Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Sci Adv ; 10(2): eadj8099, 2024 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-38198555

RESUMO

People with blindness have limited access to the high-resolution graphical data and imagery of science. Here, a lithophane codex is reported. Its pages display tactile and optical readouts for universal visualization of data by persons with or without eyesight. Prototype codices illustrated microscopy of butterfly chitin-from N-acetylglucosamine monomer to fibril, scale, and whole insect-and were given to high schoolers from the Texas School for the Blind and Visually Impaired. Lithophane graphics of Fischer-Spier esterification reactions and electron micrographs of biological cells were also 3D-printed, along with x-ray structures of proteins (as millimeter-scale 3D models). Students with blindness could visualize (describe, recall, distinguish) these systems-for the first time-at the same resolution as sighted peers (average accuracy = 88%). Tactile visualization occurred alongside laboratory training, synthesis, and mentoring by chemists with blindness, resulting in increased student interest and sense of belonging in science.


Assuntos
Cegueira , Quitina , Humanos , Adolescente , Citoesqueleto , Elétrons , Laboratórios
2.
ACS Chem Neurosci ; 2023 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-37023050

RESUMO

The heterodimerization of wild-type (WT) Cu, Zn superoxide dismutase-1 (SOD1) and mutant SOD1 might be a critical step in the pathogenesis of SOD1-linked amyotrophic lateral sclerosis (ALS). Post-translational modifications that accelerate SOD1 heterodimerization remain unidentified. Here, we used capillary electrophoresis to quantify the effect of cysteine-111 oxidation on the rate and free energy of ALS mutant/WT SOD1 heterodimerization. The oxidation of Cys111-ß-SH to sulfinic and sulfonic acid (by hydrogen peroxide) increased rates of heterodimerization (with unoxidized protein) by ∼3-fold. Cysteine oxidation drove the equilibrium free energy of SOD1 heterodimerization by up to ΔΔG = -5.11 ± 0.36 kJ mol-1. Molecular dynamics simulations suggested that this enhanced heterodimerization, between oxidized homodimers and unoxidized homodimers, was promoted by electrostatic repulsion between the two "dueling" Cys111-SO2-/SO3-, which point toward one another in the homodimeric state. Together, these results suggest that oxidation of Cys-111 promotes subunit exchange between oxidized homodimers and unoxidized homodimers, regardless of whether they are mutant or WT dimers.

3.
J Biol Chem ; 298(12): 102610, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36265587

RESUMO

The heterodimerization of WT Cu, Zn superoxide dismutase-1 (SOD1), and mutant SOD1 might be a critical step in the pathogenesis of SOD1-linked amyotrophic lateral sclerosis (ALS). Rates and free energies of heterodimerization (ΔGHet) between WT and ALS-mutant SOD1 in mismatched metalation states-where one subunit is metalated and the other is not-have been difficult to obtain. Consequently, the hypothesis that under-metalated SOD1 might trigger misfolding of metalated SOD1 by "stealing" metal ions remains untested. This study used capillary zone electrophoresis and mass spectrometry to track heterodimerization and metal transfer between WT SOD1, ALS-variant SOD1 (E100K, E100G, D90A), and triply deamidated SOD1 (modeled with N26D/N131D/N139D substitutions). We determined that rates of subunit exchange between apo dimers and metalated dimers-expressed as time to reach 30% heterodimer-ranged from t30% = 67.75 ± 9.08 to 338.53 ± 26.95 min; free energies of heterodimerization ranged from ΔGHet = -1.21 ± 0.31 to -3.06 ± 0.12 kJ/mol. Rates and ΔGHet values of partially metalated heterodimers were more similar to those of fully metalated heterodimers than apo heterodimers, and largely independent of which subunit (mutant or WT) was metal-replete or metal-free. Mass spectrometry and capillary electrophoresis demonstrated that mutant or WT 4Zn-SOD1 could transfer up to two equivalents of Zn2+ to mutant or WT apo-SOD1 (at rates faster than the rate of heterodimerization). This result suggests that zinc-replete SOD1 can function as a chaperone to deliver Zn2+ to apo-SOD1, and that WT apo-SOD1 might increase the toxicity of mutant SOD1 by stealing its Zn2+.


Assuntos
Esclerose Amiotrófica Lateral , Humanos , Superóxido Dismutase-1/genética , Superóxido Dismutase-1/química , Esclerose Amiotrófica Lateral/genética , Superóxido Dismutase/genética , Superóxido Dismutase/química , Metais , Zinco/química , Mutação
4.
J Therm Spray Technol ; 31(1-2): 130-144, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-37520908

RESUMO

Antibacterial properties of copper against planktonic bacteria population are affected by surface microstructure and topography. However, copper interactions with bacteria in a biofilm state are less studied. This work aims at better understanding the difference in biofilm inhibition of bulk, cold-sprayed, and shot-peened copper surfaces and gaining further insights on the underlying mechanisms using optical and scanning electron microscopy to investigate the topography and microstructure of the surfaces. The biofilm inhibition ability is reported for all surfaces. Results show that the biofilm inhibition performance of cold sprayed copper, while initially better, decreases with time and results in an almost identical performance than as-received copper after 18h incubation time. The shot-peened samples with a rough and ultrafine microstructure demonstrated an enhanced biofilm control, especially at 18 hr. The biofilm control mechanisms were explained by the diffusion rates and concentration of copper ions and the interaction between these ions and the biofilm, while surface topography plays a role in the bacteria attachment at the early planktonic state. Furthermore, the data suggest that surface topography plays a key role in antiviral activity of the materials tested, with a smooth surface being the most efficient.

5.
Asian Cardiovasc Thorac Ann ; 22(3): 353-5, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24585918

RESUMO

Two cases of scimitar syndrome in children under one-year old are presented. Both were repaired through a right thoracotomy, off-pump, reimplanting the venous collector in the left atrium. Tips and advantages are discussed.


Assuntos
Procedimentos Cirúrgicos Cardíacos , Síndrome de Cimitarra/cirurgia , Toracotomia , Ponte Cardiopulmonar , Evolução Fatal , Humanos , Lactente , Veias Pulmonares/cirurgia , Reimplante , Síndrome de Cimitarra/complicações , Síndrome de Cimitarra/diagnóstico , Resultado do Tratamento , Veia Cava Inferior/cirurgia
6.
Rev. esp. cardiol. (Ed. impr.) ; 66(7): 553-555, jul. 2013.
Artigo em Espanhol | IBECS | ID: ibc-113635

RESUMO

Introducción y objetivos. Para la paliación inicial de pacientes con fisiología univentricular, discordancia ventriculoarterial y estenosis subaórtica, se utilizan diversas técnicas. La cirugía tipo Fontan depende de una correcta paliación inicial que evite la aparición de estenosis subaórtica (además de hipertrofia ventricular y disfunción diastólica). Métodos. Presentamos a 7 pacientes con fisiología univentricular, transposición y estenosis subaórtica, con bajo gasto sistémico e hiperaflujo pulmonar, de 21–383 (mediana, 75) días de edad y 3,4–9,6 (mediana, 4,2) kg de peso. Todos fueron tratados mediante switch arterial paliativo, «cambiando» su estenosis subaórtica por una estenosis subpulmonar. En 6 casos se asoció cirugía de arco aórtico; en 4, septectomía auricular y en 1, resección de membrana subaórtica. Resultados. Un paciente falleció en el postoperatorio; otro sufrió recoartación, tratada mediante angioplastia; 3 pacientes han alcanzado el estadio de Glenn y 2, el de Fontan. La función ventricular es correcta en todos ellos. Conclusiones. La fisiología de ventrículo único con transposición y estenosis subaórtica se puede tratar inicialmente mediante un switch paliativo. Esta compleja técnica inicial presenta buenos resultados y permite la progresión futura hacia Glenn y Fontan (AU)


Introduction and objectives. There are several techniques for the palliative treatment of patients with single-ventricle physiology, ventriculoarterial discordance and subaortic stenosis. The Fontan procedure relies on optimal initial palliation to avoid the development of subaortic stenosis (as well as ventricular hypertrophy and diastolic dysfunction). Methods. We present seven patients with single-ventricle physiology, transposition of the great arteries and subaortic stenosis, with low systemic output and high pulmonary flow, aged 21 to 383 days (median, 75) and weighing between 3.4 and 9.6 kg (median, 4.2). All were treated with a palliative arterial switch, thus “switching” their subaortic stenosis to subpulmonary stenosis. Six patients also underwent aortic arch surgery, 4 an atrial septectomy, and 1 a subaortic membrane resection. Results. One patient died after surgery, another developed recoarctation, which was treated with an angioplasty, 3 patients reached the Glenn stage and 2 the Fontan stage. All had good ventricular function. Conclusions. A palliative switch is an effective initial treatment for single-ventricle physiology with transposition of the great arteries and subaortic stenosis. This complex initial technique produces good results and allows the patient to progress to the Glenn or Fontan stage (AU)


Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Estenose Aórtica Subvalvar/complicações , Estenose Aórtica Subvalvar/diagnóstico , Ventrículos do Coração/fisiopatologia , Transtornos da Coagulação Sanguínea/complicações , Estenose Aórtica Subvalvar/prevenção & controle , Técnica de Fontan/métodos , Técnica de Fontan/tendências , Coagulação Intravascular Disseminada/epidemiologia , Complicações Pós-Operatórias/mortalidade , Complicações Pós-Operatórias/terapia
7.
Asian Cardiovasc Thorac Ann ; 21(6): 756-8, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24569348

RESUMO

Minimally invasive cardiac surgery is gaining wide acceptance. The midaxillary approach hides the incision under the right arm. Concerns may arise regarding functional recovery should the latissimus dorsi and serratus anterior muscles be affected by this maneuver. A modified technique that spares both muscles, without splitting their fibers, is described. Six patients have been operated on, with excellent functional and cosmetic results, and no side-effects.


Assuntos
Procedimentos Cirúrgicos Cardíacos/métodos , Comunicação Interatrial/cirurgia , Toracotomia , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Comunicação Interatrial/diagnóstico , Humanos , Posicionamento do Paciente , Complicações Pós-Operatórias/prevenção & controle , Recuperação de Função Fisiológica , Toracotomia/efeitos adversos , Fatores de Tempo , Resultado do Tratamento
8.
Rev Esp Cardiol (Engl Ed) ; 66(7): 553-5, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24776204

RESUMO

INTRODUCTION AND OBJECTIVES: There are several techniques for the palliative treatment of patients with single-ventricle physiology, ventriculoarterial discordance and subaortic stenosis. The Fontan procedure relies on optimal initial palliation to avoid the development of subaortic stenosis (as well as ventricular hypertrophy and diastolic dysfunction). METHODS: We present seven patients with single-ventricle physiology, transposition of the great arteries and subaortic stenosis, with low systemic output and high pulmonary flow, aged 21 to 383 days (median, 75) and weighing between 3.4 and 9.6kg (median, 4.2). All were treated with a palliative arterial switch, thus "switching" their subaortic stenosis to subpulmonary stenosis. Six patients also underwent aortic arch surgery, 4 an atrial septectomy, and 1 a subaortic membrane resection. RESULTS: One patient died after surgery, another developed recoarctation, which was treated with an angioplasty, 3 patients reached the Glenn stage and 2 the Fontan stage. All had good ventricular function. CONCLUSIONS: A palliative switch is an effective initial treatment for single-ventricle physiology with transposition of the great arteries and subaortic stenosis. This complex initial technique produces good results and allows the patient to progress to the Glenn or Fontan stage.


Assuntos
Estenose Aórtica Subvalvar/cirurgia , Técnica de Fontan/métodos , Cardiopatias Congênitas/cirurgia , Cuidados Paliativos/métodos , Feminino , Seguimentos , Técnica de Fontan/efeitos adversos , Humanos , Lactente , Recém-Nascido , Masculino
9.
Vaccine ; 30(10): 1782-9, 2012 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-22245603

RESUMO

Ticks are acaridae ectoparasites that, while taking a blood meal, can transmit viruses, bacteria, protozoa and filarial nematodes, which cause a variety of human and animal illnesses. The use of chemical pesticides constitutes the primary measure for control of these ectoparasites. However, the intensive use of these chemicals has drawbacks such as the contamination of food, environmental pollution and development of resistance by ectoparasites. Vaccination is considered a promising alternative for controlling infestations by ectoparasites. Although emerging tick proteins have been identified recently, and have been proposed as potential targets for generating protective molecules, only a limited number of them have been evaluated in vaccine trials. More than 80 proteins are found in eukaryotic ribosomes. The protein P0 is essential for the assembly of the 60S ribosomal subunit. We have identified an immunogenic region of the ribosomal protein P0 from Rhipicephalus sp. ticks that is not very conserved compared to host P0. The efficacy of a 20 amino acid synthetic peptide from this sequence was assayed as a vaccine antigen against Rhipicephalus sanguineus infestations in an immunization and challenge experiment on rabbits. A remarkable diminution in the viability of newly molted nymphs from larvae fed on vaccinated rabbits was observed. The number of adults and the number of eggs hatching were significantly reduced, with an overall efficacy of 90%. Our results demonstrated that immunization with an immunogenic peptide of tick protein P0 greatly reduced survival of ticks, suggesting that it has promise as an effective tick control agent.


Assuntos
Proteínas de Artrópodes/imunologia , Rhipicephalus sanguineus/imunologia , Infestações por Carrapato/veterinária , Vacinas/imunologia , Sequência de Aminoácidos , Animais , Feminino , Masculino , Dados de Sequência Molecular , Peptídeos/síntese química , Peptídeos/imunologia , Coelhos , Controle de Ácaros e Carrapatos/métodos , Infestações por Carrapato/prevenção & controle , Vacinas Sintéticas/imunologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...