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1.
Epilepsy Behav ; 152: 109666, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38382188

RESUMO

PURPOSE: Although functional seizures can start at any age, little is known about the individuals for whom onset occurs after the age of 40. It has been proposed that health-related traumatic events are more relevant causal factors for people with 'later-onset functional seizures' than for those whose functional seizures begin earlier in life, however, the illness representations of people with later-onset functional seizures have not yet been investigated. This study aimed to understand the experiences and illness representations of people with later-onset functional seizures. METHODS: This was a mixed-methods study. People with later-onset functional seizures were recruited via a neurologist's caseload and online membership-led organisations. Semi-structured interview transcripts were analysed using Template Analysis according to the Common-Sense Model (CSM). Self-report measures of demographic and clinical details were collected to characterise the sample and verify themes. RESULTS: Eight people with later-onset functional seizures participated in the study. Illness representations relating to all domains of the CSM as well as an additional theme of 'Triggers' were identified. Functional seizures were characterised as a mysterious brain disorder analogous to a computer malfunction and involving involuntary movements associated with alterations in consciousness. Perceptions of duration were indefinite, and triggers were unknown or at the extremes of autonomic arousal. Half of the sample identified health-related events/trauma as causal. Opinions were divided on 'cumulative life stress' as a causal factor. Most perceived themselves to have limited or no control but having 'control' over seizures was conceptualised as different to reducing their likelihood, frequency, or impact. Later-onset functional seizures were viewed as being more detrimental for caring and financial responsibilities but to have advantages for acceptance. CONCLUSIONS: This is the first study to assess the illness representations of people with later-onset functional seizures. Many themes were similar to those identified in samples including people with earlier-onset functional seizures. Health-related trauma or events were the most strongly endorsed perceived causal factor, but with the exception of 'consequences', all representations were characterised by uncertainty. Clinicians should hold in mind the interaction between life stage and the consequences of later-onset functional seizures.


Assuntos
Encefalopatias , Convulsões , Humanos , Atitude
2.
Biol Lett ; 19(1): 20220101, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36651028

RESUMO

Mitigation measures to disperse marine mammals prior to pile-driving include acoustic deterrent devices and piling soft starts, but their efficacy remains uncertain. We developed a self-contained portable hydrophone cluster to detect small cetacean movements from the distributions of bearings to detections. Using an array of clusters within 10 km of foundation pile installations, we tested the hypothesis that harbour porpoises (Phocoena phocoena) respond to mitigation measures at offshore windfarm sites by moving away. During baseline periods, porpoise movements were evenly distributed in all directions. By contrast, animals showed significant directional movement away from sound sources during acoustic deterrent device use and piling soft starts. We demonstrate that porpoises respond to measures aimed to mitigate the most severe impacts of construction at offshore windfarms by swimming directly away from these sound sources. Portable directional hydrophone clusters now provide opportunities to characterize responses to disturbance sources across a broad suite of habitats and contexts.


Assuntos
Phocoena , Som , Animais , Phocoena/fisiologia , Ecossistema , Acústica
3.
AIDS Behav ; 26(8): 2746-2757, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35182283

RESUMO

We examined PrEP use, condomless anal sex (CAS), and PrEP adherence among men who have sex with men (MSM) attending sexual health clinics in Wales, UK. In addition, we explored the association between the introduction of measures to control transmission of SARS-CoV-2 on these outcomes. We conducted an ecological momentary assessment study of individuals in receipt of PrEP in Wales. Participants used an electronic medication cap to record PrEP use and completed weekly sexual behaviour surveys. We defined adherence to daily PrEP as the percentage of CAS episodes covered by daily PrEP (preceded by ≥ 3 days of PrEP and followed by ≥ 2 days). Sixty participants were recruited between September 2019 and January 2020. PrEP use data prior to the introduction of control measures were available over 5785 person-days (88%) and following their introduction 7537 person-days (80%). Data on CAS episodes were available for 5559 (85%) and 7354 (78%) person-days prior to and following control measures respectively. Prior to the introduction of control measures, PrEP was taken on 3791/5785 (66%) days, there were CAS episodes on 506/5559 (9%) days, and 207/406 (51%) of CAS episodes were covered by an adequate amount of daily PrEP. The introduction of pandemic-related control measures was associated with a reduction in PrEP use (OR 0.44, 95%CI 0.20-0.95), CAS (OR 0.35, 95%CI 0.17-0.69), and PrEP adherence (RR = 0.55, 95%CI 0.34-0.89) and this may have implications for the health and wellbeing of PrEP users and, in addition to disruption across sexual health services, may contribute to wider threats across the HIV prevention cascade.


Assuntos
Fármacos Anti-HIV , COVID-19 , Infecções por HIV , Profilaxia Pré-Exposição , Minorias Sexuais e de Gênero , Fármacos Anti-HIV/uso terapêutico , COVID-19/epidemiologia , COVID-19/prevenção & controle , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Infecções por HIV/prevenção & controle , Homossexualidade Masculina , Humanos , Masculino , Adesão à Medicação , Pandemias/prevenção & controle , SARS-CoV-2 , Comportamento Sexual , País de Gales/epidemiologia
4.
BMC Pregnancy Childbirth ; 22(1): 692, 2022 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-36076161

RESUMO

BACKGROUND: Almost two million stillbirths occur annually, most occurring in low- and middle-income countries. Nigeria is reported to have one of the highest stillbirth rates on the African continent. The aim was to identify sociodemographic, living environment, and health status factors associated with stillbirth and determine the associations between pregnancy and birth factors and stillbirth in the Murtala Mohammed Specialist Hospital, Kano, Nigeria. METHODS: A three-month single-site prospective observational feasibility study. Demographic and clinical data were collected. We fitted bivariable and multivariable models for stillbirth (yes/no) and three-category livebirth/macerated stillbirth/non-macerated stillbirth outcomes to explore their association with demographic and clinical factors. FINDINGS: 1,998 neonates and 1,926 mothers were enrolled. Higher odds of stillbirth were associated with low-levels of maternal education, a further distance to travel to the hospital, living in a shack, maternal hypertension, previous stillbirth, birthing complications, increased duration of labour, antepartum haemorrhage, prolonged or obstructed labour, vaginal breech delivery, emergency caesarean-section, and signs of trauma to the neonate following birth. INTERPRETATION: This work has obtained data on some factors influencing stillbirth. This in turn will facilitate the development of improved public health interventions to reduce preventable deaths and to progress maternal health within this site.


Assuntos
Saúde Materna , Natimorto , Feminino , Humanos , Incidência , Recém-Nascido , Nigéria/epidemiologia , Gravidez , Natimorto/epidemiologia , Atenção Terciária à Saúde
5.
J Acoust Soc Am ; 152(6): 3170, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36586823

RESUMO

During the COVID-19 pandemic, changes in vessel activity and associated noise have been reported globally. Sarasota Bay is home to a large and increasing number of recreational vessels as well as a long-term resident community of bottlenose dolphins, Tursiops truncatus. Data were analyzed from two hydrophones to compare the soundscape during the COVID-19 pandemic to previous years (March-May 2020 and 2018/2019). Hourly metrics were calculated: vessel passes, 95th percentile sound levels [125 Hz and 16 kHz third octave bands (TOBs), and two broader bands: 88-1122 Hz and 1781-17 959 Hz], and dolphin whistle detection to understand changes in vessel activity and the effect on wildlife. Vessel activity increased during COVID-19 restrictions by almost 80% at one site and remained the same at the other site. Of the four sound level measures, only the 125 Hz TOB and 88-1122 Hz band increased with vessel activity at both sites, suggesting that these may be appropriate measures of noise from rapid pass-bys of small vessels in very shallow (<10 m) habitats. Dolphin whistle detection decreased during COVID-19 restrictions at one site but remained the same at the site that experienced increased vessel activity. The results suggest that pandemic effects on wildlife should not be viewed as homogeneous globally.


Assuntos
Golfinho Nariz-de-Garrafa , COVID-19 , Animais , Humanos , Pandemias , Baías , COVID-19/epidemiologia , Ecossistema , Animais Selvagens
6.
Rhinology ; 60(3): 188-199, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35901492

RESUMO

BACKGROUND: Olfactory dysfunction is a cardinal symptom of COVID-19 infection, however, studies assessing long-term olfactory dysfunction are limited and no randomised-controlled trials (RCTs) of early olfactory training have been conducted. METHODOLOGY: We conducted a prospective, multi-centre study consisting of baseline psychophysical measurements of smell and taste function. Eligible participants were further recruited into a 12-week RCT of olfactory training versus control (safety information). Patient-reported outcomes were measured using an electronic survey and BSIT at baseline and 12 weeks. An additional 1-year follow-up was open to all participants. RESULTS: 218 individuals with a sudden loss of sense of smell of at least 4-weeks were recruited. Psychophysical smell loss was observed in only 32.1%; 63 participants were recruited into the RCT. The absolute difference in BSIT improvement after 12 weeks was 0.45 higher in the intervention arm. 76 participants completed 1-year follow-up; 10/19 (52.6%) of participants with an abnormal baseline BSIT test scored below the normal threshold at 1-year, and 24/29 (82.8%) had persistent parosmia. CONCLUSIONS: Early olfactory training may be helpful, although our findings are inconclusive. Notably, a number of individuals who completed the 1-year assessment had persistent smell loss and parosmia at 1-year. As such, both should be considered important entities of long-Covid and further studies to improve management are highly warranted.


Assuntos
COVID-19 , Transtornos do Olfato , Humanos , Olfato , COVID-19/complicações , Anosmia/etiologia , Treinamento Olfativo , Transtornos do Olfato/etiologia , Transtornos do Olfato/diagnóstico
7.
Rhinology ; 60(3): 207-217, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35398877

RESUMO

BACKGROUND: Sudden smell loss is a specific early symptom of COVID-19, which, prior to the emergence of Omicron, had estimated prevalence of ~40% to 75%. Chemosensory impairments affect physical and mental health, and dietary behavior. Thus, it is critical to understand the rate and time course of smell recovery. The aim of this cohort study was to characterize smell function and recovery up to 11 months post COVID-19 infection. METHODS: This longitudinal survey of individuals suffering COVID-19-related smell loss assessed disease symptoms and gustatory and olfactory function. Participants (n=12,313) who completed an initial survey (S1) about respiratory symptoms, chemosensory function and COVID-19 diagnosis between April and September 2020, were invited to complete a follow-up survey (S2). Between September 2020 and February 2021, 27.5% participants responded (n=3,386), with 1,468 being diagnosed with COVID-19 and suffering co-occurring smell and taste loss at the beginning of their illness. RESULTS: At follow-up (median time since COVID-19 onset ~200 days), ~60% of women and ~48% of men reported less than 80% of their pre-illness smell ability. Taste typically recovered faster than smell, and taste loss rarely persisted if smell recovered. Prevalence of parosmia and phantosmia was ~10% of participants in S1 and increased substantially in S2: ~47% for parosmia and ~25% for phantosmia. Persistent smell impairment was associated with more symptoms overall, suggesting it may be a key marker of long-COVID illness. The ability to smell during COVID-19 was rated slightly lower by those who did not eventually recover their pre-illness ability to smell at S2. CONCLUSIONS: While smell ability improves for many individuals who lost it during acute COVID-19, the prevalence of parosmia and phantosmia increases substantially over time. Olfactory dysfunction is associated with broader persistent symptoms of COVID-19, and may last for many months following acute COVID-19. Taste loss in the absence of smell loss is rare. Persistent qualitative smell symptoms are emerging as common long-term sequelae; more research into treatment options is strongly warranted given that even conservative estimates suggest millions of individuals may experience parosmia following COVID-19. Healthcare providers worldwide need to be prepared to treat post COVID-19 secondary effects on physical and mental health.


Assuntos
Ageusia , COVID-19 , Transtornos do Olfato , Masculino , Humanos , Feminino , COVID-19/complicações , Olfato , Anosmia/etiologia , SARS-CoV-2 , Estudos de Coortes , Teste para COVID-19 , Seguimentos , Síndrome de COVID-19 Pós-Aguda , Transtornos do Olfato/epidemiologia , Transtornos do Olfato/etiologia , Transtornos do Olfato/diagnóstico
8.
J Intellect Disabil Res ; 62(9): 798-813, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30033655

RESUMO

BACKGROUND: One in five adults with intellectual disabilities (ID) known to services display challenging behaviours (CBs), and these individuals are at risk for restrictive practices and poor care. Staff attitudes may contribute to the development and/or maintenance of CBs. We investigated the effectiveness of co-produced Who's Challenging Who? training delivered by people with ID to staff. METHOD: This study involved a cluster randomised controlled trial (RCT) of Who's Challenging Who? training with follow-up at six and 20 weeks post-randomisation. PARTICIPANTS: two staff from each of 118 residential care settings for adults with ID at least one of whom displayed aggressive CB. PRIMARY OUTCOME: Self-reported Staff Empathy for people with Challenging Behaviour Questionnaire. ANALYSIS: intention to treat of all randomised settings. ISCRTN registration: ISRCTN53763600. RESULTS: 118 residential settings (including 236 staff) were randomised to either receive training (59 settings) or to receive training after a delay (59 settings). The primary analysis included data from 121 staff in 76 settings (51% of staff, 64% of settings). The adjusted mean difference on the transformed (cubed) Staff Empathy for people with Challenging Behaviour Questionnaire score at the primary end point was 1073.2 (95% CI: -938.1 to 3084.5, P = 0.296) in favour of the intervention group (effect size Cohen's d = .19). CONCLUSIONS: This is the first large-scale RCT of a co-produced training course delivered by people with ID. Findings indicated a small positive (but statistically non-significant) effect on increased staff empathy at 20 weeks, and small to moderate effects for staff reported secondary outcomes in favour of the intervention group.


Assuntos
Atitude do Pessoal de Saúde , Empatia , Pessoal de Saúde/educação , Deficiência Intelectual/complicações , Deficiência Intelectual/reabilitação , Transtornos Mentais/complicações , Adulto , Análise por Conglomerados , Feminino , Humanos , Capacitação em Serviço/métodos , Masculino , Inquéritos e Questionários
10.
J Intellect Disabil Res ; 59(1): 68-81, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24404992

RESUMO

BACKGROUND: Anger and aggression among adults with intellectual disability (ID) are associated with a range of adverse consequences for their well-being and that of their family or staff carers. The aims were to evaluate the effectiveness of an anger management intervention for adults with mild to moderate ID and to evaluate the costs of the intervention and its impact on health and social care resource use. This paper is concerned with the latter aim. METHODS: A cluster-randomised controlled trial was conducted involving day services for adults with ID in Scotland, England and Wales. Incremental costs of delivering the intervention and its impact on subsequent total health and social care package costs were calculated. Full data comparing costs between baseline and follow-up 10 months later were collected for 67 participants in the intervention arm and 62 participants in the control arm. Cost differences between the groups at follow-up, adjusted for baseline levels, were calculated using non-parametric bootstrapping controlling for clustering. RESULTS: The mean hourly excess cost of intervention over treatment as usual was £12.34. A mean adjusted cost difference of £22.46 per person per week in favour of the intervention group was found but this was not statistically significant. CONCLUSIONS: The baseline-adjusted cost difference at follow-up would result in a fairly immediate compensation for the excess costs of intervention, provided the difference is not a statistical artefact. Further research is needed to clarify the extent to which it might represent a real saving in service support costs.


Assuntos
Ira/fisiologia , Terapia Cognitivo-Comportamental/economia , Serviços de Saúde/economia , Deficiência Intelectual/economia , Deficiência Intelectual/terapia , Adulto , Inglaterra , Feminino , Seguimentos , Serviços de Saúde/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Escócia , País de Gales
11.
Clin Exp Immunol ; 177(2): 531-43, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24749746

RESUMO

While murine CD4(+) CD39(+) regulatory T cells (T(reg)) co-express CD73 and hydrolyze exogenous (e) adenosine triphosphate (ATP) to immunosuppressive adenosine (ADO), surface co-expression of CD73 on human circulating CD4(+) CD39(+) T(reg) is rare. Therefore, the ability of human T(reg) to produce and utilize ADO for suppression remains unclear. Using mass spectrometry, we measured nucleoside production by subsets of human CD4(+) CD39(+) and CD4(+) CD39(-)CD73(+) T cells or CD19(+) B cells isolated from blood of 30 volunteers and 14 cancer patients. CD39 and CD73 expression was evaluated by flow cytometry, Western blots, confocal microscopy or reverse transcription-polymerase chain reaction (RT-PCR). Circulating CD4(+) CD39(+) T(reg) which hydrolyzed eATP to 5'-AMP contained few intracytoplasmic granules and had low CD73 mRNA levels. Only ∼1% of these T(reg) were CD39(+) CD73(+) . In contrast, CD4(+) CD39(neg) CD73(+) T cells contained numerous CD73(+) granules in the cytoplasm and strongly expressed surface CD73. In vitro-generated T(reg) (Tr1) and most B cells were CD39(+) CD73(+) . All these CD73(+) T cell subsets and B cells hydrolyzed 5'-AMP to ADO. Exosomes isolated from plasma of normal control (NC) or cancer patients carried enzymatically active CD39 and CD73(+) and, when supplied with eATP, hydrolyzed it to ADO. Only CD4(+) CD39(+) T(reg) co-incubated with CD4(+) CD73(+) T cells, B cells or CD39(+) CD73(+) exosomes produced ADO. Thus, contact with membrane-tethered CD73 was sufficient for ADO production by CD4(+) CD39(+) T(reg). In microenvironments containing CD4(+) CD73(+) T cells, B cells or CD39(+) CD73(+) exosomes, CD73 is readily available to CD4(+) CD39(+) CD73(neg) T(reg) for the production of immunosuppressive ADO.


Assuntos
5'-Nucleotidase/metabolismo , Adenosina/biossíntese , Exossomos/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , 5'-Nucleotidase/genética , Antígenos CD/metabolismo , Apirase/metabolismo , Linhagem Celular , Membrana Celular/metabolismo , Células Cultivadas , Expressão Gênica , Humanos , Imunofenotipagem , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Ativação Linfocitária , Neoplasias/genética , Neoplasias/imunologia , Neoplasias/metabolismo , Fenótipo , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo
12.
Nat Microbiol ; 7(9): 1337-1347, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35927336

RESUMO

Early development of the microbiome has been shown to affect general health and physical development of the infant and, although some studies have been undertaken in high-income countries, there are few studies from low- and middle-income countries. As part of the BARNARDS study, we examined the rectal microbiota of 2,931 neonates (term used up to 60 d) with clinical signs of sepsis and of 15,217 mothers screening for blaCTX-M-15, blaNDM, blaKPC and blaOXA-48-like genes, which were detected in 56.1%, 18.5%, 0% and 4.1% of neonates' rectal swabs and 47.1%, 4.6%, 0% and 1.6% of mothers' rectal swabs, respectively. Carbapenemase-positive bacteria were identified by MALDI-TOF MS and showed a high diversity of bacterial species (57 distinct species/genera) which exhibited resistance to most of the antibiotics tested. Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae/E. cloacae complex, the most commonly found isolates, were subjected to whole-genome sequencing analysis and revealed close relationships between isolates from different samples, suggesting transmission of bacteria between neonates, and between neonates and mothers. Associations between the carriage of antimicrobial resistance genes (ARGs) and healthcare/environmental factors were identified, and the presence of ARGs was a predictor of neonatal sepsis and adverse birth outcomes.


Assuntos
Microbioma Gastrointestinal , Sepse , Antibacterianos , Países em Desenvolvimento , Resistência Microbiana a Medicamentos , Escherichia coli , Feminino , Humanos , Lactente , Recém-Nascido , Testes de Sensibilidade Microbiana , Mães
13.
Eur Respir J ; 35(4): 761-7, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20032009

RESUMO

Little is known about actual clinical practice regarding management of smokers compared with ex-smokers and nonsmokers presenting with acute cough in primary care, and whether a lower threshold for prescribing antibiotics benefits smokers. This was a multicentre 13-country European prospective observational study of primary care clinician management of acute cough in consecutive immunocompetent adults presenting with an acute cough of

Assuntos
Antibacterianos/uso terapêutico , Padrões de Prática Médica/estatística & dados numéricos , Atenção Primária à Saúde/estatística & dados numéricos , Infecções Respiratórias/tratamento farmacológico , Infecções Respiratórias/epidemiologia , Fumar/epidemiologia , Doença Aguda , Adulto , Idoso , Atitude do Pessoal de Saúde , Tosse/tratamento farmacológico , Tosse/epidemiologia , Prescrições de Medicamentos/estatística & dados numéricos , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Índice de Gravidade de Doença
14.
AIDS Care ; 22(10): 1295-304, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20665282

RESUMO

Despite political endorsement of voluntary HIV counseling and testing (VCT), and family planning integration in Ethiopia, little is known about the reproductive health needs of VCT clients. We estimated contraceptive prevalence and need among 646 Ethiopian female VCT clients. We compared socio-demographic characteristics of contracepting VCT clients to those with unmet need and examined how these characteristics are associated with having unmet contraceptive need and being HIV-positive using multinomial logistic regression. We also assessed the quality of VCT services from clients' reports of reproductive health topics discussed in VCT sessions. Nearly 34% of female VCT clients have unmet contraceptive need. Three socio-demographic characteristics are consistently associated with both risk for unintended pregnancy and HIV: older age, marriage, and lower education. In the multivariate analysis, older age, marriage, and belonging to a minority ethnic group are significantly associated with being both HIV-positive and having unmet contraceptive need. Conversely, higher education, larger families, and frequent sexual activity are associated with reduced likelihood of experiencing these two adverse health outcomes. VCT clients report infrequent reproductive health counseling, although HIV-positive women are more likely than HIV-negative women to have discussions about contraception with VCT counselors. At the time of this study, family planning was not offered as part of VCT programs, although VCT clients demonstrate considerable need for contraceptive services.


Assuntos
Comportamento Contraceptivo , Infecções por HIV , Necessidades e Demandas de Serviços de Saúde , Serviços de Saúde Reprodutiva/normas , Adolescente , Adulto , Aconselhamento/normas , Atenção à Saúde/normas , Etiópia , Feminino , Infecções por HIV/diagnóstico , Infecções por HIV/prevenção & controle , Humanos , Modelos Logísticos , Análise Multivariada , Adulto Jovem
15.
Bull Entomol Res ; 100(3): 255-61, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19586578

RESUMO

Parasitoids are dependent on their hosts, which provide all of the resources for larval development. Parasitoid fitness, therefore, is directly related to the host quality, as determined by host size, age and health (e.g. parasitisation status); and this can only be assessed by the female parasitoid during host selection. Most studies of parasitoid-host interactions have focused on hymenopteran parasitoids rather than dipterans that are believed to be less discriminating during host selection. We assessed the impact of host quality and superparasitism on parasitoid fitness in Compsilura concinnata Meigen, a gregarious tachinid dipteran parasitoid, and its lepidopteran host the cabbage looper, Trichoplusia ni Hübner. Female C. concinnata parasitised all host stages of T. ni that were presented to them, but emergence rates were higher from older hosts. Females readily superparasitised hosts. The number of flies emerging was higher from hosts parasitised at later instars, and flies emerged earlier from heavily superparasitised hosts. Superparasitism decreased parasitoid pupal weight and development time, indicating intra-host competition between parasitoid larvae and skewed the parasitoid sex ratio in favour of males. Host discrimination does not seem to be well developed in C. concinnata. Hosts are superparasitised despite the effects of superparasitism on offspring and sex ratio. This could be due to the wide host range of C. concinnata; avoiding high superparasitism could occur naturally due to host switching and, therefore, developing host discrimination mechanisms for one host species may not be crucial.


Assuntos
Dípteros/fisiologia , Interações Hospedeiro-Parasita , Mariposas/parasitologia , Animais , Feminino , Larva/parasitologia , Masculino , Mariposas/crescimento & desenvolvimento
16.
Science ; 196(4292): 889-91, 1977 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-870965

RESUMO

Repeated DNA sequences in primates having identical or nearly identical members and exhibiting unusual phylogenetic specificity were analyzed. They appeared in repeated DNA sequences in each group of primates, probably within the last 10 to 15 million years, and are conserved to the same extent as unique DNA sequences. The finding allows a new approach to the construction of evolutionary trees.


Assuntos
Evolução Biológica , DNA , Primatas/fisiologia , Animais , Sequência de Bases , Hibridização de Ácido Nucleico , Filogenia
17.
Science ; 188(4190): 802-11, 1975 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-47650

RESUMO

The results of molecular hybridization experiments with high-molecular-weight RNA isolated from RNA tumor viruses and DNA from normal cells suggest that RNA tumor virus genomes originate from cell genes. Some RNA tumor viruses (here called class 1) appear to have been generated in recent times in that their RNA is closely related in nucleotide sequence to certain cell genes (class 1 genes). A second class of RNA tumor viruses (here called class 2) is more distantly related to genomic information of normal cells. Structural properties of the RNA of RNA tumor viruses lead us to propose that the tumor virus RNA is originated when RNA transcripts of class 1 genes are processed by a mechanism we call "paraprocessing." We postulate that RNA paraprocessing is normally used only at particular times during differentiation and is characterized by the cytoplasmic appearance of high-molecular-weight RNA chains containing terminal polyadenylic acid (200 residues). Paraprocessing of class 1 gene transcripts in committed or differentiated cells is considered to be aberrant in transcription that can lead to the generation of an RNA tumor virus genome. If the paraprocessed class 1 gene transcript codes for a reverse transcriptase, replication of the RNA becomes possible. Transfer of the replicating RNA to a new cell can result in genetic change such that the virus genome mutates, differing from the original progenitor genes. We propose that this genetic change causes class 1 viruses to become class 2. These ideas are applied to evidence concerning the biology of infection of RNA tumor viruses and concerning the involvement of RNA tumor viruses in human cancer. Genetic change can also occur during the origination of an RNA tumor virus genome by repeated reverse transcription and recombination (45) or by genetic alteration of particularly changeable cell genes ("hot spots") (43).


Assuntos
Evolução Biológica , Genes , Vírus Oncogênicos/metabolismo , Vírus de RNA/metabolismo , RNA Viral/metabolismo , Transcrição Gênica , Animais , Sequência de Bases , Gatos , Linhagem Celular , Galinhas , DNA/análise , Código Genético , Haplorrinos , Humanos , Camundongos , Mutação , Neoplasias/microbiologia , Hibridização de Ácido Nucleico , Nucleotídeos/análise , RNA Mensageiro/metabolismo , RNA Neoplásico/biossíntese , RNA Neoplásico/metabolismo , RNA Viral/análise , DNA Polimerase Dirigida por RNA/metabolismo , Recombinação Genética
18.
Science ; 290(5498): 1968-72, 2000 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-11110664

RESUMO

Feedforward models of visual cortex appear to be inconsistent with a well-known property of cortical cells: contrast invariance of orientation tuning. The models' fixed threshold broadens orientation tuning as contrast increases, whereas in real cells tuning width is invariant with contrast. We have compared the orientation tuning of spike and membrane potential responses in single cells. Both are contrast invariant, yet a threshold-linear relation applied to the membrane potential accurately predicts the orientation tuning of spike responses. The key to this apparent paradox lies in the noisiness of the membrane potential. Responses that are subthreshold on average are still capable of generating spikes on individual trials. Unlike the iceberg effect, contrast invariance remains intact even as threshold narrows orientation selectivity. Noise may, by extension, smooth the average relation between membrane potential and spike rate throughout the brain.


Assuntos
Sensibilidades de Contraste , Neurônios/fisiologia , Orientação , Córtex Visual/fisiologia , Percepção Visual , Potenciais de Ação , Animais , Gatos , Potenciais da Membrana , Microeletrodos , Modelos Neurológicos , Rede Nervosa/fisiologia , Técnicas de Patch-Clamp , Estimulação Luminosa , Córtex Visual/citologia
19.
Science ; 179(4074): 696-8, 1973 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-4346428

RESUMO

RNA tumor viruses and viruslike particles from human milk are quantitated by hybridization of the polyadenylic acid regions in their 60S to 70S RNA to radioactive polyribouridylic acid of known specific activity. The length of the polyadenylic acid region in the 60S to 70S RNA of the human milk particle is identical to that of the known oncogenic RNA viruses.


Assuntos
Leite Humano/microbiologia , Hibridização de Ácido Nucleico , Vírus Oncogênicos/isolamento & purificação , Polinucleotídeos/metabolismo , Vírus de RNA/isolamento & purificação , RNA Viral/metabolismo , Vírus da Leucose Aviária/metabolismo , Eletroforese em Gel de Poliacrilamida , Humanos , Peso Molecular , Poli U/metabolismo , Polinucleotídeos/análise , Vírus de RNA/metabolismo , RNA Viral/análise , Retroviridae/isolamento & purificação , Trítio
20.
Science ; 179(4080): 1328-30, 1973 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-4631425

RESUMO

Visna virus 70S RNA contains long stretches of polyadenylic acid [poly(A)]. The homogeneity in length of poly(4) regions is observed in 70S RNA from visna virus and all RNA tumor viruses tested, and not with other types of RNA. By this criterion visna virus resembles RNA tumor viruses.


Assuntos
Monofosfato de Adenosina/análise , Polinucleotídeos/análise , Centrifugação Zonal , Eletroforese em Gel de Poliacrilamida , Hibridização Genética , Príons , RNA Viral/análise , Trítio
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