RESUMO
The Double Asteroid Redirection Test (DART) had an impact with Dimorphos (a satellite of the asteroid Didymos) on 26 September 20221. Ground-based observations showed that the Didymos system brightened by a factor of 8.3 after the impact because of ejecta, returning to the pre-impact brightness 23.7 days afterwards2. Hubble Space Telescope observations made from 15 minutes after impact to 18.5 days after, with a spatial resolution of 2.1 kilometres per pixel, showed a complex evolution of the ejecta3, consistent with other asteroid impact events. The momentum enhancement factor, determined using the measured binary period change4, ranges between 2.2 and 4.9, depending on the assumptions about the mass and density of Dimorphos5. Here we report observations from the LUKE and LEIA instruments on the LICIACube cube satellite, which was deployed 15 days in advance of the impact of DART. Data were taken from 71 seconds before the impact until 320 seconds afterwards. The ejecta plume was a cone with an aperture angle of 140 ± 4 degrees. The inner region of the plume was blue, becoming redder with increasing distance from Dimorphos. The ejecta plume exhibited a complex and inhomogeneous structure, characterized by filaments, dust grains and single or clustered boulders. The ejecta velocities ranged from a few tens of metres per second to about 500 metres per second.
RESUMO
Rasmussen syndrome (RS) is a chronic encephalopathy with uncertain etiology and immune-mediated pathogenesis. The only definitive treatment is represented by functional hemispherectomy. We describe the case of a 6.5-year-old female patient who developed several episodes of focal, unilateral clonic seizures. Following laboratory and instrumental investigations, the patient was diagnosed as having RS. A treatment with corticosteroids, intravenous immunoglobulin, and the antiseizure medication (carbamazepine and levetiracetam) did not completely control the seizures. Therefore, the patient was treated with mycophenolate mofetil (MMF), showing a good clinical response, with reduction of the seizures, and stability of the radiological findings. This case suggests the potential utility of MMF in the immune approach to RS.
RESUMO
The near-Earth asteroid 162173 Ryugu, the target of the Hayabusa2 sample-return mission, is thought to be a primitive carbonaceous object. We report reflectance spectra of Ryugu's surface acquired with the Near-Infrared Spectrometer (NIRS3) on Hayabusa2, to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micrometers was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, which is consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.
RESUMO
The transition from quiescence to proliferation is a key regulatory step that can be induced by serum stimulation in cultured fibroblasts. The transcription factor Myc is directly induced by serum mitogens and drives a secondary gene expression program that remains largely unknown. Using mRNA profiling, we identify close to 300 Myc-dependent serum response (MDSR) genes, which are induced by serum in a Myc-dependent manner in mouse fibroblasts. Mapping of genomic Myc-binding sites by ChIP-seq technology revealed that most MDSR genes were directly targeted by Myc, but represented a minor fraction (5.5%) of all Myc-bound promoters (which were 22.4% of all promoters). Other target loci were either induced by serum in a Myc-independent manner, were not significantly regulated or were negatively regulated. MDSR gene products were involved in a variety of processes, including nucleotide biosynthesis, ribosome biogenesis, DNA replication and RNA control. Of the 29 MDSR genes targeted by RNA interference, three showed a requirement for cell-cycle entry upon serum stimulation and 11 for long-term proliferation and/or survival. Hence, proper coordination of key regulatory and biosynthetic pathways following mitogenic stimulation relies upon the concerted regulation of multiple Myc-dependent genes.
Assuntos
Mapeamento Cromossômico , Fibroblastos/metabolismo , Regulação da Expressão Gênica , Proteínas Proto-Oncogênicas c-myc/metabolismo , Soro/fisiologia , Animais , Linhagem Celular , CamundongosAssuntos
Carteolol/farmacologia , Propanolaminas/farmacologia , Anestésicos Locais , Animais , Cães , Feminino , Cobaias , Hemodinâmica/efeitos dos fármacos , Técnicas In Vitro , Masculino , Metabolismo/efeitos dos fármacos , Camundongos , Músculo Liso/efeitos dos fármacos , Gravidez , Rana esculenta , RatosRESUMO
Myc and transforming growth factor-beta (TGFbeta) signaling are mutually antagonistic, that is Myc suppresses the activation of TGFbeta-induced genes, whereas TGFbeta represses c-myc transcription. Here, we report a positive role for Myc in the TGFbeta response, consisting in the induction of an epithelial-to-mesenchymal transition (EMT) and the activation of the EMT-associated gene Snail. Knockdown of either Myc or the TGFbeta effectors SMAD3/4 in epithelial cells eliminated Snail induction by TGFbeta. Both Myc and SMAD complexes targeted the Snail promoter in vivo, DNA binding occurring in a mutually independent manner. Myc was bound prior to TGFbeta treatment, and was required for rapid Snail activation upon SMAD binding induced by TGFbeta. On the other hand, c-myc downregulation by TGFbeta was a slower event, occurring after Snail induction. The response of Snail to another cytokine, hepatocyte growth factor (HGF), also depended on Myc and SMAD4. Thus, contrary to their antagonistic effects on Cip1 and INK4b, Myc and SMADs cooperate in signal-dependent activation of Snail in epithelial cells. Although Myc also targeted the Snail promoter in serum-stimulated fibroblasts, it was dispensable for its activation in these conditions, further illustrating that the action of Myc in transcriptional regulation is context-dependent. Our findings suggest that Myc and TGFbeta signaling may cooperate in promoting EMT and metastasis in carcinomas.
Assuntos
Células Epiteliais/metabolismo , Mesoderma/metabolismo , Proteínas Proto-Oncogênicas c-myc/fisiologia , Fatores de Transcrição/genética , Fator de Crescimento Transformador beta/metabolismo , Animais , Células Cultivadas , Imunoprecipitação da Cromatina , Humanos , Immunoblotting , Glândulas Mamárias Animais/citologia , Glândulas Mamárias Animais/metabolismo , Mesoderma/citologia , Camundongos , RNA Interferente Pequeno/farmacologia , Proteína Smad2/antagonistas & inibidores , Proteína Smad2/genética , Proteína Smad2/metabolismo , Proteína Smad3/antagonistas & inibidores , Proteína Smad3/genética , Proteína Smad3/metabolismo , Proteína Smad4/antagonistas & inibidores , Proteína Smad4/genética , Proteína Smad4/metabolismo , Fatores de Transcrição da Família Snail , Fatores de Transcrição/metabolismo , Transcrição Gênica , Fator de Crescimento Transformador beta/genéticaRESUMO
Chronic treatment with various drugs reduced the increase in arterial blood pressure, the ventricular hypertrophy and the thickening of pulmonary arterial and arteriolar walls.
Assuntos
Pressão Sanguínea/efeitos dos fármacos , Cardiomegalia/induzido quimicamente , Hipertensão/fisiopatologia , Agonistas alfa-Adrenérgicos/farmacologia , Animais , Desoxicorticosterona , Diuréticos/farmacologia , Hipertensão/induzido quimicamente , Indoramina/farmacologia , Masculino , Metoprolol/farmacologia , Prazosina/farmacologia , Artéria Pulmonar/efeitos dos fármacos , Artéria Pulmonar/fisiopatologia , Ratos , Verapamil/farmacologiaRESUMO
A series of aliphatic and aromatic esters of 1,7,7-trimethyl-2-exo-piperidinobicyclo[2.2.1]heptan-3-endo-ol is described. A number of these compounds showed antiarrhythmic activity in guinea pigs and mice, as well as surface anesthesia in rabbits and infiltration anesthesia in mice. Circulatory, cardiac and respiratory effects in dogs are also described.
Assuntos
Anestésicos Locais/síntese química , Antiarrítmicos/síntese química , Canfanos/síntese química , Acetilcolina/antagonistas & inibidores , Animais , Pressão Sanguínea/efeitos dos fármacos , Canfanos/farmacologia , Fenômenos Químicos , Química , Frequência Cardíaca/efeitos dos fármacos , Antagonistas dos Receptores Histamínicos H1/síntese química , Camundongos , Coelhos , Respiração/efeitos dos fármacosRESUMO
Experimental research has shown that inosine in doses of 100-500 mg/kg has a protective effect with respect to various experimentally induced myocardiopathies.
Assuntos
Coração/efeitos dos fármacos , Inosina/farmacologia , Alanina Transaminase/análise , Animais , Aspartato Aminotransferases/análise , Columbidae , Creatina Quinase/análise , Eletrocardiografia , Emetina/farmacologia , Cobaias , Isoproterenol/farmacologia , L-Lactato Desidrogenase/análise , Masculino , Camundongos , Miocárdio/análise , Tamanho do Órgão/efeitos dos fármacos , Ratos , Tiroxina/farmacologiaRESUMO
A series of N,N-dialkyl 5-trans-carbamoyloxy-1,2,3,3-tetramethyl-2-azabicyclo [2,2,2]octanes was prepared by reaction of 1,2,3,3-tetramethyl-2-azabicyclo [2,2,2]octan-5-trans-ol with phosgene, followed by aminolysis of the resulting chlorocarbonate with aliphatic secondary amines. 5-Chloro-1,2,3,3-tetramethyl-2-azabicyclo [2,2,2] octane (cis/trans mixture) was isolated as by-product of the reaction. A number of urethanes showed antiarrhythmic activity in guinea pigs and mice, as well as surface anesthesia in rabbits and infiltration anesthesia in mice, superior or similar to lidocaine. The circulatory, cardiac and respiratory effects in dogs and hens are also described.
Assuntos
Antiarrítmicos/síntese química , Azocinas/síntese química , Anestésicos Locais , Animais , Azocinas/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Fenômenos Químicos , Química , Cães , Epinefrina/antagonistas & inibidores , Cobaias , Técnicas In Vitro , Camundongos , Contração Muscular/efeitos dos fármacos , Fluxo Sanguíneo Regional/efeitos dos fármacosRESUMO
In the dog, rat and chick, phosphocreatine-Na has not caused, from an experimental point of view, significative modifications of the cardiovascular- and respiratory-apparatus, of the reactivity of the cardio-regulator centers, of the baroreceptorial carotid-sinus and glomus reactivity, of the gangliar-, muscarinic-, histaminergic-, dopaminergic-, beta-adrenergic- and serotoninergic- vasomotor reactivity; only the vasomotor reactivity of a constrictive-type induced by epinephrine, nor-epinephrine, occlusion of the two common carotid arteries, hypertension and by BaCl2 is moderately reduced. It is interesting to note that the hypotensive response evoked by adenosine was augmented.