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1.
Aust Vet J ; 101(11): 453-459, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37644778

RESUMO

The successful rehabilitation and release of raptor chicks can be challenging, especially when the chicks are still in the post-fledging dependency period. Here, we report on a recently fledged powerful owl chick that was held in care for 33 days before being successfully reunited with its parents. We document the steps undertaken during the entire process from collection from the wild to post-release monitoring and recommend clinical procedures for treatment of raptors entering veterinary facilities. Success of this rehabilitation was facilitated by early care and treatment for potential rodenticide poisoning, as well as the integration of citizen scientists monitoring the family unit in the field while the chick was in care and during the post-release period. Given the emerging evidence of widespread rodenticide poisoning in raptors both in Australia and globally, it is critical to suspect all raptors may have been exposed to anticoagulant rodenticides and commence treatment with vitamin K immediately. Routine treatment for rodenticides early increases the probability of successful recovery post-trauma as well as reducing the time in treatment as much as possible.


Assuntos
Aves Predatórias , Rodenticidas , Estrigiformes , Animais , Anticoagulantes , Galinhas
2.
Nat Commun ; 10(1): 3593, 2019 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-31399564

RESUMO

Filopodia, dynamic membrane protrusions driven by polymerization of an actin filament core, can adhere to the extracellular matrix and experience both external and cell-generated pulling forces. The role of such forces in filopodia adhesion is however insufficiently understood. Here, we study filopodia induced by overexpression of myosin X, typical for cancer cells. The lifetime of such filopodia positively correlates with the presence of myosin IIA filaments at the filopodia bases. Application of pulling forces to the filopodia tips through attached fibronectin-coated laser-trapped beads results in sustained growth of the filopodia. Pharmacological inhibition or knockdown of myosin IIA abolishes the filopodia adhesion to the beads. Formin inhibitor SMIFH2, which causes detachment of actin filaments from formin molecules, produces similar effect. Thus, centripetal force generated by myosin IIA filaments at the base of filopodium and transmitted to the tip through actin core in a formin-dependent fashion is required for filopodia adhesion.


Assuntos
Forminas/metabolismo , Miosinas/metabolismo , Neoplasias/metabolismo , Miosina não Muscular Tipo IIA/metabolismo , Pseudópodes/fisiologia , Citoesqueleto de Actina , Animais , Células COS , Chlorocebus aethiops , Forminas/antagonistas & inibidores , Forminas/genética , Forminas/ultraestrutura , Regulação Neoplásica da Expressão Gênica , Células HeLa , Humanos , Proteínas dos Microfilamentos , Miosina não Muscular Tipo IIA/antagonistas & inibidores , Miosina não Muscular Tipo IIA/genética , Miosina não Muscular Tipo IIA/ultraestrutura , Pseudópodes/patologia , Tionas/farmacologia , Uracila/análogos & derivados , Uracila/farmacologia
3.
Cell ; 174(2): 338-349.e20, 2018 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-29937223

RESUMO

Macromolecular crowding has a profound impact on reaction rates and the physical properties of the cell interior, but the mechanisms that regulate crowding are poorly understood. We developed genetically encoded multimeric nanoparticles (GEMs) to dissect these mechanisms. GEMs are homomultimeric scaffolds fused to a fluorescent protein that self-assemble into bright, stable particles of defined size and shape. By combining tracking of GEMs with genetic and pharmacological approaches, we discovered that the mTORC1 pathway can modulate the effective diffusion coefficient of particles ≥20 nm in diameter more than 2-fold by tuning ribosome concentration, without any discernable effect on the motion of molecules ≤5 nm. This change in ribosome concentration affected phase separation both in vitro and in vivo. Together, these results establish a role for mTORC1 in controlling both the mesoscale biophysical properties of the cytoplasm and biomolecular condensation.


Assuntos
Citoplasma/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Difusão , Células HEK293 , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina/antagonistas & inibidores , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Nanopartículas/química , Nanopartículas/metabolismo , Tamanho da Partícula , Plasmídeos/genética , Plasmídeos/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Reologia , Ribossomos/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteína 1 do Complexo Esclerose Tuberosa/antagonistas & inibidores , Proteína 1 do Complexo Esclerose Tuberosa/genética , Proteína 1 do Complexo Esclerose Tuberosa/metabolismo
4.
Br J Anaesth ; 120(1): 138-145, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29397121

RESUMO

Patients with severe grades of life-threatening brain injury are commonly characterized as having devastating brain injury (DBI), which we have defined as: 'any neurological condition that is assessed at the time of hospital admission as an immediate threat to life or incompatible with good functional recovery AND where early limitation or withdrawal of therapy is being considered'. The outcome in patients with DBI is often death or severe disability, and as a consequence rapid withdrawal of life sustaining therapies is commonly contemplated or undertaken. However, accurate prognostication in life-threatening brain injury is difficult, particularly at an early stage. Evidence from controlled studies to guide decision-making is limited, and there is a risk of a 'self-fulfilling prophecy', with early prognostication leading to early withdrawal of life sustaining therapies and death. The Joint Professional Standards committee of the Faculty of Intensive Care Medicine and the Intensive Care Society convened a consensus group with representation from stakeholder professional organizations to develop clear professional guidance in this area. It recognized that the weak evidence base makes GRADE guidelines difficult to justify. We have made 12 practical, pragmatic recommendations to help clinicians deliver safe, effective, equitable, and justifiable care within resource constrained healthcare systems. In the situation where patient-centred outcomes are recognized to be unacceptable, regardless of the extent of neurological improvement, then early transition to palliative care is appropriate. These recommendations are intended to apply where the primary pathology is DBI, rather than where DBI has compounded a progressive and irreversible deterioration in other life-threatening comorbidities.


Assuntos
Lesões Encefálicas/terapia , Lesões Encefálicas/diagnóstico , Tomada de Decisão Clínica , Consenso , Cuidados Críticos , Guias como Assunto , Humanos , Cuidados Paliativos , Assistência Centrada no Paciente , Prognóstico , Sociedades Médicas
5.
J Hosp Infect ; 97(4): 430-432, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28602706

RESUMO

The car parks at the study hospital are accessed using re-usable, machine-read tickets. In the initial phase of this study, 598 staff members were observed entering the car park, and 21.6% of them put their parking ticket in their mouth. Ultraviolet dye was used to demonstrate card-to-card cross-contamination. Swabs of the ticket machine yielded commensal bacteria: coagulase-negative staphylococci and a Bacillus sp. After placing a poster on the ticket-reading machine highlighting the potential risk of infection, a further 1366 observations demonstrated a significant and persistent decline in the proportion of staff who put their ticket in their mouth (P<0.001).


Assuntos
Bacillus/isolamento & purificação , Transmissão de Doença Infecciosa/prevenção & controle , Microbiologia Ambiental , Staphylococcus/isolamento & purificação , Humanos
6.
Br J Oral Maxillofac Surg ; 55(2): 164-167, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27810115

RESUMO

Noise in the operating theatre has an adverse impact on healthcare professionals, both physically and psychologically. It can be distracting, make communication difficult, and contribute to a perceived increase in stress. Staff in theatre must deliver high quality care, and overlook noise as a potentially damaging influence. The aim of this survey was to obtain further information about the perspective of healthcare professionals on how noise can affect their practice and whether it affects their work in theatre. We distributed six closed-ended questions in the form of a Survey Monkey® questionnaire to about 50 hospitals across the UK and target groups such as medical students, the Leeds Advanced Trauma Life Support faculty group, the Court of Examiners of the Royal College of Surgeons of England, and surgical trainees sitting the Member of the Royal College of Surgeons examination. We received 519 responses of which 415 respondents (83%) thought that noise contributed to human errors. A total of 282 participants (57%) thought that the theatre was the noisiest area within the theatre suite. Both communication among staff (n=400, 80%) and concentration (n=384, 77%) were thought to be adversely affected by noise. However, 385 (78%) did not feel that music adversely affected their performance. The results provide insights into the interplay of noise and its effect on people. Although the role of music remains contentious, our results suggest that it might have a calming influence.


Assuntos
Atitude do Pessoal de Saúde , Ruído Ocupacional , Salas Cirúrgicas , Procedimentos Cirúrgicos Operatórios , Análise e Desempenho de Tarefas , Humanos , Autorrelato
7.
Br J Surg ; 102(4): 423-30, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25644529

RESUMO

BACKGROUND: Human factors including stress, repetition, burnout and fatigue are associated with possible sources of error. Objective structured clinical examinations (OSCEs), where examiners concentrate for long periods, would benefit from a human factors approach to see whether these factors affect consistency of examiner behaviour, attitude and marking. Little has been published for OSCEs, in part due to the lack of a validated tool for collecting data in this setting. METHODS: A 46-item questionnaire was developed based on the Human Factors Analysis and Classification System (HFACS) domains and completed by examiners in the Intercollegiate Membership of the Royal College of Surgeons (MRCS) examination. To refine the questionnaire, an initial analysis focused on response patterns of each item. Cronbach's α was used to assess internal consistency, and a factor analysis was performed to uncover different domains emerging from the data. RESULTS: A total of 108 examiners completed the questionnaire (90·0 per cent response rate). The questionnaire, refined to 38 items based on an initial analysis of response patterns, showed good reliability for internal consistency (Cronbach's α = 0·76) and test-retest reliability (r = 0·85, n = 48, P < 0·001). Four factors had a close themed resemblance to the original HFACS domains, but were associated with different items, suggesting that the four human-factor domains might be linked to different behaviours and attitudes in an examination setting. Analyses according to sex, professional background and experience highlighted additional stress levels in examiners from one of the surgical Royal Colleges (P <0·001), matching evidence from the situation in that College at the time of this study. CONCLUSION: The recognition and further investigation of human factors in OSCEs is needed to improve examiner experience and behaviour in order to influence delivery, candidate experience and quality assurance of these examinations.


Assuntos
Educação de Pós-Graduação em Medicina/normas , Avaliação Educacional/normas , Docentes de Medicina/normas , Especialidades Cirúrgicas/educação , Inquéritos e Questionários/normas , Análise de Variância , Análise Fatorial , Feminino , Humanos , Masculino , Competência Profissional , Papel Profissional/psicologia , Reprodutibilidade dos Testes , Fatores Sexuais
8.
Nano Lett ; 12(3): 1717-21, 2012 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-22352856

RESUMO

Coupling of the localized surface plasmons between two closely apposed gold nanoparticles (nanoantenna) can cause strong enhancements of fluorescence or Raman signal intensity from molecules in the plasmonic "hot-spot". Harnessing these properties for practical applications is challenging due to the need to fabricate gold particle arrays with well-defined nanometer spacing and a means of delivering functional molecules to the hot-spot. We report fabrication of billions of plasmon-coupled nanostructures on a single substrate by a combination of colloid lithography and plasma processing. Controlled spacing of the nanoantenna gaps is achieved by taking advantage of the fact that polystyrene particles melt together at their contact point during plasma processing. The resulting polymer thread shadows a gap of well-defined spacing between each pair of gold triangles in the final array. Confocal surface-enhanced Raman spectroscopy imaging confirms the array is functionally uniform. Furthermore, a fully intact supported membrane can be formed on the intervening substrate by vesicle fusion. Trajectories of freely diffusing individual proteins are traced as they sequentially pass through, and are enhanced by, multiple gaps. The nanoantenna array thus enables enhanced observation of a fluid membrane system without static entrapment of the molecules.


Assuntos
Ouro/química , Membranas Artificiais , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Análise Espectral Raman/métodos , Ressonância de Plasmônio de Superfície/métodos , Luz , Técnicas de Sonda Molecular , Espalhamento de Radiação
9.
Environ Microbiol ; 14(1): 101-13, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21651686

RESUMO

Desulfatibacillum alkenivorans AK-01 serves as a model organism for anaerobic alkane biodegradation because of its distinctive biochemistry and metabolic versatility. The D. alkenivorans genome provides a blueprint for understanding the genetic systems involved in alkane metabolism including substrate activation, CoA ligation, carbon-skeleton rearrangement and decarboxylation. Genomic analysis suggested a route to regenerate the fumarate needed for alkane activation via methylmalonyl-CoA and predicted the capability for syntrophic alkane metabolism, which was experimentally verified. Pathways involved in the oxidation of alkanes, alcohols, organic acids and n-saturated fatty acids coupled to sulfate reduction and the ability to grow chemolithoautotrophically were predicted. A complement of genes for motility and oxygen detoxification suggests that D. alkenivorans may be physiologically adapted to a wide range of environmental conditions. The D. alkenivorans genome serves as a platform for further study of anaerobic, hydrocarbon-oxidizing microorganisms and their roles in bioremediation, energy recovery and global carbon cycling.


Assuntos
Alcanos/metabolismo , Deltaproteobacteria/genética , Genoma Bacteriano , Ácidos/metabolismo , Álcoois/metabolismo , Anaerobiose , Biodegradação Ambiental , Crescimento Quimioautotrófico , DNA Bacteriano/genética , Deltaproteobacteria/metabolismo , Metaboloma , Anotação de Sequência Molecular , Oxirredução , Sulfatos/metabolismo
10.
Rev Sci Instrum ; 82(2): 023908, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21361612

RESUMO

Thin film growth allows for the manipulation of material on the nanoscale, making possible the creation of metastable phases not seen in the bulk. Heat capacity provides a direct way of measuring thermodynamic properties of these new materials, but traditional bulk calorimetric techniques are inappropriate for such a small amount of material. Microcalorimetry and nanocalorimetry techniques exist for the measurements of thin films but rely on an amorphous membrane platform, limiting the types of films which can be measured. In the current work, ion-beam-assisted deposition is used to provide a biaxially oriented MgO template on a suspended membrane microcalorimeter in order to measure the specific heat of epitaxial thin films. Synchrotron x-ray diffraction showed the biaxial order of the MgO template. X-ray diffraction was also used to prove the high quality of epitaxy of a film grown onto this MgO template. The contribution of the MgO layer to the total heat capacity was measured to be just 6.5% of the total addenda contribution. The heat capacity of a Fe(.49)Rh(.51) film grown epitaxially onto the device was measured, comparing favorably to literature data on bulk crystals. This shows the viability of the MgO∕SiN(x)-membrane-based microcalorimeter as a way of measuring the thermodynamic properties of epitaxial thin films.

11.
BMJ ; 341: c6801, 2010 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-21148220

RESUMO

OBJECTIVE: To determine whether the author's 20.9 lb (9.5 kg) carbon frame bicycle reduced commuting time compared with his 29.75 lb (13.5 kg) steel frame bicycle. DESIGN: Randomised trial. SETTING: Sheffield and Chesterfield, United Kingdom, between mid-January 2010 and mid-July 2010. PARTICIPANTS: One consultant in anaesthesia and intensive care. MAIN OUTCOME MEASURE: Total time to complete the 27 mile (43.5 kilometre) journey from Sheffield to Chesterfield Royal Hospital and back. RESULTS: The total distance travelled on the steel frame bicycle during the study period was 809 miles (1302 km) and on the carbon frame bicycle was 711 miles (1144 km). The difference in the mean journey time between the steel and carbon bicycles was 00:00:32 (hr:min:sec; 95% CI -00:03:34 to 00:02:30; P=0.72). CONCLUSIONS: A lighter bicycle did not lead to a detectable difference in commuting time. Cyclists may find it more cost effective to reduce their own weight rather than to purchase a lighter bicycle.


Assuntos
Ciclismo/estatística & dados numéricos , Desenho de Equipamento , Gravitação , Humanos , Masculino , Estações do Ano , Fatores de Tempo , Viagem
12.
QJM ; 102(6): 389-99, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19369483

RESUMO

INTRODUCTION: Decisions about the intensity of treatment for patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are influenced by predictions about survival and quality of life. Evidence suggests that these predictions are poorly calibrated and tend to be pessimistic. AIM: The aim of this study was to develop an outcome prediction model for COPD patients to support treatment decisions. METHODS: A prospective multi-centre cohort study in Intensive Care Units (ICU) and Respiratory High Dependency Units (RHDU) in the UK recruited patients aged 45 years and older admitted with an exacerbation of obstructive lung disease. Data were collected on patients' characteristics prior to ICU admission, and on their survival and quality of life after 180 days. An outcome prediction model was developed using multivariate logistic regression and bootstrapping. RESULTS: Ninety-two ICUs (53% of those in the UK) and three RHDUs took part. A total of 832 patients were recruited. Cumulative 180-day mortality was 37.9%. Using data available at the time of admission to the units, a prognostic model was developed which had an estimated area under the receiver operating characteristic curve ('c') of 74.7% after bootstrapping that was more discriminating than the clinicians (P = 0.033) and was well calibrated. DISCUSSION: This study has produced an outcome prediction model with slightly better discrimination and much better calibration than the participating clinicians. It has the potential to support risk adjustment and clinical decision making about admission to intensive care.


Assuntos
Asma/mortalidade , Tomada de Decisões , Doença Pulmonar Obstrutiva Crônica/mortalidade , Risco Ajustado , Índice de Gravidade de Doença , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Asma/terapia , Feminino , Humanos , Tempo de Internação , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Doença Pulmonar Obstrutiva Crônica/terapia , Fatores Sexuais , Reino Unido
13.
Thorax ; 64(2): 128-32, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18852157

RESUMO

BACKGROUND: Non-invasive ventilation is first-line treatment for patients with acutely decompensated chronic obstructive pulmonary disease (COPD), but endotracheal intubation, involving admission to an intensive care unit, may sometimes be required. Decisions to admit to an intensive care unit are commonly based on predicted survival and quality of life, but the information base for these decisions is limited and there is some evidence that clinicians tend to be pessimistic. This study examined the outcomes in patients with COPD admitted to the intensive care unit for decompensated type II respiratory failure. METHODS: A prospective cohort study was carried out in 92 intensive care units and 3 respiratory high dependency units in the UK. Patients aged 45 years and older with breathlessness, respiratory failure or change in mental status due to an exacerbation of COPD, asthma or a combination of the two were recruited. Outcomes included survival and quality of life at 180 days. RESULTS: Of the 832 patients recruited, 517 (62%) survived to 180 days. Of the survivors, 421 (81%) responded to a questionnaire. Of the respondents, 73% considered their quality of life to be the same as or better than it had been in the stable period before they were admitted, and 96% would choose similar treatment again. Function during the stable pre-admission period was a reasonable indicator of function reported by those who survived 180 days. CONCLUSIONS: Most patients with COPD who survive to 180 days after treatment in an intensive care unit have a heavy burden of symptoms, but almost all of them-including those who have been intubated-would want similar intensive care again under similar circumstances.


Assuntos
Asma/mortalidade , Doença Pulmonar Obstrutiva Crônica/mortalidade , Idoso , Asma/terapia , Estudos de Coortes , Cuidados Críticos , Feminino , Humanos , Tempo de Internação/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Estudos Prospectivos , Doença Pulmonar Obstrutiva Crônica/terapia , Qualidade de Vida , Análise de Sobrevida , Reino Unido/epidemiologia
14.
Sex Transm Infect ; 84(5): 393-4, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18550694

RESUMO

OBJECTIVES: To examine the characteristics and work attitudes of female sex workers working in licensed brothels in Victoria, Australia. METHODS: This was a cross-sectional study of sex workers working at 38 of the 92 licensed brothels operating in Victoria during 2006. RESULTS: Of the 108 women approached, 97 (90%) completed the questionnaire. Women working in the legal sex industry in Victoria were generally aged between 23 and 35 years (51%), had completed high school (26%) and had worked in the industry for more than 5 years (43%). Half had dependent children and one third were in a relationship. Women's primary motivation for working in the sex industry was financial, whether this was the reason for their starting (56%), or the barrier to their leaving (61%). Although women valued the higher income and flexibility of this work, many were concerned about sexually transmitted infections (STI) (55%), community attitudes towards the industry (47%), their physical safety (38%) and maintaining their anonymity (37%). Over half of the women would like to leave the industry. The majority (95%) supported the monthly STI checks that are part of the Victorian regulations, with only one fifth reporting that the cost of these tests was prohibitive. CONCLUSIONS: The findings of this study indicate that women working in licensed Victorian brothels come from a diverse range of backgrounds and circumstances and hold varying attitudes towards working in the sex industry. It is hoped that these findings go some way to redressing the assumptions commonly made about women working in the sex industry and reducing the stigma associated with this occupation.


Assuntos
Atitude Frente a Saúde , Trabalho Sexual/psicologia , Adulto , Estudos Transversais , Escolaridade , Feminino , Humanos , Trabalho Sexual/estatística & dados numéricos , Vitória/epidemiologia
15.
Mol Psychiatry ; 12(12): 1079-88, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17700574

RESUMO

The brain-derived neurotrophic factor (BDNF) hypothesis of depression postulates that a loss of BDNF is directly involved in the pathophysiology of depression, and that its restoration may underlie the therapeutic efficacy of antidepressant treatment. While this theory has received considerable experimental support, an increasing number of studies have generated evidence which is not only inconsistent, but also directly contradicts the hypothesis. This article provides a critical review of the clinical and preclinical studies which have been responsible for this controversy, outlining pharmacological, behavioural and genetic evidence which demonstrates the contrasting role of BDNF in regulating mood and antidepressant effects throughout the brain. I will also review key studies, both human and animal, which have investigated the association of a BDNF single-nucleotide polymorphism (Val66Met) with depression pathogenesis, and detail the number of inconsistencies which also afflict this novel area of BDNF research. The article will conclude by discussing why now is a critical time to reassess the original BDNF hypothesis of depression, and look towards the formation of new models that can provide a more valid account of the complex relationships between growth factors, mood disorders and their treatment.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Depressão/metabolismo , Modelos Biológicos , Animais , Fator Neurotrófico Derivado do Encéfalo/genética , Depressão/genética , Depressão/fisiopatologia , Humanos , Metionina/genética , Polimorfismo de Nucleotídeo Único/genética , Valina/genética
16.
Am J Primatol ; 69(11): 1307-11, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17410549

RESUMO

During the course of a 3-year ecological study on Cross River gorillas (Gorilla gorilla diehli) at the Kagwene Mountain in Cameroon, we observed three cases of tool use which may be unique to the gorillas of this region and possibly learned through interactions with humans. A non-habituated group of Cross River gorillas threw fistfuls of grass toward humans in display contexts. An individual gorilla was also observed to throw a detached branch toward researchers during another encounter. The third encounter occurred between the focal group and a local man, in which the man threw stones at the gorillas and they reacted by throwing fistfuls of grass back at him. We describe these observations and speculate that this sub-population of gorillas developed this display behavior as a response to particular local conditions.


Assuntos
Gorilla gorilla/fisiologia , Comportamento de Utilização de Ferramentas , Animais , Camarões , Aprendizagem , Masculino , Vocalização Animal
17.
J Psychopharmacol ; 20(4): 485-95, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16204321

RESUMO

Late-latency auditory and somatosensory evoked potentials are sensitive to some centrally acting drugs and to certain psychological interventions. In this experiment we compared the effects of acute doses of a benzodiazepine, diazepam and an H(1) histamine receptor-blocking sedative, diphenhydramine, on auditory and somatosensory evoked potentials within the latency range 100-500 ms in a fear conditioning paradigm. Twelve healthy males (18-30 years) participated in three sessions at weekly intervals in which they received diazepam 10mg, diphenhydramine 75 mg and placebo in a balanced, double-blind, crossover protocol. One hundred and twenty min after diphenhydramine or 60 min after diazepam, they underwent an 8 min recording period in which auditory evoked potentials elicited by 40 ms, 95 dB[A], 1 kHz tones, and somatosensory evoked potentials elicited by a mildly painful electric shock (1.8 mA, 50 ms) were recorded at Cz (vertex). Each session consisted of four blocks of trials in which either the sound pulse or the shock was presented. Alternate blocks were designated SAFE or THREAT ('context' conditions); in THREAT blocks subjects were warned that shocks would be delivered via electrodes placed on the wrist (electrodes were removed during SAFE blocks). In one SAFE and one THREAT block, the sound stimuli and shocks (shocks were delivered only in the THREAT block) were preceded by a 2 s conditioned stimulus (CS: a red light) ('cue' condition). Diazepam, but not diphenhydramine, reduced the amplitude of the P2 auditory evoked potential. The THREAT context was associated with increased N1 and reduced N2 potential amplitudes. The CS had no effect on the amplitudes, but markedly reduced the latencies of the N1, P2 and N2 potentials under the THREAT condition. Diazepam reduced the amplitudes of the somatosensory potential evoked by the shock; the CS shortened the latencies of the later components of the response. Diazepam and diphenhydramine were approximately equi-sedative in the doses used in this experiment, as judged by visual analogue self-rating scales. The results indicate that the suppression of late-latency auditory and somatosensory evoked potentials by diazepam is not simply a reflection of sedation. Late-latency evoked potentials can be modified by an aversive CS, but the components that are sensitive to the CS are different from those that are sensitive to diazepam.


Assuntos
Diazepam/farmacologia , Difenidramina/farmacologia , Potenciais Evocados Auditivos/fisiologia , Potenciais Somatossensoriais Evocados/fisiologia , Medo/fisiologia , Hipnóticos e Sedativos/farmacologia , Estimulação Acústica , Adolescente , Adulto , Atenção/fisiologia , Condicionamento Psicológico/efeitos dos fármacos , Estimulação Elétrica , Humanos , Masculino , Estimulação Luminosa
18.
Ann Occup Hyg ; 47(1): 17-30, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12505903

RESUMO

This paper summarizes the analytical and occupational hygiene findings from a recent survey of occupational exposure to metalworking fluids (MWFs) in the engineering industry. The aim of the survey was to link MWF mist exposure measurements with particular engineering processes and controls, and utilize the data obtained to develop exposure standards. At the same time the opportunity was taken to assess fluid management and control, including bacterial and fines contamination in the machine sumps. In general, occupational exposure to mineral oil MWF mist was controlled to <3 mg/m(3) (8 h time-weighted average) and to <1 mg/m(3) for water-mix MWF mist (in terms of the concentrate). These exposure values do not necessarily represent best practice, but are believed to be achievable and representative of industry as a whole. Gravimetric analysis of the total inhalable particulate was found to be a good predictor of mineral oil MWF mist but not for water-mix MWF mist. Grinding and drilling operations produced higher exposures than turning and milling for water-mix fluids. There were insufficient data to compare machining operations for mineral oil MWFs. On the whole, fluid management was found to be poor, with most sites failing to meet industry good practice or Health & Safety Executive (HSE) standards. Some of the operating procedures utilized were deficient or unsatisfactory. Poor standards of fluid management were found at all sizes of company. High levels of bacteria, endotoxin and fines were found in sumps, and control of other factors, such as water-mix fluid concentration, was often poor. Mineral oils had higher levels of fines than water-mix fluids (medians of 395 and 18 mg/l, respectively), and grinding produced high levels of fines in both types of MWF. Many water-mix sumps contained bacterial levels of >1 x 10(6) CFU/ml, and endotoxin levels of >100 000 EU/ml were not uncommon. The median values were 109 000 CFU/ml and 8039 EU/ml, respectively. Mists could potentially contain extensive contamination from bacteria and endotoxin. Analysis of the data suggests that sumps operating under typical conditions for machining (a temperature of 20 degrees C, a pH of 9 and a fluid strength below 10%), also appear to provide optimum conditions for the proliferation of bacteria. Low levels of benzo[a]pyrene (median 0.03 micro g/g) were found in the mineral oils, and low levels of N-nitrosodiethanolamine (median 0.4 micro g/ml) were found in the water-mix MWFs. The results of this work will contribute to guidance from the HSE, setting out accepted industry good practice, including guide values for MWF mist and sump fluid contaminants, with significant emphasis on sump fluid management (maintenance and monitoring), as well as control issues.


Assuntos
Poluentes Ocupacionais do Ar/análise , Óleos Industriais/análise , Exposição por Inalação/análise , Metalurgia , Exposição Ocupacional/análise , Aerossóis , Microbiologia do Ar , Monitoramento Ambiental/métodos , Humanos
19.
QJM ; 95(8): 527-38, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12145392

RESUMO

BACKGROUND: Some patients exposed to Q fever (Coxiella burnetii infection) may develop chronic fatigue. AIM: To determine whether subjects involved in the West Midlands Q fever outbreak of 1989 had increased fatigue, compared to non-exposed controls, 10 years after exposure. DESIGN: Matched cohort study comparing cases to age-, sex- and smoking-history-matched controls not exposed to Q fever. METHODS: A postal questionnaire was sent to subjects at home, followed by further assessment in hospital, including a physical examination and blood tests. RESULTS: Of 108 Q-exposed subjects, 70 (64.8%) had fatigue, 37 idiopathic chronic fatigue (ICF) (34.3%), vs. 29/80 (36.3%) and 12 (15.0%), respectively, in controls. In 77 matched pairs, fatigue was commoner in Q-exposed subjects than in controls: 50 (64.9%) vs. 27 (35.1%), p<0.0001. ICF was found in 25 (32.5%) of Q-exposed patients and 11(14.3%) of controls (p=0.01). There were 36 (46.8%) GHQ cases in Q-exposed subjects, vs. 18 (23.4%) controls (p=0.004). A matched analysis of those more intensively studied showed fatigue in 48 (66.7%) Q-exposed patients and 25 (34.7%) controls, (p<0.0001), ICF in 25 (34.7%) Q-exposed and 10 (13.9%) controls (p=0.004), and chronic fatigue syndrome (CFS) in 14 (19.4%) Q-exposed patients and three (4.2%) controls (p=0.003). Thirty-four (47.2%) Q-exposed patients were GHQ cases compared to 17 (23.6%) controls (p=0.004). DISCUSSION: Subjects who were exposed to Coxiella in 1989 had more fatigue than did controls, and some fulfilled the criteria for CFS. Whether this is due to ongoing antigen persistence or to the psychological effects of prolonged medical follow-up is uncertain.


Assuntos
Fadiga/epidemiologia , Febre Q/epidemiologia , Estudos de Casos e Controles , Doença Crônica , Inglaterra/epidemiologia , Fadiga/microbiologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Febre Q/complicações , Inquéritos e Questionários
20.
QJM ; 95(8): 539-46, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12145393

RESUMO

BACKGROUND: In 1989, an outbreak of Q fever (C. burnetii infection) with 147 confirmed cases occurred in Solihull, West Midlands. Three patients developed cardiomyopathy in the subsequent 10 years. The cohort has been followed up with respect to the development of fatigue and, in this instance, cardiac effects after the original infection. AIM: To determine whether persisting fatigue after Q fever represented sub-clinical cardiomyopathy. DESIGN: Prospective follow-up study. METHODS: All traceable subjects from the original outbreak, and community age-, sex- and smoking-matched controls, were studied. Questionnaires for idiopathic fatigue, 12-lead ECG, echocardiography, spirometry and shuttle walk distance were undertaken, and a subset with CDC-defined chronic fatigue syndrome had gated cardiac scans. RESULTS: Of the original cohort, 19 had died, three had emigrated and 10 were untraceable. Of the remaining 115, 108 responded to a mailed questionnaire and 87 were investigated further, of whom 85 provided complete data. Two developed aortic valve vegetations, one of whom died. Chronic fatigue syndrome was found in 20% of cases and 5.3% of controls (including those with co-morbidities), falling to 8.2% and 0 when excluding those with co-morbidities. There were no significant differences in ECG and echocardiographic investigations or shuttle-walk distance between those with fatigue and those without. Six of the seven patients with CFS had gated cardiac scans: all were within normal limits. CONCLUSIONS: These findings do not support the existence of a sub-clinical cardiomyopathy in the patients in this cohort who suffer from fatigue after acute Q fever, although endocarditis can occur after acute infection.


Assuntos
Cardiomiopatias/microbiologia , Síndrome de Fadiga Crônica/microbiologia , Febre Q/complicações , Cardiomiopatias/epidemiologia , Estudos de Casos e Controles , Inglaterra/epidemiologia , Síndrome de Fadiga Crônica/epidemiologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Febre Q/epidemiologia
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