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Biomedical subjects

C Pope

Publications and source records attributed to C Pope.

At least 19 recordsLinked to original sources

What defines expertise in regional anaesthesia? An observational analysis of practice.

BACKGROUND: Published work on knowledge in regional anaesthesia has focused on competence, for instance by identifying numbers of procedures required to achieve competence, or by defining criteria for successful performance of blocks. We aimed to define expertise in regional anaesthesia and examine how it is acquired. METHODS: We observed anaesthetists performing 15 regional anaesthetic blocks and analysed the resulting transcripts qualitatively and in detail. RESULTS: Expertise in regional anaesthesia encompasses technical fluency but also includes non-cognitive skills such as handling of the patient (communicating, anticipating and minimizing discomfort) and recognizing the limits of safe practice (particularly deciding when to stop trying to insert a block). Such elements may be underplayed by the experts who possess them. Focusing on a small number of regional anaesthetic procedures in detail (as is standard with such qualitative analytical approaches) has also allowed us to develop a model for the acquisition of expertise. In this model, trainees learn how to balance theoretical and practical knowledge by reflection on their clinical experiences, an iterative process which leads to the embedding of knowledge in the expert's personal repertoire of individual techniques. CONCLUSIONS: Expertise in regional anaesthesia extends beyond competence at technical performance; non-cognitive elements are also vital. Further work is needed to test our learning model, and the hypothesis that learning can be enhanced by deliberate promotion of the tacit elements of 'expertise' we have described.

Anesthesia, Conduction↗

Cultural conflicts in the weight loss experience of overweight Latinos.

OBJECTIVE: In spite of the high prevalence of obesity in the Latino population, there is limited recent information that can be used by health-care providers to develop culturally appropriate weight loss strategies for this population. Therefore, we describe weight loss experiences, attitudes and barriers in overweight Latino adults. DESIGN: Qualitative study using focus group methodology. SUBJECTS: Twenty-one overweight adults (body mass index >/=25, age >/=20 years) self-identified as Latinos. METHODS: Subjects participated in one of three focus groups. Reccurring themes within group discussions were identified by three independent investigators, one who was ethnicity concordant. RESULTS: Themes included the presence of mixed messages when determining one's appropriate weight, with participants' desire to lose weight to be healthy (based on professional advice and personal experience) conflicting with the cultural idea that being overweight is healthy. Participants described discordance when adapting to the mainstream, leading to the loss of healthy traditional habits. Participants expressed interest in weight loss and familiarity with dieting and weight loss interventions. They desired culturally appropriate nutrition education and reassurance regarding healthy dieting from health-care providers. The importance of interactions with peers during education was another relevant theme, and participants were overwhelmingly positive about group education. CONCLUSIONS: To improve health promotion for Latinos, cultural factors distinctive to this underserved population, and barriers they articulate, should be considered when developing weight loss interventions.

Adult↗

Adverse events in anaesthetic practice: qualitative study of definition, discussion and reporting.

BACKGROUND: This study aimed to explore how critical and acceptable practice are defined in anaesthesia and how this influences the discussion and reporting of adverse incidents. Method. We conducted workplace observations of, and interviews with, anaesthetists and anaesthetic staff. Transcripts were analysed qualitatively for recurrent themes and quantitatively for adverse events in anaesthetic process witnessed. We also observed departmental audit meetings and analysed meeting minutes and report forms. RESULTS: The educational value of discussing events was well-recognized; 28 events were discussed at departmental meetings, of which 5 (18%) were presented as 'critical incidents'. However, only one incident was reported formally. Our observations of anaesthetic practice revealed 103 minor events during the course of over 50 anaesthetic procedures, but none were acknowledged as offering the potential to improve safety, although some were direct violations of 'acceptable' practice. Formal reporting appears to be constrained by changing boundaries of what might be considered 'critical', by concerns of loss of control over formally reported incidents and by the perception that reporting schemes outside anaesthesia have purposes other than education. CONCLUSIONS: Despite clear official definitions of criticality in anaesthesia, there is ambiguity in how these are applied in practice. Many educationally useful events fall outside critical incident reporting schemes. Professional expertise in anaesthesia brings its own implicit safety culture but the reluctance to adopt a more explicit 'systems approach' to adverse events may impede further gains in patient safety in anaesthesia.

Anesthesia↗

Fetal gonadotrope cell origin of FSH-secreting pituitary adenoma - insight into human pituitary tumour pathogenesis.

OBJECTIVE: The pathogenesis of human pituitary adenomas remains unclear, but we report a case of FSH-secreting pituitary adenoma whose monohormonal phenotype suggests it was of fetal origin. PATIENTS: A 28-year-old woman presented with abdominal discomfort and irregular menses, enlarged multicystic ovaries and elevated serum oestradiol, with sustained high-normal FSH and low LH levels. MEASUREMENTS: Endocrine studies were performed before and after curative surgery, with assessment of tumour hormone secretion in vitro, and immunostaining of tumour tissue for a series of gonadotrope proteins. RESULTS: Immunocytochemistry showed that tumour cells were monohormonal for FSH. Normal components of gonadotrope signalling pathways were expressed, including oestrogen receptor-alpha, activin receptors, secretogranin-II and chromogranin-A. beta-glycan, the putative inhibin coreceptor, was absent. Tumour culture in vitro confirmed secretion of FSH with minimal LH, that was unsuppressed by oestradiol or inhibin-A. Human fetal pituitary tissue contained FSH-only cells at 18 weeks gestation, whereas normal adult pituitary tissue contained only bihormonal gonadotropes. CONCLUSIONS: We propose that this pituitary adenoma represents an indolent tumour of monohormonal fetal gonadotrope cells that originated early in gestation. Pituitary tumours may therefore arise from abnormal persistence of fetal cell types, with extremely slow growth over many years until reaching a size threshold to generate an endocrine syndrome. Understanding fetal pituitary architecture and function may be more informative for new insights into pituitary tumour pathogenesis than classical theories of cancer biology that invoke unrestrained cell proliferation.

Adenoma↗

Interactive toxicity of chlorpyrifos and parathion in neonatal rats: role of esterases in exposure sequence-dependent toxicity.

We previously reported that sequence of exposure to chlorpyrifos and parathion in adult rats can markedly influence toxic outcome. In the present study, we evaluated the interactive toxicity of chlorpyrifos (8 mg/kg, po) and parathion (0.5 mg/kg, po) in neonatal (7 days old) rats. Rats were exposed to the insecticides either concurrently or sequentially (separated by 4 h) and sacrificed at 4, 8, and 24 h after the first exposure for biochemical measurements (cholinesterase activity in brain, plasma, and diaphragm and carboxylesterase activity in plasma and liver). The concurrently-exposed group showed more cumulative lethality (15/24) than either of the sequential dosing groups. With sequential dosing, rats treated initially with chlorpyrifos prior to parathion (C/P) exhibited higher lethality (7/23) compared to those treated with parathion before chlorpyrifos (P/C; 1/24). At 8 h after initial dosing, brain cholinesterase inhibition was significantly greater in the C/P group (59%) compared to the P/C group (28%). Diaphragm and plasma cholinesterase activity also followed a relatively similar pattern of inhibition. Carboxylesterase inhibition in plasma and liver was relatively similar among the treatment groups across time-points. Similar sequence-dependent differences in brain cholinesterase inhibition were also noted with lower binary exposures to chlorpyrifos (2 mg/kg) and parathion (0.35 mg/kg). In vitro and ex vivo studies compared relative oxon detoxification of carboxylesterases (calcium-insensitive) and A-esterases (calcium-sensitive) in liver homogenates from untreated and insecticide pretreated rats. Using tissues from untreated rats, carboxylesterases detoxified both chlorpyrifos oxon and paraoxon, while A-esterases only detoxified chlorpyrifos oxon. With parathion pretreatment, A-esterases still detoxified chlorpyrifos oxon while liver from chlorpyrifos pretreated rats had little apparent effect on paraoxon. We conclude that while neonatal rats are less capable than adults at detoxifying many organophosphorus insecticides including chlorpyrifos and parathion, toxicant-selective differences in detoxification play a role in sequence-dependent toxicity in both neonatal and adult rats with these two insecticides.

Animals↗

What do other local providers think of NHS walk-in centres? Results of a postal survey.

OBJECTIVES: To ascertain the views of other providers of primary and emergency healthcare services about their local walk-in centre. DESIGN: Postal survey. SETTING AND PARTICIPANTS: National Health Service healthcare providers (general practitioners (GPs), practice nurses, pharmacists, Accident and Emergency (A and E) consultants) working in close proximity to 20 English walk-in centres. RESULTS: The overall response rate to the survey was 79% (n = 1591). Nearly one-third of respondents felt that patient expectations had increased since their local walk-in centre opened, although this varied across the different sites. Some providers had noticed a reduction in their workload, but 15% claimed that workloads had increased since their local walk-in centre opened. There was broad agreement that these new centres did address issues of access and that they provided appropriate care of a reasonable quality. Communication between walk-in centres and other local healthcare providers was an area of considerable concern; GPs, in particular, were anxious about the impact of the service on continuity of care. There were clear differences of opinion between different types of health professional, with doctors tending to be more critical and practice nurses being more supportive. CONCLUSION: It has been suggested that healthcare professionals, notably GPs, are universally opposed to the concept of walk-in centres. This survey shows that opinions were divided, but overall, more local providers were in favour of this new service than were opposed to it. There was more support for centres co-located with A and E departments than "shop-front"-type facilities, but there were concerns that the service offered was too limited. The success or otherwise of the walk-in centre initiative will depend, in part, on building good relationships between the centres and other local providers. Understanding the views of local providers is important for those developing walk-in centres, and for those engaged in planning services in the wider health economies where these services are placed.

Ambulatory Care Facilities↗

Making monitoring 'work': human-machine interaction and patient safety in anaesthesia.

This study aimed to explore the use of electronic monitoring within the context of anaesthetic practice. We conducted workplace observation of, and interviews with, anaesthetists and other anaesthetic staff in two UK hospitals. Transcripts were analysed inductively for recurrent themes. Whilst formal sources of knowledge in anaesthesia deal with the issue of monitoring in terms of theoretical principles and performance specifications of devices, anaesthetists in practice often 'disbelieve' monitoring information. They call on and integrate other sources of knowledge about the patient, especially from their clinical assessment. The ability to distinguish 'normal' and 'abnormal' findings is vital. Confidence in electronic information varies with experience, as does the degree to which electronic information may be considered 'redundant'. We conclude that electronic monitoring brings new dimensions of understanding but also the potential for new ways of misunderstanding. The tacit knowledge underlying the safe use of monitoring deserves greater acknowledgement in training and practice.

Anesthesia, General↗

Expertise in practice: an ethnographic study exploring acquisition and use of knowledge in anaesthesia.

BACKGROUND: Expert professional practice in any field is known to rely on both explicit (formal) and tacit (personal) forms of knowledge. Current anaesthetic training programmes appear to favour explicit knowledge and measurable competencies. We aimed to describe and explore the way different types of knowledge are learned and used in anaesthetic practice. METHOD: Qualitative approach using non-participant observation of, and semi-structured interviews with, anaesthetic staff in two English hospitals. RESULTS: The development of expertise in anaesthesia rests on the ability to reconcile and interpret many sources of knowledge--clinical, social, electronic, and experiential--and formal theoretical learning. Experts have mastered technical skills but are also able to understand the dynamic and uncertain condition of the anaesthetized patient and respond to changes in it. This expertise is acquired by working with colleagues, and, importantly, by working independently, to develop personal routines. Routines mark the successful incorporation of new knowledge but also function as a defence against the inherent uncertainty of anaesthetic practice. The habits seen in experts' routines are preferred ways of working chosen from a larger repertoire of techniques which can also be mobilized as changing circumstances demand. CONCLUSIONS: Opportunities for developing expertise are linked to the independent development of personal routines. Evidence-based approaches to professional practice may obscure the role played by the interpretation of knowledge. We suggest that the restriction of apprenticeship-style training threatens the acquisition of anaesthetic expertise as defined in this paper.

Anesthesia↗

Symptomatic and physiologic outcomes after operative treatment for extraesophageal reflux.

BACKGROUND: Pharyngeal pH monitoring has recently been used to identify patients with extraesophageal symptoms induced by gastroesophageal reflux. We employed this method of acid detection to evaluate patients with respiratory symptoms prior to and after laparoscopic Nissen fundoplication to further elucidate the relationship between GERD and respiratory symptoms. METHODS: Twenty-one consecutive patients with extraesophageal symptoms thought to be caused by reflux underwent symptomatic and functional evaluation (esophageal manometry and 24-h pH monitoring with a pharyngeal probe) before and after laparoscopic Nissen fundoplication. Episodes of pharyngeal acid exposure were considered abnormal if the pH dropped below 4, occurred simultaneously with esophageal acidification, and occurred outside meal times. RESULTS: All patients had gastroesophageal reflux disease (GERD) and respiratory symptoms; nine of 15 (60%) had evidence of pharyngeal reflux preoperatively. Antireflux procedures resulted in a significant decrease in pharyngeal reflux (7.9 to 1.6 episodes/24h; p <0.05) and esophageal acid exposure (7.5% to 2.1%; p <0.05). In patients with pharyngeal reflux and complete postoperative testing, three (60%) obtained improvement of respiratory symptoms and resolution of pharyngeal reflux. In two patients with recurrent respiratory symptoms after surgery, persistent pharyngeal reflux was detected. CONCLUSION: Operative treatment of GERD is effective in controlling extraesophageal reflux, measured subjectively and objectively. Evidence of pharyngeal reflux on pH testing helps to identify which patients with respiratory symptoms will benefit from an antireflux procedure.

Cough↗

Qualitative methods in research on healthcare quality.

There are no easy solutions to the problem of improving the quality of care. Research has shown how difficult it can be, but has failed to provide reliable and effective ways to change services and professional performance for the better. Much depends on the perspectives of users and the attitudes and behaviours of professionals in the context of their organisations and healthcare teams. Qualitative research offers a variety of methods for identifying what really matters to patients and carers, detecting obstacles to changing performance, and explaining why improvement does or does not occur. The use of such methods in future studies could lead to a better understanding of how to improve quality.

Focus Groups↗

In vivo interaction between chlorpyrifos and parathion in adult rats: sequence of administration can markedly influence toxic outcome.

Organophosphorus insecticides (OPs) generally act through a common mechanism of toxicity initiated by inhibition of acetylcholinesterase (AChE). We studied the in vivo interactive toxicity of two common OPs, chlorpyrifos (CPF) and parathion (PS), in adult male rats. Dose-response studies estimated the acute oral LD1 values for the two OPs (CPF = 80 mg/kg po; PS = 4 mg/kg po) and these dosages or relative proportions were used to evaluate interactive toxicity. Three treatment strategies were evaluated: CPF followed by PS 4 h later (CPF-1st), PS followed by CPF 4 h later (PS-1st), and simultaneous (concurrent) exposures. Using LD1 dosages, rats in the CPF-1st and concurrent groups exhibited more cholinergic toxicity (i.e., salivation, lacrimation, urination, and diarrhea signs and involuntary movements) and higher lethality (7/8 and 6/8, respectively, beginning 1 h after PS) than those in the PS-1st group (2/8 lethality, beginning 3 days after CPF). Sequential exposures to lower dosages (CPF vs PS: 60 vs 3 mg/kg; 40 vs 2 mg/kg) led to more extensive neurotoxicity in the CPF-1st group compared to the other groups. Following lower dosages (40 vs 2 mg/kg), brain ChE inhibition was more extensive in the CPF-1st group at all time points (64-85%) and the concurrent group at 4 and 24 h after exposure (46-83%) compared to rats receiving PS first (7-48%). No differences were noted however, in plasma (71-93% inhibition) or liver (72-81%) cholinesterase activities nor were there group-related differences in plasma (50-60% inhibition) or liver (>85% inhibition) carboxylesterase activities. Incubation of liver samples with oxons in the presence or absence of calcium (i.e., 2 mM CaCl(2) or EGTA) prior to addition of ChE (striatal sample) substantially blocked ChE inhibition by CPO (IC50: without liver = 4 nM; liver + calcium = 279 nM; liver + EGTA = 48 nM) but had lesser effects on PO-mediated inhibition (IC50: without liver = 17 nM; liver + EGTA = 56 nM; liver + calcium = 57 nM). Liver homogenate from animals preexposed to PS substantially decreased ChE inhibition by CPO when calcium was included (IC50: +EGTA = 8 nM; +calcium = 225 nM), but liver homogenate from animals preexposed to CPF was ineffective at blocking PO-induced inhibition (IC50: +EGTA = 16 nM; +calcium = 16 nM). We conclude that prior inhibition of carboxylesterase activity impacts toxicity of subsequent exposure to PS more than CPF because of more active detoxification of CPO by A-esterase. Together, these findings indicate that interactive toxicity from combined exposures to two OP insecticides can be markedly influenced by the sequence of administration.

Animals↗

Organ-specific regulation of the CD8 T cell response to Listeria monocytogenes infection.

The intestinal mucosal CD8 T cell response to infection with Listeria monocytogenes was measured using MHC class I tetramers and was compared with the response in peripheral blood, secondary lymphoid tissue, and liver. To assess the vaccination potential of Listeria and to analyze responses in C57BL/6 mouse strains, a recombinant Listeria expressing OVA (rLM-ova) was generated. The response peaked at 9 days postinfection with a much larger fraction of the intestinal mucosa and liver CD8 T cell pool OVA specific, as compared with the spleen. However, these differences were not linked to bacterial titers in each site. The higher responses in lamina propria and liver resulted in a larger CD8 memory population in these tissues. Furthermore, the level of memory induced was dependent on infectious dose and inversely correlated with the magnitude of the recall response after oral challenge. Recall responses in the tissues were most robust in the lamina propria and liver, and reactivated Ag-specific T cells produced IFN-gamma. Infection of CD40- or MHC class II-deficient mice induced poor CD8 T cell responses in the intestinal mucosa, but only partially reduced responses in the spleen and liver. Overall, the results point to novel pathways of tissue-specific regulation of primary and memory antimicrobial CD8 T cell responses.

Administration, Oral↗

Inhibition of forskolin-stimulated cAMP formation in vitro by paraoxon and chlorpyrifos oxon in cortical slices from neonatal, juvenile, and adult rats.

Parathion (PS) and chlorpyrifos (CPF) are organophosphorus insecticides, which elicit toxicity following biotransformation to the potent acetylcholinesterase inhibitors, paraoxon (PO) and chlorpyrifos oxon (CPO). Both oxons have also been shown to interact directly with muscarinic receptors coupled to inhibition of adenylyl cyclase. Immature animals are more sensitive than adults to the acute toxicity of PS and CPF but little is known regarding possible age-related differences in interactions between these toxicants and muscarinic receptors. We compared the inhibition of forskolin-stimulated cAMP formation by PO and CPO (1 nM-1 mM) in vitro in brain slices from 7-, 21-, and 90-day-old rats to the effects of well-known muscarinic agonists, carbachol and oxotremorine (100 microM). Both agonists inhibited cAMP formation in tissues from all age groups and both were more effective in adult and juvenile (20-26% inhibition) than in neonatal (12-13% inhibition) tissues. Atropine (10 microM) completely blocked agonist-induced inhibition in all cases. PO maximally inhibited (37-46%) cAMP formation similarly in tissues from all age groups, but atropine blocked those effects only partially and only in tissues from 7-day-old rats. CPO similarly inhibited cAMP formation across age groups (27-38%), but ATR was partially effective in tissues from all three age groups. Both oxons were markedly more potent in tissues from younger animals. We conclude that PO and CPO can directly inhibit cAMP formation through muscarinic receptor-dependent and independent mechanisms and that the developing nervous system may be more sensitive to these noncholinesterase actions.

Aging↗

SLE in a United States-Mexico border community.

This report describes the results of a clinic-based study conducted to verify a community-reported excess prevalence of systemic lupus erythematosus (SLE) and a possible connection between ethnicity and environmental factors in the reporting of SLE in the United States-Mexico border town of Nogales, Arizona. A community group in Nogales reported 37 cases of SLE in its community, suggesting a prevalence rate of 200 per 100,000. This report describes 19 definite and 7 probable cases of SLE using the 1982 American College of Rheumatology criteria. All definite and probable cases were self-identified, Mexican-American females. This yields a prevalence rate of 94 per 100,000, among the highest reported to date. The majority of cases resided within 3 miles of the United States-Mexico border and within 1 mile of the polluted Nogales Wash or ground wells with documented toxins. It remains to be determined whether this confirms that SLE is more common in Mexican-Americans or whether environmental factors, especially pollutants, are predominantly responsible. In addition to the need to be aware about the apparent increased risk of SLE in many Latin-Americans, clinicians should ask about possible environmental factors.

Journal Article↗