremely complicated and cumbersome. The ultimate risk is that the ECG may end up being considered "just" an image rather than a voltage-versus-time signal as it has always been. A critical review of the most commonly used formats for digital ECG will be given, focusing in particular to those linked with DICOM, HL7 and SCP-ECG standards, and highlighting the respective advantages and limitations with special emphasis to the needs typically encountered by the research community. The goal is to provide a snapshot of the present, and to discuss mid- and long-term potential directions and changes, emphasizing what digital ECG organizations could do to "save" ECG information and facilitate its widespread exchange.


Asunto(s)
Electrocardiografía/métodos , Almacenamiento y Recuperación de la Información/métodos , Humanos , Integración de Sistemas
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