Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 89
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
Mol Cell ; 78(1): 57-69.e4, 2020 04 02.
Artículo en Inglés | MEDLINE | ID: mdl-32059760

RESUMEN

Homeothermic organisms maintain their core body temperature in a narrow, tightly controlled range. Whether and how subtle circadian oscillations or disease-associated changes in core body temperature are sensed and integrated in gene expression programs remain elusive. Furthermore, a thermo-sensor capable of sensing the small temperature differentials leading to temperature-dependent sex determination (TSD) in poikilothermic reptiles has not been identified. Here, we show that the activity of CDC-like kinases (CLKs) is highly responsive to physiological temperature changes, which is conferred by structural rearrangements within the kinase activation segment. Lower body temperature activates CLKs resulting in strongly increased phosphorylation of SR proteins in vitro and in vivo. This globally controls temperature-dependent alternative splicing and gene expression, with wide implications in circadian, tissue-specific, and disease-associated settings. This temperature sensor is conserved across evolution and adapted to growth temperatures of diverse poikilotherms. The dynamic temperature range of reptilian CLK homologs suggests a role in TSD.


Asunto(s)
Empalme Alternativo , Regulación de la Temperatura Corporal/genética , Expresión Génica , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Tirosina Quinasas/metabolismo , Reptiles/genética , Animales , Evolución Biológica , Células HEK293 , Humanos , Proteínas Serina-Treonina Quinasas/química , Proteínas Serina-Treonina Quinasas/fisiología , Proteínas Tirosina Quinasas/química , Proteínas Tirosina Quinasas/fisiología , Reptiles/metabolismo , Factores de Empalme Serina-Arginina/metabolismo
2.
Brief Bioinform ; 24(1)2023 01 19.
Artículo en Inglés | MEDLINE | ID: mdl-36572655

RESUMEN

The time since deposition (TSD) of a bloodstain, i.e., the time of a bloodstain formation is an essential piece of biological evidence in crime scene investigation. The practical usage of some existing microscopic methods (e.g., spectroscopy or RNA analysis technology) is limited, as their performance strongly relies on high-end instrumentation and/or rigorous laboratory conditions. This paper presents a practically applicable deep learning-based method (i.e., BloodNet) for efficient, accurate, and costless TSD inference from a macroscopic view, i.e., by using easily accessible bloodstain photos. To this end, we established a benchmark database containing around 50,000 photos of bloodstains with varying TSDs. Capitalizing on such a large-scale database, BloodNet adopted attention mechanisms to learn from relatively high-resolution input images the localized fine-grained feature representations that were highly discriminative between different TSD periods. Also, the visual analysis of the learned deep networks based on the Smooth Grad-CAM tool demonstrated that our BloodNet can stably capture the unique local patterns of bloodstains with specific TSDs, suggesting the efficacy of the utilized attention mechanism in learning fine-grained representations for TSD inference. As a paired study for BloodNet, we further conducted a microscopic analysis using Raman spectroscopic data and a machine learning method based on Bayesian optimization. Although the experimental results show that such a new microscopic-level approach outperformed the state-of-the-art by a large margin, its inference accuracy is significantly lower than BloodNet, which further justifies the efficacy of deep learning techniques in the challenging task of bloodstain TSD inference. Our code is publically accessible via https://github.com/shenxiaochenn/BloodNet. Our datasets and pre-trained models can be freely accessed via https://figshare.com/articles/dataset/21291825.


Asunto(s)
Manchas de Sangre , Teorema de Bayes , Aprendizaje Automático
3.
Eur Spine J ; 33(3): 924-931, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38008871

RESUMEN

OBJECTIVE: To evaluate the validity of intraoperative evoked potential (EP) including motor evoked potential (MEP) and somatosensory evoked potentials (SEP) as a biomarker for predicting neural function changes after thoracic spinal decompression (TSD) surgery. METHOD: A consecutive series of 336 TSD surgeries were reviewed between 2010 and 2021 from four spine center. All patients with TSD were divided into 3 groups according to different intraoperative EP results: group 1, EP alerts; group 2, no obvious EP deterioration; group 3, EP improvement compared with baselines. The lower limb Japanese Orthopedic Association (JOA) scores (as well as early and long-term JOA recovery rate) were utilized to quantitatively assess pre- and postoperative neural function change. RESULTS: Among the 3 subgroups according to the different EP changes, the early JOA recovery rate (RR%) in the EP improvement group was significantly better than the other two groups (51.3 ± 58.6* vs. 27.5 ± 31.2 and 33.3 ± 43.1; p < 0.01) after 3-month follow-up. The mean MEP and SEP amplitude were from 116 ± 57 µV to 347 ± 71 µV (p < 0.01) and from 1.86 ± 0.24 µV to 2.65 ± 0.29 µV (p < 0.01) between spinal cord pre-decompression and post-decompression. Moreover, multivariate logistic regression analysis revealed that risk factors of EP improvement were duration of symptom (p < 0.001, OR 10.9) and Preop. neurologic deficit degree (p = 0.013, OR 7.46). CONCLUSION: The intraoperative EP can predict postoperative neural function changes as a biomarker during TSD. Patient with EP improvement probably has better prognosis for early neural function recovery. The duration of symptom and preoperative neurologic deficit degree may be related to intraoperative EP improvement.


Asunto(s)
Potenciales Evocados Motores , Potenciales Evocados Somatosensoriales , Humanos , Potenciales Evocados Somatosensoriales/fisiología , Potenciales Evocados Motores/fisiología , Columna Vertebral , Biomarcadores , Descompresión , Estudios Retrospectivos
4.
Sensors (Basel) ; 24(12)2024 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-38931491

RESUMEN

To accurately identify the deflection data collected by a traffic speed deflectometer (TSD) and eliminate the noise in the measured signals, a TSD signal denoising method based on the partial swarm optimization-variational mode decomposition (PSO-VMD) method is proposed. Initially, the VMD algorithm is used for modal decomposition, calculating the correlation coefficients between each decomposed mode and the original signal for modal selection and signal reconstruction; Then, the particle swarm optimization algorithm is utilized to optimize the number of modes K and the value α for the VMD algorithm, adopting fuzzy entropy as the affinity function to circumvent effects from sequence decomposition and forecasting accuracy, thus identifying the optimal combination of hyperparameters. Finally, the analysis on simulated signals indicates that the PSO-VMD method secures the best parameters, showing a clear advantage in denoising. Denoising real TSD data validates that the approach proposed herein achieves commendable outcomes in TSD deflection noise reduction, offering a feasible strategy for TSD signal denoising.

5.
J Clin Psychol ; 80(3): 678-691, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38265356

RESUMEN

OBJECTIVE: Despite the clinical significance of emotional diversity, also known as emodiversity, there has been limited investigation into the therapeutic interventions that influence this construct. In the current study we examined the association between immediate therapist self-disclosure (TSD) and emodiversity among two diagnostic groups who tend to experience emotional difficulties: people with schizophrenia and people with emotional disorders (i.e., depression and/or anxiety). METHOD: The sample comprised 74 clients (37 diagnosed with schizophrenia and 37 with emotional disorders) treated by 45 therapists in a university clinic setting. Following each session, clients self-reported their emotions, and therapists completed a measure of frequency and centrality of their immediate TSD during the session. RESULTS: Longitudinal multilevel models indicated that immediate TSD was positively associated with clients' global emodiversity, both at the within- and the between-client levels, as well as with clients' negative emodiversity at the between-client level. Moreover, clients with emotional disorders and clients with schizophrenia did not differ in the association between immediate TSD and emodiversity. In addition, across groups, clients treated by therapists who used more immediate TSD on average showed greater increases in global emodiversity during treatment. CONCLUSIONS: immediate TSD is associated with clients' ability to experience rich and diverse emotional experiences across different disorders. The theoretical and clinical implications of these findings are discussed.


Asunto(s)
Esquizofrenia , Humanos , Esquizofrenia/terapia , Revelación , Relaciones Profesional-Paciente , Emociones , Trastornos del Humor , Psicoterapia
6.
Chemistry ; 29(59): e202301934, 2023 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-37544915

RESUMEN

Herein, we describe a new method for the synthesis of α-carbonyl selenocyanates by reacting triselenium dicyanide (TSD) and styrenes under blue light irradiation and O2 atmosphere. The reactions are triggered by the formation of Se-centered radical species, followed by the addition/oxidation of the styrene π-bond. α-Carbonyl selenocyanates and α-hydroxy selenocyanates were obtained in moderate to excellent yields from aryl- and alkyl-substituted alkenes, respectively. It was demonstrated that α-carbonyl selenocyanates could be used as a synthetic platform in a multicomponent reaction strategy to prepare 2-phenylimidazo[1,2-a]pyridine derivatives, which were evaluated for their photophysical properties. Overall, this new method provides a useful tool for synthesizing α-carbonyl selenocyanates, and demonstrates their potential for use in the synthesis of other compounds, thus giving new synthetic opportunities to construct organic selenocyanate compounds.

7.
Am Nat ; 200(4): 532-543, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36150201

RESUMEN

AbstractSpecies with environmental sex determination (ESD) have persisted through deep time, despite massive environmental perturbation in the geological record. Understanding how species with temperature-dependent sex determination (TSD), a type of ESD, persist through climate change is particularly timely given the current climate crisis, as highly biased sex ratios and extinction are predicted. Since 1982, we have studied primary sex ratios of a reptile with TSD (Chelydra serpentina). Primary sex ratios remained unchanged over time, despite warming in the environment. Resilience of the primary sex ratio occurred via a portfolio effect, realized through remarkable intra-annual variation in nest-level sex ratios, leading to a relatively consistent mean annual sex ratio. Intra-annual variation in nest-level sex ratios was related to variation in egg burial depth coupled with large clutch sizes, creating thermal gradients in the nest and promoting mixed-sex clutches. Furthermore, both locally and globally, sustained increases in nighttime air temperature contribute more to warming than increases in daily maximum temperature, but development rate was affected more strongly by maximum daily air temperature, conferring additional resilience to overall warming. Our study suggests that some TSD species may be resilient to warming and provides an example of how ESD may persist under environmental change.


Asunto(s)
Razón de Masculinidad , Tortugas , Animales , Cambio Climático , Reptiles , Procesos de Determinación del Sexo , Temperatura
8.
Proc Biol Sci ; 289(1976): 20220689, 2022 06 08.
Artículo en Inglés | MEDLINE | ID: mdl-35642367

RESUMEN

Evolutionary transitions in sex-determining systems have occurred frequently yet understanding how they occur remains a major challenge. In reptiles, transitions from genetic to temperature-dependent sex determination can occur if the gene products that determine sex evolve thermal sensitivity, resulting in sex-reversed individuals. However, evidence of sex reversal is limited to oviparous reptiles. Here we used thermal experiments to test whether sex reversal is responsible for differences in sex determination in a viviparous reptile, Carinascincus ocellatus, a species with XY sex chromosomes and population-specific sex ratio response to temperature. We show that sex reversal is occurring and that its frequency is related to temperature. Sex reversal was unidirectional (phenotypic males with XX genotype) and observed in both high- and low-elevation populations. We propose that XX-biased genotypic sex ratios could produce either male- or female-biased phenotypic sex ratios as observed in low-elevation C. ocellatus under variable rates of XX sex reversal. We discuss reasons why sex reversal may not influence sex ratios at high elevation. Our results suggest that the mechanism responsible for evolutionary transitions from genotypic to temperature-dependent sex determination is more complex than can be explained by a single process such as sex reversal.


Asunto(s)
Lagartos , Razón de Masculinidad , Animales , Clima , Femenino , Humanos , Lagartos/genética , Masculino , Cromosomas Sexuales , Procesos de Determinación del Sexo
9.
J Evol Biol ; 35(12): 1709-1720, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-35877473

RESUMEN

Understanding the evolution and regulation of nucleolar organizing regions (NORs) is important to elucidate genome structure and function. This is because ribosomal gene (rDNA) copy number and activity mediate protein biosynthesis, stress response, ageing, disease, dosage compensation and genome stability. Here, we found contrasting dosage compensation of sex-linked NORs in turtles with male and female heterogamety. Most taxa examined exhibit homomorphic rRNA gene clusters in a single autosome pair (determined by 28S rDNA fluorescence in situ hybridization), whereas NORs are sex-linked in Apalone spinifera, Pelodiscus sinensis and Staurotypus triporcatus. Full-dosage compensation upregulates the male X-NOR (determined via silver staining-AgNOR) in Staurotypus (who lacks Y-NOR) compared with female X-AgNORs. In softshell Apalone and Pelodiscus, who share homologous ZZ/ZW micro-chromosomes, their enlarged W-NOR is partially active (due to 28S rDNA invasion by R2 retroelements), whereas their smaller Z-NOR is silent in females but active in both male-Zs (presumably because the W-NOR meets cellular demands and excessive NOR activity is costly). We hypothesize that R2 disruption favoured W enlargement to add intact 28S-units, perhaps facilitated by reduced recombination during sex chromosome evolution. The molecular basis of the potentially adaptive female Z-silencing is likely intricate and perhaps epigenetic, as non-ribosomal Z genes are active in Apalone females. Yet, Emydura maquarii exhibit identical heteromorphism in their autosomal NOR (R2 invaded 28S-units and the small-autosome NOR is silent), suggesting that the softshell turtle pattern can evolve independent of sex chromosome evolution. Our study illuminates the complex sex chromosome evolution and dosage compensation of non-model systems that challenges classic paradigms.


Asunto(s)
Tortugas , Animales , Masculino , Femenino , Tortugas/genética , Hibridación Fluorescente in Situ , Evolución Molecular , Cromosomas Sexuales/genética , ADN Ribosómico , Compensación de Dosificación (Genética)
10.
Sensors (Basel) ; 22(10)2022 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-35632165

RESUMEN

Heterogeneity is a problem in storing and exchanging data in a digital health information system (HIS) following semantic and structural integrity. The existing literature shows different methods to overcome this problem. Fast healthcare interoperable resources (FHIR) as a structural standard may explain other information models, (e.g., personal, physiological, and behavioral data from heterogeneous sources, such as activity sensors, questionnaires, and interviews) with semantic vocabularies, (e.g., Systematized Nomenclature of Medicine-Clinical Terms (SNOMED-CT)) to connect personal health data to an electronic health record (EHR). We design and develop an intuitive health coaching (eCoach) smartphone application to prove the concept. We combine HL7 FHIR and SNOMED-CT vocabularies to exchange personal health data in JavaScript object notion (JSON). This study explores and analyzes our attempt to design and implement a structurally and logically compatible tethered personal health record (PHR) that allows bidirectional communication with an EHR. Our eCoach prototype implements most PHR-S FM functions as an interoperability quality standard. Its end-to-end (E2E) data are protected with a TSD (Services for Sensitive Data) security mechanism. We achieve 0% data loss and 0% unreliable performances during data transfer between PHR and EHR. Furthermore, this experimental study shows the effectiveness of FHIR modular resources toward flexible management of data components in the PHR (eCoach) prototype.


Asunto(s)
Registros de Salud Personal , Systematized Nomenclature of Medicine , Registros Electrónicos de Salud , Prueba de Estudio Conceptual , Semántica
11.
Molecules ; 27(13)2022 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-35807373

RESUMEN

A novel method of ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed for the identification and quantification of four potential genotoxic impurities (PGIs) in the active pharmaceutical ingredients of TSD-1, a novel P2Y12 receptor antagonist. Four PGIs were named, 4-nitrobenzenesulfonic acid, methyl 4-nitrobenzenesulfonate, ethyl 4-nitrobenzenesulfonate, and isopropyl 4-nitrobenzenesulfonate. Following the International Conference of Harmonization (ICH) guidelines, this methodology is capable of quantifying four PGIs at 15.0 ppm in samples of 0.5 mg/mL concentration. This validated approach presented very low limits (0.1512−0.3897 ng/mL), excellent linearity (coefficients > 0.9900), and a satisfactory recovery range (94.9−115.5%). The method was sufficient in terms of sensitivity, linearity, precision, accuracy, selectivity, and robustness and, thus, has high practicality in the pharmaceutical quality control of TSD-1.


Asunto(s)
Contaminación de Medicamentos , Espectrometría de Masas en Tándem , Cromatografía Líquida de Alta Presión/métodos , Cromatografía Liquida , Daño del ADN , Preparaciones Farmacéuticas , Reproducibilidad de los Resultados , Espectrometría de Masas en Tándem/métodos
12.
Proteins ; 89(11): 1587-1601, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34288098

RESUMEN

ß-hexosaminidase A (HexA) protein is responsible for the degradation of GM2 gangliosides in the central and peripheral nervous systems. Tay-Sachs disease occurs when HexA within Hexosaminidase does not properly function and harmful GM2 gangliosides begin to build up within the neurons. In this study, in silico methods such as SIFT, PolyPhen-2, PhD-SNP, and MutPred were utilized to analyze the effects of nonsynonymous single nucleotide polymorphisms (nsSNPs) on HexA in order to identify possible pathogenetic and deleterious variants. Molecular dynamics (MD) simulations showed that two mutants, P25S and W485R, experienced an increase in structural flexibility compared to the native protein. Particularly, there was a decrease in the overall number and frequencies of hydrogen bonds for the mutants compared to the wildtype. MM/GBSA calculations were performed to help assess the change in binding affinity between the wildtype and mutant structures and a mechanism-based inhibitor, NGT, which is known to help increase the residual activity of HexA. Both of the mutants experienced a decrease in the binding affinity from -23.8 kcal/mol in wildtype to -20.9 and -18.7 kcal/mol for the P25S and W485R variants of HexA, respectively.


Asunto(s)
Gangliósido G(M2)/química , Simulación de Dinámica Molecular , Mutación Puntual , Polimorfismo de Nucleótido Simple , Enfermedad de Tay-Sachs/genética , Cadena alfa de beta-Hexosaminidasa/química , Acetilglucosamina/análogos & derivados , Acetilglucosamina/química , Acetilglucosamina/farmacología , Sitios de Unión , Sistema Nervioso Central/enzimología , Sistema Nervioso Central/patología , Gangliósido G(M2)/metabolismo , Expresión Génica , Humanos , Enlace de Hidrógeno , Neuronas/enzimología , Neuronas/patología , Sistema Nervioso Periférico/enzimología , Sistema Nervioso Periférico/patología , Unión Proteica , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Dominios y Motivos de Interacción de Proteínas , Enfermedad de Tay-Sachs/enzimología , Enfermedad de Tay-Sachs/patología , Termodinámica , Tiazoles/química , Tiazoles/farmacología , Cadena alfa de beta-Hexosaminidasa/genética , Cadena alfa de beta-Hexosaminidasa/metabolismo
13.
Neurobiol Dis ; 157: 105444, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34265424

RESUMEN

Task-specific dystonia is a neurological movement disorder that abnormal contractions of muscles result in the twisting of fixed postures or muscle spasm during specific tasks. Due to the rareness and the pathophysiology of the disease, there is no test to confirm the diagnosis of task-specific dystonia, except comprehensive observations by the experts. Evidence from neural electrophysiological data suggests that enhanced low frequency (4-12 Hz) oscillations in the subcortical structure of the globus pallidus were associated with the pathological abnormalities concerning ß and γ rhythms in motor areas and motor cortical network in patients with task-specific dystonia. However, whether patients with task-specific dystonia have any low-frequency abnormalities in motor cortical areas remains unclear. In this study, we hypothesized that low-frequency abnormalities are present in core motor areas and motor cortical networks in patients with task-specific dystonia during performing the non-symptomatic movements and those low-frequency abnormalities can help the diagnosis of this disease. We tested this hypothesis by using EEG, effective connectivity analysis, and a machine learning method. Fifteen patients with task-specific dystonia and 15 healthy controls were recruited. The machine learning method identified 8 aberrant movement-related network connections concerning low frequency, ß and γ frequencies, which enabled the separation of the data of patients from those of controls with an accuracy of 90%. Importantly, 7 of the 8 aberrant connections engaged the premotor area contralateral to the affected hand, suggesting an important role of the premotor area in the pathological abnormities. The patients exhibited significantly lower low frequency activities during the movement preparation and significantly lower ß rhythms during movements compared with healthy controls in the core motor areas. Our findings of low frequency- and ß-related abnormalities at the cortical level and aberrant motor network could help diagnose task-specific dystonia in the clinical setting, and the importance of the contralesional premotor area suggests its diagnostic potential for task-specific dystonia.


Asunto(s)
Ondas Encefálicas/fisiología , Trastornos Distónicos/diagnóstico , Vías Eferentes/fisiopatología , Corteza Motora/fisiopatología , Adulto , Ritmo beta/fisiología , Estudios de Casos y Controles , Trastornos Distónicos/fisiopatología , Electroencefalografía , Femenino , Humanos , Aprendizaje Automático , Masculino , Persona de Mediana Edad , Adulto Joven
14.
J Exp Biol ; 224(Pt Suppl 1)2021 02 24.
Artículo en Inglés | MEDLINE | ID: mdl-33627463

RESUMEN

The unprecedented advancement of global climate change is affecting thermal conditions across spatial and temporal scales. Reptiles with temperature-dependent sex determination (TSD) are uniquely vulnerable to even fine-scale variation in incubation conditions and are a model system for investigating the impacts of shifting temperatures on key physiological and life-history traits. The ways in which current and predicted future climatic conditions translate from macro- to ultra-fine scale temperature traces in subterranean nests is insufficiently understood. Reliably predicting the ways in which fine-scale, daily and seasonally fluctuating nest temperatures influence embryonic development and offspring phenotypes is a goal that remains constrained by many of the same logistical challenges that have persisted throughout more than four decades of research on TSD. However, recent advances in microclimate and developmental modeling should allow us to move farther away from relatively coarse metrics with limited predictive capacity and towards a fully mechanistic model of TSD that can predict incubation conditions and phenotypic outcomes for a variety of reptile species across space and time and for any climate scenario.


Asunto(s)
Cambio Climático , Procesos de Determinación del Sexo , Animales , Reptiles , Razón de Masculinidad , Temperatura
15.
J Integr Neurosci ; 20(1): 87-93, 2021 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-33834694

RESUMEN

Sleep deprivation has deteriorating effects on cognitive functions and activation of brain inflammation mechanisms has been reported by some studies following total sleep deprivation. Some studies have reported the health benefits of punicalagin, a main abstract from Punica granatum L., including those for the treatment of Alzheimer's disease. The antioxidant characteristic of punicalagin and the fact that sleep deprivation accelerates mediators of inflammation led us to further explore the possible neuroprotective role of punicalagin in total sleep deprivation memory impairment in a rat model. In this study, male Wistar rats were implanted with a canula in the lateral ventricle to receive intracerebroventricular injections (drug or vehicle). The animals were trained for the passive avoidance test and then received intracerebroventricular injections of different doses of punicalagin (0.001, 0.01, or 0.1 µg/rat). Then, they were placed in the sleep deprivation apparatus for 24 hours and tested afterwards for memory retrieval and locomotion. Our results indicated that 24 hours of total sleep deprivation impaired memory processes. PG microinjection before TSD did not prevent the deteriorating effect of total sleep deprivation on memory, and only showed a tendency of restoring the memory impairment. Comparison of the locomotor activity between the animals in different groups showed a significant increase in the total sleep deprivation sham groups that received two of the highest doses of punicalagin. Considering the reported beneficial actions of PG by other studies, further investigation is needed into the possible effects of PG in memory alterations.


Asunto(s)
Taninos Hidrolizables/farmacología , Trastornos de la Memoria/tratamiento farmacológico , Trastornos de la Memoria/etiología , Fármacos Neuroprotectores/farmacología , Privación de Sueño/complicaciones , Animales , Conducta Animal/efectos de los fármacos , Taninos Hidrolizables/administración & dosificación , Inyecciones Intraventriculares , Masculino , Fármacos Neuroprotectores/administración & dosificación , Placebos , Ratas , Ratas Wistar
16.
Biom J ; 63(1): 122-133, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-33000873

RESUMEN

Bioequivalence studies are the pivotal clinical trials submitted to regulatory agencies to support the marketing applications of generic drug products. Average bioequivalence (ABE) is used to determine whether the mean values for the pharmacokinetic measures determined after administration of the test and reference products are comparable. Two-stage 2×2 crossover adaptive designs (TSDs) are becoming increasingly popular because they allow making assumptions on the clinically meaningful treatment effect and a reliable guess for the unknown within-subject variability. At an interim look, if ABE is not declared with an initial sample size, they allow to increase it depending on the estimated variability and to enroll additional subjects at a second stage, or to stop for futility in case of poor likelihood of bioequivalence. This is crucial because both parameters must clearly be prespecified in protocols, and the strategy agreed with regulatory agencies in advance with emphasis on controlling the overall type I error. We present an iterative method to adjust the significance levels at each stage which preserves the overall type I error for a wide set of scenarios which should include the true unknown variability value. Simulations showed adjusted significance levels higher than 0.0300 in most cases with type I error always below 5%, and with a power of at least 80%. TSDs work particularly well for coefficients of variation below 0.3 which are especially useful due to the balance between the power and the percentage of studies proceeding to stage 2. Our approach might support discussions with regulatory agencies.


Asunto(s)
Proyectos de Investigación , Estudios Cruzados , Humanos , Tamaño de la Muestra , Equivalencia Terapéutica
17.
Bull Math Biol ; 82(7): 89, 2020 07 07.
Artículo en Inglés | MEDLINE | ID: mdl-32638157

RESUMEN

In many oviparous species, the incubation temperature of the egg determines the sex of the offspring. This is known as temperature-dependent sex determination (TSD). The probability of the hatched offspring being male or female varies across the incubation temperature range. This leads to the appearance of different TSD patterns in species such as FM pattern where females are predominately born at lower temperature and males at higher temperature, FMF pattern where the probability of female being born is higher at extreme temperatures and of the male being born is high at intermediate temperatures. We analyze an enzymatic reaction system proposed in the literature involving sex hormones with positive feedback effect to understand the emergence of different TSD patterns. The nonlinearity in the model is accounted through temperature sensitivity of the reaction rates affecting the catalytic mechanism in the reaction system. We employ a dynamical systems approach of singularity theory and bifurcation analysis to divide the parameter plane of temperature sensitivities into different regions where different TSD patterns are observed. Bifurcation analysis in association with the delineation of the parameter space for different TSD pattern has led to the identification of a subspace where all the TSD patterns observed in nature can be realized. We also show how modulation of the sex hormone in the species can be used to change the probability of occurrence of a specific sex, thereby preventing the extinction of endangered species.


Asunto(s)
Modelos Biológicos , Oviparidad/fisiología , Procesos de Determinación del Sexo/fisiología , Animales , Aromatasa/fisiología , Estrógenos/fisiología , Femenino , Masculino , Conceptos Matemáticos , Dinámicas no Lineales , Razón de Masculinidad , Análisis de Sistemas , Temperatura , Testosterona/fisiología
18.
Glob Chang Biol ; 25(2): 522-535, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30567014

RESUMEN

Few studies have looked into climate change resilience of populations of wild animals. We use a model higher vertebrate, the green sea turtle, as its life history is fundamentally affected by climatic conditions, including temperature-dependent sex determination and obligate use of beaches subject to sea level rise (SLR). We use empirical data from a globally important population in West Africa to assess resistance to climate change within a quantitative framework. We project 200 years of primary sex ratios (1900-2100) and create a digital elevation model of the nesting beach to estimate impacts of projected SLR. Primary sex ratio is currently almost balanced, with 52% of hatchlings produced being female. Under IPCC models, we predict: (a) an increase in the proportion of females by 2100 to 76%-93%, but cooler temperatures, both at the end of the nesting season and in shaded areas, will guarantee male hatchling production; (b) IPCC SLR scenarios will lead to 33.4%-43.0% loss of the current nesting area; (c) climate change will contribute to population growth through population feminization, with 32%-64% more nesting females expected by 2120; (d) as incubation temperatures approach lethal levels, however, the population will cease growing and start to decline. Taken together with other factors (degree of foraging plasticity, rookery size and trajectory, and prevailing threats), this nesting population should resist climate change until 2100, and the availability of spatial and temporal microrefugia indicates potential for resilience to predicted impacts, through the evolution of nest site selection or changes in nesting phenology. This represents the most comprehensive assessment to date of climate change resilience of a marine reptile using the most up-to-date IPCC models, appraising the impacts of temperature and SLR, integrated with additional ecological and demographic parameters. We suggest this as a framework for other populations, species and taxa.


Asunto(s)
Cambio Climático , Razón de Masculinidad , Tortugas/fisiología , Animales , Femenino , Calentamiento Global , Guinea Bissau , Masculino , Estaciones del Año , Temperatura
19.
Gen Comp Endocrinol ; 273: 172-183, 2019 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-29990492

RESUMEN

The high biodiversity of fish in the Neotropical region contrasts with scarce or biased studies on the mechanisms involved in the sex determination in members of this fauna. In this review, we attempted to compile the information available on determination, differentiation, and manipulation of sex for Neotropical species, with special focus on silversides and other two speciose groups, known as characins (Characiformes) and catfishes (Siluriformes). Currently, there is plenty of information available on chromosomal sex determination systems, which includes both male and female heterogamety with many variations, and sex chromosomes evolution at the macro chromosomal level. However, there is hitherto a blank in information at micro, gene/molecule levels and in research related to the effects of environmental cues on sex determination; most of reported studies are limited to silversides and guppies. In view of such a high diversity, it is critically necessary to establish key model species for relevant Neotropical fish taxa and also multi-disciplinary research groups in order to uncover the main patterns and trends that dictate the mechanisms of sex determination and gonadal differentiation in this icthyofauna. By increasing our knowledge on sex determination/differentiation with the identification of sex chromosome-linked markers or sex-determining genes, characterization of the onset timing of morphological gonadal differentiation, and determination of the environmental-hormonal labile period of gonadal sex determination in reference species, it will be possible to use those information as guidelines for application in other related groups. Overall, the strategic advance in this research field will be crucial for the development of biotechnological tools for aquaculture industry and for conservation of fish fauna from the Neotropical Region.


Asunto(s)
Acuicultura , Fenómenos Ecológicos y Ambientales , Peces/fisiología , Procesos de Determinación del Sexo , Clima Tropical , Animales , Bagres/genética , Femenino , Masculino
20.
Int J Legal Med ; 132(3): 781-785, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29034416

RESUMEN

We report a case of a double homicide in which the victims, a man and his daughter, were simultaneously killed by a single gunshot. The temperature-based nomogram method for estimation of the time since death was used to ascertain the reliability of the method in a case of simultaneous demise, where the exact time of death was obtained from the analysis of security cameras.In the case presented, the victims differed for a great number of parameters (e.g., atmospheric conditions, thermal insulation of lower trunk, and, above all, body weight), except for the time of death, that was simultaneous. The correct application of the method permitted us to conclude that the estimated time since death was fully consistent with the circumstantial data obtained by the analysis of security cameras.No previous papers reporting the use of the nomogram method in a case of ascertained simultaneously death exists in literature; issues concerning the use of the nomogram method have been presented as well.


Asunto(s)
Temperatura Corporal , Nomogramas , Cambios Post Mortem , Heridas por Arma de Fuego/patología , Adulto , Femenino , Homicidio , Humanos , Lactante , Masculino , Reproducibilidad de los Resultados , Factores de Tiempo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA