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1.
J Neurosci ; 43(40): 6731-6744, 2023 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-37643860

RESUMO

Pain from bacterial infection was believed to be the consequence of inflammation induced by bacterial products. However recent studies have shown that bacterial products can directly activate sensory neurons and induce pain. The mechanisms by which bacteria induce pain are poorly understood, but toll-like receptor (TLR)4 and transient receptor potential A1 (TRPA1) receptors are likely important integrators of pain signaling induced by bacteria. Using male and female mice we show that sensory neuron activation by bacterial lipopolysaccharides (LPS) is mediated by both TRPA1 and TLR4 and involves the mobilization of extracellular and intracellular calcium. We also show that LPS induces neuronal sensitization in a process dependent on TLR4 receptors. Moreover, we show that TLR4 and TRPA1 are both involved in sensory neurons response to LPS stimulation. Activation of TLR4 in a subset of sensory neurons induces TRPA1 upregulation at the cell membrane through vesicular exocytosis, contributing to the initiation of neuronal sensitization and pain. Collectively these data highlight the importance of sensory neurons to pathogen detection, and their activation by bacterial products like LPS as potentially important to early immune and nociceptive responses.SIGNIFICANCE STATEMENT Bacterial infections are often painful and the recent discovery that bacteria can directly stimulate sensory neurons leading to pain sensation and modulation of immune system have highlighted the importance of nervous system in the response to bacterial infection. Here, we showed that lipopolysaccharide, a major bacterial by-product, requires both toll-like receptor (TLR)4 and transient receptor potential A1 (TRPA1) receptors for neuronal activation and acute spontaneous pain, but only TLR4 mediates sensory neurons sensitization. Moreover, we showed for the first time that TLR4 sensitize sensory neurons through a rapid upregulation of TRPA1 via vesicular exocytosis. Our data highlight the importance of sensory neurons to pathogen detection and suggests that TLR4 would be a potential therapeutic target to modulate early stage of bacteria-induced pain and immune response.


Assuntos
Infecções Bacterianas , Canais de Potencial de Receptor Transitório , Animais , Feminino , Masculino , Camundongos , Infecções Bacterianas/metabolismo , Lipopolissacarídeos/farmacologia , Dor/metabolismo , Células Receptoras Sensoriais/metabolismo , Receptor 4 Toll-Like/metabolismo , Canais de Potencial de Receptor Transitório/metabolismo , Canal de Cátion TRPA1 , Regulação para Cima
2.
J Virol ; 90(2): 904-16, 2016 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-26537673

RESUMO

UNLABELLED: HIV-1 infection leads to the progressive depletion of the CD4 T cell compartment by various known and unknown mechanisms. In vivo, HIV-1 infects both activated and resting CD4 T cells, but in vitro, in the absence of any stimuli, resting CD4 T cells from peripheral blood are resistant to infection. This resistance is generally attributed to an intracellular environment that does not efficiently support processes such as reverse transcription (RT), resulting in abortive infection. Here, we show that in vitro HIV-1 infection of resting CD4 T cells induces substantial cell death, leading to abortive infection. In vivo, however, various microenvironmental stimuli in lymphoid and mucosal tissues provide support for HIV-1 replication. For example, common gamma-chain cytokines (CGCC), such as interleukin-7 (IL-7), render resting CD4 T cells permissible to HIV-1 infection without inducing T cell activation. Here, we find that CGCC primarily allow productive infection by preventing HIV-1 triggering of apoptosis, as evidenced by early release of cytochrome c and caspase 3/7 activation. Cell death is triggered both by products of reverse transcription and by virion-borne Vpr protein, and CGCC block both mechanisms. When HIV-1 RT efficiency was enhanced by SIVmac239 Vpx protein, cell death was still observed, indicating that the speed of reverse transcription and the efficiency of its completion contributed little to HIV-1-induced cell death in this system. These results show that a major restriction on HIV-1 infection in resting CD4 T cells resides in the capacity of these cells to survive the early steps of HIV-1 infection. IMPORTANCE: A major consequence of HIV-1 infection is the destruction of CD4 T cells. Here, we show that delivery of virion-associated Vpr protein and the process of reverse transcription are each sufficient to trigger apoptosis of resting CD4 T cells isolated from peripheral blood. While these 2 mechanisms have been previously described in various cell types, we show for the first time their concerted effect in inducing resting CD4 T cell depletion. Importantly, we found that cytokines such as IL-7 and IL-4, which are particularly active in sites of HIV-1 replication, protect resting CD4 T cells from these cytopathic effects and, primarily through this protection, rather than through enhancement of specific replicative steps, they promote productive infection. This study provides important new insights for the understanding of the early steps of HIV-1 infection and T cell depletion.


Assuntos
Apoptose , Linfócitos T CD4-Positivos/virologia , Citocinas/metabolismo , Transcriptase Reversa do HIV/metabolismo , HIV-1/fisiologia , Transcrição Reversa , Produtos do Gene vpr do Vírus da Imunodeficiência Humana/metabolismo , Linfócitos T CD4-Positivos/fisiologia , Células Cultivadas , Humanos
3.
Chemistry ; 23(34): 8104-8117, 2017 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-28032925

RESUMO

Understanding the complex world of material growth and tunability has mystified the minds of material scientists and has been met with increasing efforts to close the gap between controllability and applicability. The reality of this journey is frustratingly tortuous but is being eased through better conceptual appreciation of metal crystalline frameworks that originate from shape and size dependent solvent responsive growth patterns. The quantum confinement of TiO2 in the range of 0.8-2 nm has been synthetically challenging to achieve but lessons from biomineralization processes have enabled alternative routes to be explored via self-induced pre-nucleation events. In driving this concept, we have incorporated many of these key features integrating aspects of low temperature annealing at the interface of complex heterogeneous nucleation between hard and soft materials to arrest the biomimetic amorphous phase of TiO2 to a tunable crystalline quantumized state. The stabilization of metastable states of quantum sized TiO2 driven by kinetic and thermodynamic processes show hallmarks of biomineralized controlled events that suggest the inter-play between new pathways and interfacial energies that preferentially favor low dimensionality at the quantum scale. This provides the potential to re-direct synthetic assemblies under tightly controlled parameters to generate a host of new materials with size, shape and anisotropic properties as smart stimuli responsive materials. These new stabilities leading to the growth arrest of TiO2 are discussed in terms of molecular interactions and structural frameworks that were previously inaccessible via conventional routes. There exists an undiscovered parallel between synthetic and biomineralized routes enabling unprecedented access to the availability and tunability of novel quantum confined materials. The parametrics of complex material design at the crossroads of synthetically and biologically driven processes is only now surfacing.

4.
Phys Chem Chem Phys ; 19(41): 28207-28215, 2017 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-29026899

RESUMO

Titanium dioxide (TiO2) with exposed (001) facets (TiO2(001)) has attractive photocatalytic properties. However, the high recombination rate of the photo-excited charge carriers on this surface often limits its application. Here, we report that a few-layered 1T-MoS2 coating on TiO2(001) nanosheets (abbreviated as MST) can be a promising candidate that overcomes some of the challenges of TiO2(001). Computational and experimental results demonstrate that MST as a photocatalyst exhibits a significantly low-charge recombination rate as well as excellent long-term durability. The synthesized MST 2D nanocomposites show a 31.9% increase in photocatalytic activity for hydrogen (H2) production relative to the counterpart TiO2(001). MST offers a new route for further improvement of the photocatalytic activity of TiO2 with exposed high energy facets.

5.
Retrovirology ; 13: 1, 2016 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-26728316

RESUMO

BACKGROUND: HIV-1 integration is prone to a high rate of failure, resulting in the accumulation of unintegrated viral genomes (uDNA) in vivo and in vitro. uDNA can be transcriptionally active, and circularized uDNA genomes are biochemically stable in non-proliferating cells. Resting, non-proliferating CD4 T cells are prime targets of HIV-1 infection and latently infected resting CD4 T cells are the major barrier to HIV cure. Our prior studies demonstrated that uDNA generates infectious virions when T cell activation follows rather than precedes infection. RESULTS: Here, we characterize in primary resting CD4 T cells the dynamics of integrated and unintegrated virus expression, genome persistence and sensitivity to latency reversing agents. Unintegrated HIV-1 was abundant in directly infected resting CD4 T cells. Maximal gene expression from uDNA was delayed compared with integrated HIV-1 and was less toxic, resulting in uDNA enrichment over time relative to integrated proviruses. Inhibiting integration with raltegravir shunted the generation of durable latency from integrated to unintegrated genomes. Latent uDNA was activated to de novo virus production by latency reversing agents that also activated latent integrated proviruses, including PKC activators, histone deacetylase inhibitors and P-TEFb agonists. However, uDNA responses displayed a wider dynamic range, indicating differential regulation of expression relative to integrated proviruses. Similar to what has recently been demonstrated for latent integrated proviruses, one or two applications of latency reversing agents failed to activate all latent unintegrated genomes. Unlike integrated proviruses, uDNA gene expression did not down modulate expression of HLA Class I on resting CD4 T cells. uDNA did, however, efficiently prime infected cells for killing by HIV-1-specific cytotoxic T cells. CONCLUSIONS: These studies demonstrate that contributions by unintegrated genomes to HIV-1 gene expression, virus production, latency and immune responses are inherent properties of the direct infection of resting CD4 T cells. Experimental models of HIV-1 latency employing directly infected resting CD4 T cells should calibrate the contribution of unintegrated HIV-1.


Assuntos
Linfócitos T CD4-Positivos/virologia , HIV-1/fisiologia , Latência Viral , Replicação Viral , Adulto , Células Cultivadas , DNA Viral/metabolismo , Perfilação da Expressão Gênica , Humanos , Transcrição Gênica
6.
Dalton Trans ; 52(36): 12832-12844, 2023 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-37622345

RESUMO

Green energy production is becoming increasingly important in mitigating the effects of climate change, and the photocatalytic approach could be a potential solution. However, the main barriers to its commercialization are ineffective catalysis due to recombination, poor optical absorption, and sluggish carrier migration. Here, we fabricated a two-dimensional (2D) reduced niobium oxide photocatalyst synthesized by an in situ thermal method followed by copper incorporation. Compared to its counterparts, pure Nb2O5 (0.092 mmol g-1 CO) and r-Nb2O5 (0.216 mmol g-1 CO), the strongly bonded Cu/r-Nb2O5 (0.908 mmol g-1) sample produced an exceptional amount of CO. The separation of charge carriers and efficient use of light resulted in a remarkable photocatalytic performance. The acceptor levels were created by the Cu nanophase, and the carrier trapping states were created by the oxygen vacancies. This mechanism was supported by ESR and DRIFT analyses, which showed that enough free radicals were produced. This study opens up new possibilities for developing efficient photocatalysts that will generate green fuel.

8.
Elife ; 102021 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-33884953

RESUMO

Learning about temporal structure is adaptive because it enables the generation of expectations. We examined how the brain uses experience in structured environments to anticipate upcoming events. During fMRI (functional magnetic resonance imaging), individuals watched a 90 s movie clip six times. Using a hidden Markov model applied to searchlights across the whole brain, we identified temporal shifts between activity patterns evoked by the first vs. repeated viewings of the movie clip. In many regions throughout the cortex, neural activity patterns for repeated viewings shifted to precede those of initial viewing by up to 15 s. This anticipation varied hierarchically in a posterior (less anticipation) to anterior (more anticipation) fashion. We also identified specific regions in which the timing of the brain's event boundaries was related to those of human-labeled event boundaries, with the timing of this relationship shifting on repeated viewings. With repeated viewing, the brain's event boundaries came to precede human-annotated boundaries by 1-4 s on average. Together, these results demonstrate a hierarchy of anticipatory signals in the human brain and link them to subjective experiences of events.


Anticipating future events is essential. It allows individuals to plan and prepare what they will do seconds, minutes, or hours in the future. But how the brain can predict future events in both the short-term and long-term is not yet clear. Researchers know that the brain processes images or other sensory information in stages. For example, visual features are processed from lines to shapes to objects, and eventually scenes. This staged approach allows the brain to create representations of many parts of the world simultaneously. A similar hierarchy may be at play in anticipation. Different parts of the brain may track what is happening now, and what could happen in the next few seconds and minutes. This would provide a way for the brain to forecast upcoming events in the immediate, near, and more distant future at the same time. Now, Lee et al. show that the regions in the back of the brain anticipate the immediate future, while longer-term predictions are made in brain regions near the front. In the experiments, study participants watched a 90-second clip of the movie 'The Grand Budapest Hotel' six times while undergoing functional magnetic resonance imaging (fMRI). Then, Lee et al. used computer modeling to compare the brain activity captured by fMRI during successive viewings. This allowed the researchers to watch participants' brain activity moment-by-moment. As the participants repeatedly watched the movie clip, their brains began to anticipate what was coming next. Regions near the back of the brain like the visual cortex anticipated events in the next 1 to 4 seconds. Areas in the middle of the brain anticipated 5 to 8 seconds in the future. The front of brain anticipated 8 to 15 seconds into the future. Lee et al. show that many parts of the brain work together to predict the near and more distant future. More research is needed to understand how this information translates into actions. Learning more may help scientists understand how diseases or injuries affect people's ability to plan and respond to future events.


Assuntos
Antecipação Psicológica , Encéfalo/fisiologia , Aprendizagem , Percepção do Tempo , Percepção Visual , Adaptação Psicológica , Adulto , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Cadeias de Markov , Modelos Neurológicos , Vias Neurais/fisiologia , Reconhecimento Automatizado de Padrão , Estimulação Luminosa , Fatores de Tempo , Adulto Jovem
9.
Artigo em Inglês | MEDLINE | ID: mdl-31627456

RESUMO

In many low income developing countries, socioeconomic, environmental and demographic factors have been linked to around half of the disease related deaths that occur each year. The aim of this study is to investigate the sociodemographic factors, mother and child health status, water, sanitation, and hygienic conditions of a Nepalese community residing in a hilly rural village, and to identify factors associated with mother and child health status and the occurrence of diarrheal and febrile disease. A community-based cross-sectional survey was carried out and 315 households from the village of Narjamandap were included in this study. Factors associated with diarrhea, febrile disease, and full maternal and under-five immunizations were assessed using logistic regression. Results showed that higher education level (middle school versus primary education; Odds Ratio (OR): 0.55, p = 0.04; high school versus primary education; OR 0.21, p = 0.001) and having a toilet facility at home were significantly associated with a lower risk of developing diarrhea and febrile disease (OR 0.49, p = 0.01), while, interestingly, the use of improved water supply was associated with higher risk (OR 3.07, p = 0.005). In terms of maternal immunization, the odds of receiving a tetanus toxoid vaccination were higher in women who had regular antenatal checkups (OR 12.9, p < 0.001), and in those who developed complications during pregnancy (OR 4.54, p = 0.04); for under-five immunization, the odds of receiving full vaccination were higher among children from households that reported diarrhea (OR 2.76, p < 0.001). The findings of this study indicated that gaps still exist in the mother and child healthcare being provided, in terms of receiving antenatal checkups and basic immunizations, as evidenced by irregular antenatal checkups, incomplete and zero vaccination cases, and higher under-five deaths. Specific public health interventions to promote maternal health and the health of under-five children are suggested.


Assuntos
Saúde da Criança , Nível de Saúde , Higiene , Mães , Saneamento/métodos , Adulto , Criança , Pré-Escolar , Estudos Transversais , Países em Desenvolvimento , Diarreia/epidemiologia , Feminino , Humanos , Imunização/efeitos adversos , Modelos Logísticos , Nepal/epidemiologia , Razão de Chances , Pobreza , Gravidez , Saúde Pública , População Rural , Banheiros , Água , Abastecimento de Água
10.
Sci Rep ; 8(1): 13198, 2018 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-30181551

RESUMO

Sensory neurons innervating the dental pulp have unique morphological and functional characteristics compared to neurons innervating other tissues. Stimulation of dental pulp afferents whatever the modality or intensity of the stimulus, even light mechanical stimulation that would not activate nociceptors in other tissues, produces an intense pain. These specific sensory characteristics could involve receptors of the Transient Receptor Potential channels (TRP) family. In this study, we compared the expression of the cold sensitive receptors TRPM8 and TRPA1 in trigeminal ganglion neurons innervating the dental pulp, the skin of the cheek or the buccal mucosa and we evaluated the involvement of these receptors in dental pulp sensitivity to cold. We showed a similar expression of TRPM8, TRPA1 and CGRP in sensory neurons innervating the dental pulp, the skin or the mucosa. Moreover, we demonstrated that noxious cold stimulation of the tooth induced an overexpression of cFos in the trigeminal nucleus that was not prevented by the genetic deletion of TRPM8 or the administration of the TRPA1 antagonist HC030031. These data suggest that the unique sensory characteristics of the dental pulp are independent to TRPM8 and TRPA1 receptors expression and functionality.


Assuntos
Polpa Dentária/inervação , Células Receptoras Sensoriais/metabolismo , Canal de Cátion TRPA1/metabolismo , Canais de Cátion TRPM/metabolismo , Sensação Térmica , Gânglio Trigeminal/citologia , Animais , Células Cultivadas , Temperatura Baixa , Feminino , Masculino , Camundongos Endogâmicos C57BL , Células Receptoras Sensoriais/citologia , Pele/inervação , Canal de Cátion TRPA1/análise , Canais de Cátion TRPM/análise , Gânglio Trigeminal/metabolismo
11.
Sci Rep ; 6: 31147, 2016 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-27498979

RESUMO

A one-dimensional (1D) nanostructure having a porous network is an exceptional photocatalytic material to generate hydrogen (H2) and decontaminate wastewater using solar energy. In this report, we synthesized nanoporous 1D microrods of graphitic carbon nitride (g-C3N4) via a facile and template-free chemical approach at room temperature. The use of concentrated acids induced etching and lift-off because of strong oxidation and protonation. Compared with the bulk g-C3N4, the porous 1D microrod structure showed five times higher photocatalytic degradation performance toward methylene blue dye (MB) under visible light irradiation. The photocatalytic H2 evolution of the 1D nanostructure (34 µmol g(-1)) was almost 26 times higher than that of the bulk g-C3N4 structure (1.26 µmol g(-1)). Additionally, the photocurrent stability of this nanoporous 1D morphology over 24 h indicated remarkable photocorrosion resistance. The improved photocatalytic activities were attributed to prolonged carrier lifetime because of its quantum confinement effect, effective separation and transport of charge carriers, and increased number of active sites from interconnected nanopores throughout the microrods. The present 1D nanostructure would be highly suited for photocatalytic water purification as well as water splitting devices. Finally, this facile and room temperature strategy to fabricate the nanostructures is very cost-effective.

12.
J Nanosci Nanotechnol ; 14(12): 8915-9, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25970981

RESUMO

Since direct printing technology has developed intensively, low-cost fabrication and reliability have become critical challenges for mass production of printed electronic devices. The silver/copper (Ag/Cu) nanopaste was manufactured by Ag nanopaste mixed with different proportions of Cu nanoparticles ranging from 0 to 5 vol.% in order to investigate the influences of Cu content on the electrical properties and electrochemical migration (ECM) characteristics. The patterns were constructed on a glass wafer via screen printing with the Ag/Cu nanopaste. They were then annealed through debinding for 30 min in air followed by sintering for 30 min in a hydrogen atmosphere at various temperatures (150, 200, 250, and 300 degrees C). The electrical resistivity of printed patterns that were sintered at 150 degrees C grew with increases in the percentage of Cu content in the Ag/Cu nanopaste, while printed patterns that were sintered at 300 degrees C show similar electrical resistivity values of around 2-3 µΩ cm regardless of Cu content. The ECM characteristics of the printed patterns were evaluated by performing a water drop test. The printed patterns that were sintered at higher temperatures showed longer ECM times. At 300 degrees C, the ECM time was considerably lengthened when the Cu content was over 2 vol.%, and the 5 vol.% Cu pattern showed the longest ECM time of 305 s, which was around 1.65 times that of the Ag pattern.

13.
PLoS One ; 9(10): e110719, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25330112

RESUMO

HIV-1 hijacks and disrupts many processes in the cells it infects in order to suppress antiviral immunity and to facilitate its replication. Resting CD4 T cells are important early targets of HIV-1 infection in which HIV-1 must overcome intrinsic barriers to viral replication. Although resting CD4 T cells are refractory to infection in vitro, local environmental factors within lymphoid and mucosal tissues such as cytokines facilitate viral replication while maintaining the resting state. These factors can be utilized in vitro to study HIV-1 replication in resting CD4 T cells. In vivo, the migration of resting naïve and central memory T cells into lymphoid tissues is dependent upon expression of CD62L (L-selectin), a receptor that is subsequently down-modulated following T cell activation. CD62L gene transcription is maintained in resting T cells by Foxo1 and KLF2, transcription factors that maintain T cell quiescence and which regulate additional cellular processes including survival, migration, and differentiation. Here we report that HIV-1 down-modulates CD62L in productively infected naïve and memory resting CD4 T cells while suppressing Foxo1 activity and the expression of KLF2 mRNA. Partial T cell activation was further evident as an increase in CD69 expression. Several other Foxo1- and KLF2-regulated mRNA were increased or decreased in productively infected CD4 T cells, including IL-7rα, Myc, CCR5, Fam65b, S1P1 (EDG1), CD52, Cyclin D2 and p21CIP1, indicating a profound reprogramming of these cells. The Foxo1 inhibitor AS1842856 accelerated de novo viral gene expression and the sequella of infection, supporting the notion that HIV-1 suppression of Foxo1 activity may be a strategy to promote replication in resting CD4 T cells. As Foxo1 is an investigative cancer therapy target, the development of Foxo1 interventions may assist the quest to specifically suppress or activate HIV-1 replication in vivo.


Assuntos
Fatores de Transcrição Forkhead/biossíntese , Infecções por HIV/genética , Fatores de Transcrição Kruppel-Like/biossíntese , Selectina L/biossíntese , Ativação Linfocitária/genética , Linfócitos T CD4-Positivos/imunologia , Proteína Forkhead Box O1 , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/imunologia , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/imunologia , Infecções por HIV/imunologia , Infecções por HIV/patologia , Infecções por HIV/virologia , HIV-1/genética , HIV-1/patogenicidade , Humanos , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/imunologia , Selectina L/imunologia , Ativação Linfocitária/imunologia , Tecido Linfoide/imunologia , Quinolonas/administração & dosagem , Receptores de Interleucina-7/biossíntese , Receptores de Interleucina-7/imunologia , Replicação Viral/efeitos dos fármacos , Replicação Viral/genética , Replicação Viral/imunologia
14.
J Aging Soc Policy ; 19(2): 107-24, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17409049

RESUMO

In response to increased consumer demand, state governments are publishing more detailed information about the quality of nursing homes. In 2002, Ohio legislation mandated the publication of a Long-Term Care Consumer Guide that included information on nursing home resident and family satisfaction surveys. Using the 2002 Ohio Nursing Home Resident Satisfaction Survey as an example, this article addresses two research questions: (1) how can statewide resident face-to-face satisfaction interviews be implemented to maximize participation of residents and facilities and produce reliable and valid results, and (2) how satisfied are residents with their nursing home experiences, overall and by level of cognitive function.


Assuntos
Comportamento do Consumidor , Coleta de Dados/métodos , Entrevistas como Assunto , Casas de Saúde/legislação & jurisprudência , Qualidade da Assistência à Saúde , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Ohio
15.
Head Neck ; 27(5): 362-9, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15818558

RESUMO

BACKGROUND: Hyperbaric oxygen (HBO2) is used to promote healing in irradiated tissues, but concern persists about the possibility that it may promote residual tumor growth. METHODS: The tumor growth of SQ20B and Detroit 562 head and neck squamous cell carcinoma xenografts were studied after single-dose irradiation and 5x/week HBO2 treatment at 2.4 atm absolute for 90 minutes. The effect of HBO2 treatment on tumor hypoxia and vasculature was also examined by immunohistochemical analysis. RESULTS: HBO2 treatment increased tumor oxygenation during the treatment interval but did not promote the growth of either irradiated or unirradiated tumors. No increase in tumor vascular endothelial growth factor expression or vascularization was detected. CONCLUSIONS: This study found no evidence for persistent changes in tumor microenvironment or tumor growth promotion caused by hyperbaric oxygen exposure.


Assuntos
Carcinoma de Células Escamosas/irrigação sanguínea , Carcinoma de Células Escamosas/metabolismo , Neoplasias de Cabeça e Pescoço/irrigação sanguínea , Neoplasias de Cabeça e Pescoço/metabolismo , Oxigenoterapia Hiperbárica , Animais , Carcinoma de Células Escamosas/patologia , Hipóxia Celular , Relação Dose-Resposta à Radiação , Neoplasias de Cabeça e Pescoço/patologia , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Nus , Neoplasias Experimentais , Neovascularização Patológica , Transplante Heterólogo , Fator A de Crescimento do Endotélio Vascular/metabolismo
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