RESUMEN
Sunscreens are an important aspect of photoprotection. Their efficacy in reducing photocarcinogenesis and photoaging is widely documented. Although there are concerns regarding long-term sunscreen safety, the advantages of sunscreen use are far more compelling. In addition, novel technologies and ultraviolet filters are improving the aesthetics and efficacy of modern products.
Asunto(s)
Envejecimiento de la Piel , Neoplasias Cutáneas/prevención & control , Protectores Solares/uso terapéutico , HumanosRESUMEN
The human spinal cord contains segregated sensory and motor pathways that have been difficult to quantify using conventional magnetic resonance imaging (MRI) techniques. Multiple sclerosis is characterized by both focal and spatially diffuse spinal cord lesions with heterogeneous pathologies that have limited attempts at linking MRI and behaviour. We used a novel magnetization-transfer-weighted imaging approach to quantify damage to spinal white matter columns and tested its association with sensorimotor impairment. We studied 42 participants with multiple sclerosis who each underwent MRI at 3 Tesla and quantitative tests of sensorimotor function. We measured cerebrospinal-fluid-normalized magnetization-transfer signals in the dorsal and lateral columns and grey matter of the cervical cord. We also measured brain lesion volume, cervical spinal cord lesion number and cross-sectional area, vibration sensation, strength, walking velocity and standing balance. We used linear regression to assess the relationship between sensorimotor impairment and MRI abnormalities. We found that the dorsal column cerebrospinal-fluid-normalized magnetization-transfer signal specifically correlated with vibration sensation (R = 0.58, P < 0.001) and the lateral column signal with strength (R = -0.45, P = 0.003). Spinal cord signal measures also correlated with walking and balance dysfunction. A stepwise multiple regression showed that the dorsal column signal and diagnosis subtype alone explained a significant portion of the variance in sensation (R(2) = 0.54, P < 0.001), whereas the lateral column signal and diagnosis subtype explained a significant portion of the variance in strength (R(2) = 0.30, P < 0.001). These results help to understand the anatomic basis of sensorimotor disability in multiple sclerosis and have implications for testing the effects of neuroprotective and reparative interventions.
Asunto(s)
Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética/métodos , Esclerosis Múltiple/patología , Médula Espinal/patología , Adulto , Análisis de Varianza , Tobillo , Encéfalo/patología , Estudios de Casos y Controles , Vértebras Cervicales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Esclerosis Múltiple/fisiopatología , Esclerosis Múltiple Crónica Progresiva/patología , Esclerosis Múltiple Crónica Progresiva/fisiopatología , Esclerosis Múltiple Recurrente-Remitente/patología , Esclerosis Múltiple Recurrente-Remitente/fisiopatología , Fuerza Muscular , Análisis de Regresión , Trastornos de la Sensación/patología , Trastornos de la Sensación/fisiopatología , Umbral Sensorial , Médula Espinal/fisiopatología , Dedos del Pie , VibraciónRESUMEN
The two major zona pellucida proteins of the zebrafish chorion, Zp2 and Zp3, are encoded by multicopy genes arranged in tandem arrays on chromosomes 20 and 2, respectively. Expression of these zp genes in zebrafish is oocyte specific, and we report herein that their activity in developing oocytes is dependent on conserved CCAAT box sites in their promoters. A 140-bp region immediately upstream of the transcription initiation site (position 1) of the zp2 genes has been homogenized by gene conversion and contains a single CCAAT box located at -138 that is necessary for promoter activity in oocytes residing in stage I and early stage II ovarian follicles as determined by microinjection of promoter constructs linked to a luciferase reporter gene. The zp3 gene promoters have two inverted CCAAT boxes located in a region of shared homology within the initial 175 nucleotides. Serial deletion of these sites resulted in incremental decreases in luciferase activity. Double-stranded oligonucleotides containing CCAAT box sequences from both genes formed CCAAT box-specific complexes with ovarian follicle extracts in an electrophoretic mobility shift assay. We also found that the expression of the separate zebrafish zp3b gene, more closely related to two oocyte-expressed medaka zpc genes than to the tandemly arrayed zebrafish zp3 genes, is not CCAAT box dependent. The significance that these results have in furthering our understanding of the regulation of zebrafish zp gene evolution and regulation is discussed.