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1.
Nature ; 530(7590): 313-6, 2016 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-26779950

RESUMO

Interfacing a single photon with another quantum system is a key capability in modern quantum information science. It allows quantum states of matter, such as spin states of atoms, atomic ensembles or solids, to be prepared and manipulated by photon counting and, in particular, to be distributed over long distances. Such light-matter interfaces have become crucial to fundamental tests of quantum physics and realizations of quantum networks. Here we report non-classical correlations between single photons and phonons--the quanta of mechanical motion--from a nanomechanical resonator. We implement a full quantum protocol involving initialization of the resonator in its quantum ground state of motion and subsequent generation and read-out of correlated photon-phonon pairs. The observed violation of a Cauchy-Schwarz inequality is clear evidence for the non-classical nature of the mechanical state generated. Our results demonstrate the availability of on-chip solid-state mechanical resonators as light-matter quantum interfaces. The performance we achieved will enable studies of macroscopic quantum phenomena as well as applications in quantum communication, as quantum memories and as quantum transducers.

2.
Crit Care Med ; 46(5): 691-698, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29271844

RESUMO

OBJECTIVE: Sepsis is a leading cause of mortality in noncoronary ICUs. Although immediate start of antibiotics reduces sepsis-related mortality, antibiotics are often administered for too long, leading to suboptimal treatment and, importantly, contributes to antimicrobial resistance. Prior literature suggests that procalcitonin correlates with infection and thus may help to guide the decision on when to stop antibiotic treatment. This study was conducted as part of a regulatory submission to the U.S. Food and Drug Administration and aimed to summarize the evidence of procalcitonin guidance on efficacy and safety outcomes in adult patients with sepsis. DATA SOURCES: PubMed and the Cochrane Database of Systematic Reviews. STUDY SELECTION: English-language randomized controlled trials evaluating procalcitonin use among adult patients with suspected or confirmed sepsis published between January 2004 and May 2016. DATA EXTRACTION: Inverse-variance weighting fixed and random effects meta-analyses were performed on the following efficacy and safety endpoints: antibiotic duration, all-cause mortality, and length of ICU stay. Two reviewers independently extracted data elements from identified studies and measured risk of bias with the Cochrane Risk of Bias Tool. DATA SYNTHESIS: From a total of 369 potentially eligible articles, 10 randomized controlled trials containing 3,489 patients were used for analysis. Procalcitonin-guided patients had shorter antibiotics duration compared with controls (7.35 vs. 8.85 d; weighted mean difference, -1.49 d; 95% CI, -2.27 to -0.71; p < 0.001). Procalcitonin use had no adverse impact on mortality (risk ratio, 0.90; 95% CI, 0.79-1.03; p = 0.114) and length of ICU stay (11.09 d vs. 11.91 d; weighted mean difference, -0.84 d; 95% CI, -2.52 to 0.84; p = 0.329). CONCLUSIONS: In adult patients with suspected or confirmed sepsis, procalcitonin guidance reduces antibiotics duration with no observed adverse effects on patient outcomes.


Assuntos
Pró-Calcitonina/sangue , Sepse/sangue , Antibacterianos/uso terapêutico , Biomarcadores/sangue , Estado Terminal/terapia , Humanos , Sepse/diagnóstico , Sepse/tratamento farmacológico
3.
Clin Chem Lab Med ; 56(8): 1200-1209, 2018 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-29715176

RESUMO

Although effective for bacterial lower respiratory tract infections (LRTIs), antibiotic treatment is often incorrectly prescribed for non-bacterial LRTIs. Procalcitonin has emerged as a promising biomarker to diagnose bacterial infections and guide antibiotic treatment decisions. As part of a regulatory submission to the U.S. Food and Drug Administration, this systematic review and meta-analysis summarizes the effects of procalcitonin-guided antibiotic stewardship on antibiotic use and clinical outcomes in adult LRTI patients. PubMed and the Cochrane Database of Systematic Reviews were searched for English-language randomized controlled trials published between January 2004 and May 2016. Random and fixed effects meta-analyses were performed to study efficacy (initiation of antibiotics, antibiotic use) and safety (mortality, length of hospital stay). Eleven trials were retained, comprising 4090 patients. Procalcitonin-guided patients had lower odds of antibiotic initiation (odds ratio: 0.26; 95% confidence interval [CI]: 0.13-0.52) and shorter mean antibiotic use (weighted mean difference: -2.15 days; 95% CI: -3.30 to -0.99) compared to patients treated with standard care. Procalcitonin use had no adverse impact on mortality (relative risk: 0.94; 95% CI: 0.69-1.28) and length of hospital stay (weighted mean difference: -0.15 days; 95% CI: -0.60 to 0.30). Procalcitonin guidance reduces antibiotic initiation and use among adults with LRTIs with no apparent adverse impact on length of hospital stay or mortality.


Assuntos
Antibacterianos/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Biomarcadores/sangue , Pró-Calcitonina/sangue , Infecções Respiratórias/tratamento farmacológico , Infecções Bacterianas/mortalidade , Uso Indevido de Medicamentos/prevenção & controle , Humanos , Tempo de Internação , Infecções Respiratórias/mortalidade
4.
6.
J Neurotrauma ; 40(7-8): 706-719, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36267001

RESUMO

Two blood-based brain biomarker tests such as the combination of glial fibrillary acidic protein and ubiquitin C-terminal hydrolase-L1 (GFAP+UCH-L1) or S100B have potential to reduce the need for head computed tomography (CT) scanning in patients with mild traumatic brain injury (mTBI). We assessed the clinical and economic impact of using GFAP+UCH-L1 versus CT scan and GFAP+UCH-L1 versus S100B to screen adults with suspected mTBI presenting to an emergency department (ED). A decision model was developed to estimate costs and health outcomes of GFAP+UCH-L1, CT scan, and S100B associated with these screening protocols. Model parameters were extracted from peer-reviewed articles, clinical guidelines, and expert opinion. Analysis was performed from a French health care system perspective (costs in 2020 euros). In the model, patients with a positive biomarker receive a CT scan to confirm the presence of intracranial lesions (ICLs). Depending on clinical state and biomarker and CT results, patients were discharged immediately, kept for observation in the ED, admitted for in-hospital stay and observation, or admitted for surgical management. Incorrect test results may lead to delayed treatment and poor outcomes or overtreatment. GFAP+UCH-L1 use was associated with an overall decrease in CT scans when compared with CT screening or S100B use (325.42 and 46.43 CTs per 1000 patients, respectively). The use of GFAP+UCH-L1 resulted in modest cost savings when compared with CT scanning and with S100B. In all cases, use of GFAP+UCH-L1 marginally improved quality-adjusted life-years (QALYs) and outcomes. Thus, screening with GFAP+UCH-L1 reduced the need for CT scans when compared with systematic CT scan screening or use of S100B while maintaining similar costs and health outcomes.


Assuntos
Concussão Encefálica , Lesões Encefálicas Traumáticas , Adulto , Humanos , Concussão Encefálica/diagnóstico por imagem , Análise Custo-Benefício , Ubiquitina Tiolesterase , Lesões Encefálicas Traumáticas/diagnóstico , Biomarcadores , Encéfalo , Proteína Glial Fibrilar Ácida
7.
Artigo em Inglês | MEDLINE | ID: mdl-36714285

RESUMO

Objectives: To review methodologies and outcomes reporting among these studies and to develop a conceptual framework of outcomes to assist in guiding studies and production of clinical metrics. Data sources: PubMed and Embase from January 1, 2012, thru December 1, 2021. Study eligibility criteria: Studies evaluating highly multiplex molecular respiratory diagnostics and their impact on either clinical or economic outcomes. Methods: A systematic literature review (SLR) of methodologies and outcomes reporting was performed. A qualitative synthesis of identified SLRs and associated primary studies was conducted to develop conceptual framework for outcomes. Results: Ultimately, 4 systemic literature reviews and their 12 associated primary studies were selected for review. Most primary studies included patient outcomes focusing on antimicrobial exposure changes such as antibiotic (80%) and antiviral use (50%) or occupancy changes such as hospital length of stay (60%). Economic outcomes were infrequently reported, and societal outcomes, such as antibiotic resistance impact, were absent from the reviewed literature. Qualitative evidence synthesis of reported outcomes yielded a conceptual framework of outcomes to include operational, patient, economic, and societal domains. Conclusions: Our review highlights the significant heterogeneity in outcomes reporting among clinical impact studies for highly multiplex molecular respiratory diagnostics. Furthermore, we developed a conceptual framework of outcomes domains that may act as a guide to improve considerations in outcomes selection and reporting when evaluating clinical impact of these tests. These improvements may be important in synthesizing the evidence for informing clinical decision making, guidelines, and financial reimbursement.

8.
Nat Geosci ; 16(8): 730-738, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37564379

RESUMO

The Middle Eocene Climatic Optimum (around 40 million years ago) was a roughly 400,000-year-long global warming phase associated with an increase in atmospheric CO2 concentrations and deep-ocean acidification that interrupted the Eocene's long-term cooling trend. The unusually long duration, compared with early Eocene global warming phases, is puzzling as temperature-dependent silicate weathering should have provided a negative feedback, drawing down CO2 over this timescale. Here we investigate silicate weathering during this climate warming event by measuring lithium isotope ratios (reported as δ7Li), which are a tracer for silicate weathering processes, from a suite of open-ocean carbonate-rich sediments. We find a positive δ7Li excursion-the only one identified for a warming event so far -of ~3‰. Box model simulations support this signal to reflect a global shift from congruent weathering, with secondary mineral dissolution, to incongruent weathering, with secondary mineral formation. We surmise that, before the climatic optimum, there was considerable soil shielding of the continents. An increase in continental volcanism initiated the warming event, but it was sustained by an increase in clay formation, which sequestered carbonate-forming cations, short-circuiting the carbonate-silicate cycle. Clay mineral dynamics may play an important role in the carbon cycle for climatic events occurring over intermediate (i.e., 100,000 year) timeframes.

9.
Sci Adv ; 9(34): eadf9999, 2023 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-37624887

RESUMO

The body fossil and biomarker records hint at an increase in biotic complexity between the two Cryogenian Snowball Earth episodes (ca. 661 million to ≤650 million years ago). Oxygen and nutrient availability can promote biotic complexity, but nutrient (particularly phosphorus) and redox dynamics across this interval remain poorly understood. Here, we present high-resolution paleoredox and phosphorus phase association data from multiple globally distributed drill core records through the non-glacial interval. These data are first correlated regionally by litho- and chemostratigraphy, and then calibrated within a series of global chronostratigraphic frameworks. The combined data show that regional differences in postglacial redox stabilization were partly controlled by the intensity of phosphorus recycling from marine sediments. The apparent increase in biotic complexity followed a global transition to more stable and less reducing conditions in shallow to mid-depth marine environments and occurred within a tolerable climatic window during progressive cooling after post-Snowball super-greenhouse conditions.

10.
Cancer Cell ; 6(6): 625-30, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15607966

RESUMO

N-Myc oncogene amplification is a frequent event in neuroblastoma and is strongly correlated with advanced disease stage and treatment failure. Similarly to c-Myc oncogenic activation, N-Myc deregulation promotes both cell proliferation and p53-dependent apoptosis by sensitizing cells to a variety of insults. Intriguingly, p53 mutations are uncommon in neuroblastomas, strongly suggesting that an alternative cooperating event circumvents this safeguard against oncogene-driven neoplasia. By performing a pangenomic cDNA microarray analysis, we demonstrate that human Twist is constantly overexpressed in N-Myc-amplified neuroblastomas. H-Twist overexpression is responsible for the inhibition of the ARF/p53 pathway involved in the Myc-dependent apoptotic response. This oncogenic cooperation of two key regulators of embryogenesis causes cell transformation and malignant outgrowth.


Assuntos
Transformação Celular Neoplásica/genética , Neuroblastoma/patologia , Proteínas Nucleares/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Fatores de Transcrição/metabolismo , Animais , Apoptose/fisiologia , Northern Blotting , Western Blotting , Caspase 3 , Caspase 8 , Caspases/metabolismo , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Inibidor p16 de Quinase Dependente de Ciclina/genética , Inibidor de Quinase Dependente de Ciclina p21 , Fibroblastos/patologia , Citometria de Fluxo , Amplificação de Genes , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Marcação In Situ das Extremidades Cortadas , Camundongos , Neuroblastoma/genética , Neuroblastoma/metabolismo , Proteínas Nucleares/genética , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas Proto-Oncogênicas c-myc/genética , Proto-Oncogenes/genética , RNA Interferente Pequeno/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição/genética , Transfecção , Ensaio Tumoral de Célula-Tronco , Proteína Supressora de Tumor p14ARF/genética , Proteína Supressora de Tumor p53/metabolismo , Proteína 1 Relacionada a Twist
11.
Sci Adv ; 8(41): eabm8191, 2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36240275

RESUMO

Mapping the history of atmospheric O2 during the late Precambrian is vital for evaluating potential links to animal evolution. Ancient O2 levels are often inferred from geochemical analyses of marine sediments, leading to the assumption that the Earth experienced a stepwise increase in atmospheric O2 during the Neoproterozoic. However, the nature of this hypothesized oxygenation event remains unknown, with suggestions of a more dynamic O2 history in the oceans and major uncertainty over any direct connection between the marine realm and atmospheric O2. Here, we present a continuous quantitative reconstruction of atmospheric O2 over the past 1.5 billion years using an isotope mass balance approach that combines bulk geochemistry and tectonic recycling rate calculations. We predict that atmospheric O2 levels during the Neoproterozoic oscillated between ~1 and ~50% of the present atmospheric level. We conclude that there was no simple unidirectional rise in atmospheric O2 during the Neoproterozoic, and the first animals evolved against a backdrop of extreme O2 variability.

12.
Nat Commun ; 9(1): 4081, 2018 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-30287825

RESUMO

Oxygen is essential for animal life, and while geochemical proxies have been instrumental in determining the broad evolutionary history of oxygen on Earth, much of our insight into Phanerozoic oxygen comes from biogeochemical modelling. The GEOCARBSULF model utilizes carbon and sulphur isotope records to produce the most detailed history of Phanerozoic atmospheric O2 currently available. However, its predictions for the Paleozoic disagree with geochemical proxies, and with non-isotope modelling. Here we show that GEOCARBSULF oversimplifies the geochemistry of sulphur isotope fractionation, returning unrealistic values for the O2 sourced from pyrite burial when oxygen is low. We rebuild the model from first principles, utilizing an improved numerical scheme, the latest carbon isotope data, and we replace the sulphur cycle equations in line with forwards modelling approaches. Our new model, GEOCARBSULFOR, produces a revised, highly-detailed prediction for Phanerozoic O2 that is consistent with available proxy data, and independently supports a Paleozoic Oxygenation Event, which likely contributed to the observed radiation of complex, diverse fauna at this time.

13.
BMC Cancer ; 6: 216, 2006 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-16945123

RESUMO

BACKGROUND: One of the most thoroughly studied systems in relation to its prognostic relevance in patients with breast cancer, is the plasminogen activation system that comprises of, among others, the urokinase Plasminogen Activator (uPA) and its main inhibitor, the Plasminogen Activator Inhibitor-1 (PAI-1). In this study, we investigated the prognostic value of uPA and PAI-1 at the mRNA level in lymph node- and hormone receptor-positive breast cancer. METHODS: The study included a retrospective series of 87 patients with hormone-receptor positive and axillary lymph node-positive breast cancer. All patients received radiotherapy, adjuvant anthracycline-based chemotherapy and five years of tamoxifen treatment. The median patient age was 54 and the median follow-up time was 79 months. Distant relapse occurred in 30 patients and 22 patients died from breast cancer during follow-up. We investigated the prognostic value of uPA and PAI-1 at the mRNA level as measured by real-time quantitative RT-PCR. RESULTS: uPA and PAI-1 gene expression was not found to be correlated with any of the established clinical and pathological factors. Metastasis-free Survival (MFS) and Breast Cancer specific Survival (BCS) were significantly shorter in patients expressing high levels of PAI-1 mRNA (p < 0.0001; p < 0.0001; respectively). In Cox multivariate analysis, the level of PAI-1 mRNA appeared to be the strongest prognostic factor for MFS (Hazard Ratio (HR) = 10.12; p = 0.0002) and for BCS (HR = 13.17; p = 0.0003). Furthermore, uPA gene expression was not significantly associated neither with MFS (p = 0.41) nor with BCS (p = 0.19). In a Cox-multivariate regression analysis, uPA expression did not demonstrate significant independent prognostic value. CONCLUSION: These findings indicate that high PAI-1 mRNA expression represents a strong and independent unfavorable prognostic factor for the development of metastases and for breast cancer specific survival in a population of hormone receptor- and lymph node-positive breast cancer patients.


Assuntos
Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Ativador de Plasminogênio Tipo Uroquinase/metabolismo , Feminino , Humanos , Pessoa de Meia-Idade , Metástase Neoplásica , Prognóstico , RNA Mensageiro/metabolismo , Receptores de Estrogênio , Receptores de Progesterona , Estudos Retrospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sobrevida
14.
Cancer Lett ; 225(1): 111-20, 2005 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-15922863

RESUMO

Neuroblastoma (NB) is the most common extracranial solid tumor of childhood and the third most common pediatric cancer. Although numerous factors including patient age, disease stage and genetic abnormalities have been shown to be predictive of outcome, the mechanisms responsible for the highly variable clinical behavior of this tumor remain largely unknown. In order to gain new insights into the biology of this tumor, we performed microarray analysis and compared the gene expression patterns of NB detected by mass screening, characterized by highly probable spontaneous regression, versus stage 4 NB with poor prognosis. The bioinformatics analysis revealed a set of 19 discriminatory genes that may play a significant role in the natural progression of the disease. Validation of these results and further mechanistic studies would shed new light on the biology of tumor progression, and provide new tools to predict clinical outcome in children with NB.


Assuntos
Perfilação da Expressão Gênica , Programas de Rastreamento , Neuroblastoma/genética , Análise de Sequência com Séries de Oligonucleotídeos , Pré-Escolar , Biologia Computacional , Progressão da Doença , Feminino , Genoma , Humanos , Imunoquímica , Lactente , Masculino
15.
Protein Sci ; 12(1): 143-52, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12493837

RESUMO

The human genome contains numerous genes whose protein products are unknown in terms of structure, interaction partner, expression, and function. To unravel the function of these orphan genes, it is of particular value to isolate native forms of protein and peptide products derived from these genes. From human blood ultrafiltrate, we characterized a novel gene-encoded, cysteine-rich, and cationic peptide that we termed liver-expressed antimicrobial peptide 2 (LEAP-2). We identified several circulating forms of LEAP-2 differing in their amino-terminal length, all containing a core structure with two disulfide bonds formed by cysteine residues in relative 1-3 and 2-4 positions. Molecular cloning of the cDNA showed that LEAP-2 is synthesized as a 77-residue precursor, which is predominantly expressed in the liver and highly conserved among mammals. This makes it a unique peptide that does not exhibit similarity with any known human peptide regarding its primary structure, disulfide motif, and expression. Analysis of the LEAP-2 gene resulted in the identification of an alternative promoter and at least four different splicing variants, with the two dominating transcripts being tissue-specifically expressed. The largest native LEAP-2 form of 40 amino acid residues is generated from the precursor at a putative cleavage site for a furin-like endoprotease. In contrast to smaller LEAP-2 variants, this peptide exhibited dose-dependent antimicrobial activity against selected microbial model organisms. LEAP-2 shares some characteristic properties with classic peptide hormones and it is expected that the isolation of this novel peptide will help to unravel its physiological role.


Assuntos
Anti-Infecciosos/química , Peptídeos Catiônicos Antimicrobianos/química , Proteínas Sanguíneas/química , Fígado/metabolismo , Processamento Alternativo , Sequência de Aminoácidos , Animais , Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos/genética , Peptídeos Catiônicos Antimicrobianos/isolamento & purificação , Peptídeos Catiônicos Antimicrobianos/farmacologia , Sequência de Bases , Proteínas Sanguíneas/genética , Proteínas Sanguíneas/isolamento & purificação , Proteínas Sanguíneas/farmacologia , Clonagem Molecular , DNA Complementar/genética , Dissulfetos/química , Relação Dose-Resposta a Droga , Hemofiltração , Humanos , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Especificidade de Órgãos , Saccharomyces cerevisiae/efeitos dos fármacos , Alinhamento de Sequência , Espectrometria de Massas por Ionização por Electrospray
16.
Mol Cancer Res ; 11(12): 1611-23, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24145173

RESUMO

UNLABELLED: Glioblastoma multiforme, the most common primary brain tumor, is highly refractory to therapy, mainly due to its ability to form micrometastases, which are small clusters or individual cells that rapidly transverse the brain and make full surgical resection impossible. Here, it is demonstrated that the invasive phenotype of glioblastoma multiforme is orchestrated by the transcription factor NF-κB which, via metalloproteinases (MMP), regulates fibronectin processing. Both, cell lines and tumor stem cells from primary glioblastoma multiforme, secrete high levels of fibronectin which when cleaved by MMPs forms an extracellular substrate. Subsequently, forming and interacting with their own microenvironment, glioblastoma multiforme cells are licensed to invade their surroundings. Mechanistic study revealed that NF-κB inhibition, either genetically or pharmacologically, by treatment with Disulfiram, significantly abolished the invasive phenotype in the chick chorioallantoic membrane assay. Furthermore, having delineated the underlying molecular mechanism of glioblastoma multiforme invasion, the potential of a disulfiram-based therapy was revealed in a highly invasive orthotrophic glioblastoma multiforme mouse model. IMPLICATIONS: This study defines a novel therapeutic approach that inhibits micrometastases invasion and reverts lethal glioblastoma into a less aggressive disease.


Assuntos
Dissulfiram/farmacologia , Inibidores Enzimáticos/farmacologia , Fibronectinas/metabolismo , Glioblastoma/patologia , NF-kappa B/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Glioblastoma/metabolismo , Humanos , Metaloproteases/genética , Metaloproteases/metabolismo , Camundongos , NF-kappa B/genética , Invasividade Neoplásica , Microambiente Tumoral
17.
Eur J Neurosci ; 23(8): 2012-26, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16630049

RESUMO

Coordination of motoneuron activity is a fundamental prerequisite for the generation of functional locomotor patterns. We investigate the neural mechanisms that coordinate activity of motoneuron pools in the vertebrate spinal cord with differing phases of activity in the locomotor cycle in a simple motor system, the lamprey swimming network. In the region of dorsal fins the lamprey spinal cord contains two groups of motoneurons: the myotomal motoneurons that innervate the trunk muscles; and the fin motoneurons controlling muscle fibres of the dorsal fins. We investigated the activity of fin muscles during swimming in vivo and that of fin motoneurons during fictive swimming in vitro. During swimming in vivo with cycle periods of 4-8 Hz, fin muscle activity covered a broad portion of the cycle, with the peak of activity out-of-phase to the ipsilateral myotomal muscles. During fictive swimming evoked by N-methyl-d-aspartate in the isolated spinal cord, fin motoneurons expressed similar out-of-phase activity. The phase relationship of the synaptic drive to fin motoneurons was examined by recording their activity intracellular during fictive swimming. Three different forms of membrane potential oscillation with different time courses in the locomotor cycle could be distinguished. Sagittal lesions of the spinal cord in the segment where fin motoneurons are recorded and up to one segment rostral and caudal from it did not influence the out-of-phase activity pattern of the motoneurons. Our results indicate that coordination of fin motoneuron activity with the locomotor activity of myotomal motoneurons does not depend on intrasegmental contralateral premotor elements.


Assuntos
Lampreias/fisiologia , Locomoção/fisiologia , Neurônios Motores/fisiologia , Músculos/fisiologia , Natação , Animais , Comportamento Animal , Dextranos/farmacocinética , Relação Dose-Resposta a Droga , Estimulação Elétrica/métodos , Eletromiografia/métodos , Feminino , Lateralidade Funcional/fisiologia , Masculino , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Potenciais da Membrana/efeitos da radiação , Neurônios Motores/classificação , Neurônios Motores/efeitos dos fármacos , Músculos/citologia , N-Metilaspartato/farmacologia , Medula Espinal/citologia , Medula Espinal/efeitos dos fármacos , Medula Espinal/fisiologia
18.
Genomics ; 81(2): 175-83, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12620395

RESUMO

Human beta-defensins are a family of cationic peptides that share a pattern of six conserved cysteine residues. We describe the cloning and characterization of the cDNAs of five novel beta-defensin genes (DEFB25-DEFB29) clustered on chromosome 20p13, which were identified using a bioinformatics approach. Expression analysis revealed the occurrence of the transcripts in only a few organs, with the highest abundance in the male genital tract. Examination of beta-defensin expression in human epididymis by real-time quantitative RT-PCR revealed a distribution along the functionally different segments of the epididymal duct. In situ hybridization for one of the cDNAs shows mRNA restriction to the epithelial cell layer of the epididymis, known to secrete factors responsible for sperm maturation. We suggest that the novel peptides carry out physiological functions in the male genital tract that may not be directly related to bacterial growth inhibition in host defense.


Assuntos
Cromossomos Humanos Par 20 , Epididimo/metabolismo , beta-Defensinas/genética , Sequência de Aminoácidos , Clonagem Molecular , Humanos , Hibridização In Situ , Masculino , Dados de Sequência Molecular , Especificidade de Órgãos , Alinhamento de Sequência , beta-Defensinas/metabolismo
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