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BACKGROUND: Urogynaecological conditions, such as pelvic organ prolapse, urinary incontinence, and urinary tract infection, can have a profound impact on people's lives. The Independent Medicines and Medical Devices Safety Review highlights missed opportunities to prevent harm when patient voices are not incorporated into healthcare policy and practice. This resonates with the Women's Health Strategy for England. The National Institute for Health and Care Research (NIHR) Policy Research Programme funded this in-depth qualitative exploration of people's experiences of living with urogynaecological conditions, and of seeking healthcare treatment, to inform health and social care improvements in the UK. METHODS: We conducted in-depth interviews online or by telephone (April 2021-December 2021) and used reflexive thematic analysis to develop themes that cut across urogynaecological conditions. RESULTS: We spoke to seventy-four adults aged 22-84 across a range of backgrounds and lived experiences of urogynaecological conditions, including pelvic organ prolapse, urinary incontinence and persistent or recurring urinary tract infection. Eight themes were developed: [1] I get no respite from my own body; [2] I feel confined and separated; [3] I can no longer be 'me'; [4] I am constrained by stigma, shame and silence; [5] I feel fragmented and lost in the healthcare system; [6] I need to be heard, believed, and valued; [7] I need respect as an equal partner in healthcare; and [8] (Re)connected to a more open community. CONCLUSIONS: High quality care focuses on the whole person rather than their body parts. Openness and candour support a shared decision-making model of care. A culture of shame can have a negative impact on access to health care and recovery.
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Prolapso de Órgão Pélvico , Incontinência Urinária , Adulto , Humanos , Feminino , Pesquisa Qualitativa , Incontinência Urinária/terapia , Atenção à Saúde , Prolapso de Órgão Pélvico/terapia , Reino UnidoRESUMO
We sought to supplement medical physics textbook knowledge and clinical learning with case-based discussions. To our knowledge, this is the first report on a structured combined applied physics curriculum for radiation oncology (RO) and medical physics (MP) trainees. We reviewed our yearly applied physics course given from the years 2016-2021 inclusive. The number of applied physics trainees ranged from 7 to 14 per year (2-9 RO and 3-6 MP residents per year). Each session was taught by a pair of (RO and MP) faculty members. Twenty-nine case-based sessions were given yearly (2016 to 2019). Because of the COVID-19 pandemic restrictions, the course was shortened to 8 case-based sessions in 2020 and 2021. For the years 2016-2021, the mean and median teaching evaluation scores were 4.65 and 5, respectively (range 2-5), where 1 represents worse teaching quality and 5, the best teaching quality. For the year 2021, 2 questions relating to the video virtual format (implemented due to the covid-19 pandemic), revealed consistent high scores with the mean and median responses of 4.14 and 5, respectively (range 1-5). The results from the teaching evaluation scores indicate that the trainees highly valued the teaching sessions and teachers. Our experience indicates that a case-based applied physics course was delivered successfully with continued high teaching evaluation scores. A video virtual platform for an applied physics course could be useful, especially for small programs without a structured applied physics curriculum.
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COVID-19 , Internato e Residência , Radioterapia (Especialidade) , Humanos , Radioterapia (Especialidade)/educação , Pandemias , Física Médica/educação , CurrículoRESUMO
BACKGROUND: Research nurses, midwives and allied health professionals are members of an important emergent profession delivering clinical research and, in the United Kingdom, have been the focus of considerable investment by the National Institute for Health Research (NIHR). This paper considers the experiences of research nurses, midwives and allied health professionals in relation to professional identity work, recognizing these are coproduced alongside others that they interact with (including patients, clinical staff and other research staff). METHODS: Semi-structured interviews were conducted with 45 nurses, midwives and allied health professionals in the UK about their experiences of working in research delivery. Interviews were transcribed verbatim and thematically coded and analysed. RESULTS: Our analysis highlights how research nurses, midwives and allied health professionals adjust to new roles, shift their professional identities and undertake identity work using uniforms, name badges and job titles as they negotiate complex identities. CONCLUSIONS: Research nurses, midwives and allied health professionals experience considerable challenges as they enter and transition to a research delivery role, with implications for their sense of professional identities. A change in the work that they undertake and how they are (or perceive they are) viewed by others (including clinical non-research colleagues and patients) has implications for their sense of professional and individual identity. The tensions involved extend to their views on symbols of professional identity, such as uniforms, and as they seek to articulate and demonstrate the value of their conjoined role in research and as a healthcare professional, within the unfolding landscape of health research. We embed our study findings in the context of the newly emerging clinical research practitioner workforce, which further exacerbates and complicates the role and identity complexity for nurses, midwives and allied health professionals in research delivery.
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Tocologia , Enfermeiras e Enfermeiros , Pessoal Técnico de Saúde , Feminino , Humanos , Gravidez , Pesquisa Qualitativa , Medicina Estatal , Reino Unido , Recursos HumanosRESUMO
BACKGROUND: Acne vulgaris is a common skin condition affecting approximately 95% of adolescents to some extent. First-line treatments are topical preparations but nonadherence is common. A substantial proportion of patients take long courses of oral antibiotics, associated with antibiotic resistance. OBJECTIVES: This study aimed to explore young people's views and experiences of acne and its treatments. METHODS: We report a secondary thematic analysis of interview data collected by researchers in the Health Experiences Research Group (HERG), University of Oxford. A total of 25 transcripts from young people aged 13-24 years with acne were included. RESULTS: Acne is often perceived as a short-term self-limiting condition of adolescence and this appears to have implications for seeking treatment or advice. Participants widely perceived topical treatments as being ineffective, which seemed related to unrealistic expectations around speed of onset of action. Many participants felt they had tried all available topical treatments, although were unsure what was in them or unaware of differences between cosmetic and pharmaceutical treatments. They had concerns around how to use topicals 'properly' and how to avoid side-effects. They were also concerned about the side-effects or necessity of oral treatments, although few seemed aware of antibiotic resistance. CONCLUSIONS: People with acne need support to manage their condition effectively, particularly a better understanding of different topicals, how to use them and how to avoid side-effects. Unrealistic expectations about the onset of action of treatments appears to be a common cause of frustration and nonadherence. Directing people towards accessible evidence-based information is crucial. What's already known about this topic? There is a common perception that acne is a short-term condition that will resolve without treatment. Previous research has shown that nonadherence to topical treatments is common and that oral antibiotics are the most commonly prescribed treatment for acne in the U.K. Further research is needed to understand how young people perceive acne treatments and the implications of this for treatment adherence and self-management. What does this study add? People often said they had tried all available topical preparations for acne, but seemed confused between cosmetic and pharmaceutical treatments. People seemed unsure how to use topical treatments 'properly' or how to avoid side-effects. This was rarely discussed with health professionals. People's perception of acne as a short-term condition appeared to influence their expectations around onset of action of treatment and their views about its effectiveness and necessity. What are the clinical implications of the work? The perception of acne as a short-term condition has implications for self-management and motivation to seek and adhere to treatments. Providing advice about onset of action of treatments and how to prevent side-effects is crucial, including directing people towards accessible, written, evidence-based information. People's confusion about the different topical treatments available may be alleviated by such information, or by encouraging photos or other recordings of treatments tried and for how long. Linked Comment: Prior. Br J Dermatol 2020; 183:208-209. Plain language summary available online.
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Acne Vulgar , Acne Vulgar/tratamento farmacológico , Administração Oral , Adolescente , Adulto , Antibacterianos/uso terapêutico , Humanos , Percepção , Inquéritos e Questionários , Adulto JovemRESUMO
BACKGROUND: Eczema is a common childhood inflammatory skin condition, affecting more than one in five children. A popular perception is that children 'outgrow eczema', although epidemiological studies have shown that, for many, eczema follows a lifelong episodic course. OBJECTIVES: To explore the perceptions of young people about the nature of their eczema and how these perceptions relate to their self-care and adapting to living with eczema. METHODS: This is a secondary inductive thematic analysis of interviews conducted for Healthtalk.org. In total 23 interviews with young people with eczema were included. Of the 23 participants, 17 were female and six male, ranging from 17 to 25 years old. RESULTS: Participants generally experienced eczema as an episodic long-term condition and reported a mismatch between information received about eczema and their experiences. The experience of eczema as long term and episodic had implications for self-care, challenging the process of identifying triggers of eczema flare-ups and evaluating the success of treatment regimens. Participants' experiences of eczema over time also had implications for adaptation and finding a balance between accepting eczema as long term and hoping it would go away. This linked to a gradual shift in treatment expectations from 'cure' to 'control' of eczema. CONCLUSIONS: For young people who continue to experience eczema beyond childhood, a greater focus on self-care for a long-term condition may be helpful. Greater awareness of the impact of early messages around 'growing out of' eczema and provision of high-quality information may help patients to manage expectations and support adaptation to treatment regimens. What's already known about this topic? There is a common perception that people 'grow out of' eczema, but for many people eczema follows a lifelong episodic course. Qualitative work has shown that parents can find that being told their child will grow out of eczema is dismissive, and that they have difficulty with messages about 'control not cure' of eczema. It is unclear how young people perceive their eczema and the implications of this perception for their adaptation and self-care. What does this study add? The message that many people 'grow out of' eczema has a potentially detrimental effect for young people where the condition persists. This has implications for young people's perceptions of their eczema, their learning to self-care and how they adapt to living with eczema and eczema treatments. What are the clinical implications of this work? Clinicians need to promote awareness among young people that eczema is a long-term episodic condition in order to engage them with effective self-care. Young people transitioning to self-care need evidence-based information that is specific and relatable to them.
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Eczema , Autocuidado , Administração Tópica , Adolescente , Adulto , Criança , Eczema/tratamento farmacológico , Feminino , Humanos , Masculino , Filmes Cinematográficos , Pais , Pesquisa Qualitativa , Adulto JovemRESUMO
AIMS: To identify core competencies for postgraduate radiation oncology trainees in global health and cancer that may inform revisions across radiation oncology residency specialty training curricula. MATERIALS AND METHODS: A review of the literature was conducted to identify all potential global health competency items. An international two-phase Delphi process was conducted with experts in oncology. In phase 1, all experts scored, on a nine-point Likert scale, the degree to which they agreed an item should be included in the competency profile. Items with a mean score ≥7 were included, those scoring 4-6 were reviewed in phase 2, and items scored ≤3 were excluded. In phase 2, items were discussed and subsequently ranked for inclusion or exclusion in the competency profile. Items with >75% voting for inclusion were included in the final competency profile. RESULTS: In total, 142 potential global health competency items were identified. Sixty-one items were removed as redundant or irrelevant, leaving 81 items for the Delphi process. Eighteen specialists were invited to participate, with 10 (56%) agreeing to participate in phase 1 of the Delphi process. Participants represented 10 centres in seven countries. Of the 81 items ranked in phase 1, 72 items (89%) had a mean score ≥7 and were automatically included in the final competency profile. The remaining nine items received a score of 4-6 and were discussed in phase 2 of the Delphi process, of which three received <75% agreement for inclusion and were excluded. The result was a final list of 78 enabling competency items. CONCLUSIONS: The radiation oncology global health competency profile represents an international consensus on the items that can inform radiation oncology training requirements.
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Competência Clínica/normas , Educação Médica Continuada/normas , Saúde Global , Internato e Residência/normas , Neoplasias/terapia , Médicos/normas , Radioterapia (Especialidade)/educação , Técnica Delphi , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Inquéritos e QuestionáriosRESUMO
BACKGROUND: The radiotherapy (rt) volumes in anaplastic (atc) and differentiated thyroid carcinoma (dtc) are controversial. METHODS: We retrospectively examined the patterns of failure after postoperative intensity-modulated rt for atc and dtc. Computed tomography images were rigidly registered with the original rt plans. Recurrences were considered in-field if more than 95% of the recurrence volume received 95% of the prescribed dose, out-of-field if less than 20% received 95% of the dose, and marginal otherwise. RESULTS: Of 30 dtc patients, 4 developed regional recurrence: 1 being in-field (level iii), and 3 being out-of-field (all level ii). Of 5 atc patients, all 5 recurred at 7 sites: 2 recurrences being local, and 5 being regional [2 marginal (intramuscular to the digastric and sternocleidomastoid), 3 out-of-field (retropharyngeal, soft tissues near the manubrium, and lateral to the sternocleidomastoid)]. CONCLUSIONS: In dtc, locoregional recurrence is unusual after rt. Out-of-field dtc recurrences infrequently occurred in level ii. Enlarged treatment volumes to level ii must be balanced against a potentially greater risk of toxicity.
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Plane parallel ionization chambers are an important tool for dosimetry and absolute calibration of electron beams used for radiotherapy. Most dosimetric protocols require corrections for recombination and polarity effects, which are to be determined experimentally as they depend on chamber design and radiation quality. Both effects were investigated in electron beams from a linear accelerator (Varian 21CD) for a set of four tissue equivalent plane parallel ionization chambers customized for the present research by Standard Imaging (Madison WI). All four chambers share the same design and air cavity dimensions, differing only in the diameter of their collecting electrode and the corresponding width of the guard ring. The diameters of the collecting electrodes were 2 mm, 4 mm, 10 mm and 20 mm. Measurements were taken using electron beams of nominal energy 6 to 20 MeV in a 10 cm x 10 cm field size with a SSD of 100 cm at various depths in a Solid Water slab phantom. No significant variation of recombination effect was found with radiation quality, depth of measurement or chamber design. However, the polarity effect exceeded 5% for the chambers with small collecting electrode for an effective electron energy below 4 MeV at the point of measurement. The magnitude of the effect increased with decreasing electron energy in the phantom. The polarity correction factor calculated following AAPM protocol TG51 ranged from approximately 1.00 for the 20.0 mm chamber to less than 0.95 for the 2 mm chamber at 4.1 cm depth in a electron beam of nominally 12 MeV. By inverting the chamber it could be shown that the polarity effect did not depend on the polarity of the electrode first traversed by the electron beam. Similarly, the introduction of an air gap between the overlying phantom layer and the chambers demonstrated that the angular distribution of the electrons at the point of measurement had a lesser effect on the polarity correction than the electron energy itself. The magnitude of the absolute difference between charge collected at positive and negative polarity was found to correlate with the area of the collecting electrode which is consistent with the explanation that differences in thickness of the collecting electrodes and the number of electrons stopped in them contribute significantly to the polarity effect. Overall, the polarity effects found in the present study would have a negligible effect on electron beam calibration at a measurement depth recommended by most calibration protocols. However, the present work tested the corrections under extreme conditions thereby aiming at greater understanding of the mechanism underlying the correction factors for these chambers. This may lead to better chamber design for absolute dosimetry and electron beam characterization with less reliance on empirical corrections.
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Artefatos , Eletrodos , Radiometria/instrumentação , Radioterapia Conformacional/instrumentação , Elétrons/uso terapêutico , Desenho de Equipamento , Análise de Falha de Equipamento , Radiometria/métodos , Dosagem Radioterapêutica , Radioterapia Conformacional/métodos , Reprodutibilidade dos Testes , Espalhamento de Radiação , Sensibilidade e Especificidade , Eletricidade EstáticaRESUMO
1. Glycine was bath-applied to outside-out patches taken from cultured mouse spinal cord neurons. Glycine-activated chloride channels had at least six open states with permeabilities of 40 (A), 68 (B), 100 (C), 145 (D), 180 (E), and 250 (F) al/s (1 attoliter = 10(-18) liter). Usually no more than two such states were seen in any given patch. The usual extracellular chloride concentration was 157 mM; chloride concentration in the electrode (on the cytoplasmic face of the patch) was varied between 7 and 170 mM, replaced at lower concentrations with either of the inert anions gluconate or methane sulphonate. 2. With normal (7 mM) chloride concentration in the electrode, openings to state D were the most probable, and the average permeability of all openings was 115 al/s. When the cytoplasmic chloride concentration was 20 mM, the most probable open state was the lower-permeability state (C), and the average permeability was 92 al/s. In symmetrical 170 mM chloride, the most probable open state was B and the mean permeability 77 al/s. 3. The glycine-activated channels had a vanishingly small permeability to fluoride. However, in experiments in which 150 mM gluconate in the pipette was replaced by fluoride, the most probable open state was B, as in the high-chloride solution. Thus the two halides had similar effects on open state preference. 4. With external and internal chloride concentrations of 7 and 157 mM, respectively, single-channel current-voltage relations could be fit with constant field relations appropriate to one or more of the permeability states.(ABSTRACT TRUNCATED AT 250 WORDS)
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Cloretos/fisiologia , Glicina/fisiologia , Proteínas de Membrana/fisiologia , Medula Espinal/fisiologia , Transmissão Sináptica/fisiologia , Animais , Células Cultivadas , Canais de Cloreto , Embrião de Mamíferos , Líquido Intracelular/fisiologia , Potenciais da Membrana/fisiologia , Camundongos , Inibição Neural/fisiologiaRESUMO
The properties of the Ca2(+)-activated K+ channel in unfertilized hamster oocytes were investigated at the single-channel level using inside-out excised membrane patches. The results indicate a new type of Ca2(+)-activated K+ channel which has the following characteristics: (1) single-channel conductance of 40-85 pS for outward currents in symmetrical K+ (150 mM) solutions. (2) inward currents of smaller conductance (10-50 pS) than outward currents, i.e. the channel is outwardly rectified in symmetrical K+ solutions, (3) channel activity dependent on the internal concentration of free Ca2+ and the membrane potential, (4) modification of the channel activity by internal adenosine 5' diphosphate (0.1 mM) producing a high open probability regardless of membrane potential.
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Cálcio/farmacologia , Oócitos/fisiologia , Canais de Potássio/fisiologia , Animais , Cricetinae , Feminino , Técnicas In Vitro , Potenciais da Membrana/fisiologia , Canais de Potássio/efeitos dos fármacosRESUMO
Expression of receptors for the hypothalamic regulatory peptide, gonadotrophin-releasing hormone (GnRH), was investigated by intracellular recording from Xenopus oocytes injected with poly(A)+ mRNA isolated from rat anterior pituitary glands. Membrane depolarizations were induced in oocytes in a dose-dependent fashion following the application of GnRH (10nM - 1 microM) or a GnRH superactive agonist, buserelin (1nM - 1 microM). The response was reversibly blocked by the addition of a GnRH antagonist (1 microM). TRH (10nM - 1 microM) had no effect on most of these oocytes. In contrast, some other oocytes which showed no responses to GnRH or to the GnRH agonist, displayed depolarizing responses to TRH (10nM - 1 microM). A relatively small number of oocytes responded to both ligands. Control oocytes did not respond to the GnRH analogues or to TRH. This successful expression of the GnRH receptor could provide a new approach to the study of the receptor, and serve as a means for the isolation and cloning of the encoding genes.
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Receptores LHRH/biossíntese , Animais , Feminino , Regulação da Expressão Gênica , Técnicas In Vitro , Potenciais da Membrana , Microinjeções , Oócitos/metabolismo , Adeno-Hipófise/análise , Poli A/isolamento & purificação , RNA Mensageiro/isolamento & purificação , Ratos , Ratos Endogâmicos , Receptores LHRH/genética , Receptores de Neurotransmissores/genética , Receptores de Neurotransmissores/metabolismo , Receptores do Hormônio Liberador da Tireotropina , Xenopus laevisRESUMO
A transient change of membrane potential and resistance could be evoked after a long latency (ca. 9 s) by a single calcium action potential in some unfertilized hamster eggs. The estimated reversal potential for the delayed response was close to EK supporting the conclusion that K channels were opened indirectly by the Ca2+ influx through voltage-gated channels. A second action potential elicited after the first did not induce a similar response. A number of treatments (insertion of a Ca2+ pipette, application of Na+-free solution, La3+ or high external pH) likely to raise [Ca2+]i also induced similar large changes of potential and resistance after which a single action potential failed to evoke a large delayed response. The evidence indicates that a small rise in [Ca2+]i activates a slow process leading to a further large increase in [Ca2+]i.
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Cálcio/farmacologia , Óvulo/fisiologia , Canais de Potássio/fisiologia , Potenciais de Ação , Animais , Cricetinae , Feminino , Técnicas In Vitro , Mesocricetus , Óvulo/efeitos dos fármacosRESUMO
1. The effect of external pH (pHo) on the membrane potential and resistance of unfertilized zona-free hamster eggs was investigated by intracellular recording techniques. 2. A hyperpolarization of the hamster egg membrane was induced by raising the extracellular pH above 8.0. This hyperpolarization was accompanied by a rise in membrane conductance and was reversible by washing the egg. 3. The estimated value of the reversal potential of the hyperpolarizing response to a solution with pHo 9.5 was about -85 mV. The membrane potential changed linearly with log [K+]o with a slope of 43 +/- 2 mV (mean +/- S.D.; n = 4) for a 10-fold change in [K+]o, while it was unaltered by the removal of Cl- from the solution. 4. The amplitude of the pHo-induced hyperpolarization decreased substantially as [Ca2+]o was lowered from 20 to 1 mM. Sr2+ could substitute for Ca2+ in sustaining the response to high pHo, whereas Ba2+ or Mg2+ could not. 5. Injection of the Ca2+ chelator EGTA into the egg prevented the pHo-induced hyperpolarization suggesting that a rise in [Ca2+]i is required. 6. The rate of rise of Ca2+ action potentials was reversibly enhanced by raising pHo. However, influx through the voltage-gated Ca2+ channels is not involved in initiation and maintenance of the pHo-induced response, as responses were not affected by the Ca2+ channel blocker La3+. 7. The duration of the hyperpolarization evoked by intracellular Ca2+ injection in eggs bathed in normal solution or Na+-free solution was greatly prolonged by raising pHo. 8. It is suggested that a rise in external pH produces an increase in [Ca2+]i, activating a Ca2+-mediated K+ conductance which hyperpolarizes the egg membrane. 9. It is concluded that both a Na+-Ca2+ exchange system and a Ca2+ pump are responsible for Ca2+ extrusion and that inhibition of the Ca2+ pump by high pHo is the chief mechanism underlying the pH-induced hyperpolarization in hamster eggs. Although the Na+-Ca2+ exchange system is facilitated at high pHo, the effect of this facilitation of efflux is outweighed by the inhibition of the Ca2+ pump.
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Óvulo/fisiologia , Canais de Potássio/fisiologia , Potenciais de Ação/efeitos dos fármacos , Animais , Canais de Cálcio/fisiologia , Cricetinae , Ácido Egtázico/farmacologia , Condutividade Elétrica , Concentração de Íons de Hidrogênio , Potenciais da Membrana/efeitos dos fármacos , Mesocricetus , Potássio/farmacologia , Sódio/farmacologiaRESUMO
A prospective study of 97 consecutive patients with inversion ankle injuries who were referred by their family practitioner to an accident and emergency department was carried out. Clinical features and resultant diagnosis were compared with 403 consecutive patients who referred themselves direct to the accident unit during the study period. There was no significant difference in the incidence of serious injuries between the two referral groups. Multivariate analysis of the combined referral groups revealed that age over 60 years, inability to weight-bear and distal fibular tenderness were critical diagnostic parameters and this result has been reported elsewhere. Further analysis of these features in each referral sub-group showed that significantly more patients referred by their family doctor were in the important over 60 years age group but that the incidence of the other diagnostic parameters were similar in the two populations. Using the presence of any one of these criteria as an indication for hospital referral with a view to X-ray examination, 70% of the patients seen first by their own doctor did actually warrant radiography compared with 58% in the self-referred group. However, it is apparent that more efficient hospital referral from family practice is possible by use of the clinical parameters described above and no serious fracture would have been missed by a general practitioner using such a policy in this population. Analysis of the reasons for referral by general practitioners is discussed and a suggested management regime is provided for all patients with inversion ankle injuries who attend their own doctor in the first instance.
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Traumatismos do Tornozelo , Serviço Hospitalar de Emergência/estatística & dados numéricos , Medicina de Família e Comunidade , Encaminhamento e Consulta/estatística & dados numéricos , Entorses e Distensões/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Escócia , Entorses e Distensões/terapiaRESUMO
At room temperature micro-injections of calcium or strontium produced transient hyperpolarizations with an associated rise in input conductance. By contrast micro-injections of potassium, barium, magnesium, cobalt or lanthanum did not produce hyperpolarizations. The reversal potential for the hyperpolarizing response was about -80 mV. Some responses to calcium injections appeared to suffer from an additional transient leak conductance generated by the injected current. In these cases the recovery of the potential and the conductance to normal values was prolonged. The reversal potential of this additional leak pathway was about -10 mV. Experiments designed to investigate the role of active calcium extrusion from the cells showed that extracellular lanthanum or quercetin caused a pronounced slowing of the recovery phase of the potential and conductance response to calcium injection. The metabolic uncoupler dinitrophenol also prolonged the calcium-evoked responses. The replacement of extracellular sodium by lithium or choline produced no alteration in the time course of the calcium-evoked responses, thus suggesting that sodium-calcium exchange exerts no rate control on the recovery phase of those responses.