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1.
Neurobiol Dis ; 199: 106593, 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38971480

RESUMO

Impaired lipid metabolism is a risk factor for Parkinson's disease (PD) and dementia with Lewy bodies (DLB) and can shift the physiological α-synuclein (αS) tetramer-monomer (T:M) ratio toward aggregation prone monomers. A resultant increase in phospho-serine 129+ αS monomers associating with excess mono- and polyunsaturated fatty acids contributes to the αS aggregation. We previously reported that decreasing the release of monounsaturated fatty acids (MUFAs) by reducing or inhibiting the hormone sensitive lipase (LIPE) reversed pathologic αS phosphorylation and improved soluble αS homeostasis in cultured αS triplication PD neurons and reduced DAergic neurodegeneration in a C.elegans αS model. However, assessing LIPE as a potential therapeutic target for progressive PD motor phenotypes has not been investigated. 3K αS mice, representing a biochemical and neuropathological amplification of the E46K fPD-causing mutation, have decreased αS T:M ratios, lipidic aggregates, and a L-DOPA responsive PD-like motor syndrome. Here, we reduced LIPE by crossings of 3K mice with LIPE null mice, which attenuated motor deficits in male LIPE+/- knockdown (LKD)-3K mice. Heterozygous LIPE reduction was associated with an improved αS T:M ratio, and dopaminergic neurotransmitter levels and fiber densities. In female 3K-LKD mice, an increase in pS129+ and larger lipid droplets (LDs) likely decreased the benefits seen in males. Reducing LIPE decreased MUFA release from neutral lipid storage, thereby reducing MUFA in phospholipid membranes with which αS interacts. Our study highlights fatty acid turnover as a therapeutic target for Lewy body diseases and support LIPE as a promising target in males. LIPE regulation represents a novel approach to mitigate PD and DLB risk and treat disease.

2.
Ecol Appl ; 33(6): e2890, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37212374

RESUMO

Outbreaks of the spongy moth Lymantria dispar can have devastating impacts on forest resources and ecosystems. Lepidoptera-specific insecticides, such as Bacillus thuringiensis var. kurstaki (BTK) and tebufenozide, are often deployed to prevent heavy defoliation of the forest canopy. While it has been suggested that using BTK poses less risk to non-target Lepidoptera than leaving an outbreak untreated, in situ testing of this assumption has been impeded by methodological challenges. The trade-offs between insecticide use and outbreaks have yet to be addressed for tebufenozide, which is believed to have stronger side effects than BTK. We investigated the short-term trade-offs between tebufenozide treatments and no-action strategies for the non-target herbivore community in forest canopies. Over 3 years, Lepidoptera and Symphyta larvae were sampled by canopy fogging in 48 oak stands in southeast Germany during and after a spongy moth outbreak. Half of the sites were treated with tebufenozide and changes in canopy cover were monitored. We contrasted the impacts of tebufenozide and defoliator outbreaks on the abundance, diversity, and functional structure of chewing herbivore communities. Tebufenozide treatments strongly reduced Lepidoptera up to 6 weeks after spraying. Populations gradually converged back to control levels after 2 years. Shelter-building species dominated caterpillar assemblages in treated plots in the post-spray weeks, while flight-dimorphic species were slow to recover and remained underrepresented in treated stands 2 years post-treatment. Spongy moth outbreaks had minor effects on leaf chewer communities. Summer Lepidoptera decreased only when severe defoliation occurred, whereas Symphyta declined 1 year after defoliation. Polyphagous species with only partial host plant overlap with the spongy moth were absent from heavily defoliated sites, suggesting greater sensitivity of generalists to defoliation-induced plant responses. These results demonstrate that both tebufenozide treatments and spongy moth outbreaks alter canopy herbivore communities. Tebufenozide had a stronger and longer lasting impact, but it was restricted to Lepidoptera, whereas the outbreak affected both Lepidoptera and Symphyta. These results are tied to the fact that only half of the outbreak sites experienced severe defoliation. This highlights the limited accuracy of current defoliation forecast methods, which are used as the basis for the decision to spray insecticides.


Assuntos
Bacillus thuringiensis , Inseticidas , Mariposas , Animais , Ecossistema
3.
Glob Chang Biol ; 21(2): 935-46, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25242342

RESUMO

Shifts in tree species distributions caused by climatic change are expected to cause severe losses in the economic value of European forestland. However, this projection disregards potential adaptation options such as tree species conversion, shorter production periods, or establishment of mixed species forests. The effect of tree species mixture has, as yet, not been quantitatively investigated for its potential to mitigate future increases in production risks. For the first time, we use survival time analysis to assess the effects of climate, species mixture and soil condition on survival probabilities for Norway spruce and European beech. Accelerated Failure Time (AFT) models based on an extensive dataset of almost 65,000 trees from the European Forest Damage Survey (FDS)--part of the European-wide Level I monitoring network--predicted a 24% decrease in survival probability for Norway spruce in pure stands at age 120 when unfavorable changes in climate conditions were assumed. Increasing species admixture greatly reduced the negative effects of unfavorable climate conditions, resulting in a decline in survival probabilities of only 7%. We conclude that future studies of forest management under climate change as well as forest policy measures need to take this, as yet unconsidered, strongly advantageous effect of tree species mixture into account.


Assuntos
Biodiversidade , Mudança Climática , Fagus/fisiologia , Florestas , Picea/fisiologia , Conservação dos Recursos Naturais , Secas , Alemanha , Temperatura Alta , Longevidade
4.
Environ Manage ; 56(2): 373-88, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25896820

RESUMO

Multi-criteria decision analysis (MCDA) is a decision aid frequently used in the field of forest management planning. It includes the evaluation of multiple criteria such as the production of timber and non-timber forest products and tangible as well as intangible values of ecosystem services (ES). Hence, it is beneficial compared to those methods that take a purely financial perspective. Accordingly, MCDA methods are increasingly popular in the wide field of sustainability assessment. Hybrid approaches allow aggregating MCDA and, potentially, other decision-making techniques to make use of their individual benefits and leading to a more holistic view of the actual consequences that come with certain decisions. This review is providing a comprehensive overview of hybrid approaches that are used in forest management planning. Today, the scientific world is facing increasing challenges regarding the evaluation of ES and the trade-offs between them, for example between provisioning and regulating services. As the preferences of multiple stakeholders are essential to improve the decision process in multi-purpose forestry, participatory and hybrid approaches turn out to be of particular importance. Accordingly, hybrid methods show great potential for becoming most relevant in future decision making. Based on the review presented here, the development of models for the use in planning processes should focus on participatory modeling and the consideration of uncertainty regarding available information.


Assuntos
Técnicas de Apoio para a Decisão , Agricultura Florestal/métodos , Agricultura Florestal/organização & administração , Florestas , Modelos Teóricos , Ecossistema , Agricultura Florestal/economia , Técnicas de Planejamento , Incerteza
5.
Clin Radiol ; 69(5): 468-72, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24529541

RESUMO

AIM: To compare uterine peristalsis between symptomatic fibroid patients and normal subjects and to determine the possible effect of fibroid characteristics on uterine peristalsis at high-field magnetic resonance imaging (MRI). MATERIALS AND METHODS: The present study included 20 symptomatic fibroid patients (age range 39-53 years) and 20 normal subjects (age range 19-46 years). MRI images were obtained during the peri-ovulatory phase using 3 T MRI using a sagittal T2 turbo spin-echo sequence and a half-Fourier acquisition single-shot turbo spin-echo sequence for display on cine mode. Two radiologists independently evaluated the images for the presence of uterine peristalsis by confidence level. In cases where peristalsis was present, the images were also evaluated for peristalsis frequency and direction. For fibroid patients, uterine and index fibroid volume, fibroid burden and index fibroid location were also recorded. RESULTS: Uterine peristalsis was significantly decreased in symptomatic fibroid patients compared with normal controls (p < 0.01). Peristalsis frequency in fibroid patients was also lower than in normal subjects. Direction of peristalsis was cervix-to-fundus for the majority of fibroid patients and controls. There was no significant relationship between fibroid characteristics, such as uterine volume, index fibroid volume, index fibroid location, and fibroid number in fibroid patients with, and fibroid patients without peristalsis. CONCLUSION: In women with symptomatic fibroids, the presence of uterine peristalsis is significantly decreased compared to normal controls on 3 T cine MRI. The presence of fibroids appears to disturb the normal conduction of uterine peristalsis and may interfere with fluid (e.g., menses, sperm) transport.


Assuntos
Leiomioma/fisiopatologia , Imagem Cinética por Ressonância Magnética , Peristaltismo , Neoplasias Uterinas/fisiopatologia , Útero/fisiopatologia , Adulto , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Leiomioma/patologia , Ciclo Menstrual , Pessoa de Meia-Idade , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Estados Unidos/epidemiologia , Neoplasias Uterinas/patologia , Útero/patologia
6.
Int Endod J ; 47(10): 942-8, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24386931

RESUMO

AIM: To compare the efficacy of reciprocating and rotary NiTi-instruments in removing filling material from curved root canals using micro-computed tomography. METHODOLOGY: Sixty curved root canals were prepared and filled with gutta-percha and sealer. After determination of root canal curvatures and radii in two directions as well as volumes of filling material, the teeth were assigned to three comparable groups (n = 20). Retreatment was performed using Reciproc, ProTaper Universal Retreatment or Hedström files. Percentages of residual filling material and dentine removal were assessed using micro-CT imaging. Working time and procedural errors were recorded. Statistical analysis was performed by variance procedures. RESULTS: No significant differences amongst the three retreatment techniques concerning residual filling material were detected (P > 0.05). Hedström files removed significantly more dentine than ProTaper Universal Retreatment (P < 0.05), but the difference concerning dentine removal between both NiTi systems was not significant (P > 0.05). Reciproc and ProTaper Universal Retreatment were significantly faster than Hedström files (P = 0.0001). No procedural errors such as instrument fracture, blockage, ledging or perforation were detected for Hedström files. Three perforations were recorded for ProTaper Universal Retreatment, and in both NiTi groups, one instrument fracture occured. CONCLUSIONS: Remnants of filling material were observed in all samples with no significant differences between the three techniques. Hedström files removed significantly more dentine than ProTaper Universal Retreatment, but no significant differences between both NiTi systems were detected. Procedural errors were observed with ProTaper Universal Retreatment and Reciproc.


Assuntos
Cavidade Pulpar/diagnóstico por imagem , Endodontia/instrumentação , Níquel , Titânio , Microtomografia por Raio-X
7.
Int Endod J ; 45(6): 580-9, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22264204

RESUMO

AIM: To compare the efficacy of two rotary NiTi retreatment systems and Hedström files in removing filling material from curved root canals. METHODOLOGY: Curved root canals of 57 extracted teeth were prepared using FlexMaster instruments and filled with gutta-percha and AH Plus. After determination of root canal curvatures and radii in two directions, the teeth were assigned to three identical groups (n = 19). The root fillings were removed with D-RaCe instruments, ProTaper Universal Retreatment instruments or Hedström files. Pre- and postoperative micro-CT imaging was used to assess the percentage of residual filling material as well as the amount of dentine removal. Working time and procedural errors were recorded. Data were analysed using analysis of covariance and analysis of variance procedures. RESULTS: D-RaCe instruments were significantly more effective than ProTaper Universal Retreatment instruments and Hedström files (P < 0.05). Hedström files removed significantly less dentine than the rotary NiTi systems (P < 0.0001). D-RaCe instruments were significantly faster compared to both other groups (P < 0.05). No procedural errors such as instrument fracture, blockage, ledging or perforation were detected in the Hedström group. In the ProTaper group, four instrument fractures and one lateral perforation were observed. Five instrument fractures were recorded for D-RaCe. CONCLUSIONS: D-RaCe instruments were associated with significantly less residual filling material than ProTaper Universal Retreatment instruments and hand files. Hedström files removed significantly less dentine than both rotary NiTi systems. Retreatment with rotary NiTi systems resulted in a high incidence of procedural errors.


Assuntos
Ligas Dentárias , Cavidade Pulpar/ultraestrutura , Guta-Percha/química , Níquel , Materiais Restauradores do Canal Radicular/química , Preparo de Canal Radicular/instrumentação , Titânio , Ligas Dentárias/química , Cavidade Pulpar/lesões , Dentina/ultraestrutura , Resinas Epóxi/química , Desenho de Equipamento , Falha de Equipamento , Humanos , Teste de Materiais , Níquel/química , Retratamento , Propriedades de Superfície , Fatores de Tempo , Titânio/química , Microtomografia por Raio-X
8.
Curr Opin Cell Biol ; 12(6): 705-9, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11063935

RESUMO

Senescence is now understood to be the final phenotypic state adopted by a cell in response to several distinct cell physiological processes, including proliferation, oncogene activation and oxygen free radical toxicity. The role of telomere maintenance in immortalization and the roles of p16(INK4A), p19(ARF), p53 and other genes in senescence are being further elucidated. Significant progress continues to be made in our understanding of cellular senescence and immortalization.


Assuntos
Senescência Celular/genética , Animais , Divisão Celular/genética , Regulação da Expressão Gênica , Genes p16/genética , Humanos , Camundongos , Oncogenes/genética , Estresse Oxidativo/genética , Proteínas/genética , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/genética , Telômero/genética , Telômero/metabolismo , Proteína Supressora de Tumor p14ARF
9.
Nat Med ; 5(10): 1164-70, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10502820

RESUMO

Telomerase is a ribonucleoprotein enzyme that maintains the protective structures at the ends of eukaryotic chromosomes, called telomeres. In most human somatic cells, telomerase expression is repressed, and telomeres shorten progressively with each cell division. In contrast, most human tumors express telomerase, resulting in stabilized telomere length. These observations indicate that telomere maintenance is essential to the proliferation of tumor cells. We show here that expression of a mutant catalytic subunit of human telomerase results in complete inhibition of telomerase activity, reduction in telomere length and death of tumor cells. Moreover, expression of this mutant telomerase eliminated tumorigenicity in vivo. These observations demonstrate that disruption of telomere maintenance limits cellular lifespan in human cancer cells, thus validating human telomerase reverse transcriptase as an important target for the development of anti-neoplastic therapies.


Assuntos
Mutação , Neoplasias Experimentais/prevenção & controle , RNA , Telomerase/antagonistas & inibidores , Telomerase/genética , Apoptose , Neoplasias da Mama , Domínio Catalítico/genética , Divisão Celular , Neoplasias do Colo , Proteínas de Ligação a DNA , Desenho de Fármacos , Feminino , Vetores Genéticos , Humanos , Neoplasias Experimentais/enzimologia , Neoplasias Ovarianas , Retroviridae/genética , Inibidores da Transcriptase Reversa , Telômero/metabolismo , Células Tumorais Cultivadas
10.
Int J Immunogenet ; 38(2): 133-8, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21108742

RESUMO

Toll-like receptors (TLRs) are innate immune mediators that stimulate nuclear factor kappa B and the inflammatory cytokines. TLR1 is expressed in renal tubular epithelial cells when the kidney is injured, but the role of TLR1 gene in glomerulonephritis has not been clearly elucidated. We aimed to investigate the association of TLR1 polymorphisms with immunoglobulin A nephropathy (IgAN) in children. One hundred and ninety pediatric patients with biopsy-proven IgAN and 283 healthy control subjects were enrolled. Two single nucleotide polymorphisms of TLR1 gene [rs4833095 (missense, Asn248Ser) and rs5743557 (promoter, -414C/T)] were selected and genotyped by direct sequencing. For rs4833095, the C/T genotype in the codominant model (vs. the T/T genotype) [odds ratio (OR) = 2.11, 95% confidence interval (CI): 1.21-3.69, P = 0.009] and the genotype containing C allele (C/T and C/C) in the dominant model (vs. the T/T genotype) (OR = 1.97, 95% CI: 1.16-3.34, P = 0.012) were associated with an increased risk of IgAN. For rs5743557, the T/T genotype in the codominant model (vs. the C/C genotype) (OR = 1.74, 95% CI: 1.02-2.96, P = 0.041) appeared to be associated with IgAN risk. In haplotype analysis, the CT haplotype revealed an association with IgAN (codominant model, OR = 1.38, 95% CI: 1.06-1.80, P = 0.017; dominant model, OR = 1.76, 95% CI: 1.16-2.67, P = 0.008). After Bonferroni correction, the association of the genotypes of rs4833095 and the CT haplotype with IgAN risk remained significant. These findings suggest that TLR1 gene polymorphisms may affect IgAN susceptibility in Korean children.


Assuntos
Povo Asiático/genética , Predisposição Genética para Doença , Glomerulonefrite por IGA/genética , Polimorfismo de Nucleotídeo Único/genética , Receptor 1 Toll-Like/genética , Adolescente , Estudos de Casos e Controles , Criança , Demografia , Feminino , Frequência do Gene/genética , Haplótipos/genética , Humanos , Masculino , República da Coreia
11.
Gene Ther ; 17(12): 1442-52, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20668482

RESUMO

Hepatocyte growth factor (HGF) has been shown to induce angiogenesis in vivo and has potential as a candidate gene for 'therapeutic angiogenesis'. In vivo, two isoforms of HGF, HGF723 and HGF728, consisting of 723 and 728 amino acids, are generated through alternative splicing between exons 4 and 5, but the biological effects of their coexpression have not yet been elucidated. In this study, we generated a series of genomic-complementary DNA (cDNA) hybrids of the HGF gene by inserting various truncated intron 4 into the junction of exons 4 and 5 of HGF cDNA and analyzed the biological activities of these hybrid constructs. We showed that: (1) the hybrid called HGF-X7, which contained 1502 base pairs of intron 4, could drive a higher level of HGF expression than other hybrid constructs and cDNAs of each isoform alone; (2) the pCK vector was most efficient for the gene expression of HGF-X7; (3) coexpression of both isoforms of HGF could more efficiently induce the migration of human umbilical vein endothelial cell (HUVEC) and of the mouse myoblast cell line C2C12 myoblasts than a single isoform of HGF and human vascular endothelial growth factor (VEGF)165 at a given concentration; (4) intramuscular administration of pCK-HGF-X7 resulted in transient and localized HGF expression in the injected muscle without an increase in the HGF protein levels in other tissues including serum; and (5) intramuscular injection of pCK-HGF-X7 could more efficiently increase the number of angiographically recognizable collateral vessels, as well as improve an intra-arterial Doppler wire-measured blood flow in the rabbit model of hindlimb ischemia when compared with the identical vector encoding VEGF165 gene. These results showed that transfer of the genomic-cDNA hybrid of the HGF gene could be used as a potential therapeutic approach to human vascular diseases.


Assuntos
Artérias , Circulação Colateral/efeitos dos fármacos , DNA/uso terapêutico , Terapia Genética , Fator de Crescimento de Hepatócito/genética , Fator de Crescimento de Hepatócito/metabolismo , Isquemia/terapia , Animais , Artérias/crescimento & desenvolvimento , Artérias/metabolismo , Linhagem Celular , Movimento Celular/efeitos dos fármacos , DNA/genética , DNA Complementar/genética , Modelos Animais de Doenças , Extremidades/irrigação sanguínea , Feminino , Expressão Gênica , Técnicas de Transferência de Genes , Engenharia Genética , Vetores Genéticos/genética , Fator de Crescimento de Hepatócito/farmacologia , Humanos , Íntrons/genética , Isquemia/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Coelhos , Fluxo Sanguíneo Regional/efeitos dos fármacos
12.
J Exp Med ; 178(5): 1831-6, 1993 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-7901319

RESUMO

Effective T cell immune responses require the molecular interplay between adhesive and signaling events mediated by the T cell receptor for antigen (TCR) and other cell surface coreceptor molecules. In this report, we have distinguished between the role of regulated adhesion and transmembrane signaling in coreceptor function using the T cell glycoprotein CD2. By binding its ligands on antigen-presenting cell (APC), CD2 serves both to initiate signal transduction events and to promote cellular adhesion. Furthermore, the avidity of CD2 for one ligand, CD58 (LFA-3), is regulated by TCR signaling. We have expressed wild type CD2 and a series of mutated CD2 molecules in an antigen-specific murine T cell hybridoma. Structure-function studies using these stably transfected cell lines identify two structurally and functionally distinct regions of the 116 amino acid (aa) cytoplasmic domain. One region is required for CD2-mediated signal transduction, and a separate COOH-terminal 21 aa portion is required for CD2 activity regulation. Cell lines expressing CD2 molecules lacking the cytoplasmic segment required for CD2-initiated IL-2 production retain the ability to upregulate CD2 avidity. Conversely, cell lines expressing CD2 mutants lacking the cytoplasmic segment required for avidity regulation retain the ability to initiate CD2-specific signaling. In antigen-specific T cell responses, basal binding of CD2 to its ligands enhances antigen responsiveness only minimally, whereas regulated avidity and transmembrane signaling are both required for optimal coreceptor function. Taken together, these studies demonstrate the independent contributions of regulated adhesion and intracellular signaling in CD2 coreceptor function.


Assuntos
Antígenos de Diferenciação de Linfócitos T/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Receptores Imunológicos/metabolismo , Transdução de Sinais , Linfócitos T/imunologia , Animais , Antígenos de Diferenciação de Linfócitos T/biossíntese , Sequência de Bases , Antígenos CD2 , Comunicação Celular , Linhagem Celular , Humanos , Hibridomas/imunologia , Camundongos , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Sondas de Oligonucleotídeos , Oligonucleotídeos Antissenso , Reação em Cadeia da Polimerase , Receptores Imunológicos/biossíntese , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/metabolismo , Transfecção
13.
J Cell Biol ; 104(2): 263-75, 1987 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-3543023

RESUMO

Human mesothelial cells, endothelial cells, and type II kidney epithelial cells growing in culture devote approximately 3% of their total protein synthesis to the production of an Mr approximately 46-kD, pI 7.1, secreted glycoprotein (designated Sp46). Fibroblasts make about 1/10th as much Sp46 as these cell types, and their synthesis is dependent upon hydrocortisone. Keratinocytes, urothelial cells, conjunctival epithelial cells, and mammary epithelial cells do not make detectable amounts of Sp46. Mesothelial cells secrete Sp46 onto the substratum, and from there it is subsequently released into the medium. Immunofluorescence analysis using specific antisera discloses that Sp46 is deposited beneath cells as a fine coating on the substratum. In sparse cultures, Sp46 is detected in trails behind motile cells. In contrast, secreted fibronectin coalesces into fibers, most of which remain in contact with and on top of the cells; thus Sp46 does not preferentially bind to fibronectin. About 6 kD of the mass of human Sp46 is N-linked oligosaccharide, which is terminally sialated before secretion. Sp46 has a low glycine content, indicating that it is not a collagenlike protein. Its NH2-terminal sequence over the first 40 amino acids does not resemble any protein for which sequence information is available. Sp46 appears to be a novel extracellular glycoprotein, high-level constitutive expression of which is restricted to mesoderm-derived epithelial and endothelial cells. We therefore propose for it the name "mesosecrin."


Assuntos
Endotélio/metabolismo , Glicoproteínas/biossíntese , Rim/metabolismo , Sequência de Aminoácidos , Células Cultivadas , Epitélio/metabolismo , Fibroblastos/metabolismo , Fibronectinas/biossíntese , Imunofluorescência , Glicoproteínas/isolamento & purificação , Humanos , Cinética , Metionina/metabolismo , Peso Molecular , Inibidor 1 de Ativador de Plasminogênio , Radioisótopos de Enxofre
14.
Science ; 220(4600): 924-8, 1983 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-6189184

RESUMO

The adult mouse brain contains complex populations of polyadenylated [poly(A)+] and nonpolyadenylated [poly(A)-] messenger RNA's (mRNA's). These mRNA's are separate sequence populations, similar in complexity, and in combination are equivalent to approximately 150,000 different mRNA sequences, of average length. Essentially all of the "adult" poly(A)+ mRNA's are present in the brain at birth. In contrast, most of the poly(A)- mRNA's are absent. Brain poly(A)- mRNA's begin to appear soon after birth, but the full adult complement is not reached until young adulthood. This suggests that these poly(A)- mRNA's specify proteins required for the biological capabilities of the brain that emerge during the course of postnatal development.


Assuntos
Encéfalo/crescimento & desenvolvimento , Regulação da Expressão Gênica , Animais , Diferenciação Celular , Clonagem Molecular , DNA/fisiologia , Feto/fisiologia , Cobaias , Rim/metabolismo , Fígado/metabolismo , Camundongos , Especificidade de Órgãos , Poli A/fisiologia , RNA/fisiologia , RNA Mensageiro/fisiologia , RNA Ribossômico/fisiologia , Ratos
15.
Science ; 229(4719): 1263-5, 1985 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-2412293

RESUMO

A repeated 82 base pair sequence in genomic DNA of the rat was previously proposed as being a control element governing brain (neuron) specific genetic expression. This intronic sequence, termed the brain "identifier" (ID), is complementary to small RNA species localized in brain cytoplasm, and it was thought to be represented specifically in RNA produced by brain nuclei in vitro. The RNA blot analyses of total nuclear and polyadenylated heterogeneous nuclear RNA described in the present report show that this ID sequence is also present in the liver and kidney in abundances similar to those in the brain. This repeated sequence is not, therefore, restricted to transcripts produced in the brain as suggested from previous transcriptional "runoff" experiments. Measurements on rat and mouse nuclear RNA indicate that the abundance of ID sequence transcript is roughly proportional to the number of copies of this repeat in the respective genomes. This suggests a rather random genomic location and transcription of this sequence. From these results it seems improbable that the ID sequence functions as a transcriptional-level control element in genes expressed specifically in the brain.


Assuntos
Química Encefálica , Genes , RNA/análise , Animais , Sequência de Bases , Clonagem Molecular , Rim/análise , Fígado/análise , Camundongos , Crista Neural/análise , Hibridização de Ácido Nucleico , Ratos , Transcrição Gênica
16.
Science ; 173(3992): 158-61, 1971 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-4996550

RESUMO

Under normal conditions of DNA renaturation, about 60 percent of mouse DNA fragments renature at a rate consistent with their being present only once per sperm. These nonrepeated sequences (also called single-copy or unique) may be used in RNA-DNA hybridization experiments to provide quantitative estimates of RNA diversity. About 10 percent of the mouse single-copy sequences are transcribed in mouse brain tissue. Estimates of about 3 percent were obtained for mouse liver and kidney RNA's. If only one of the complementary DNA strands is transcribed, this hybridization value implies that the equivalent of at least 300,000 different sequences of 1000 nucleotides are expressed in mouse brain tissue. It is suggested that the large amount of DNA in mammals is functionally important, and that a substantial proportion of the genome is expressed in the brain.


Assuntos
Encéfalo/metabolismo , DNA/metabolismo , Código Genético , Polinucleotídeos/metabolismo , Animais , Bacillus subtilis , Sequência de Bases , Isótopos de Carbono , Núcleo Celular/análise , DNA Bacteriano/metabolismo , Escherichia coli , Temperatura Alta , Rim/citologia , Células L , Fígado/citologia , Camundongos , Desnaturação de Ácido Nucleico , Hibridização de Ácido Nucleico , Timidina/metabolismo , Trítio
17.
Science ; 197(4303): 582-5, 1977 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-327551

RESUMO

DNA-RNA hybridization experiments show that essentially all of the genomic information is transcribed. High, intermediate, and rare abundance classes of messenger RNA (mRNA) are present, and their estimated complexities are equal to about 240, 1300, and 700 average-sized mRNA species, respectively. The high abundance mRNA species are present, an average, two to three copies per cell and constitute about 95 percent of the mRNA mass. Intermediate abundance mRNA species are present, on average, about once per 35 cells. The relative abundance and complexity of these mRNA classes correspond well with previous respective measurements on protein. Rare RNA species are thought to represent maximally repressed genes. Analysis of RNA synthesized in vitro by isolated nucleoids (chromosomes) suggests that sense and nonsense sequences are extensively interspersed on a given strand of the DNA.


Assuntos
DNA Bacteriano/metabolismo , RNA Bacteriano/biossíntese , RNA Mensageiro/biossíntese , Transcrição Gênica , Mapeamento Cromossômico , Cromossomos/metabolismo , Escherichia coli , Genes , Genes Reguladores , Cinética , Peso Molecular , Hibridização de Ácido Nucleico , Óperon , RNA Bacteriano/análise , RNA Mensageiro/análise
18.
Science ; 256(5065): 1805-7, 1992 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-1377404

RESUMO

The interaction of the T cell glycoprotein CD2 with one ligand, CD58, contributes to T cell function. We have identified CD59, a glycoprotein with complement-inhibitory function, as a second physiological ligand for CD2. Antibodies to CD59 inhibit CD2-dependent T cell activation in murine T cell hybridomas expressing human CD2. In an in vitro binding assay with purified CD58 and CD59, CD2+ cells bind not only immobilized CD58 but also CD59. With two complementary approaches, it was demonstrated that the binding sites on CD2 for CD58 and CD59 are overlapping but nonidentical. These observations suggest that direct interactions between CD2 and both CD58 and CD59 contribute to T cell activation and adhesion.


Assuntos
Antígenos CD/metabolismo , Antígenos de Diferenciação de Linfócitos T/metabolismo , Glicoproteínas de Membrana/metabolismo , Receptores de Antígenos de Linfócitos T/fisiologia , Receptores Imunológicos/metabolismo , Animais , Sítios de Ligação , Antígenos CD2 , Antígenos CD58 , Antígenos CD59 , Relação Dose-Resposta a Droga , Humanos , Hibridomas , Imunidade Celular , Técnicas In Vitro , Camundongos , Linfócitos T/imunologia
19.
Science ; 206(4419): 643-9, 1979 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-17796918

RESUMO

Ice crystals in the form of right hexagonal prisms have faces that form 90 degrees prisms. Light rays were traced through these prism faces by computer calculation, and the light patterns that would be produced in the sky for a particular distribution of crystal orientations were simulated. Crystals with random orientations produce a 46 degrees halo. Hexagonal plate crystals with nearly horizontal end faces produce circumzenithal and circumhorizontal arcs. Hexagonal column crystals with horizontal axes produce supralateral and infralateral arcs. Plate crystals spinning about a horizontal axis that is a face diagonal of the crystal produce a series of arcs touching the 46 degrees halo. Each of these effects was simulated for several elevations of the sun.

20.
J Clin Invest ; 108(5): 725-32, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11544278

RESUMO

The immortalization of human cells is a critical step in multistep carcinogenesis. Oral-esophageal carcinomas, a model system to investigate molecular mechanisms underlying squamous carcinogenesis, frequently involve cyclin D1 overexpression and inactivation of the p53 tumor suppressor. Therefore, our goal was to establish the functional role of cyclin D1 overexpression and p53 inactivation in the immortalization of primary human oral squamous epithelial cells (keratinocytes) as an important step toward malignant transformation. Cyclin D1 overexpression alone was found to induce extension of the replicative life span of normal oral keratinocytes, whereas the combination of cyclin D1 overexpression and p53 inactivation led to their immortalization. This study also demonstrates that immortalization of oral keratinocytes can be independent of telomerase activation, involving an alternative pathway of telomere maintenance (ALT).


Assuntos
Carcinoma de Células Escamosas/etiologia , Transformação Celular Neoplásica , Ciclina D1/genética , Genes p53 , Queratinócitos/fisiologia , Neoplasias Bucais/etiologia , Carcinoma de Células Escamosas/enzimologia , Ciclo Celular , Divisão Celular , Linhagem Celular , Ciclina D1/metabolismo , Humanos , Queratinócitos/citologia , Queratinócitos/enzimologia , Boca/citologia , Neoplasias Bucais/enzimologia , Mutação , Telomerase/fisiologia , Transdução Genética
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