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1.
Rev Geophys ; 58(1): e2019RG000660, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32734279

RESUMO

Aerosols interact with radiation and clouds. Substantial progress made over the past 40 years in observing, understanding, and modeling these processes helped quantify the imbalance in the Earth's radiation budget caused by anthropogenic aerosols, called aerosol radiative forcing, but uncertainties remain large. This review provides a new range of aerosol radiative forcing over the industrial era based on multiple, traceable, and arguable lines of evidence, including modeling approaches, theoretical considerations, and observations. Improved understanding of aerosol absorption and the causes of trends in surface radiative fluxes constrain the forcing from aerosol-radiation interactions. A robust theoretical foundation and convincing evidence constrain the forcing caused by aerosol-driven increases in liquid cloud droplet number concentration. However, the influence of anthropogenic aerosols on cloud liquid water content and cloud fraction is less clear, and the influence on mixed-phase and ice clouds remains poorly constrained. Observed changes in surface temperature and radiative fluxes provide additional constraints. These multiple lines of evidence lead to a 68% confidence interval for the total aerosol effective radiative forcing of -1.6 to -0.6 W m-2, or -2.0 to -0.4 W m-2 with a 90% likelihood. Those intervals are of similar width to the last Intergovernmental Panel on Climate Change assessment but shifted toward more negative values. The uncertainty will narrow in the future by continuing to critically combine multiple lines of evidence, especially those addressing industrial-era changes in aerosol sources and aerosol effects on liquid cloud amount and on ice clouds.

2.
Ultrasound Obstet Gynecol ; 56(5): 694-704, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-31682302

RESUMO

OBJECTIVES: Our primary aim was to confirm whether intertwin discordance in ventricular strain and ductus venosus (DV) time intervals predicts twin-twin transfusion syndrome (TTTS). Secondary aims were to create gestational-age ranges for ventricular strain in uncomplicated monochorionic diamniotic (MCDA) twin pregnancies without selective intrauterine growth restriction (sIUGR) and to characterize the relationship of ventricular strain with gestational age in MCDA twin pregnancies with sIUGR that did not develop TTTS. METHODS: In the period 2015-2018, we enrolled 150 MCDA twin pregnancies consecutively into this prospective, blinded study of global longitudinal left and right ventricular strain. With the observer blinded to twin pairing and pregnancy outcome, videoclips of the four-chamber view, which had been recorded during ultrasound surveillance in the usual window for development of TTTS (16-26 completed gestational weeks), underwent offline measurement of strain. Uncomplicated MCDA twin pregnancies, without sIUGR, were used to test the association between strain, gestational age and estimated fetal weight using mixed-effects multilevel regression. Inter-rater reliability was tested in 208 strain measurements in 31 fetuses from pregnancies which did not develop TTTS and within-fetus variation was assessed in 16 such fetuses, in which multiple four-chamber views were taken on the same day. The effect of sIUGR on strain in otherwise uncomplicated MCDA twin pregnancy was analyzed. MCDA twin pregnancies were defined as 'pre-TTTS' when, having been referred for TTTS evaluation, they did not satisfy Quintero staging criteria, but subsequently developed TTTS requiring laser treatment. MCDA pregnancies which did not develop TTTS comprised the 'non-TTTS' group. Cardiovascular parameters measured in these cases included tissue Doppler parameters and DV early filling time as a percentage of the cardiac cycle (DVeT%). Intertwin strain and DVeT% discordance was compared between non-TTTS and pre-TTTS cases, matched for gestational age. RESULTS: Paired strain data were available for intertwin comparison in 127/150 MCDA twin pregnancies, comprising 14 pre-TTTS and 113 non-TTTS pregnancies, after exclusions. Scans were collected at a median frame rate of 97 (range, 28-220) Hz. Laser therapy was performed at a median gestational age of 20.6 (range, 17.2-26.6) weeks. There were no group differences in right (RV) or left (LV) ventricular strain discordance between 68/113 non-TTTS and 13/14 pre-TTTS MCDA twin pregnancies < 20 completed gestational weeks (RV, P = 0.338; LV, P = 0.932). DVeT% discordance > 3.6% was found in eight of 13 pre-TTTS pregnancies. In non-TTTS pregnancies, the estimated variability in ventricular strain within each twin during the day was high (RV, 19.7; LV, 12.9). However, within each pair (intertwin variation), variability was low (RV, 5.5; LV, 2.9). Interclass correlation reflecting the proportion of total variability represented by the variability between twin pairs was low (RV, 0.22; LV, 0.18). Both RV (P < 0.001) and LV (P = 0.025) strain showed a negative association with gestational age. Among non-TTTS MCDA twin pregnancies, LV strain was, on average, higher by 1.83 in sIUGR compared with normally grown fetuses (P = 0.023), with no statistically significant difference in RV strain (P = 0.271). CONCLUSIONS: Although ventricular strain has been reported previously as a possible predictor of developing TTTS, in this blinded, prospective study, we found no significant intergroup differences in ventricular strain in pre-TTTS compared with age-matched non-TTTS MCDA twin pregnancies. We recommend using DVeT% discordance as a more practical screening tool in MCDA twin pregnancies. This study also provides new information on the changes with gestational age, and the biological and technical variation, of global longitudinal ventricular strain in uncomplicated MCDA twin pregnancies and those with isolated sIUGR. © 2019 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.


Assuntos
Coração Fetal/fisiopatologia , Feto/irrigação sanguínea , Ventrículos do Coração/fisiopatologia , Gravidez de Gêmeos , Gêmeos/estatística & dados numéricos , Adulto , Feminino , Retardo do Crescimento Fetal/fisiopatologia , Coração Fetal/embriologia , Peso Fetal , Transfusão Feto-Fetal/fisiopatologia , Idade Gestacional , Ventrículos do Coração/embriologia , Humanos , Análise Multinível , Circulação Placentária , Gravidez , Estudos Prospectivos , Análise de Regressão , Reprodutibilidade dos Testes , Método Simples-Cego , Ultrassonografia Pré-Natal
3.
Psychiatr Psychol Law ; 26(1): 97-109, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31984067

RESUMO

The number of older inmates in New South Wales prisons has increased over the past ten years but it is unclear whether corrective services can cater for the increase. The current study reports the results of a qualitative study about ageing in prison. Eight prison chaplains from four corrective facilities in NSW were interviewed using a semi-structured interview schedule. The results of a thematic analysis revealed four main themes: the system, the services, the environment and the inmate. The themes reveal a system that is not designed to cope with an ageing population. Inmates become resentful of what has happened to them rather than for the damage they have done to somebody else. The system lacks processes and programmes to enable proper rehabilitation. The issues raised by the chaplains in terms of services, the environment and the inmates decrease the possibility that an older inmate will adapt to the environment and successfully age in place.

5.
Child Care Health Dev ; 40(2): 250-8, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23294101

RESUMO

BACKGROUND: Neonatal Follow-Up (NFU) programmes provide health services for families of infants at high risk of developmental problems following difficult or extremely premature birth: yet, up to 30% of families do not attend these programmes with their infants. METHODS: The study objective was to determine maternal and infant factors that predicted attendance at NFU programmes. Utilizing Andersen's Behavioural Model of Health Services Use, a prospective two-phase multi-site descriptive cohort study was conducted in three Canadian Neonatal Intensive Care Units (NICU) that refer to two affiliated NFU programmes. In Phase 1, 357 mothers completed standardized questionnaires that addressed maternal and infant factors, prior to their infants' NICU discharge. In Phase 2, attendance at NFU was followed at three time points over a 12-month period. Factors of interest included predisposing factors (e.g. demographic characteristics and social context); enabling factors (e.g. social support, travel distance, and income); and infant illness severity (i.e. needs factors). Multivariate logistic regression was used to estimate the odds ratio for each independent factor. RESULTS: Mothers parenting alone, experiencing higher levels of worry about maternal alcohol or drug use, or at greater distances from NFU were less likely to attend. Mothers experiencing higher maternal stress at the time of the infant's NICU hospitalization were more likely to attend NFU. No infant factors were predictive of NFU attendance. CONCLUSIONS: Mothers at risk of not attending NFU programmes with their infants require better identification, triage, referral and additional support to promote engagement with NFU programmes and improved quality of life for their high-risk infants.


Assuntos
Assistência ao Convalescente/organização & administração , Deficiências do Desenvolvimento/prevenção & controle , Mães/educação , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Encaminhamento e Consulta , Adulto , Canadá/epidemiologia , Deficiências do Desenvolvimento/diagnóstico , Deficiências do Desenvolvimento/epidemiologia , Feminino , Seguimentos , Humanos , Lactente , Cuidado do Lactente , Recém-Nascido , Recém-Nascido Prematuro , Masculino , Relações Mãe-Filho , Mães/psicologia , Poder Familiar , Participação do Paciente , Gravidez , Estudos Prospectivos , Apoio Social , Inquéritos e Questionários
6.
Community Ment Health J ; 50(3): 331-5, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24193296

RESUMO

This study examined racial/ethnic differences in self-reported depressive symptoms in a clinical population at a northeastern community mental health center. Two hundred eighty-two individuals presenting for mental health intake completed the Beck Depression Inventory-II in either English or Spanish. Latinas reported higher severity of depressive symptoms compared to both African Americans and non-Latina whites. Latinas showed higher levels on both the somatic and the affective/cognitive scales of the BDI-II. These findings differ somewhat from previous reports, some of which suggest that Latinas exhibit elevation specifically in somatic symptoms. Findings are discussed in terms of their implications for assessment and treatment.


Assuntos
Centros Comunitários de Saúde Mental/estatística & dados numéricos , Depressão/etnologia , Disparidades nos Níveis de Saúde , Hispânico ou Latino/psicologia , Populações Vulneráveis/psicologia , Adulto , População Negra/psicologia , População Negra/estatística & dados numéricos , Connecticut/epidemiologia , Depressão/epidemiologia , Feminino , Hispânico ou Latino/estatística & dados numéricos , Humanos , Masculino , Escalas de Graduação Psiquiátrica , Estudos Retrospectivos , População Urbana/estatística & dados numéricos , Populações Vulneráveis/etnologia , Populações Vulneráveis/estatística & dados numéricos , População Branca/psicologia , População Branca/estatística & dados numéricos
7.
Radiography (Lond) ; 29(1): 234-239, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36608377

RESUMO

INTRODUCTION: Radiographer abnormality flagging systems have been in use in the UK for over 30 years, with the guidance of the Society and College of Radiographers indicated that the preliminary clinical evaluation (PCE), or comment, be the preferred system of choice. This study aimed to provide an updated assessment of current practice based upon a previous 2008 study. METHODS: A cross-sectional online survey was disseminated via Twitter and aimed at departmental and reporting leads. It requested information on the types of flagging and reporting systems operated, scope of the systems employed, required education of participants, and the role of audit. RESULTS: Responses were received from 31 Trusts within the UK. Red dot systems were employed in 90% (n = 28) of sites, with 26% (n = 8) undertaking PCE. Skeletal radiographs were most commonly reviewed (90%; n = 28) followed by chest (58%; n = 18) and abdomen (32%; n = 10). Only 13% (n = 4) sites indicated if the image was normal but 71% (n = 22) allowed the radiographer to indicate if they were unsure. There was marked variation in the educational requirements and use of audit. CONCLUSION: Compared to 2008 there appears to be quite minimal change in practices in the UK. There does appear to be some increase in the use of flagging systems generally and a higher proportion of PCE systems in comparison to red dot but the use of education and audit does not necessarily show much development in the past 15 years. IMPLICATIONS FOR PRACTICE: Significant conclusions cannot be drawn due to limited sample size, however, it may support further study and consideration in relation to implementation and potentially standardisation of abnormality detection systems may be justified.


Assuntos
Pessoal Técnico de Saúde , Controle de Qualidade , Humanos , Estudos Transversais , Radiografia , Reino Unido
8.
Radiography (Lond) ; 28(4): 1122-1126, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36103731

RESUMO

INTRODUCTION: The chest X-ray (CXR) is the most frequently performed radiographic examination. This study evaluates radiographers' ability to localise traumatic CXR pathology and provide a preliminary clinical evaluation (PCE) for these cases. METHODS: This observer study was performed in a district general hospital in the United Kingdom (UK). A 58-case image bank was used with 20 positive cases. Participants were awarded a maximum of three points, based on abnormality recognition and descriptive accuracy. Localisation data were recorded with ROCView. Training was delivered via short online recorded tutorials covering an introduction of a systematic search strategy for CXR, how to recognise the common abnormalities covered in the tests, how to structure a PCE and multiple practice cases to review at participants' own pace. Pre- and post-training data was recorded. RESULTS: Nine participants completed the study. Overall, pooled sensitivity remained consistent (78.9%-78.8%) following training, specificity and accuracy showed improvement of 79.0%-89.9% and 78.9%-86.0% respectively. An increase in the number of correct localisations and PCE scores were also evident. Participants performed better at correctly identifying a pneumothorax compared to skeletal abnormalities. CONCLUSION: Improvements in performance were evident for most participants' abnormality localisations and PCE scores, following the training intervention. The study highlighted areas of CXR PCE that may require further training, such as detecting superimposed or subtle abnormalities. IMPLICATIONS FOR PRACTICE: This study provides additional support for the development of PCE systems in additional areas of imaging practice.


Assuntos
Competência Clínica , Serviço Hospitalar de Emergência , Pessoal Técnico de Saúde , Humanos , Radiografia , Reino Unido
9.
Radiography (Lond) ; 27(4): 1033-1037, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33906804

RESUMO

INTRODUCTION: The preliminary clinical evaluation (PCE) abnormality flagging system is a progression from the red dot system. The need for a PCE service may be reduced by immediate "hot" reporting services, however, PCE can be valuable in those Trusts that do not have a "hot reporting"service, as well as in the out of hours setting. This study aimed to identify what information clinicians require within the PCE to aid decision making. METHODS: Emergency Department (ED) clinicians and Radiology reporters were approached to complete a paper survey seeking their preferences on various aspects of the What, Where, How model, regarding their usefulness. Questions were a combination of multiple choice, Likert scale, and free-text. RESULTS: Thirty participants (20 ED clinicians and 10 Radiology Reporters) provided a 100% response rate. Overall, Where was considered to be most significant (n = 18, 60%), followed by What (n = 11, 37%). Half of participants (n = 15, 50%) considered How to be least significant. ED clinicians found all aspects of the What, Where, How useful, in particular the Where, but to a slightly lesser extent regarding how much displacement was involved. Overall, the information ranked as least useful was how much movement, followed by direction of movement, and type of fracture. The preferred style for a PCE comment is a bullet format. CONCLUSION: PCE content should accommodate the preferences of ED referrers. Our findings suggest clinicians want information pertaining to what the abnormality is (i.e. the type of injury), where it was (more specific than simply which bone) and if displacement is present. IMPLICATIONS FOR PRACTICE: These findings add to the current knowledge base and provide support to the local department when implementing the PCE system.


Assuntos
Fraturas Ósseas , Radiologia , Serviço Hospitalar de Emergência , Humanos , Radiografia , Inquéritos e Questionários
10.
Radiography (Lond) ; 27(4): 1006-1013, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33875356

RESUMO

INTRODUCTION: The chest x-ray (CXR) is the most commonly performed x-ray examination in England, UK. Reporting radiographers provide a cost-effective and safe solution for managing CXR backlogs, but not all Trusts support this service development. This study aimed to establish the service enablers and challenges associated with training and employing radiographers to report CXR images in acute hospital sites in England, UK. METHODS: Approval for this electronic survey was granted in 84 of 146 (58%) Trusts approached. The survey was open for 10 weeks during August to October 2020, comprising of qualitative and quantitative questions. Data was exported in to an Excel spreadsheet where manual thematic analysis was performed. Descriptive statistics were also generated. RESULTS: Sample size was 75 (89% response rate). Thirty-three departments (44%) had at least one trainee. Most departments (n = 53, 71%) employ at least one CXR reporting radiographer. A total of 121/160 (76%) radiographers report CXRs. Number of reporting sessions shows progression. Factors enabling training and employment arise from service improvements, financial pressures, and developing the workforce. The main challenges relate to staffing issues with a number of associated sub-themes. A small faction indicated lack of radiographer interest to report CXRs due to litigation worries; possibly uncovering a new and emerging issue. CONCLUSION: Enablers and challenges associated with radiographers reporting CXRs are similar to previous studies. The growth of CXR reporting radiographers and reporting sessions indicates a continuing reliance on radiographers to contributing to managing CXR backlogs. IMPLICATIONS FOR PRACTICE: It is recommended that potential trainees are explicitly informed of the legal protection that will be provided, to prevent accountability concerns impacting on the continuing progression in this area of advanced practice.


Assuntos
Pessoal Técnico de Saúde , Inglaterra , Humanos , Radiografia , Reino Unido , Raios X
11.
Radiography (Lond) ; 26(4): 302-307, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32224096

RESUMO

INTRODUCTION: The preliminary clinical evaluation (PCE) system involves the radiographer providing an immediate comment highlighting an abnormality on the x-ray image. This can be a valuable service development though it must be recognised that the structure of the PCE may impede its usefulness. This study aimed to assess radiographers' ability to form a concise description of radiographic abnormalities by evaluating their structure and brevity. METHOD: A convenience sampling approach was used and the study was open to all radiographers (n = 48) in a United Kingdom (UK) hospital. Participants provided a PCE for 35 abnormal appendicular cases, which were assessed for the number of words used, lexical density and Gunning-Fog index; comparisons were made with a gold standard. PCE accuracy was evaluated with a scoring system and statistical analysis was completed with SPSS. RESULTS: 21 participants took part. The mean (SD,range) words used was greater than the gold standard (9.5 (3.89,14.9) vs 5.6 (1.46,7)). The mean (SD,range) lexical density was lower than the gold standard (73.8 (4.02,20.1) vs 100 (0,0)), and the mean Gunning-Fog index was also lower (15.1 (3.79,18.3) vs 20.7 (6.82,22.6)). The mean (SD,range) PCE score was 2.8 (0.34,1.17), compared to 5 (0,0) for the gold standard, and this was a statistically significant difference (t (21) = -29,p = .001). CONCLUSION: Participants used too many words in their PCE comments with reduced descriptive content that did not match the reading level of the gold standard. Areas for suggested improvement in practice include introduction of a comment-forming model with additional education. These findings provide an interesting addition to the growing PCE knowledge base. IMPLICATIONS FOR PRACTICE: Dedicated training prior to implementation and participation, to standardise comment structure, could improve the effectiveness of the PCE system.


Assuntos
Pessoal Técnico de Saúde , Competência Clínica , Extremidades , Humanos , Reino Unido , Raios X
12.
J Cell Biol ; 31(1): 55-77, 1966 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-5971975

RESUMO

The fine structure and cytochemistry of the extremely large RNA puffs, or Balbiani rings, in salivary gland nuclei of midge, Chironomus thummi, larvae have been investigated. The Balbiani rings are composed of a diffuse mass of electron-opaque 400 to 500 A granules, short threads about 180 to 220 A in diameter and associated fine chromatin fibrils. These components appear to be organized into brushlike elements which form the ring. Electron microscope cytochemistry has shown that the granules and short threads contain RNA. After ribonuclease digestion, only 50 to 100 A chromatin fibrils were apparent in the Balbiani ring, and the granules were no longer demonstrable. Deoxyribonuclease digestion had no apparent effect on these structures. Observations indicate that the granules are formed from the short threads and released into the nucleoplasm in which they are evenly distributed. At the nuclear envelope, many granules have been observed partially or completely within the nuclear pores. These granules become elongated and are shown to penetrate the center of the pore in a rodlike form, about 200 A in diameter. The Balbiani ring granules are not normally visible within the cytoplasm adjacent to the nuclear envelope, but have been rarely found in this region. It is suggested that the granules represent the product of the Balbiani ring, possibly a messenger RNA bound to protein, and that they regularly pass into the cytoplasm through a narrow central channel in the pores of the nuclear envelope.


Assuntos
Núcleo Celular/metabolismo , Cromossomos/metabolismo , Citoplasma/metabolismo , RNA/metabolismo , Glândulas Salivares/metabolismo , Animais , Transporte Biológico , Nucléolo Celular , Desoxirribonucleases/metabolismo , Dípteros/metabolismo , Histocitoquímica , Microscopia Eletrônica , RNA Mensageiro/metabolismo
13.
J Cell Biol ; 54(3): 468-92, 1972 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-5044756

RESUMO

Highly purified mitochondrial ribosomes (mitoribosomes) have been obtained from the yeast Candida utilis. Sedimentation analysis in sucrose gradients made in 5 mM MgCl(2), 1 mM Tris, pH 7.4 and 50 mM KCl clearly distinguishes mitoribosomes (72S) from cytoplasmic ribosomes (cytoribosomes) (78S). Mitoribosomes are completely dissociated into 50S and 36S subunits at 10(-4)M MgCl(2) whereas complete dissociation of cytoribosomes into 61S and 37S subunits occurs only at 10(-6)M MgCl(2) Electron microscopy of negatively stained mitoribosomes (72S peak) shows bipartite profiles, about 265 x 210 x 200 A Characteristic views are interpreted as frontal, dorsal, and lateral projections of the particles, the latter is observed in two enantiomorphic forms Mitoribosome 50S subunits display rounded profiles bearing a conspicuous knoblike projection, reminiscent of the large bacterial subunit. The 36S subunits show a variety of angular profiles. Mitoribosomal subunits are subject to artifactual dimerization at high Mg(2+) concentration Under these conditions, a supplementary 80S peak arises. Electron microscopic observation of the 80S peak reveals closely paired particles of the 50S type Buoyant density determinations after glutaraldehyde fixation show a single peak at rho = 1.48 for mitoribosomes and 1.53 for cytoribosomes In the presence of ethylenediaminetetraacetate (EDTA), two species of RNA, 21S and 16S, are obtained from mitoribosomes, while 25S and 17S RNA are obtained from cytoribosomes It is established that the small and large RNA species are derived from the 36S and 50S subunits, respectively, by extraction of the RNA from each subunit The G + C content of the RNA is lower for mitoribosomes (33%) than for cytoribosomes (50%). Incubation of C utilis mitochondria with leucine-(14)C results in the labeling of 72S mitoribosomes. The leucine-(14)C incorporation is inhibited by chloramphenicol and resistant to cycloheximide Puromycin strips the incorporated radioactivity from the 72S mitoribosomes, which is consistent with the view that leucine-(14)C is incorporated into nascent polypeptide chains at the level of mitoribosomes


Assuntos
Candida/citologia , Mitocôndrias/análise , Ribossomos/análise , Adenina/análise , Isótopos de Carbono , Centrifugação com Gradiente de Concentração , Cloranfenicol/farmacologia , Citosina/análise , Depressão Química , Guanina/análise , Leucina/metabolismo , Microscopia Eletrônica , Mitocôndrias/metabolismo , Modelos Estruturais , Isótopos de Fósforo , Biossíntese de Proteínas , Puromicina/farmacologia , RNA Ribossômico/análise , RNA Ribossômico/isolamento & purificação , Uracila/análise
14.
J Cell Biol ; 60(3): 628-40, 1974 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-4207397

RESUMO

Mitochondrial and cytoplasmic ribosomes from Tetrahymena pyriformis have been isolated and studied by the techniques of polyacrylamide gel electrophoresis and electron microscopy used in conjunction. Although the two ribosome types show the same coefficient of sedimentation (80S) in sucrose gradients, they can be distinguished by gel electrophoresis: mitoribosomes migrate in a single band, considerably slower than the cytoribosome band. Electron microscope observations of negatively stained cytoribosomes show typical rounded or triangular profiles, about 275 x 230 A; mitoribosome profiles are much larger and clearly elongate, about 370 x 240 A. An electron-opaque spot delimits two nearly equal size subunits. In mixtures of mito- and cytoribosomes, each type can be recognized by its characteristic electrophoretic mobility and by its distinctive fine structure. Cytoribosomal 60S and 40S subunits each produce a distinct electrophoretic band. On the contrary, neither electrophoretic analysis, using a variety of conditions, nor electron microscopy is able to discern two different subunit types in the single 55S mitoribosomal subunit peak. Electrophoretic analysis of RNA shows that both ribosomal RNA species are present in the mitoribosomal subunit fraction. These results establish that mitoribosomes from T. pyriformis dissociate into two subunits endowed with the same sedimentation coefficient, the same electrophoretic mobility, and a similar morphology.


Assuntos
Mitocôndrias/análise , Tetrahymena pyriformis/citologia , Animais , Centrifugação com Gradiente de Concentração , Citoplasma , Eletroforese em Gel de Poliacrilamida , Histocitoquímica , Concentração de Íons de Hidrogênio , Microscopia Eletrônica , RNA/análise , RNA Ribossômico/análise , Ribossomos , Espectrofotometria Ultravioleta
15.
Science ; 287(5461): 2267-71, 2000 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-10731149

RESUMO

Sensory axons become functional late in development when Schwann cells (SC) stop proliferating and differentiate into distinct phenotypes. We report that impulse activity in premyelinated axons can inhibit proliferation and differentiation of SCs. This neuron-glial signaling is mediated by adenosine triphosphate acting through P2 receptors on SCs and intracellular signaling pathways involving Ca2+, Ca2+/calmodulin kinase, mitogen-activated protein kinase, cyclic adenosine 3',5'-monophosphate response element binding protein, and expression of c-fos and Krox-24. Adenosine triphosphate arrests maturation of SCs in an immature morphological stage and prevents expression of O4, myelin basic protein, and the formation of myelin. Through this mechanism, functional activity in the developing nervous system could delay terminal differentiation of SCs until exposure to appropriate axon-derived signals.


Assuntos
Axônios/fisiologia , Proteínas Imediatamente Precoces , Neurônios Aferentes/fisiologia , Células de Schwann/citologia , Células de Schwann/fisiologia , Potenciais de Ação , Trifosfato de Adenosina/metabolismo , Animais , Cálcio/metabolismo , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Diferenciação Celular , Divisão Celular , Células Cultivadas , Técnicas de Cocultura , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteína 1 de Resposta de Crescimento Precoce , Estimulação Elétrica , Gânglios Espinais/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Genes fos , Camundongos , Microscopia Confocal , Bainha de Mielina/metabolismo , Fosforilação , Proteínas Proto-Oncogênicas c-fos/metabolismo , Receptores Purinérgicos P2/metabolismo , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
16.
Science ; 243(4892): 794-6, 1989 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-2916126

RESUMO

Animals clearly choose what they eat and can even choose among chemically different sugars. The physiological and biochemical mechanisms that constrain feeding choices are largely unknown. In this study, European starlings (Sturnus vulgaris) preferred mixture solutions of D-glucose plus D-fructose to equimolar (double molar caloric value) solutions of sucrose. Intubation feeding of sucrose did not increase blood glucose levels. Sucrose is a useless energy source for these birds because they lack a single digestive enzyme (sucrase) on the small intestinal brush border membrane. However, the membranes possessed separate maltase and isomaltase disaccharidases. This expression pattern and expression patterns of membrane disaccharidases among mammals suggest a role for intestinal enzymes in the coevolutionary interactions between vertebrates and their plant food sources.


Assuntos
Aves/fisiologia , Comportamento Alimentar/fisiologia , Intestinos/fisiologia , Animais , Evolução Biológica , Dissacaridases/fisiologia , Dissacarídeos/metabolismo , Mucosa Intestinal/enzimologia , Microvilosidades/enzimologia , Sacarase/metabolismo
17.
Science ; 156(3779): 1234-7, 1967 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-6025542

RESUMO

Mitochondrial DNA of Saccharomyces cerevisiae contains a satellite DNA (density, 1.682) that appears to exist as open-ended filaments at least 5 microns long. DNA from intact cells contains circular filaments whose lengths vary from 0.5 to 7 microns, with a great majority at 1.95 microns. The circular DNA has a density similar to that of the major nuclear peak (1.697). When heat-denatured mitochondrial-satellite DNA is renatured, it cross-links to form a molecule that is larger than the native molecule. The formation of cross-links results in hypersharpening of the density profiles in cesium chloride and also leads to failure to pass Millipore filter paper.


Assuntos
DNA/análise , Mitocôndrias/análise , Saccharomyces/citologia , Centrifugação com Gradiente de Concentração , Técnicas In Vitro , Microscopia Eletrônica
18.
Science ; 270(5240): 1369-72, 1995 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-7481827

RESUMO

Development of the mammalian nervous system is regulated by neural impulse activity, but the molecular mechanisms are not well understood. If cell recognition molecules [for example, L1 and the neural cell adhesion molecule (NCAM)] were influenced by specific patterns of impulse activity, cell-cell interactions controlling nervous system structure could be regulated by nervous system function at critical stages of development. Low-frequency electrical pulses delivered to mouse sensory neurons in culture (0.1 hertz for 5 days) down-regulated expression of L1 messenger RNA and protein (but not NCAM). Fasciculation of neurites, adhesion of neuroblastoma cells, and the number of Schwann cells on neurites was reduced after 0.1-hertz stimulation, but higher frequencies or stimulation after synaptogenesis were without effect.


Assuntos
Moléculas de Adesão de Célula Nervosa/biossíntese , Neurônios Aferentes/metabolismo , Animais , Axônios/fisiologia , Adesão Celular , Células Cultivadas , Regulação para Baixo , Estimulação Elétrica , Gânglios Espinais/citologia , Complexo Antígeno L1 Leucocitário , Camundongos , Fatores de Crescimento Neural/farmacologia , Moléculas de Adesão de Célula Nervosa/genética , Neuritos/fisiologia , Neurônios Aferentes/fisiologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Células de Schwann/fisiologia , Medula Espinal/citologia , Medula Espinal/fisiologia , Células Tumorais Cultivadas
19.
Science ; 179(4078): 1140-2, 1973 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-4120259

RESUMO

Duodenal mucosa obtained from two patients with Menkes' syndrome contained abnormally large amounts of copper. The defect in copper absorption in this disease must lie in the process of intracellular handling or of transport across the serosal cell membrane. Fibroblastic cells cultured from the skin of patients and of heterozygous females show intense metachromasia in primary culture which disappears in subculture. These cells may be useful for the study of copper transport in vitro and for the identification of heterozygotes in affected families.


Assuntos
Encefalopatias/genética , Cobre/metabolismo , Transtornos do Crescimento/metabolismo , Transporte Biológico , Encefalopatias/metabolismo , Células Cultivadas , Pré-Escolar , Aberrações Cromossômicas , Cobre/análise , Feminino , Fibroblastos , Transtornos do Crescimento/genética , Cabelo , Haploidia , Heterozigoto , Humanos , Lactente , Deficiência Intelectual/metabolismo , Mucosa Intestinal/análise , Mucosa Intestinal/metabolismo , Masculino , Pele/análise , Pele/metabolismo , Coloração e Rotulagem
20.
Radiography (Lond) ; 25(3): 214-219, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31301778

RESUMO

INTRODUCTION: Radiographers have been providing reporting solutions for a number of years. Given the persistent radiologist vacancies and the increased demand on imaging services, the utilisation of reporting radiographers is widespread across England. Capacity and demand issues may lead to reporting boundaries being extended. The aim was to generate an updated appraisal of participants' scopes of practice in the West Midlands of region of England. METHOD: Reporting radiographers at 11 healthcare institutions across the West Midlands region were invited to participate in an online survey. Topics covered included reporting scope of practice, onward referrals and suggestion of treatments. Descriptive statistics were generated in Microsoft Excel and free responses were analysed manually. RESULTS: Response rate was 47% (40/86). The majority (n = 34, 85%) report Emergency Department skeletal examinations, only 12 (30%) report adult chests and only three (8%) report paediatric chests. Of those permitted to refer to other modalities, 85% (n = 23/27) actively do so. Of those permitted to refer to specialist teams, 97% (n = 31/32) actively do so. Only 23% of all participants (n = 9/40) suggest treatments in their reports. CONCLUSION: An increased number of participants report chest and abdominal examinations than previously identified. Restrictions in paediatric scopes of practice and adult GP chest examinations are also evident. Participants stated they do include recommendations in their reports by referring to other modalities and for specialist opinions. Suggesting treatment is not common practice and is considered an area for further advancement.


Assuntos
Competência Clínica/normas , Padrões de Prática Médica/normas , Radiografia/normas , Radiologia/normas , Âmbito da Prática , Inglaterra , Humanos , Exame Físico/estatística & dados numéricos , Encaminhamento e Consulta
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