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OBJECTIVES: Topical drug administration is commonly applied to control oral inflammation. However, it requires sufficient drug adherence and a high degree of bioavailability. Here, we tested the hypothesis whether an ester-based core-multishell (CMS) nanocarrier is a suitable nontoxic drug-delivery system that penetrates efficiently to oral mucosal tissues, and thereby, increase the bioavailability of topically applied drugs. MATERIAL AND METHODS: To evaluate adhesion and penetration, the fluorescence-labeled CMS 10-E-15-350 nanocarrier was applied to ex vivo porcine masticatory and lining mucosa in a Franz cell diffusion assay and to an in vitro 3D model. In gingival epithelial cells, potential cytotoxicity and proliferative effects of the nanocarrier were determined by MTT and sulphorhodamine B assays, respectively. Transepithelial electrical resistance (TEER) was measured in presence and absence of CMS 10-E-15-350 using an Endohm-12 chamber and a volt-ohm-meter. Cellular nanocarrier uptake was analyzed by laser scanning microscopy. Inflammatory responses were determined by monitoring pro-inflammatory cytokines using real-time PCR and ELISA. RESULTS: CMS nanocarrier adhered to mucosal tissues within 5 min in an in vitro model and in ex vivo porcine tissues. The CMS nanocarrier exhibited no cytotoxic effects and induced no inflammatory responses. Furthermore, the physical barrier expressed by the TEER remained unaffected by the nanocarrier. CONCLUSIONS: CMS 10-E-15-350 adhered to the oral mucosa and adhesion increased over time which is a prerequisite for an efficient drug release. Since TEER is unaffected, CMS nanocarrier may enter the oral mucosa transcellularly. CLINICAL RELEVANCE: Nanocarrier technology is a novel and innovative approach for efficient topical drug delivery at the oral mucosa.
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Nanopartículas , Absorção Cutânea , Administração Cutânea , Animais , Portadores de Fármacos/metabolismo , Ésteres/metabolismo , Mucosa Bucal , Pele , SuínosRESUMO
Background: The German multicenter randomized phase II larynx organ preservation (LOP) trial DeLOS-II was carried out to prove the hypothesis that cetuximab (E) added to induction chemotherapy (IC) and radiotherapy improves laryngectomy-free survival (LFS; survival with preserved larynx) in locally advanced laryngeal/hypopharyngeal cancer (LHSCC). Patients and methods: Treatment-naïve patients with stage III/IV LHSCC amenable to total laryngectomy (TL) were randomized to three cycles IC with TPF [docetaxel (T) and cisplatin (P) 75 mg/m2/day 1, 5-FU (F) 750 mg/m2/day days 1-5] followed by radiotherapy (69.6 Gy) without (A) or with (B) standard dose cetuximab for 16 weeks throughout IC and radiotherapy (TPFE). Response to first IC-cycle (IC-1) with ≥30% endoscopically estimated tumor surface shrinkage (ETSS) was used to define early responders; early salvage TL was recommended to non-responders. The primary objective was 24 months LFS above 35% in arm B. Results: Of 180 patients randomized (July 2007 to September 2012), 173 fulfilled eligibility criteria (A/B: larynx 44/42, hypopharynx 41/46). Because of 4 therapy-related deaths among the first 64 randomized patients, 5-FU was omitted from IC in the subsequent 112 patients reducing further fatal toxicities. Thus, IC was TPF in 61 patients and TP in 112 patients, respectively. The primary objective (24 months LFS above 35%) was equally met by arms A (40/85, 47.1%) as well as B (41/88, 46.6%). One hundred and twenty-three early responders completed IC+RT; their overall response rates (TPF/TP) were 94.7%/87.2% in A versus 80%/86.0% in B. The 24 months overall survival (OS) rates were 68.2% and 69.3%. Conclusions: Despite being accompanied by an elevated frequency in adverse events, the IC with TPF/TP plus cetuximab was feasible but showed no superiority to IC with TPF/TP regarding LFS and OS at 24 months. Both early response and 24 months LFS compare very well to previous LOP trials and recommend effective treatment selection and stratification by ETSS. Clinical trial information: NCT00508664.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Quimiorradioterapia/mortalidade , Neoplasias Hipofaríngeas/terapia , Neoplasias Laríngeas/terapia , Laringectomia/mortalidade , Radioterapia/mortalidade , Terapia de Salvação , Adulto , Idoso , Cetuximab/administração & dosagem , Cisplatino/administração & dosagem , Terapia Combinada , Docetaxel/administração & dosagem , Feminino , Fluoruracila/administração & dosagem , Seguimentos , Humanos , Neoplasias Hipofaríngeas/patologia , Quimioterapia de Indução , Neoplasias Laríngeas/patologia , Masculino , Pessoa de Meia-Idade , Tratamentos com Preservação do Órgão , Prognóstico , Taxa de SobrevidaRESUMO
Brachial plexus lesions mostly occur in young patients as a result of high-speed accidents. They are often diagnosed and treated after a delay. This has been shown to worsen the prognosis of surgical reconstructions evidently. In 70-80% of traumatic lesions functional reinnervation can be achieved by various surgical procedures. An early sufficient diagnosis and the subsequent referral of the patient to an appropriate competence center for consultation and, if necessary, surgery are therefore essential.
Assuntos
Plexo Braquial/lesões , Plexo Braquial/cirurgia , Humanos , Procedimentos Neurocirúrgicos , Prognóstico , Procedimentos de Cirurgia PlásticaRESUMO
Aldehyde dehydrogenase 5a1-deficient (aldh5a1-/-) mice, the murine orthologue of human succinic semialdehyde dehydrogenase deficiency (SSADHD), manifest increased GABA (4-aminobutyric acid) that disrupts autophagy, increases mitochondria number, and induces oxidative stress, all mitigated with the mTOR (mechanistic target of rapamycin) inhibitor rapamycin [1]. Because GABA regulates mTOR, we tested the hypothesis that aldh5a1-/- mice would show altered levels of mRNA for genes associated with mTOR signaling and oxidative stress that could be mitigated by inhibiting mTOR. We observed that multiple metabolites associated with GABA metabolism (γ-hydroxybutyrate, succinic semialdehyde, D-2-hydroxyglutarate, 4,5-dihydrohexanoate) and oxidative stress were significantly increased in multiple tissues derived from aldh5a1-/- mice. These metabolic perturbations were associated with decreased levels of reduced glutathione (GSH) in brain and liver of aldh5a1-/- mice, as well as increased levels of adducts of the lipid peroxidation by-product, 4-hydroxy-2-nonenal (4-HNE). Decreased liver mRNA levels for multiple genes associated with mTOR signaling and oxidative stress parameters were detected in aldh5a1-/- mice, and several were significantly improved with the administration of mTOR inhibitors (Torin 1/Torin 2). Western blot analysis of selected proteins corresponding to oxidative stress transcripts (glutathione transferase, superoxide dismutase, peroxiredoxin 1) confirmed gene expression findings. Our data provide additional preclinical evidence for the potential therapeutic efficacy of mTOR inhibitors in SSADHD.
Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/tratamento farmacológico , Erros Inatos do Metabolismo dos Aminoácidos/metabolismo , Deficiências do Desenvolvimento/tratamento farmacológico , Deficiências do Desenvolvimento/metabolismo , Deleção de Genes , Succinato-Semialdeído Desidrogenase/deficiência , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/metabolismo , Ácido gama-Aminobutírico/metabolismo , Erros Inatos do Metabolismo dos Aminoácidos/genética , Animais , Deficiências do Desenvolvimento/genética , Modelos Animais de Doenças , Feminino , Glutationa/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Naftiridinas/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Succinato-Semialdeído Desidrogenase/genética , Succinato-Semialdeído Desidrogenase/metabolismo , Transcriptoma/efeitos dos fármacosRESUMO
We hypothesized that blood levels of γ-aminobutyric acid (GABA) and γ-hydroxybutyric acid (GHB), biomarkers of succinic semialdehyde dehydrogenase deficiency (SSADHD), would correlate with age. GABA and GHB were quantified in plasma and red blood cells (RBCs) from 18 patients (age range 5-41 years; median 8). Both metabolites negatively correlated with age (P < 0.05). Plasma and RBC GHB declined with age, reaching a nadir and approximate steady state by 10 years. Declining plasma GABA achieved this approximate steady state at 30-40 years of age. These biomarker relationships may reflect further GABA- and GHB-ergic neurotransmission imbalances that correlate with the onset of adolescent/adulthood neuropsychiatric morbidity and epilepsy in SSADHD.
Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/sangue , Erros Inatos do Metabolismo dos Aminoácidos/metabolismo , Biomarcadores/sangue , Deficiências do Desenvolvimento/sangue , Deficiências do Desenvolvimento/metabolismo , Succinato-Semialdeído Desidrogenase/deficiência , Ácido gama-Aminobutírico/metabolismo , Adolescente , Adulto , Criança , Pré-Escolar , Epilepsia/sangue , Epilepsia/metabolismo , Feminino , Humanos , Hidroxibutiratos/metabolismo , Masculino , Succinato-Semialdeído Desidrogenase/sangue , Succinato-Semialdeído Desidrogenase/metabolismo , Transmissão Sináptica/fisiologia , Adulto JovemRESUMO
BACKGROUND: Investigation of conformational changes in a protein is a prerequisite to understand its biological function. To explore these conformational changes in proteins we developed a strategy with the combination of molecular dynamics (MD) simulations and electron paramagnetic resonance (EPR) spectroscopy. The major goal of this work is to investigate how far computer simulations can meet the experiments. METHODS: Vinculin tail protein is chosen as a model system as conformational changes within the vinculin protein are believed to be important for its biological function at the sites of cell adhesion. MD simulations were performed on vinculin tail protein both in water and in vacuo environments. EPR experimental data is compared with those of the simulated data for corresponding spin label positions. RESULTS: The calculated EPR spectra from MD simulations trajectories of selected spin labelled positions are comparable to experimental EPR spectra. The results show that the information contained in the spin label mobility provides a powerful means of mapping protein folds and their conformational changes. CONCLUSIONS: The results suggest the localization of dynamic and flexible regions of the vinculin tail protein. This study shows MD simulations can be used as a complementary tool to interpret experimental EPR data.
Assuntos
Simulação por Computador , Espectroscopia de Ressonância de Spin Eletrônica , Simulação de Dinâmica Molecular , Vinculina/química , Conformação Proteica , Marcadores de SpinRESUMO
Gammaretroviral vectors are an efficient means to effect gene therapy. However, genotoxicity from insertion at nonrandom sites can confer a competitive advantage to transduced cells, resulting in clonal proliferation or neoplasia. Six pig-tailed macaques (Macaca nemestrina) underwent total body irradiation and reconstitution with autologous stem cells genetically modified by a gammaretroviral vector overexpressing HOXB4. Two animals were euthanized owing to irradiation- or transplantation-associated toxicity, whereas the other 4 had successful reconstitution. Of the 4 macaques with successful reconstitution, 1 has no long-term follow-up information; 1 was euthanized owing to infection with simian varicella virus infection 18 months post-total body irradiation; and the 2 others are described herein as case Nos. 1 and 2. After being stable for 3 years, case No. 1 developed pancytopenia and petechiation, and after 2 years of stability case No. 2 developed anemia and thrombocytopenia. Despite therapy, the animals deteriorated and were euthanized. Gross findings included emaciation; case No. 1 also had hemorrhage, peritonitis, and cholecystitis. Histologically, bone marrow was hypercellular with predominately blast cells of all hematopoietic lineages, though with myeloid predominance, and with maturation arrest and blast cell dysplasia (myelodysplasia). Myelodysplasia was likely from a combination of insertional mutagenesis by the retroviral vector and overexpression of HOXB4. Consequences of myelodysplasia included the blood dyscrasias and, in case No. 1, hemorrhage, bacterial cholecystitis, hepatitis, and peritonitis.
Assuntos
Proteínas de Homeodomínio/genética , Macaca nemestrina , Doenças dos Macacos/patologia , Síndromes Mielodisplásicas/veterinária , Fatores de Transcrição/genética , Animais , Evolução Fatal , Terapia Genética/efeitos adversos , Terapia Genética/métodos , Terapia Genética/veterinária , Vetores Genéticos , Masculino , Doenças dos Macacos/genética , Mutagênese Insercional/métodos , Síndromes Mielodisplásicas/genética , Síndromes Mielodisplásicas/patologiaRESUMO
Perennial herbaceous plants such as switchgrass (Panicum virgatum L.) are being evaluated as cellulosic bioenergy crops. Two major concerns have been the net energy efficiency and economic feasibility of switchgrass and similar crops. All previous energy analyses have been based on data from research plots (<5 m2) and estimated inputs. We managed switchgrass as a biomass energy crop in field trials of 3-9 ha (1 ha = 10,000 m2) on marginal cropland on 10 farms across a wide precipitation and temperature gradient in the midcontinental U.S. to determine net energy and economic costs based on known farm inputs and harvested yields. In this report, we summarize the agricultural energy input costs, biomass yield, estimated ethanol output, greenhouse gas emissions, and net energy results. Annual biomass yields of established fields averaged 5.2-11.1 Mg x ha(-1) with a resulting average estimated net energy yield (NEY) of 60 GJ x ha(-1) x y(-1). Switchgrass produced 540% more renewable than nonrenewable energy consumed. Switchgrass monocultures managed for high yield produced 93% more biomass yield and an equivalent estimated NEY than previous estimates from human-made prairies that received low agricultural inputs. Estimated average greenhouse gas (GHG) emissions from cellulosic ethanol derived from switchgrass were 94% lower than estimated GHG from gasoline. This is a baseline study that represents the genetic material and agronomic technology available for switchgrass production in 2000 and 2001, when the fields were planted. Improved genetics and agronomics may further enhance energy sustainability and biofuel yield of switchgrass.
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Etanol/química , Panicum/química , Agricultura/métodos , Poluentes Atmosféricos , Biomassa , Celulose/química , Conservação de Recursos Energéticos , Conservação dos Recursos Naturais , Produtos Agrícolas , Fontes Geradoras de Energia , Meio Ambiente , Gasolina , Geografia , Efeito Estufa , Meio-Oeste dos Estados UnidosRESUMO
OBJECTIVE: Illustration of a nowadays only rarely performed operative procedure for the treatment of osteonecrosis of the femoral head to prevent or at least delay advanced arthrosis and the need for a total hip replacement. The pedicled vascularized iliac bone graft is raised without the need for special microsurgical techniques and has less vascular complications often seen in free vascularized grafts. INDICATIONS: Early stages of osteonecrosis of the femoral head stages II and III according to the Association Research Circulation Osseous (ARCO) up to the detection of fracture lines (crescent sign) but without mechanical insufficiency. CONTRAINDICATIONS: Osteonecrosis of the femoral head with collapse of the femoral head (ARCO stage ≥IIIB) and mechanical insufficiency. Patients who are noncompliant or a not able to take the weight off the operated leg. Patients who had radiotherapy or an operation on ipsilateral inguinal lymph nodes and patients who have vascular anomalies or severe arteriosclerosis. SURGICAL TECHNIQUE: Debridement of the femoral head osteonecrosis and implantation of a pedicled vascularized iliac bone graft. POSTOPERATIVE MANAGEMENT: Free movement of the hip joint 4 weeks after surgery. Outward rotation of the hip joint allowed after 3 months and restriction of weight load on the operated leg for at least 3-6 months postoperatively depending on the bony consolidation. RESULTS: Vascularized bone grafts for the treatment of femoral head necrosis show better clinical and radiological results than avascular bone grafts. Nevertheless, after 5 years follow-up approximately 25% of the operated hips formerly in stage II show further progression of radiological necrosis. In stage III all hips eventually show progress of femoral head collapse and the need of a total hip replacement. Concerning the outcome of a free vascularized bone graft (fibula flap) compared to the pedicled vascularized graft from the iliac crest for treatment, the anatomically demanding area and a higher complication rate should be considered even though the cancellous bone of the iliac crest is biologically ideal. Nowadays a free vascularized fibular graft is the most frequently used bone graft for treatment of femoral head necrosis.
Assuntos
Necrose da Cabeça do Fêmur , Ílio , Transplante Ósseo , Cabeça do Fêmur , Seguimentos , Humanos , Resultado do TratamentoRESUMO
The adaptive advantage of epibenthic articulate brachiopods over inarticulate forms resulted from a modification of the mechanics of shell opening from an indirect hydraulic system to a direct muscular one. As a consequence, the articulate brachiopods were able to reduce the complex muscular system of the ancestral inarticulates, freeing two-thirds of the space within the shell for enlargement of the feeding apparatus. The original hydraulic mechanism of the inarticulate brachiopods most likely evolved from the hydrostatic skeleton of metameric lower invertebrates, probably polychaete-like annelids, as shown by a biomechanical analysis. The transitional stages between such annelids and inarticulate brachiopods are presented and explained as adaptive improvements in body construction.
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Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder characterized by increased incidence of benign and malignant tumors of neural crest origin. Mutations that activate the protooncogene ras, such as loss of Nf1, cooperate with inactivating mutations at the p53 tumor suppressor gene during malignant transformation. One hundred percent of mice harboring null Nf1 and p53 alleles in cis synergize to develop soft tissue sarcomas between 3 and 7 months of age. These sarcomas exhibit loss of heterozygosity at both gene loci and express phenotypic traits characteristic of neural crest derivatives and human NF1 malignancies.
Assuntos
Modelos Animais de Doenças , Genes da Neurofibromatose 1 , Genes p53 , Neurofibromatose 1/genética , Neurofibromatose 1/patologia , Sarcoma/patologia , Animais , Biomarcadores Tumorais , Diferenciação Celular , Transformação Celular Neoplásica , Cruzamentos Genéticos , Feminino , Heterozigoto , Humanos , Perda de Heterozigosidade , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mutação , Crista Neural/metabolismo , Crista Neural/patologia , Sarcoma/genética , Células de Schwann/metabolismo , Células de Schwann/patologia , Células Tumorais CultivadasRESUMO
Microwave atomic clocks have been the de facto standards for precision time and frequency metrology over the past 50 years, finding widespread use in basic scientific studies, communications, and navigation. However, with its higher operating frequency, an atomic clock based on an optical transition can be much more stable. We demonstrate an all-optical atomic clock referenced to the 1.064-petahertz transition of a single trapped 199Hg+ ion. A clockwork based on a mode-locked femtosecond laser provides output pulses at a 1-gigahertz rate that are phase-coherently locked to the optical frequency. By comparison to a laser-cooled calcium optical standard, an upper limit for the fractional frequency instability of 7 x 10(-15) is measured in 1 second of averaging-a value substantially better than that of the world's best microwave atomic clocks.
RESUMO
The mutagenicity of r-8,t-9-dihydroxy-t-10, 11-oxy-8,9,10,11-tetrahydrobenz[a]anthracene (BA-8,9-diol 10, 11-oxide) toward Salmonella typhimurium TA 100 is not decreased by the presence of large amounts of highly purified microsomal or cytosolic epoxide hydrolase. However, highly purified dihydrodiol dehydrogenase inactivates this diol epoxide, which is a major DNA-binding metabolite of benz[a]anthracene. The K-region epoxide, benz[a]anthracene 5,6-oxide (BA 5,6-oxide) is efficiently inactivated by microsomal epoxide hydrolase, is much less readily inactivated by cytosolic epoxide hydrolase, and is not inactivated by dihydrodiol dehydrogenase. This inactivation of a diol epoxide by dihydrodiol dehydrogenase points to a new significance of this enzyme and a new level of control for diol epoxides.
Assuntos
Oxirredutases do Álcool/metabolismo , Benzo(a)Antracenos/metabolismo , Inativação Metabólica , Oxirredutases atuantes sobre Doadores de Grupo CH-CH , Oxirredutases , Benzo(a)Antracenos/farmacologia , Epóxido Hidrolases/metabolismo , Testes de Mutagenicidade , Mutação/efeitos dos fármacos , Salmonella typhimurium/efeitos dos fármacosRESUMO
AIMS: Cardiac magnetic resonance (CMR) was used to assess whether cardiac function or tissue composition was affected in patients with well-functioning metal-on-metal hip resurfacing arthroplasties (MoMHRA) when compared with a group of controls, and to assess if metal ion levels correlated with any of the functional or structural parameters studied. PATIENTS AND METHODS: In all, 30 participants with no significant cardiac history were enrolled: 20 patients with well-functioning MoMHRA at mean follow-up of 8.3 years post-procedure (ten unilateral, ten bilateral; 17 men, three women) and a case-matched control group of ten non-MoM total hip arthroplasty patients (six men, four women). The mean age of the whole cohort (study group and controls) at the time of surgery was 50.6 years (41.0 to 64.0). Serum levels of cobalt and chromium were measured, and all patients underwent CMR imaging, including cine, T2* measurements, T1 and T2 mapping, late gadolinium enhancement, and strain measurements. RESULTS: None of the MoMHRA patients showed clinically significant cardiac functional abnormality. The MoMHRA patients had larger indexed right and left end diastolic volumes (left ventricular (LV): 74 ml/m2vs 67 ml/m2, p = 0.045; right ventricular: 80 ml/m2vs 71 ml/m2, p = 0.02). There was a small decrease in T2 time in the MoMHRA patients (median 49 ms vs 54 ms; p = 0.0003). Higher metal ion levels were associated with larger LV volumes and with shorter T2 time. CONCLUSION: Although cardiac function is not clinically adversely affected in patients with well-functioning MoMHRA, modern imaging is able to demonstrate subtle changes in structure and function of the heart. As these changes correlate with systemic ion measurements, they may be consequences of wear debris deposition. Longer, longitudinal studies are necessary to determine whether cardiac function will become affected. Cite this article: Bone Joint J 2019;101-B:540-546.
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Artroplastia de Quadril/efeitos adversos , Coração/diagnóstico por imagem , Articulação do Quadril/cirurgia , Prótese de Quadril/efeitos adversos , Imagem Cinética por Ressonância Magnética/métodos , Próteses Articulares Metal-Metal/efeitos adversos , Adulto , Idoso , Estudos de Casos e Controles , Cromo/sangue , Cobalto/sangue , Feminino , Coração/fisiopatologia , Articulação do Quadril/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/diagnóstico por imagem , Complicações Pós-Operatórias/etiologiaRESUMO
Neural crest cells of vertebrate embryos produce neurons, glia, pigment cells, and connective tissue in vivo and in vitro. To test the developmental potential of apparently undifferentiated crest cells, we have used the monoclonal antibody A2B5, which recognizes a cell surface glycolipid characteristic of neurons, to identify and immunoablate a subpopulation of cultured avian neural crest cells with a neuronal phenotype. Our results indicate that a limited neurogenic precursor subpopulation is present in cultures of avian neural crest cells and that the fate of this subpopulation can be influenced by environmental conditions arising when dispersal of neural crest cells is delayed.
Assuntos
Anticorpos Monoclonais/farmacologia , Desenvolvimento Embrionário e Fetal , Gangliosídeos/imunologia , Crista Neural/citologia , Plasticidade Neuronal , Codorniz/embriologia , Animais , Diferenciação Celular , Divisão Celular , Células Cultivadas , Crista Neural/imunologia , Crista Neural/fisiologia , Timidina , Fatores de TempoRESUMO
To investigate how the onset of neurotrophic factor dependence in neurons is coordinated with the arrival of their axons in the target field, we have studied the survival of four populations of cranial sensory neurons whose axons reach their common central target field, the hindbrain, at different times. We show that neurons whose axons reach the hindbrain first survive for a short time in culture before responding to brain-derived neurotrophic factor (BDNF). Neurons whose axons reach the hindbrain later survive longer before responding to BDNF. These differences in survival, which arise prior to gangliogenesis, may play a role in coordinating trophic interactions for cranial sensory neurons.
Assuntos
Nervos Cranianos/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Neurônios Aferentes/fisiologia , Animais , Fator Neurotrófico Derivado do Encéfalo , Sobrevivência Celular , Células Cultivadas , Embrião de Galinha , Nervos Cranianos/embriologia , Desenvolvimento Embrionário e Fetal , Fatores de Crescimento Neural/fisiologia , Proteínas do Tecido Nervoso/farmacologia , Vias Neurais/embriologia , Vias Neurais/fisiologia , Neurônios Aferentes/efeitos dos fármacos , Neurônios Aferentes/metabolismo , Gânglio Nodoso/citologia , Gânglio Nodoso/efeitos dos fármacos , Gânglio Nodoso/fisiologia , Rombencéfalo/embriologia , Fatores de Tempo , Nervo Vestibular/embriologiaRESUMO
We have studied the early development of chicken embryo sensory neurons in culture before they become dependent on neurotrophic factors for survival. During this period, they undergo a distinct change in morphology:initially they have small, spindle-shaped, phase-dark cell bodies, which become spherical and phase bright and extend long neurites. Although this maturational change occurs in isolated cells grown in chemically defined medium, it is accelerated by brain-derived neurotrophic factor (BDNF) or neurotrophin-3 and is retarded by antisense oligonucleotides that inhibit expression of the common, low affinity neurotrophic factor receptor (gp75NGFR) and by antisense BDNF oligonucleotides. We conclude that neurotrophic factors play a role in the earliest stages of sensory neuron development and suggest that they operate by an autocrine mechanism at this time.
Assuntos
Proteínas do Tecido Nervoso/farmacologia , Neurônios Aferentes/efeitos dos fármacos , Animais , Autorradiografia , Axônios/fisiologia , Sequência de Bases , Fator Neurotrófico Derivado do Encéfalo , Movimento Celular/fisiologia , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Embrião de Galinha , Gânglios Espinais/química , Gânglios Espinais/citologia , Gânglios Espinais/ultraestrutura , Expressão Gênica/genética , Imuno-Histoquímica , Dados de Sequência Molecular , Fatores de Crescimento Neural/farmacologia , Proteínas do Tecido Nervoso/genética , Neurônios Aferentes/citologia , Neurônios Aferentes/ultraestrutura , Neurotrofina 3 , Oligonucleotídeos Antissenso/farmacologia , RNA Mensageiro/genética , Receptores de Superfície Celular/análise , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/fisiologia , Receptores de Fator de Crescimento Neural , Transdução de Sinais/fisiologiaRESUMO
We report the in vitro assessment of pharmacotoxicity for the high-affinity GHB receptor ligand, NCS-382, using neuronal stem cells derived from mice with a targeted deletion of the aldehyde dehydrogenase 5a1 gene (succinic semialdehyde dehydrogenase(SSADH)-deficient mice). These animals represent a phenocopy of the human disorder of GABA metabolism, SSADH deficiency, that metabolically features accumulation of both GABA and the GABA-analog γ-hydroxybutyric acid in conjunction with a nonspecific neurological phenotype. We demonstrate for the first time using MDCK cells that NCS-382 is actively transported and capable of inhibiting GHB transport. Following these in vitro assays with in vivo studies in aldh5a1-/- mice, we found the ratio of brain/liver GHB to be unaffected by chronic NCS-382 administration (300mg/kg; 7 consecutive days). Employing a variety of cellular parameters (reactive oxygen and superoxide species, ATP production and decay, mitochondrial and lysosomal number, cellular viability and necrosis), we demonstrate that up to 1mM NCS-382 shows minimal evidence of pharmacotoxicity. As well, studies at the molecular level indicate that the effects of NCS-382 at 0.5mM are minimally toxic as evaluated using gene expression assay. The cumulative data provides increasing confidence that NCS-382 could eventually be considered in the therapeutic armament for heritable SSADH deficiency.
Assuntos
Benzocicloeptenos/metabolismo , Benzocicloeptenos/toxicidade , Erros Inatos do Metabolismo dos Aminoácidos , Animais , Anticonvulsivantes/metabolismo , Anticonvulsivantes/toxicidade , Biomarcadores , Sobrevivência Celular , Deficiências do Desenvolvimento , Células Epiteliais , Regulação da Expressão Gênica/efeitos dos fármacos , Genótipo , Humanos , Camundongos , Camundongos Knockout , Mitocôndrias/metabolismo , Células-Tronco Neurais/metabolismo , Neurônios , Espécies Reativas de Oxigênio/metabolismo , Receptores de Superfície Celular , Succinato-Semialdeído Desidrogenase/deficiência , Superóxidos/metabolismoRESUMO
The repressible acid phosphatase gene PHO5 of Saccharomyces cerevisiae requires the two positively acting regulatory proteins PHO2 and PHO4 for expression. pho2 or pho4 mutants are not able to derepress the PHO5 gene under low-Pi conditions. Here we show that both PHO2 and PHO4 bind specifically to the PHO5 promoter in vitro. Gel retardation assays using promoter deletions revealed two regions involved in PHO4 binding. Further characterization by DNase I footprinting showed two protected areas, one located at -347 to -373 (relative to the ATG initiator codon) (UASp1) and the other located at -239 to -262 (UASp2). Exonuclease III footprint experiments revealed stops at -349 and -368 (UASp1) as well as at -245 and -260 (UASp2). Gel retardation assays with the PHO2 protein revealed a binding region that lay between the two PHO4-binding sites. DNase I footprint analysis suggested a PHO2-binding site covering the region between -277 and -296.
Assuntos
Proteínas de Ligação a DNA , Proteínas Fúngicas/genética , Genes Fúngicos , Proteínas de Homeodomínio , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Transativadores , Fatores de Transcrição , Fosfatase Ácida/genética , Sequência de Bases , Sítios de Ligação , DNA Fúngico/genética , DNA Fúngico/metabolismo , Escherichia coli/genética , Proteínas Fúngicas/metabolismo , Regulação da Expressão Gênica , Regiões Promotoras Genéticas , Saccharomyces cerevisiae/metabolismoRESUMO
In contrast to higher eukaryotes, little is known about the nature of the sequences which direct 3'-end formation of pre-mRNAs in the yeast Saccharomyces cerevisiae. The hexanucleotide AAUAAA, which is highly conserved and crucial in mammals, does not seem to have any functional importance for 3'-end formation in yeast cells. Instead, other elements have been proposed to serve as signal sequences. We performed a detailed investigation of the yeast ACT1, ADH1, CYC1, and YPT1 cDNAs, which showed that the polyadenylation sites used in vivo can be scattered over a region spanning up to 200 nucleotides. It therefore seems very unlikely that a single signal sequence is responsible for the selection of all these polyadenylation sites. Our study also showed that in the large majority of mRNAs, polyadenylation starts directly before or after an adenosine residue and that 3'-end formation of ADH1 transcripts occurs preferentially at the sequence PyAAA. Site-directed mutagenesis of these sites in the ADH1 gene suggested that this PyAAA sequence is essential for polyadenylation site selection both in vitro and in vivo. Furthermore, the 3'-terminal regions of the yeast genes investigated here are characterized by their capacity to act as signals for 3'-end formation in vivo in either orientation.