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1.
Osteoarthritis Cartilage ; 27(3): 444-448, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30502450

RESUMO

OBJECTIVE: Cam hip morphology is associated with femoroacetabular impingement (FAI) syndrome and causes hip osteoarthritis (OA). We aimed to assess the prevalence of cam hip morphology in a sample representative of the general population, using a measure with a predefined diagnostic accuracy. DESIGN: Patients aged 16-65, who were admitted to a major trauma centre and received a computed tomography (CT) pelvis were retrospectively screened for eligibility. Subjects with proximal femoral, acetabular or pelvic fractures and those who were deceased were excluded. Eligible subjects were divided into 10 groups based on gender and age. 20 subjects from each group were included. Subjects' index of multiple deprivation (IMD) and ethnicity were recorded. CT imaging was assessed and alpha angles (a measure of cam morphology) measured in the anterosuperior aspect of the femoral head neck junction. An alpha angle greater than 60° was considered to represent cam morphology. This measure and technique has a predefined sensitivity of 80% and specificity of 73% to detect cam morphology associated with FAI syndrome. The prevalence of cam morphology was reported as a proportion of subjects affected with 95% confidence intervals. RESULTS: 200 subjects were included. The sample was broadly representative of the UK general population in terms of IMD. 155 subjects (86%) identified as white. Cam morphology was present in 47% (95% CI 42,51) of subjects. CONCLUSIONS: In this sample, broadly representative of the UK general population 47% of subjects had cam hip morphology; a hip shape associated with FAI syndrome and OA.


Assuntos
Impacto Femoroacetabular/epidemiologia , Articulação do Quadril/patologia , Adolescente , Adulto , Fatores Etários , Idoso , Feminino , Impacto Femoroacetabular/diagnóstico por imagem , Impacto Femoroacetabular/patologia , Articulação do Quadril/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite do Quadril/patologia , Prevalência , Fatores Sexuais , Tomografia Computadorizada por Raios X , Reino Unido/epidemiologia , Adulto Jovem
2.
Br J Surg ; 106(13): 1726-1734, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31573088

RESUMO

BACKGROUND: There is growing interest in and provision of cadaveric simulation courses for surgical trainees. This is being driven by the need to modernize and improve the efficiency of surgical training within the current challenging training climate. The objective of this systematic review is to describe and evaluate the evidence for cadaveric simulation in postgraduate surgical training. METHODS: A PRISMA-compliant systematic literature review of studies that prospectively evaluated a cadaveric simulation training intervention for surgical trainees was undertaken. All relevant databases and trial registries were searched to January 2019. Methodological rigour was assessed using the widely validated Medical Education Research Quality Index (MERSQI) tool. RESULTS: A total of 51 studies were included, involving 2002 surgical trainees across 69 cadaveric training interventions. Of these, 22 assessed the impact of the cadaveric training intervention using only subjective measures, five measured impact by change in learner knowledge, and 23 used objective tools to assess change in learner behaviour after training. Only one study assessed patient outcome and demonstrated transfer of skill from the simulated environment to the workplace. Of the included studies, 67 per cent had weak methodology (MERSQI score less than 10·7). CONCLUSION: There is an abundance of relatively low-quality evidence showing that cadaveric simulation induces short-term skill acquisition as measured by objective means. There is currently a lack of evidence of skill retention, and of transfer of skills following training into the live operating theatre.


ANTECEDENTES: Existe un interés creciente en los cursos de simulación con cadáveres para la formación de residentes en cirugía, así como en aumentar la disponibilidad de dichos cursos. Ello es debido a la necesidad de modernizar y mejorar la eficiencia del entrenamiento en el marco actual del reto que supone la formación quirúrgica. El objetivo de esta revisión sistemática era describir y evaluar la evidencia del uso de la simulación con cadáveres en la formación quirúrgica de posgrado. MÉTODOS: Siguiendo la normativa PRISMA, se realizó una revisión sistemática de la literatura de estudios que evaluaban prospectivamente el entrenamiento quirúrgico mediante la simulación con cadáveres. Se realizaron búsquedas en todas las bases de datos relevantes y en registros de ensayos clínicos hasta enero de 2019. Se evaluó el rigor metodológico utilizando la herramienta MERSQI (Medical Education Research Quality Index), ampliamente validada. RESULTADOS: Se incluyeron 51 estudios, con un total de 2.002 residentes de cirugía y 69 intervenciones de formación con simulación con cadáveres. Del total de dichos estudios, 22 evaluaron el impacto de la cirugía con cadáver utilizando solo medidas subjetivas, 5 midieron el impacto por el cambio en el conocimiento del alumno y 23 utilizaron herramientas objetivas para evaluar el cambio en el comportamiento del alumno después de la formación. Solo un estudio evaluó el resultado en pacientes, demostrando la transferencia de habilidades del entorno simulado al lugar de trabajo. De los estudios incluidos, el 55% tenía una metodología débil (puntuación MERSQI < 10,7). CONCLUSIÓN: Existe amplia evidencia, pero de baja calidad, referente a la simulación con cadáveres en la formación quirúrgica, demostrando que esta popular herramienta puede ser útil para adquirir habilidades a corto plazo, tal como indican los resultados derivados de medidas objetivas. Actualmente hay una falta de evidencia basada en estudios longitudinales respecto a la retención de habilidades y de cómo estas se transfieren al quirófano real una vez finalizada la formación. Se requieren futuros ensayos aleatorizados de alta calidad para abordar este punto.


Assuntos
Competência Clínica , Simulação por Computador , Educação de Pós-Graduação em Medicina/métodos , Cirurgia Geral/educação , Treinamento por Simulação/métodos , Cadáver , Humanos
3.
Osteoarthritis Cartilage ; 24(6): 949-61, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26778530

RESUMO

OBJECTIVE: Cam hip shape morphology is a recognised cause of femoroacetabular impingement (FAI) and is associated with hip osteoarthritis. Our aim was to systematically review the available epidemiological evidence assessing the prevalence of cam hip shape morphology in the general population and any studied subgroups including subjects with and without hip pain. DESIGN: All studies that reported the prevalence of cam morphology, measured by alpha angles, in subjects aged 18 and over, irrespective of study population or presence of hip symptoms were considered for inclusion. We searched AMED, MEDLINE, EMBASE, CINAHL and CENTRAL in October 2015. Two authors independently identified eligible studies and assessed risk of bias. We planned to pool data of studies considered clinically homogenous. RESULTS: Thirty studies met inclusion criteria. None of the included studies were truly population-based: three included non-representative subgroups of the general population, 19 included differing clinical populations, while eight included professional athletes. All studies were judged to be at high risk of bias. Due to substantial clinical heterogeneity meta analysis was not possible. Across all studies, the prevalence estimates of cam morphology ranged from 5 to 75% of participants affected. We were unable to demonstrate a higher prevalence in selected subgroups such as athletes or those with hip pain. CONCLUSIONS: There is currently insufficient high quality data to determine the true prevalence of cam morphology in the general population or selected subgroups. Well-designed population-based epidemiological studies that use homogenous case definitions are required to determine the prevalence of cam morphology and its relationship to hip pain.


Assuntos
Articulação do Quadril , Impacto Femoroacetabular , Humanos , Osteoartrite do Quadril , Dor , Prevalência
4.
Br J Sports Med ; 50(19): 1169-76, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27629403

RESUMO

The 2016 Warwick Agreement on femoroacetabular impingement (FAI) syndrome was convened to build an international, multidisciplinary consensus on the diagnosis and management of patients with FAI syndrome. 22 panel members and 1 patient from 9 countries and 5 different specialties participated in a 1-day consensus meeting on 29 June 2016. Prior to the meeting, 6 questions were agreed on, and recent relevant systematic reviews and seminal literature were circulated. Panel members gave presentations on the topics of the agreed questions at Sports Hip 2016, an open meeting held in the UK on 27-29 June. Presentations were followed by open discussion. At the 1-day consensus meeting, panel members developed statements in response to each question through open discussion; members then scored their level of agreement with each response on a scale of 0-10. Substantial agreement (range 9.5-10) was reached for each of the 6 consensus questions, and the associated terminology was agreed on. The term 'femoroacetabular impingement syndrome' was introduced to reflect the central role of patients' symptoms in the disorder. To reach a diagnosis, patients should have appropriate symptoms, positive clinical signs and imaging findings. Suitable treatments are conservative care, rehabilitation, and arthroscopic or open surgery. Current understanding of prognosis and topics for future research were discussed. The 2016 Warwick Agreement on FAI syndrome is an international multidisciplinary agreement on the diagnosis, treatment principles and key terminology relating to FAI syndrome.Author note The Warwick Agreement on femoroacetabular impingement syndrome has been endorsed by the following 25 clinical societies: American Medical Society for Sports Medicine (AMSSM), Association of Chartered Physiotherapists in Sports and Exercise Medicine (ACPSEM), Australasian College of Sports and Exercise Physicians (ACSEP), Austian Sports Physiotherapists, British Association of Sports and Exercise Medicine (BASEM), British Association of Sport Rehabilitators and Trainers (BASRaT), Canadian Academy of Sport and Exercise Medicine (CASEM), Danish Society of Sports Physical Therapy (DSSF), European College of Sports and Exercise Physicians (ECOSEP), European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA), Finnish Sports Physiotherapist Association (SUFT), German-Austrian-Swiss Society for Orthopaedic Traumatologic Sports Medicine (GOTS), International Federation of Sports Physical Therapy (IFSPT), International Society for Hip Arthroscopy (ISHA), Groupo di Interesse Specialistico dell'A.I.F.I., Norwegian Association of Sports Medicine and Physical Activity (NIMF), Norwegian Sports Physiotherapy Association (FFI), Society of Sports Therapists (SST), South African Sports Medicine Association (SASMA), Sports Medicine Australia (SMA), Sports Doctors Australia (SDrA), Sports Physiotherapy New Zealand (SPNZ), Swedish Society of Exercise and Sports Medicine (SFAIM), Swiss Society of Sports Medicine (SGMS/SGSM), Swiss Sports Physiotherapy Association (SSPA).


Assuntos
Impacto Femoroacetabular/diagnóstico , Impacto Femoroacetabular/terapia , Acetábulo/fisiopatologia , Congressos como Assunto , Consenso , Articulação do Quadril/fisiopatologia , Humanos , Sociedades
6.
Ultrasound Obstet Gynecol ; 37(3): 283-9, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21105021

RESUMO

OBJECTIVES: To improve the prenatal diagnosis of achondroplasia by constructing charts of fetal size, defining frequency of sonographic features and exploring the role of non-invasive molecular diagnosis based on cell-free fetal deoxyribonucleic acid (DNA) in maternal plasma. METHODS: Data on fetuses with a confirmed diagnosis of achondroplasia were obtained from our databases, records reviewed, sonographic features and measurements determined and charts of fetal size constructed using the LMS (lambda-mu-sigma) method and compared with charts used in normal pregnancies. Cases referred to our regional genetics laboratory for molecular diagnosis using cell-free fetal DNA were identified and results reviewed. RESULTS: Twenty-six cases were scanned in our unit. Fetal size charts showed that femur length was usually on or below the 3(rd) centile by 25 weeks' gestation, and always below the 3(rd) by 30 weeks. Head circumference was above the 50(th) centile, increasing to above the 95(th) when compared with normal for the majority of fetuses. The abdominal circumference was also increased but to a lesser extent. Commonly reported sonographic features were bowing of the femora, frontal bossing, short fingers, a small chest and polyhydramnios. Analysis of cell-free fetal DNA in six pregnancies confirmed the presence of the c.1138G > A mutation in the FGRF3 gene in four cases with achondroplasia, but not the two subsequently found to be growth restricted. CONCLUSIONS: These data should improve the accuracy of diagnosis of achondroplasia based on sonographic findings, and have implications for targeted molecular confirmation that can reliably and safely be carried out using cell-free fetal DNA.


Assuntos
Acondroplasia/diagnóstico , DNA/sangue , Doenças Fetais/diagnóstico , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos/sangue , Acondroplasia/diagnóstico por imagem , Acondroplasia/genética , Antropometria/métodos , DNA/genética , Feminino , Doenças Fetais/diagnóstico por imagem , Doenças Fetais/genética , Humanos , Troca Materno-Fetal , Mutação/genética , Polimorfismo de Nucleotídeo Único , Gravidez , Diagnóstico Pré-Natal/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Ultrassonografia
8.
Proc Inst Mech Eng H ; 225(8): 769-82, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21922954

RESUMO

Range of motion of the hip joint is a major contributor to dislocation post total hip replacement. Impingement is often treated as a surrogate for dislocation and occurs--prosthetically--when the neck of the femoral component contacts with the rim of the pelvic acetabular cup. This impingement is caused by movement of the leg during activities of daily living. This article analyses hip joint range of motion and its implication for impingement. A systematic literature review was undertaken with the purpose of establishing a range of motion benchmark for total hip replacement. This paper proposes a method by which a three-dimensional range of motion boundary established from the literature can be presented. The nominal boundary is also validated experimentally using a number of configurations of a neutral hip joint coordinate frame.


Assuntos
Artroplastia de Quadril , Articulação do Quadril/fisiopatologia , Luxações Articulares/etiologia , Amplitude de Movimento Articular , Acetábulo/fisiopatologia , Algoritmos , Artroplastia de Quadril/efeitos adversos , Artroplastia de Quadril/métodos , Fenômenos Biomecânicos , Cabeça do Fêmur/fisiopatologia , Articulação do Quadril/cirurgia , Prótese de Quadril , Humanos , Instabilidade Articular/etiologia , Instabilidade Articular/fisiopatologia
9.
Trials ; 22(1): 211, 2021 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-33726810

RESUMO

BACKGROUND: UK FASHIoN was a multicentre randomised controlled trial comparing hip arthroscopic surgery (HA) with personalised hip therapy (PHT, physiotherapist-led conservative care), for patients with hip pain attributed to femoroacetabular impingement (FAI) syndrome. Our aim was to describe the treatment and trial participation experiences of patients, to contextualise the trial results and offer further information to assist treatment decision-making in FAI. METHODS: We conducted in-depth semi-structured telephone interviews with a purposive sample of trial participants from each of the trial arms. They were interviewed after they received treatment and completed their first year of trial participation. Thematic analysis and constant comparison analytical approaches were used to identify themes of patient treatment experiences during the trial. RESULTS: Forty trial participants were interviewed in this qualitative study. Their baseline characteristics were similar to those in the main trial sample. On average, their hip-related quality of life (iHOT-33 scores) at 12 months follow-up were lower than average for all trial participants, indicating poorer hip-related quality of life as a consequence of theoretical sampling. Patient experiences occurred in five patient groups: those who felt their symptoms improved with hip arthroscopy, or with personal hip therapy, patients who felt their hip symptoms did not change with PHT but did not want HA, patients who decided to change from PHT to HA and a group who experienced serious complications after HA. Interviewees mostly described a trouble-free, enriching and altruistic trial participation experience, although most participants expected more clinical follow-up at the end of the trial. CONCLUSION: Both HA and PHT were experienced as beneficial by participants in the trial. Treatment success appeared to depend partly on patients' prior own expectations as well as their outcomes, and future research is needed to explore this further. Findings from this study can be combined with the primary results to inform future FAI patients. TRIAL REGISTRATION: Arthroscopic surgery for hip impingement versus best conventional care ( ISRCTN64081839 ). 28/02/2014.


Assuntos
Artroscopia , Impacto Femoroacetabular , Artroscopia/efeitos adversos , Impacto Femoroacetabular/diagnóstico por imagem , Impacto Femoroacetabular/cirurgia , Articulação do Quadril/diagnóstico por imagem , Articulação do Quadril/cirurgia , Humanos , Avaliação de Resultados da Assistência ao Paciente , Qualidade de Vida , Resultado do Tratamento , Reino Unido
10.
Prenat Diagn ; 30(9): 865-72, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20665529

RESUMO

OBJECTIVE: The objective was to improve the prenatal diagnosis of Brachmann-de Lange syndrome (BDLS) by defining the sonographic criteria. METHODS: Retrospective review of Fetal Medicine Unit (FMU) notes from 1998 to 2009 to identify all cases seen with a final diagnosis of BDLS. Literature review undertaken to ascertain all cases where sonographic features of BDLS had been described. Information was pooled to define the most common features. RESULTS: Seven cases were identified from review of FMU records. The diagnosis was suspected prenatally in four of the seven. All had asymmetrical forearm defects with oligodactyly/polydactyly, five had intrauterine growth restriction (IUGR) and five had abnormal facial features including micrognathia and/or a long overhanging philtrum. A further 28 cases were identified in the literature, but the diagnosis was only suspected prenatally in nine. Overall the most common feature was IUGR (80%); upper limb anomalies were detected in nearly half of cases. Other common features included facial anomalies (40%), diaphragmatic hernia (34%), increased nuchal translucency/fold (37%) and cardiac anomalies (14%). CONCLUSIONS: Identification of asymmetrical oligodactyly with or without forearm anomalies associated with microcephaly and/or IUGR or diaphragmatic hernia are findings that should arouse suspicion of BDLS, although definitive diagnosis at present would have to await delivery in the majority of cases.


Assuntos
Síndrome de Cornélia de Lange/diagnóstico por imagem , Retardo do Crescimento Fetal/diagnóstico por imagem , Ultrassonografia Pré-Natal , Feminino , Antebraço/anormalidades , Antebraço/diagnóstico por imagem , Hérnia Diafragmática/diagnóstico por imagem , Humanos , Deformidades Congênitas dos Membros/diagnóstico por imagem , Microcefalia/diagnóstico por imagem , Gravidez , Estudos Retrospectivos
11.
J Hip Preserv Surg ; 3(4): 304-311, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29632690

RESUMO

To determine whether it was feasible to perform a randomized controlled trial (RCT) comparing arthroscopic hip surgery to conservative care in patients with femoroacetabular impingement (FAI). This study had two phases: a pre-pilot and pilot RCT. In the pre-pilot, we conducted interviews with clinicians who treated FAI and with FAI patients to determine their views about an RCT. We developed protocols for operative and conservative care. In the pilot RCT, we determined the rates of patient eligibility, recruitment and retention, to investigate the feasibility of the protocol and we established methods to assess treatment fidelity. In the pre-pilot phase, 32 clinicians were interviewed, of which 26 reported theoretical equipoise, but in example scenarios 7 failed to show clinical equipoise. Eighteen patients treated for FAI were also interviewed, the majority of whom felt that surgery and conservative care were acceptable treatments. Surgery was viewed by patients as a 'definitive solution'. Patients were motivated to participate in research but were uncomfortable about randomization. Randomization was more acceptable if the alternative was available at the end of the trial. In the pilot phase, 151 patients were assessed for eligibility. Sixty were eligible and invited to take part in the pilot RCT; 42 consented to randomization. Follow-up was 100% at 12 months. Assessments of treatment fidelity were satisfactory. An RCT to compare arthroscopic hip surgery with conservative care in patients with FAI is challenging but feasible. Recruitment has started for a full RCT.

12.
BMJ Open ; 6(8): e012453, 2016 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-27580837

RESUMO

INTRODUCTION: Femoroacetabular impingement (FAI) syndrome is a recognised cause of young adult hip pain. There has been a large increase in the number of patients undergoing arthroscopic surgery for FAI; however, a recent Cochrane review highlighted that there are no randomised controlled trials (RCTs) evaluating treatment effectiveness. We aim to compare the clinical and cost-effectiveness of arthroscopic surgery versus best conservative care for patients with FAI syndrome. METHODS: We will conduct a multicentre, pragmatic, assessor-blinded, two parallel arm, RCT comparing arthroscopic surgery to physiotherapy-led best conservative care. 24 hospitals treating NHS patients will recruit 344 patients over a 26-month recruitment period. Symptomatic adults with radiographic signs of FAI morphology who are considered suitable for arthroscopic surgery by their surgeon will be eligible. Patients will be excluded if they have radiographic evidence of osteoarthritis, previous significant hip pathology or previous shape changing surgery. Participants will be allocated in a ratio of 1:1 to receive arthroscopic surgery or conservative care. Recruitment will be monitored and supported by qualitative intervention to optimise informed consent and recruitment. The primary outcome will be pain and function assessed by the international hip outcome tool 33 (iHOT-33) measured 1-year following randomisation. Secondary outcomes include general health (short form 12), quality of life (EQ5D-5L) and patient satisfaction. The primary analysis will compare change in pain and function (iHOT-33) at 12 months between the treatment groups, on an intention-to-treat basis, presented as the mean difference between the trial groups with 95% CIs. The study is funded by the Health Technology Assessment Programme (13/103/02). ETHICS AND DISSEMINATION: Ethical approval is granted by the Edgbaston Research Ethics committee (14/WM/0124). The results will be disseminated through open access peer-reviewed publications, including Health Technology Assessment, and presented at relevant conferences. TRIAL REGISTRATION NUMBER: ISRCTN64081839; Pre-results.


Assuntos
Artroscopia/métodos , Impacto Femoroacetabular/cirurgia , Articulação do Quadril/fisiopatologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise Custo-Benefício , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Medição da Dor , Satisfação do Paciente , Modalidades de Fisioterapia , Qualidade de Vida , Projetos de Pesquisa , Resultado do Tratamento , Reino Unido , Adulto Jovem
13.
Neurosci Biobehav Rev ; 9(4): 615-22, 1985.
Artigo em Inglês | MEDLINE | ID: mdl-4080280

RESUMO

The cognitive states that underlie animal behavior may include conscious, subjective, mental experiences. Familiar arguments to the contrary are inconclusive. Interactive communication between social animals may well include the exchange of information about subjective feelings and thoughts. Objective data about the subjective experiences of certain animals may thus be potentially accessible through analysis of their communicative signals.


Assuntos
Comportamento Animal , Estado de Consciência , Adaptação Biológica , Comunicação Animal , Animais , Sistema Nervoso Central/fisiologia , Cognição , Teoria Psicológica , Pensamento , Vocalização Animal
14.
Ann N Y Acad Sci ; 950: 191-205, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11797749

RESUMO

Addressing the title's question from the perspective of Whitehead's process theology, fourteen basic notions of which are explained, I argue that the universe is not designed in six common senses of that notion: It was not created out of nothing, all at once, through punctuated creationism, from a blueprint, solely for humans, or even with humans specifically in mind. But it is designed in two looser senses of the term: It reflects a divine aim at richness of experience, and it involved a divine establishment of this cosmic epoch's fundamental contingent principles--an idea that is consistent with process theism's view of divine power as purely persuasive.


Assuntos
Meio Ambiente Extraterreno , Teologia , Humanos , Relações Metafísicas Mente-Corpo , Dinâmica não Linear
15.
Science ; 182(4111): 464-6, 1973 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-17832462
16.
Science ; 185(4154): 814, 1974 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-17833686
17.
Science ; 152(3722): 677, 1966 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-17779543
18.
Biotechnol Prog ; 17(2): 304-10, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11312708

RESUMO

There is a need to develop methods for producing enantiomerically pure pharmaceuticals because the racemic mixtures made today will probably not be allowed in the future. Synthetic chiral catalysts are being developed for this purpose, as well as new product separation techniques. Another possible option is to use biocatalysts, such as purified enzymes or whole microbial cells, since these can result in the production of mostly a single enantiomer. This study emphasizes the use of alginate-entrapped yeast cells to catalyze the reduction of ketones as a model system. The emphasis is on the factors that might limit the reactivity of such cells, such as equilibrium conditions, substrate or product inhibition, solvent toxicity, loss of cell viability, or the degradation of intracellular levels of enzymes or cofactors. It was found that there was a progressive loss of catalytic activity of the immobilized yeast cells, which appeared to be mainly associated with a loss of cell viability and a decline of intracellular NAD(H) levels during the reaction. The other factors investigated did not have a large effect. A regeneration scheme was developed in order to replenish the intracellular NAD(H) lost during the reaction, which involved removing the biocatalyst from the reaction and supplying the cells with a nutrient source. This resulted in an increase in the NAD(H) to initial levels and also resulted in a maintenance of the ketone reduction rate over time.


Assuntos
Hexanos/química , Cetonas/metabolismo , Saccharomyces cerevisiae/metabolismo , Álcool Desidrogenase/metabolismo , Catálise , Oxirredução
19.
Ultrasound Med Biol ; 11(1): 37-41, 1985.
Artigo em Inglês | MEDLINE | ID: mdl-3160154

RESUMO

A combined pulsed Doppler and linear array scanner is used to measure volume blood flow in 75 aortas and 45 umbilical veins of foetuses in the 3rd trimester. The mean aortic flow was 277 ml/min/kg and the mean umbilical venous flow was 122 ml/min/kg. Mean flow in the portal veins of normal subjects was found to be between 0.6 and 2.0 l/min. Clear signals were obtained from the adult kidney but no volume flow calculation has yet been attempted. The use of a spectrum analyser is considered fundamental to the accurate interpretation and processing of the Doppler signals. Medical and electronic artefacts are described which would not be detected without the use of an analyser.


Assuntos
Feto/fisiologia , Troca Materno-Fetal , Reologia , Ultrassonografia/instrumentação , Adulto , Aorta/fisiologia , Velocidade do Fluxo Sanguíneo , Feminino , Humanos , Veia Porta/fisiologia , Gravidez , Circulação Renal , Análise Espectral/instrumentação , Veias Umbilicais/fisiologia
20.
Ultrasound Med Biol ; 11(1): 27-36, 1985.
Artigo em Inglês | MEDLINE | ID: mdl-3160153

RESUMO

A method is proposed for estimating the volume blood flow of deep lying vessels in the foetus and in adult portal vein and renal vessels. The equipment combines a 3.5 MHz linear array scanner with a 2 or 4 MHz pulsed Doppler. The pulsed Doppler tranducer is connected to the linear array by two movable arms. A real time spectrum analyser is used to process the Doppler signals. A water bath was used to perform an in vitro calibration of the complete system and to adjust the registration of the Doppler sample volume with the echo picture. Several possible inaccuracies in vessel diameter measurement are discussed and the mean of several caliper measurements described by Eik-Ness (1982) is used. Time Motion is thought to be the better method but is more complicated in practice.


Assuntos
Feto/fisiologia , Troca Materno-Fetal , Sistema Porta/fisiologia , Circulação Renal , Reologia , Ultrassonografia/instrumentação , Adulto , Aorta/fisiologia , Velocidade do Fluxo Sanguíneo , Feminino , Humanos , Gravidez , Análise Espectral , Fatores de Tempo , Veias Umbilicais/fisiologia
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