Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 144
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
J Synchrotron Radiat ; 28(Pt 4): 1216-1228, 2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-34212887

RESUMEN

A multi-frame, X-ray diffraction (XRD) detector system has been developed for use in time-resolved XRD measurements during single-event experiments at the Dynamic Compression Sector (DCS) at the Advanced Photon Source (APS). The system is capable of collecting four sequential XRD patterns separated by 153 ns, the period of the APS storage ring in the 24-bunch mode. This capability allows an examination of the temporal evolution of material dynamics in single-event experiments, such as plate impact experiments, explosive detonations, and split-Hopkinson pressure bar experiments. This system is available for all user experiments at the DCS. Here, the system description and measured performance parameters (detective quantum efficiency, spatial and temporal resolution, and dynamic range) are presented along with procedures for synchronization and image post-processing.

2.
J Evol Biol ; 29(7): 1379-93, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-27062053

RESUMEN

Maternal effects are widely documented in animals and plants, but not in fungi or other eukaryotes. A principal cause of maternal effects is asymmetrical parental investment in a zygote, creating greater maternal vs. paternal influence on offspring phenotypes. Asymmetrical investments are not limited to animals and plants, but are also prevalent in fungi and groups including apicomplexans, dinoflagellates and red algae. Evidence suggesting maternal effects among fungi is sparse and anecdotal. In an experiment designed to test for maternal effects across sexual reproduction in the model fungus Neurospora crassa, we measured offspring phenotypes from crosses of all possible pairs of 22 individuals. Crosses encompassed reciprocals of 11 mating-type 'A' and 11 mating-type 'a' wild strains. After controlling for the genetic and geographic distances between strains in any individual cross, we found strong evidence for maternal control of perithecia (sporocarp) production, as well as maternal effects on spore numbers and spore germination. However, both parents exert equal influence on the percentage of spores that are pigmented and size of pigmented spores. We propose a model linking the stage-specific presence or absence of maternal effects to cellular developmental processes: effects appear to be mediated primarily through the maternal cytoplasm, and, after spore cell walls form, maternal influence on spore development is limited. Maternal effects in fungi, thus far largely ignored, are likely to shape species' evolution and ecologies. Moreover, the association of anisogamy and maternal effects in a fungus suggests maternal effects may also influence the biology of other anisogamous eukaryotes.


Asunto(s)
Herencia Materna , Neurospora crassa/genética , Esporas Fúngicas , Animales , Neurospora , Fenotipo , Plantas
3.
Heredity (Edinb) ; 116(2): 182-9, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26419337

RESUMEN

We present a novel algorithm for the design of crossing experiments. The algorithm identifies a set of individuals (a 'crossing-set') from a larger pool of potential crossing-sets by maximizing the diversity of traits of interest, for example, maximizing the range of genetic and geographic distances between individuals included in the crossing-set. To calculate diversity, we use the mean nearest neighbor distance of crosses plotted in trait space. We implement our algorithm on a real dataset of Neurospora crassa strains, using the genetic and geographic distances between potential crosses as a two-dimensional trait space. In simulated mating experiments, crossing-sets selected by our algorithm provide better estimates of underlying parameter values than randomly chosen crossing-sets.


Asunto(s)
Algoritmos , Cruzamientos Genéticos , Modelos Genéticos , Neurospora/genética , Genes del Tipo Sexual de los Hongos , Genotipo
4.
J Biomech ; 118: 110256, 2021 03 30.
Artículo en Inglés | MEDLINE | ID: mdl-33545573

RESUMEN

American football players are frequently exposed to head impacts, which can cause concussions and may lead to neurodegenerative diseases such as chronic traumatic encephalopathy (CTE). Player position appears to influence the risk of concussion but there is limited work on its effect on the risk of CTE. Computational modelling has shown that large brain deformations during head impacts co-localise with CTE pathology in sulci. Here we test whether player position has an effect on brain deformation within the sulci, a possible biomechanical trigger for CTE. We physically reconstructed 148 head impact events from video footage of American Football games. Players were separated into 3 different position profiles based on the magnitude and frequency of impacts. A detailed finite element model of TBI was then used to predict Green-Lagrange strain and strain rate across the brain and in sulci. Using a one-way ANOVA, we found that in positions where players were exposed to large magnitude and low frequency impacts (e.g. defensive back and wide receiver), strain and strain rate across the brain and in sulci were highest. We also found that rotational head motion is a key determinant in producing large strains and strain rates in the sulci. Our results suggest that player position has a significant effect on impact kinematics, influencing the magnitude of deformations within sulci, which spatially corresponds to where CTE pathology is observed. This work can inform future studies investigating different player-position risks for concussion and CTE and guide design of prevention systems.


Asunto(s)
Conmoción Encefálica , Encefalopatía Traumática Crónica , Fútbol Americano , Encefalopatía Traumática Crónica/etiología , Cabeza , Dispositivos de Protección de la Cabeza , Humanos , Estados Unidos
5.
J Neonatal Perinatal Med ; 13(2): 159-165, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32538879

RESUMEN

BACKGROUND: Given the limited available evidence on chloral hydrate safety in neonatal populations and the discrepancy in chloral hydrate acceptance between the US and other countries, we sought to clarify the safety profile of chloral hydrate compared to other sedatives in hospitalized infants. METHODS: We included all infants <120 days of life who underwent a minor procedure and were administered chloral hydrate, clonidine, clonazepam, dexmedetomidine, diazepam, ketamine, lorazepam, midazolam, propofol, or pentobarbital on the day of the procedure. We characterized the distribution of infant characteristics and evaluated the relationship between drug administration and any adverse event. We performed propensity score matching, regression adjustment (RA), and inverse probability weighting (IPW) to ensure comparison of similar infants and to account for confounding by indication and residual bias. Results were assessed for robustness to analytical technique by reanalyzing the main outcomes with multivariate logistic regression, a doubly robust IPW with RA model, and a doubly robust augmented IPW model with bias-correction. RESULTS: Of 650 infants, 497 (76%) received chloral hydrate, 79 (12%) received midazolam, 54 (8%) received lorazepam, and 15 (2%) received pentobarbital. Adverse events occurred in 41 (6%) infants. Using propensity score matching, chloral hydrate was associated with a decreased risk of an adverse event compared to other sedatives, risk difference (95% confidence interval) of -12.79 (-18.61, -6.98), p <  0.001. All other statistical methods resulted in similar findings. CONCLUSION: Administration of chloral hydrate to hospitalized infants undergoing minor procedures is associated with a lower risk for adverse events compared to other sedatives.


Asunto(s)
Hidrato de Cloral/uso terapéutico , Hospitalización , Hipnóticos y Sedantes/uso terapéutico , Insuficiencia Respiratoria/inducido químicamente , Diagnóstico por Imagen/métodos , Técnicas de Diagnóstico Oftalmológico , Electroencefalografía/métodos , Femenino , Edad Gestacional , Humanos , Lactante , Recién Nacido , Modelos Logísticos , Lorazepam/uso terapéutico , Masculino , Midazolam/uso terapéutico , Análisis Multivariante , Terapia por Inhalación de Oxígeno , Pentobarbital/uso terapéutico , Polisomnografía/métodos , Puntaje de Propensión , Respiración Artificial , Insuficiencia Respiratoria/terapia
6.
J R Soc Interface ; 17(166): 20200066, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32453981

RESUMEN

Hutchinson-Gilford progeria syndrome (HGPS) is an ultra-rare disorder with devastating sequelae resulting in early death, presently thought to stem primarily from cardiovascular events. We analyse novel longitudinal cardiovascular data from a mouse model of HGPS (LmnaG609G/G609G) using allometric scaling, biomechanical phenotyping, and advanced computational modelling and show that late-stage diastolic dysfunction, with preserved systolic function, emerges with an increase in the pulse wave velocity and an associated loss of aortic function, independent of sex. Specifically, there is a dramatic late-stage loss of smooth muscle function and cells and an excessive accumulation of proteoglycans along the aorta, which result in a loss of biomechanical function (contractility and elastic energy storage) and a marked structural stiffening despite a distinctly low intrinsic material stiffness that is consistent with the lack of functional lamin A. Importantly, the vascular function appears to arise normally from the low-stress environment of development, only to succumb progressively to pressure-related effects of the lamin A mutation and become extreme in the peri-morbid period. Because the dramatic life-threatening aortic phenotype manifests during the last third of life there may be a therapeutic window in maturity that could alleviate concerns with therapies administered during early periods of arterial development.


Asunto(s)
Cardiopatías , Progeria , Animales , Aorta , Ratones , Músculo Liso Vascular , Mutación , Progeria/genética , Análisis de la Onda del Pulso
7.
Bone ; 136: 115329, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32224162

RESUMEN

Pyrophosphate (PPi) serves as a potent and physiologically important regulator of mineralization, with systemic and local concentrations determined by several key regulators, including: tissue-nonspecific alkaline phosphatase (ALPL gene; TNAP protein), the progressive ankylosis protein (ANKH; ANK), and ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1; ENPP1). Results to date have indicated important roles for PPi in cementum formation, and we addressed several gaps in knowledge by employing genetically edited mouse models where PPi metabolism was disrupted and pharmacologically modulating PPi in a PPi-deficient mouse model. We demonstrate that acellular cementum growth is inversely proportional to PPi levels, with reduced cementum in Alpl KO (increased PPi levels) mice and excess cementum in Ank KO mice (decreased PPi levels). Moreover, simultaneous ablation of Alpl and Ank results in reestablishment of functional cementum in dKO mice. Additional reduction of PPi by dual deletion of Ank and Enpp1 does not further increase cementogenesis, and PDL space is maintained in part through bone modeling/remodeling by osteoclasts. Our results provide insights into cementum formation and expand our knowledge of how PPi regulates cementum. We also demonstrate for the first time that pharmacologic manipulation of PPi through an ENPP1-Fc fusion protein can regulate cementum growth, supporting therapeutic interventions targeting PPi metabolism.


Asunto(s)
Cementogénesis , Difosfatos , Animales , Cemento Dental , Ratones , Osteoclastos
8.
Mol Cell Biol ; 10(5): 2096-103, 1990 May.
Artículo en Inglés | MEDLINE | ID: mdl-2183019

RESUMEN

The N-myc gene is expressed specifically in the early developmental stages of numerous cell lineages. To assay for sequences that could potentially regulate N-myc expression, we transfected constructs that contained murine N-myc genomic sequences linked to a reporter gene and genomic clones that contained the complete human or murine N-myc genes into cell lines that either express or do not express the endogenous N-myc gene. Following either transient or stable transfection, the introduced N-myc sequences were expressed regardless of the expression status of the endogenous gene. In contrast, when the clones containing the complete human N-myc gene were introduced into the germline of transgenic mice, expression in some transgenic lines paralleled the tissue- and stage-specific expression of the endogenous murine gene. These findings demonstrate differences in the regulation of N-myc genes in recipient cells following in vitro versus in vivo introduction, suggesting that early developmental events may play a role in the regulation of N-myc expression.


Asunto(s)
Proteínas Proto-Oncogénicas/genética , Factores de Edad , Animales , Northern Blotting , Encéfalo/crecimiento & desarrollo , Regulación de la Expresión Génica , Riñón/crecimiento & desarrollo , Ratones , Ratones Transgénicos , Proteínas Proto-Oncogénicas c-myc , ARN Mensajero/genética , Proteínas Recombinantes de Fusión , Transcripción Genética , Transfección
9.
Mol Cell Biol ; 12(4): 1578-84, 1992 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1549113

RESUMEN

We have used nuclear run-on and DNase I sensitivity analyses to study the activity of the N-myc genes in cell lines that represent different stages of B-cell development. Both transformed pre-B-cell lines and a nontransformed pre-B-cell clone transcribe the N- and c-myc genes at substantial levels; in the nontransformed clone, transcription of these genes is regulated by the pre-B-cell growth factor interleukin-7. In contrast, transformed cell lines that represent the more mature stages of the B-cell pathway and mitogen-stimulated normal splenic B lymphocytes express the c-myc gene but do not express the N-myc gene at detectable levels. Down-regulation of N-myc expression in these cells occurs at the level of transcriptional initiation. Correspondingly, a set of DNase I-hypersensitive sites present in the 5' region of the N-myc promoter of pre-B-cell lines are absent in B-cell lines. To further elucidate this process, we have constructed fusion cell lines between an N-myc-expressing pre-B-cell line and a nonexpressing myeloma line; the hybrid cell lines transcriptionally down-regulate the pre-B copies of the N-myc gene. Lack of N-myc expression in a number of nonlymphoid cell lines also resulted from lack of N-myc transcription. Together, our findings demonstrate that the down-regulation of N-myc expression in the later stages of B-cell development is mediated primarily at the level of transcriptional initiation. They further show that dominant, trans-acting factors present in more mature B-lineage cell lines act to down-regulate the transcription of N-myc.


Asunto(s)
Linfocitos B/metabolismo , Diferenciación Celular/genética , Regulación hacia Abajo , Genes myc/genética , Regiones Promotoras Genéticas/genética , Animales , Núcleo Celular/metabolismo , Sistema Libre de Células/metabolismo , Células Cultivadas , Mapeo Cromosómico , Desoxirribonucleasa I/metabolismo , Humanos , Hibridomas/metabolismo , Activación de Linfocitos , Ratones , Precursores del ARN/genética , Precursores del ARN/metabolismo , Procesamiento Postranscripcional del ARN , Transcripción Genética
10.
Neurotoxicology ; 28(6): 1110-9, 2007 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-17669499

RESUMEN

Circulating uranium rapidly enters the brain and may cause adverse effects on the nervous system that are potentially modulated by stress. In this study, the neurological effects of a single intramuscular injection of 0, 0.1, 0.3, or 1 mg uranium/kg (as uranyl acetate, UA) in rats were examined in the presence and absence of stress. Treatment with UA produced time and dose-dependent increases in serum and regional brain uranium levels. While serum levels returned to control levels by day 30, brain levels remained elevated. Application of stress did not affect the distribution or retention of uranium. Exposure to 1 mg U/kg significantly decreased ambulatory activity, weight gain, forelimb grip strength and transiently impaired working memory. Effects on grip strength and memory were prevented by application of stress prior to uranium exposure. Striatal dopamine content was reduced by 30% 3 days after treatment with 1mg/kg (59+/-6 nmol/mg tissue versus 41+/-5 nmol/mg tissue), but levels returned to control 7 days after uranium exposure. The effect on dopamine was ameliorated by prior application of stress. Exposure to UA did not alter 3,4 dihydroxyphenylacetic acid (DOPAC) levels or numbers of D2 receptors in the striatum. No effect of uranium or stress was observed on levels of GABA, serotonin, norepinephrine, or glutathione (GSH) in the striatum, hippocampus, cerebellum, or cortex. These results indicate that single intramuscular exposures to uranium produce sustained elevation of brain uranium levels and at doses above 0.3 mg/kg can have adverse neurological effects. Application of stress prior to uranium administration modulates neurological effects, but the mechanism is not due to effects on uranium distribution. Uranium exposure also produced renal toxicity which must be considered to accurately assess the effects of uranium on neurological function.


Asunto(s)
Conducta Animal/efectos de los fármacos , Encéfalo/efectos de los fármacos , Síndromes de Neurotoxicidad/etiología , Compuestos Organometálicos/toxicidad , Estrés Psicológico/complicaciones , Animales , Peso Corporal/efectos de los fármacos , Encéfalo/metabolismo , Encéfalo/fisiopatología , Química Encefálica/efectos de los fármacos , Corticosterona/sangre , Dopamina/metabolismo , Relación Dosis-Respuesta a Droga , Glutatión/metabolismo , Inyecciones Intramusculares , Enfermedades Renales/inducido químicamente , Locomoción/efectos de los fármacos , Masculino , Memoria/efectos de los fármacos , Fuerza Muscular/efectos de los fármacos , Síndromes de Neurotoxicidad/complicaciones , Síndromes de Neurotoxicidad/metabolismo , Síndromes de Neurotoxicidad/fisiopatología , Neurotransmisores/metabolismo , Compuestos Organometálicos/administración & dosificación , Compuestos Organometálicos/farmacocinética , Ratas , Ratas Sprague-Dawley , Estrés Psicológico/metabolismo , Estrés Psicológico/fisiopatología , Factores de Tiempo , Distribución Tisular
11.
J Fr Ophtalmol ; 40(6): e193-e200, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28601345

RESUMEN

The management of severe keratoconus requires corneal transplantation, for which the gold standard is deep anterior lamellar keratoplasty (DALK), preserving the healthy Descemet's membrane and endothelium. The safety and reproducibility of corneal cuts have been improved by the evolution of femtosecond lasers in refractive surgery, and femtosecond laser in DALK would seem to provide the same advantages over the manual method. In our retrospective study, we compare functional and anatomical results of femtosecond-assisted DALK versus manual trephination DALK in patients with keratoconus in stage 4 of the Krumeich classification. It is a retrospective study including all patients with stage 4 keratoconus who underwent femtosecond laser-assisted DALK between November 2012 and November 2015 in Nantes university medical center. We compared those patients to a group of patients who underwent manual DALK in the same period, paired by age and maximal keratometry. We assessed visual acuity, pachymetry, endothelial cell density (specular microscopy), and keratometry before surgery and at 4, 8 and 12 months of follow-up. Laser settings and intraoperative complications were recorded. Nineteen patients underwent surgery by femtosecond-assisted DALK, 6 women and 12 men with average age 30.2±10.8 years at transplantation. They were paired with a group of 17 patients who underwent manual DALK in order to compare results. Before surgery, mean visual acuity in the femtosecond group was 0.90 logMAR versus 0.89 logMAR in the manual group, showing no statistically significant difference (P=0.96). Both groups were similar in terms of preoperative age, mean keratometry, pachymetry and endothelial cell density. Average visual acuity post-surgery was 0.27; 0.26; and 0.14 logMAR for femtosecond DALK versus 0.27; 0.17 et 0.25 for manual DALK at 4, 8 and 12 months follow-up respectively, showing no statistically significant difference. After surgery, at 4, 8 and 12 months, mean pachymetry was similar in both groups, and average endothelial cell density was 2390 cells/mm2 for femto DALK versus 2531 cells/mm2 for manual DALK at 12 months of follow-up, showing no statistically significant difference (P=0.5726). The rate of Descemet's membrane microperforations during the procedure was low and similar for both groups. Our study allows for a 12-month follow-up, with assessment of visual recovery, anatomic result and endothelial safety in a series of 19 femtosecond laser-assisted DALK with no statistical significant difference versus the manual trephination group. Femtosecond laser allows for increased reproducibility of the DALK procedure without reducing adverse effects during surgery. Femtosecond laser seems to improve the technique of the DALK procedure, and future developments could improve the reproducibility of DALK even further. A medical economics study would be necessary to determine the cost-effectiveness of femtosecond laser-assisted DALK.


Asunto(s)
Queratoplastia Endotelial de la Lámina Limitante Posterior/métodos , Queratocono/cirugía , Queratoplastia Penetrante/métodos , Terapia por Láser/métodos , Adulto , Córnea/cirugía , Trasplante de Córnea/efectos adversos , Trasplante de Córnea/métodos , Queratoplastia Endotelial de la Lámina Limitante Posterior/efectos adversos , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Humanos , Complicaciones Intraoperatorias/etiología , Complicaciones Intraoperatorias/patología , Queratocono/patología , Queratoplastia Penetrante/efectos adversos , Terapia por Láser/efectos adversos , Rayos Láser , Masculino , Estudios Retrospectivos , Resultado del Tratamiento , Agudeza Visual , Adulto Joven
12.
J Fr Ophtalmol ; 40(7): 571-579, 2017 Sep.
Artículo en Francés | MEDLINE | ID: mdl-28844326

RESUMEN

The management of severe keratoconus requires corneal transplantation, for which the gold standard is deep anterior lamellar keratoplasty (DALK), preserving the healthy Descemet's membrane and endothelium. The safety and reproducibility of corneal cuts have been improved by the evolution of femtosecond lasers in refractive surgery, and femtosecond laser in DALK would seem to provide the same advantages over the manual method. In our retrospective study, we compare functional and anatomical results of femtosecond assisted DALK versus manual trephination DALK in patients with keratoconus in stage 4 of the Krumeich classification. It is a retrospective study including all patients with stage 4 keratoconus who underwent femtosecond laser assisted DALK between November 2012 and November 2015 in Nantes hospital. We compared those patients to a group of patients who underwent manual DALK in the same period, paired by age and maximal keratometry. We assessed visual acuity, pachymetry, endothelial cell density (specular microscopy), and keratometry before surgery and at 4, 8 and 12 months of follow-up. Laser settings and intraoperative complications were recorded. Nineteen patients underwent surgery by femtosecond assisted DALK, 6 women and 12 men with average age 30.2±10.8 years at transplantation. They were paired with a group of 17 patients who underwent manual DALK in order to compare results. Before surgery, mean visual acuity in the femtosecond group was 0.90 logMAR versus 0.89 logMAR in the manual group, showing no statistically significant difference (P=0.96). Both groups were similar in terms of preoperative age, mean keratometry, pachymetry and endothelial cell density. Average visual acuity post-surgery was 0.27, 0.26; and 0.14 logMAR for femtosecond DALK versus 0.27, 0.17 et 0.25 for manual DALK at 4, 8 and 12 months follow-up, respectively showing no statistically significant difference. After surgery, at 4, 8 and 12 months, mean pachymetry was similar in both groups, and average endothelial cell density was 2390 cells/mm2 in femtoDALK versus 2531 cells/mm2 in manual DALK at 12 months of follow-up, showing no statistically significant difference (P=0.5726). The rate of Descemet's membrane microperforations during the procedure was low and similar for both groups. Our study allows for a 12 month follow-up, with assessment of visual recovery, anatomical result and endothelial safety in a sample of 19 femtosecond laser assisted DALK with no statistical significant difference versus the manual trephination group. Femtosecond laser allows for increased reproducibility of the DALK procedure without reducing adverse effects during surgery. Femtosecond laser seems to improve the technique of the DALK procedure, and future developments could improve the reproducibility of DALK even further. A medical economics study would be necessary to determine the cost effectiveness of femtosecond laser assisted DALK.


Asunto(s)
Queratocono/cirugía , Queratoplastia Penetrante/métodos , Terapia por Láser , Adulto , Progresión de la Enfermedad , Femenino , Humanos , Queratocono/patología , Terapia por Láser/métodos , Rayos Láser , Masculino , Estudios Retrospectivos , Resultado del Tratamiento , Adulto Joven
13.
Curr Opin Neurobiol ; 7(1): 40-7, 1997 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9039803

RESUMEN

The conservation of transcriptional regulatory mechanisms across species, combined with the restricted expression of these molecules in time and space within the embryo, has offered new insights into CNS cell specification. Studies examining transcriptional control in the generation of specific cell classes within the cerebellar cortex have been particularly elucidative.


Asunto(s)
Cerebelo/citología , Cerebelo/embriología , Genes , Animales , Diferenciación Celular/genética , Desarrollo Embrionario y Fetal , Células Madre/citología , Células Madre/metabolismo
14.
Placenta ; 27(4-5): 502-9, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-15990165

RESUMEN

Methylnitrosourea (MNU) is a multisystem teratogen that damages proliferating cells through macromolecule alkylation and generation of reactive oxygen species (ROS). Murine dams exposed to MNU midgestation produce offspring with distal limb malformations, an outcome reduced by maternal immune stimulation. Immunostimulatory effects of antioxidant therapy may in part explain this improved birth outcome. The present study hypothesizes that placental, rather than fetal, damage from excessive ROS may contribute to MNU-induced embryopathy. Fetal limbs and placentas were examined in immunotolerant CD-1 and immunosensitive C57BL/6N mice exposed to MNU, dietary antioxidant butylated hydroxytoluene (BHT), or both. MNU increased fetal resorptions and incidence of syndactyly, oligodactyly, polydactyly, and interdigital webbing, and decreased fetal size in both mouse strains. BHT reduced syndactyly and oligodactyly in both strains, and reduced polydactyly in C57BL/6N mice. Increased webbing in MNU and MNU+BHT groups likely represented maturational delay. Placentas from CD-1 and C57BL/6N MNU-exposed dams demonstrated decreased trophoblasts and increased necrosis of endothelium. Similar to distal limb defects, placental damage was reduced in mice receiving MNU+BHT. These results suggest that placental damage and fetal defects caused by MNU are in part ROS-mediated, and reduced distal limb defects following MNU+BHT may be related to improved placental integrity and function.


Asunto(s)
Antioxidantes/administración & dosificación , Hidroxitolueno Butilado/administración & dosificación , Suplementos Dietéticos , Deformidades Congénitas de las Extremidades/inducido químicamente , Deformidades Congénitas de las Extremidades/prevención & control , Desarrollo Musculoesquelético/efectos de los fármacos , Placentación/efectos de los fármacos , Alquilantes/efectos adversos , Animales , Extremidades/crecimiento & desarrollo , Femenino , Masculino , Exposición Materna/efectos adversos , Metilnitrosourea/efectos adversos , Ratones , Ratones Endogámicos C57BL , Embarazo
15.
Cancer Res ; 46(12 Pt 1): 6217-22, 1986 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-2430692

RESUMEN

Activation of myc-family oncogenes has been implicated in the genesis of a variety of neoplasms. In addition, these genes exhibit specific patterns of expression during murine development. We now report that N- and c-myc are differentially expressed in normal developing human renal tissues and in Wilms' tumor, a neoplasm which derives from primitive kidney cells. Twelve of 13 Wilms' tumors tested exhibited greatly enhanced levels of expression which occurred in the absence of gene amplification. We also detected N-myc expression in other primitive neoplasms including medulloblastoma and hepatoblastoma. Our observations suggest that N-myc expression is not limited to neuroectodermal tumors as was previously thought, but is a marker for several neoplasms that derive from primitive cell precursors. Finally, high level expression of N-myc was associated with markedly diminished levels of c-myc, suggesting that enhanced expression of N-myc gene might lead to down-regulation of c-myc.


Asunto(s)
Neoplasias Renales/genética , Proteínas Proto-Oncogénicas/análisis , Proto-Oncogenes , Tumor de Wilms/genética , Feto/análisis , Amplificación de Genes , Humanos , Factor II del Crecimiento Similar a la Insulina/genética , Riñón/análisis , Proteínas Proto-Oncogénicas c-myc , ARN/análisis
16.
Biochim Biophys Acta ; 444(3): 875-85, 1976 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-990277

RESUMEN

Uptake of 22Na and 42K into ejaculated boar spermatozoa was measured in vitro. Cells were suspended either in seminal plasma or in a biological salt solution of essentially the same composition as boar seminal plasma. Samples were incubated at 30 degrees C. Correction was made for extracellular space in the centrifuged sperm pellet. This was determined as 22Na-space, which was less (P less than 0.001) than [14C] carboxyinulin space. Large differences were observed among individual ejaculates. The half-time for potassium uptake into the spermatozoa averaged 11.5 min, which is much faster than that for leukocytes or erythrocytes. When the spermatozoa were suspended in the biological salt solution, the initial rate of 42K uptake was significantly decreased. This may be due to disturbances of the protein components of the sperm membrane. The uptake of 22Na into the spermatozoa was slow. Sodium and potassium transport appeared not to be coupled in the 3/2 ratio which has been reported for erythrocyte membranes. The average concentration of sodium was 108 mM in seminal plasma and 26 mM in the spermatozoa (112 mmol/kg water and 38 mmol/kg water, respectively). The corresponding figures for potassium were 26 mM and 51 mM (27 mmol/kg water and 74 mmol/kg water). The random error for a single determination for the various methods used varied between 2.4 and 13.3% of the mean.


Asunto(s)
Potasio/metabolismo , Sodio/metabolismo , Espermatozoides/metabolismo , Análisis de Varianza , Animales , Transporte Biológico Activo , Bovinos , Técnicas In Vitro , Inulina/metabolismo , Cinética , Masculino , Semen/fisiología
17.
Circulation ; 101(24): 2863-9, 2000 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-10859294

RESUMEN

BACKGROUND: Cardiac hypertrophy is considered a necessary compensatory response to sustained elevations of left ventricular (LV) wall stress. METHODS AND RESULTS: To test this, we inhibited calcineurin with cyclosporine (CsA) in the setting of surgically induced pressure overload in mice and examined in vivo parameters of ventricular volume and function using echocardiography. Normalized heart mass increased 45% by 5 weeks after thoracic aortic banding (TAB; heart weight/body weight, 8.3+/-0.9 mg/g [mean+/-SEM] versus 5. 7+/-0.1 mg/g unbanded, P<0.05). Similar increases were documented in the cell-surface area of isolated LV myocytes. In mice subjected to TAB+CsA treatment, we observed complete inhibition of hypertrophy (heart weight/body weight, 5.2+/-0.3 mg/g at 5 weeks) and myocyte surface area (endocardial and epicardial fractions). The mice tolerated abolition of hypertrophy with no signs of cardiovascular compromise, and 5-week mortality was not different from that of banded mice injected with vehicle (TAB+Veh). Despite abolition of hypertrophy by CsA (LV mass by echo, 83+/-5 mg versus 83+/-2 mg unbanded), chamber size (end-diastolic volume, 33+/-6 microL versus 37+/-1 microL unbanded), and systolic ejection performance (ejection fraction, 97+/-2% versus 97+/-1% unbanded) were normal. LV mass differed significantly in TAB+Veh animals (103+/-5 mg, P<0.05), but chamber volume (end-diastolic volume, 44+/-6 microL), ejection fraction (92+/-2%), and transstenotic pressure gradients (70+/-14 mm Hg in TAB+Veh versus 77+/-11 mm Hg in TAB+CsA) were not different. CONCLUSIONS: In this experimental setting, calcineurin blockade with CsA prevented LV hypertrophy due to pressure overload. TAB mice treated with CsA maintain normal LV size and systolic function.


Asunto(s)
Adaptación Fisiológica , Cardiomegalia/etiología , Hipertensión/complicaciones , Hipertensión/fisiopatología , Enfermedad Aguda , Animales , Aorta Torácica , Inhibidores de la Calcineurina , Cardiomegalia/diagnóstico por imagen , Cardiomegalia/prevención & control , Ciclosporina/farmacología , Ecocardiografía , Inhibidores Enzimáticos/farmacología , Hemodinámica/efectos de los fármacos , Hipertensión/diagnóstico por imagen , Hipertensión/etiología , Ligadura , Masculino , Ratones , Ratones Endogámicos C57BL
18.
Diabetes ; 48(5): 1093-100, 1999 May.
Artículo en Inglés | MEDLINE | ID: mdl-10331415

RESUMEN

We studied the effect of moxonidine, an imidazoline ligand, on metabolic and hemodynamic parameters in Zucker diabetic fatty rats, a model of type 2 diabetes. In one group (metabolic group), 8-week-old rats were started on a diet containing either moxonidine (3 or 10 mg x kg(-1) x day(-1)) or vehicle for 4 weeks. Body weight and food intake were monitored daily, plasma insulin and glucose were monitored weekly, and an oral glucose tolerance test (OGTT) was performed at study's end. In another group of rats (hemodynamic group), radio frequency transmitters were implanted 1 week before starting the diet, and mean blood pressure, heart rate, and motor activity were continuously monitored at baseline and for 4 weeks after beginning drug exposure. Moxonidine (10 mg x kg(-1) x day(-1)) significantly decreased elevated glucose levels and prevented the decrease in plasma insulin noted in vehicle-treated or pair-fed groups. Moxonidine also decreased fasting glucose (3 and 10 mg x kg(-1) x day(-1)) and prevented the decrease in fasting insulin (10 mg x kg(-1) x day(-1)) compared with vehicle. Fasting glucose at 10 mg x kg(-1) x day(-1) was equivalent to lean littermates. Both doses significantly increased glucose disposal and the insulin secretory response during the OGTT. Moxonidine lowered daily mean arterial pressure compared with both baseline values and vehicle and decreased daily heart rates. Motor activity was unaffected, except for an increase in the 10 mg x kg(-1) x day(-1) group during low activity periods. Moxonidine did not significantly affect body weight, fluid intake, or urine volume, but the 10 mg x kg(-1) x day(-1) dose reduced urinary protein excretion compared with vehicle-treated animals. These results demonstrate that, in an animal model of type 2 diabetes, the antihypertensive agent moxonidine induces a beneficial effect on abnormal glucose metabolism and renal protein excretion at doses that are effective in lowering arterial blood pressures and heart rate.


Asunto(s)
Antihipertensivos/farmacología , Glucemia/metabolismo , Diabetes Mellitus Tipo 2/fisiopatología , Hemodinámica/efectos de los fármacos , Imidazoles/farmacología , Animales , Antihipertensivos/uso terapéutico , Presión Sanguínea , Ritmo Circadiano , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Ingestión de Alimentos , Prueba de Tolerancia a la Glucosa , Frecuencia Cardíaca , Imidazoles/uso terapéutico , Insulina/sangre , Masculino , Actividad Motora , Proteinuria , Ratas , Ratas Zucker , Equilibrio Hidroelectrolítico
19.
Genetics ; 154(3): 1213-29, 2000 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10866651

RESUMEN

We have screened for zygotic embryonic lethal mutations affecting cuticular morphology in Nasonia vitripennis (Hymenoptera; Chalcidoidea). Our broad goal was to investigate the use of Nasonia for genetically surveying conservation and change in regulatory gene systems, as a means to understand the diversity of developmental strategies that have arisen during the course of evolution. Specifically, we aim to compare anteroposterior patterning gene functions in two long germ band insects, Nasonia and Drosophila. In Nasonia, unfertilized eggs develop as haploid males while fertilized eggs develop as diploid females, so the entire genome can be screened for recessive zygotic mutations by examining the progeny of F1 females. We describe 74 of >100 lines with embryonic cuticular mutant phenotypes, including representatives of coordinate, gap, pair-rule, segment polarity, homeotic, and Polycomb group functions, as well as mutants with novel phenotypes not directly comparable to those of known Drosophila genes. We conclude that Nasonia is a tractable experimental organism for comparative developmental genetic study. The mutants isolated here have begun to outline the extent of conservation and change in the genetic programs controlling embryonic patterning in Nasonia and Drosophila.


Asunto(s)
Proteínas de Drosophila , Proteínas Nucleares , Factores de Transcripción , Avispas/embriología , Avispas/genética , Cigoto , Animales , Proteínas de Unión al ADN/biosíntesis , Desarrollo Embrionario , Femenino , Proteínas de Homeodominio/biosíntesis , Proteínas de Insectos/biosíntesis , Masculino , Mutación , Fenotipo
20.
Arch Gen Psychiatry ; 45(9): 822-6, 1988 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-3046554

RESUMEN

Thirty-six stabilized schizophrenic outpatients were randomly assigned to receive either 5 or 25 mg of fluphenazine decanoate biweekly and were followed up for two years. The best and worst outcomes were found in groups with good or poor information-processing abilities (as measured by a partial-report span-of-apprehension task) given the same 25-mg dose of fluphenazine decanoate. The 86% two-year survival rate of the patients with poor span performance was considerably better, while the 44% one-year and the 21% two-year survival rates of patients with good span performance were considerably lower than previously reported survival rates for schizophrenic patients receiving a conventional dose of fluphenazine. The significant correlations in a patient's span performance for periods up to one year were consistent with the hypothesis that this task taps processes associated with vulnerability to schizophrenic disorder.


Asunto(s)
Flufenazina/análogos & derivados , Desempeño Psicomotor , Esquizofrenia/tratamiento farmacológico , Adulto , Ensayos Clínicos como Asunto , Relación Dosis-Respuesta a Droga , Flufenazina/administración & dosificación , Humanos , Masculino , Persona de Mediana Edad , Distribución Aleatoria , Recurrencia , Psicología del Esquizofrénico
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA