Heavy metal pollution and co-selection for antibiotic resistance: A microbial palaeontology approach

Frequent and persistent heavy metal pollution has profound effects on the composition and activity of microbial communities. Heavy metals select for metal resistance but can also co-select for resistance to antibiotics, which is a global health concern. We here document metal concentration, metal resistance and antibiotic resistance along a sediment archive from a pond in the North West of the United Kingdom covering over a century of anthropogenic pollution. We specifically focus on zinc, as it is a ubiquitous and toxic metal contaminant known to co-select for antibiotic resistance, to assess the impact of temporal variation in heavy metal pollution on microbial community diversity and to quantify the selection effects of differential heavy metal exposure on antibiotic resistance. Zinc concentration and bioavailability was found to vary over the core, likely reflecting increased industrialisation around the middle of the 20th century. Zinc concentration had a significant effect on bacterial community composition, as revealed by a positive correlation between the level of zinc tolerance in culturable bacteria and zinc concentration. The proportion of zinc resistant isolates was also positively correlated with resistance to three clinically relevant antibiotics (oxacillin, cefotaxime and trimethoprim). The abundance of the class 1 integron-integrase gene, intI1, marker for anthropogenic pollutants correlated with the prevalence of zinc- and cefotaxime resistance but not with oxacillin and trimethoprim resistance. Our microbial palaeontology approach reveals that metal-contaminated sediments from depths that pre-date the use of antibiotics were enriched in antibiotic resistant bacteria, demonstrating the pervasive effects of metal-antibiotic co-selection in the environment.

The value of the Frenchay Aphasia Screening Test in screening for dysphasia: better than the clinician?

We have evaluated the Frenchay Aphasia Screening Test (FAST) in an elderly population living in the community, and in patients with a first stroke. Fifty-one elderly people aged 69-90 years were screened. Ten subjects failed the test (score < 25/30). There was an inverse relationship between age and the FAST score ( r s = -0.35, p = 0.02, 95% Cl 0.09-0.57). I n a group of 82 elderly patients, mean age 80 (6 years), admitted with a first stroke, the FAST was applied at one and seven days and the result compared with a clinical assessment and a speech therapy assessment. At day one 28 patients failed the test due to a reduced level of consciousness. The use of the FAST increased the sensitivity of screening from 87% to 96%, but reduced its specificity from 100% to 61 %. The positive and negative predictive values were 65% and 95% respectively.

Assessing the performance of the Oxford Nanopore Technologies MinION

The Oxford Nanopore Technologies (ONT) MinION is a new sequencing technology that potentially offers read lengths of tens of kilobases (kb) limited only by the length of DNA molecules presented to it. The device has a low capital cost, is by far the most portable DNA sequencer available, and can produce data in real-time. It has numerous prospective applications including improving genome sequence assemblies and resolution of repeat-rich regions. Before such a technology is widely adopted, it is important to assess its performance and limitations in respect of throughput and accuracy. In this study we assessed the performance of the MinION by re-sequencing three bacterial genomes, with very different nucleotide compositions ranging from 28.6% to 70.7%; the high G + C strain was underrepresented in the sequencing reads. We estimate the error rate of the MinION (after base calling) to be 38.2%. Mean and median read lengths were 2 kb and 1 kb respectively, while the longest single read was 98 kb. The whole length of a 5 kb rRNA operon was covered by a single read. As the first nanopore-based single molecule sequencer available to researchers, the MinION is an exciting prospect; however, the current error rate limits its ability to compete with existing sequencing technologies, though we do show that MinION sequence reads can enhance contiguity of de novo assembly when used in conjunction with Illumina MiSeq data.

The ABC's of disaster response

The readiness of our healthcare facilities to respond to terrorist acts or naturally occurring epidemics and disasters has been at the center of public attention since September 11, 2001. The many other tragic events that have occurred throughout the world since then further reinforce the need for all healthcare facilities and medical personnel to increase their level of preparedness if they wish to optimize outcomes. Maximizing survival rates and minimizing disability during any MCI hinges on rapid, seamless, and coordinated response between first responders and first receivers. The Incident Command System and the HEICS are organizational tools that form the foundation for such a rapid and coordinated response. The ICS provides a simple and adaptable management structure that is capable of being expanded or contracted to meet the needs of a specific situation. The HEICS adapts the ICS into the hospital setting and, in addition to the benefits stated above; its use of the ICS nomenclature and terminology facilitates the communication and the sharing of resources between all agencies and health care institutions involved. A basic knowledge and understanding of the ICS principles and structure is essential for all individuals participating in a disaster response. Previous efforts at disaster preparedness have focused predominantly on the pre-hospital and rescue phase of the disaster response, but a complete and coordinated community response requires creation of integrated disaster plans. True readiness can only be achieved by testing and modifying these plans through integrated simulation drills and table top exercises. Hospital-wide drills are essential to educate all staff members as to their institutional plan and serve as the only substitute at present to first hand experience. At present, there is no evidence-based literature to define what constitutes the best medical response by medical personnel within a disaster setting. This information will likely evolve over the next several decades as we now recognize Disaster Medicine as a separate scientific and medical entity. In the interim, we can develop and modify our response plans based on the "lessons learned" from past experience. Prior events have demonstrated that general surgeons and surgical subspecialists are critical components to a successful hospital response for the vast majority of all mass casualty incidents. Thus, surgeons must take responsibility for increasing their knowledge and understanding of basic disaster management principles and must play an active role in developing their institutional disaster plans.

Wild-type oestrogen receptor beta (ERbeta1) mRNA and protein expression in Tamoxifen-treated post-menopausal breast cancers

This study has tested the hypothesis that comparison of protein and mRNA expression for ERα and ERβ1 by human breast cancers provides novel information relating to the clinical and pathological characteristics of human breast cancers. Expression of ERα and ERβ1 was identified in 167 invasive cancers from postmenopausal women treated only with endocrine therapy. The cohort included 143 cases receiving only adjuvant Tamoxifen following surgery. ERα and ERβ1 expression was analysed by immunohistochemistry and reverse transcription RT–PCR and compared with clinical progression of individual cancers. ERα protein was closely associated with the corresponding RNA detected by RT–PCR (Chi-square, P<0.001). In contrast, ERβ1 protein and mRNA were inconsistent. Although an association was identified between ERα and ERβ mRNAs (Chi-square, P<0.001) and between ERα protein and ERβ1 mRNA (Chi-square, P<0.027), no association was identified for the ERα and ERβ1 proteins detected by immunohistochemistry. ERβ1 was not associated with outcome. However, in the absence of ERα, ERβ1 protein expression was associated with elevated cell proliferation. There was a trend for the ERβ1 protein-positive cases to have a worse outcome, both within the group as a whole as well as within the ERα-positive Tamoxifen-treated cases. This study has confirmed the hypothesis that expression of ERα is an important determinant of breast cancer progression, and has further demonstrated that ERβ1 may play a role in the response of breast cancers to endocrine therapy.

Correlation of mRNA for oestrogen receptor beta splice variants ERbeta1, ERbeta2/ERbetacx and ERbeta5 with outcome in endocrine-treated breast cancer

This study has been performed to test the hypothesis that different oestrogen receptor beta (ERbeta) splice variants may be important determinants of clinical parameters, including outcome, in post-menopausal women with breast cancer receiving adjuvant endocrine treatment but no chemotherapy. Splice variants ERbeta1, ERbeta2 and ERbeta5 have been analysed by semi-quantitative RT-PCR in a cohort of 105 patients with primary breast cancer. Clinical correlates included age, grade, size, nodal status, ERalpha, progesterone receptor, Ki67, relapse-free survival (RFS) and overall survival (OS). Seventy per cent of cases were ERbeta1 positive, 69% ERbeta2 positive and 70% ERbeta5 positive. Within the cohort, 47% were positive for all three variants while 10% were negative for all three. ERbeta1 exhibited no discernible relationship with disease outcome. ERbeta2 and ERbeta5 expression was significantly associated with better RFS (P<0.005), and ERbeta2 with better OS (P=0.0002). In multivariate analysis, ERbeta2 (P=0.006), nodal status and the level of Ki67 expression were independent predictors for RFS while ERbeta2 (P=0.0008) and Ki67 status were independent predictors for OS. In the ERalpha-positive cases, or in the subset of those receiving adjuvant tamoxifen, ERbeta2 was significantly associated with good RFS (P<0.0005) and was the only independent marker of OS. We conclude that precise identification of splice variants of ERbeta are more important assessors than is ERbeta1 alone of the biological status of individual breast cancers, and hence in predicting their response to endocrine therapy.

Early Carotid Surgery in Acute Stroke: A Multicentre Randomised Pilot Study

BACKGROUND

Standard practice has been to delay carotid endarterectomy (CEA) for 2 months following acute stroke to avoid a perceived risk of cerebral haemorrhage. We investigated whether early CEA reduces early recurrent stroke and improves outcome in partial anterior circulation infarction (PACI).

METHODS

Patients with PACI and a Barthel score of >18 before stroke underwent carotid duplex and CT imaging within 7 days of stroke. Forty consenting patients fit for surgery with greater than 70% ipsilateral carotid stenosis were randomised, 19 to 'early' (within 24 h) and 21 to 'delayed' surgery (at 8 weeks). Modified Rankin and Barthel scores were recorded at 1 week, 2 months, 6 and 12 months.

RESULTS

Rankin scores improved more rapidly following 'early' surgery to a score of 1 (0-4) at 2 and 6 months compared with 2.5 and 2 (1-4), respectively, for delayed surgery (p < 0.05). Barthel scores were also significantly improved following 'early' CEA at 7 days but both groups reached a median score of 20 by 2 months. Four 'delayed' and 3 'early' patients suffered extension or recurrence of neurological deficits with 1 death in each group.

CONCLUSIONS

Early CEA within 7 days of ischaemic stroke improved functional outcome with earlier hospital discharge. A large multicentre study is needed to exclude the possibility that 'early' CEA increases the risk of cerebral haemorrhage or death.

Increased risk of malignant progression in benign proliferating breast lesions defined by expression of heat shock protein 27

Heat shock protein 27 (hsp-27) is a regulator of oestrogen receptor (ER) expression and a modulator of intracellular homeostasis. In this laboratory, Shaaban et al demonstrated the importance of ER-α, together with Ki67, in enhancing the progression of benign breast lesions of defined morphological types. To better understand the mechanisms by which ER-α promotes breast neoplasia, this study was performed to test the hypothesis that the roles of ER-α and hsp-27 may be defined by their quantitative expression in proliferative breast lesions of varying histological risk. The expression of hsp-27 was identified using a specific monoclonal antibody and analysed to assess the proportion of positive epithelial cells using digitised morphometric image analysis. The expression of ER-α was analysed by immunohistochemistry and Western blotting in a variety of benign (HUMA121) and malignant mammary cell lines, including ER-α(+) (MCF7, ZR-75, T47D) and ER-α(−) (MDA-MB 231) breast cancer cell lines. The data confirm that, during progression from normal through proliferative breast lesions to in situ cancer, there was a significant increase in both the proportion and the optical density of the epithelial cells expressing hsp-27. The mean levels of expression ranged from 7.4% of the total number of epithelial cells in normal lobules to 25.17% of epithelial cells in hyperplasias of usual type (HUT) to 61.1% of epithelial cells in ductal carcinoma in situ (P<0.001). The study has confirmed the expression of hsp-27 to be closely associated with ER-α(+) expression, and that its regulated expression occurs early along the mammary oncogenic pathway, supporting the initial hypothesis. It is our proposal that the differential expression of hsp-27 modulates the phenotypic behaviour of morphologically benign epithelial cells and hence may be an important determinant in initiating, or promoting, a population of human mammary cancers.

Can undergraduate education have an effect on the ways in which pre-registration house officers conceptualise communication?

AIMS

In 1994 Manchester Medical School introduced a learner-centred course using problem-based learning (PBL), which emphasises effective communication skills. This study explored how 2 cohorts of graduates conceptualised communication within their role as pre-registration house officer (PRHOs).

METHODS

Graduates from the last year of the traditional and first year of the new course were interviewed 3 months after starting work. They were asked how well their courses had prepared them for working as PRHOs and were given a specific question about communication skills. Interviews were tape-recorded, transcribed, coded and analysed.

RESULTS

In all, 24 traditional course graduates (TCGs) and 23 new course graduates (NCGs) were interviewed. Traditional course graduates tended to conceptualise communication as informing people rather than as involving negotiation or having therapeutic effects. Most TCGs considered good communicators 'were born that way' and did not think communication skills could be learned. Many NCGs had a richer concept of communication that recognised communication has therapeutic benefits for patients and involved negotiation. They understood it was possible to teach communication skills. However, a minority of NCGs conceptualised communication in a similar way to TCGs.

CONCLUSION

Our study suggests that the new course has helped NCGs acquire a more complex concept of communication in their role as PRHOs.

The contribution of genetic factors to thrombotic and bleeding outcomes in coronary patients randomised to IIb/IIIa antagonists

Genetic variants are risk factors for coronary disease, but their role in recurrent events and in response to treatment is less clear. We genotyped genetic variants implicated in primary coronary disease in 924 Caucasians with acute coronary syndromes participating in the OPUS-TIMI16 trial of the GPIIb/IIIa antagonist orbofiban. These were the platelet glycoprotein (GP) receptors GPIIIa, GPIa, GPIbalpha; platelet ligands beta-fibrinogen and von Willebrand Factor (vWF); interleukins (IL) IL-1RN, and IL-6; adhesion proteins E-selectin and P-selectin; and metalloproteinase MMP-9. Cox modelling of all genetic variants demonstrated no significant impact on the composite endpoint (P = 0.88), which included myocardial infarction (MI), death, recurrent ischemia, urgent revascularisation and stroke, but a significant impact on recurrent myocardial infarction alone (chi(2) = 20.4, 10 df, P = 0.04). There was a significant interaction of the polymorphisms with orbofiban treatment influencing bleeding outcomes (P = 0.004). Thus, genetic polymorphisms may be associated with subsequent myocardial infarction, and may also be associated with treatment-associated bleeding among coronary patients.

Small-group work and assessment in a PBL curriculum: a qualitative and quantitative evaluation of student perceptions of the process of working in small groups and its assessment

The problem based learning (PBL) curriculum at Manchester emphasizes small-group work. This is supported through group assessment where students assess key aspects of their group's function. In the study described here the authors evaluated students' perceptions of both PBL group work and what a group assessment needs to assess. They aimed to produce a description of the cognitive and motivational influences on group process and unpack the ways they contribute to a successful PBL group so that the kinds of skills an effective assessment should assess could be identified. Focus groups and a questionnaire were used to generate the data. The focus group results indicate that students support PBL group work as a method of learning, and that those groups that work cooperatively are perceived as facilitating the most motivating learning environment. The students supported the assessment being summative and felt that it could be simplified to measure: behavioural skills contributing to maximizing motivation of the group process; and cognitive skills relating to the content of the group discussion. The questionnaire results also supported the use of a summative assessment of small-group work that evaluates the domains of group process and the content of the group discussion.

Students' conceptual model of a good community attachment

BACKGROUND

In 1994, Manchester University Medical School introduced a new integrated curriculum using problem-based learning and which places an increased emphasis on community-based education.

AIMS

Students commonly use a particular label ("a good GP" (general practitioner)) to describe a positive experience in the community. The purpose of the study was to explore what students mean by "a good GP" and how this relates to their perceptions of the value of the community aspect of the course.

METHOD

Three single-year focus groups were run with year 3, 4 and 5 students. A model was then derived which was explored and checked against the views of a cross-year focus group.

RESULTS

A theoretical model based on student conceptualization of "a good GP" was developed. "A good GP" was found to consist of the GP as a teacher, as a role model and as an indicator of a positive learning environment. With regard to "good teacher", students felt that the GP's enthusiasm about teaching and involving the student in an active learning process was important. For "good role model", students emphasized communication skills and non-judgmental attitudes. With regard to "good learning environment", a friendly atmosphere, variety of activities, and flexibility shown by the staff of the health centre were important.

CONCLUSIONS

Students hold a complex conceptual model of "a good GP" which the label does not convey. We suggest that for evaluations of student experiences it is important to explore in depth what students mean by particular terms or labels.

Students' conceptual model of a good community attachment

BACKGROUND

In 1994, Manchester University Medical School introduced a new integrated curriculum using problem-based learning and which places an increased emphasis on community-based education.

AIMS

Students commonly use a particular label ("a good GP" (general practitioner)) to describe a positive experience in the community. The purpose of the study was to explore what students mean by "a good GP" and how this relates to their perceptions of the value of the community aspect of the course.

METHOD

Three single-year focus groups were run with year 3, 4 and 5 students. A model was then derived which was explored and checked against the views of a cross-year focus group.

RESULTS

A theoretical model based on student conceptualization of "a good GP" was developed. "A good GP" was found to consist of the GP as a teacher, as a role model and as an indicator of a positive learning environment. With regard to "good teacher", students felt that the GP's enthusiasm about teaching and involving the student in an active learning process was important. For "good role model", students emphasized communication skills and non-judgmental attitudes. With regard to "good learning environment", a friendly atmosphere, variety of activities, and flexibility shown by the staff of the health centre were important.

CONCLUSIONS

Students hold a complex conceptual model of "a good GP" which the label does not convey. We suggest that for evaluations of student experiences it is important to explore in depth what students mean by particular terms or labels.

Small group learning in the final year of a medical degree: a quantitative and qualitative evaluation

The new undergraduate medical curriculum in Manchester uses problem-based learning (PBL) throughout the course. However, the major difference from other PBL schools is that in years 3 & 4 (phase 2) the students can use clinical experience when discussing the paper cases. The process is then developed further in year 5 (phase 3), in which there are no set PBL 'triggers' and students bring their own cases to the groups for discussion. In this study, we have explored what happens in the phase 3 (year 5) group sessions and how the students view them. A questionnaire and focus groups were used to generate data, from which a model was developed of what happens in a 'good' group session. The data suggest that most groups run on a case-presentation and discussion format, most commonly about clinical management and diagnosis. Students want tutors to act as an expert resource and to be flexible in allowing students to direct the discussions. University guidance about the group sessions was not generally used.

How well prepared are graduates for the role of pre-registration house officer? A comparison of the perceptions of new graduates and educational supervisors

OBJECTIVE

The principal aim of undergraduate medical education is to produce competent pre-registration house officers (PRHOs). We examined and compared the perceptions of graduates and educational supervisors concerning how well prepared graduates were for their first post.

METHODS

A postal questionnaire was sent to house officers who had graduated from Manchester 3 months earlier and also to educational supervisors of PRHOs in the North-west Region. The questionnaires were based on the competencies set out by the General Medical Council of the United Kingdom.

RESULTS

The response rates were 66% from the graduates and 76% from the supervisors. Of the 18 broad areas of competence listed, only four were rated more than 'quite well prepared' by at least 50% of the graduates ('understanding disease processes', 'communicating effectively', 'awareness of limitations' and 'working in a team'). Similarly, more than half of educational supervisors rated graduates as more than quite competent in only three areas ('awareness of limitations', 'keeping accurate records' and 'working in a team'). Within the competencies surveyed, there were differences between the perceptions of graduates and educational supervisors on the preparedness of graduates for the skills they may require as a pre-registration house officer.

CONCLUSION

Overall, given that most graduates and supervisors perceived the preparedness as 'quite well' or less, the undergraduate course had only partially met its objectives. A mismatch in ratings could be attributed to either inappropriate expectations on the part of the educational supervisors or the graduates or an inaccurate assessment by either group of respondents.

The combination of bedside swallowing assessment and oxygen saturation monitoring of swallowing in acute stroke: a safe and humane screening tool

BACKGROUND

dysphagia is common in acute stroke. Accurate detection of the presence or absence of aspiration by bedside swallowing assessment is difficult without objective methods, tending to over-diagnose aspiration. As a result, some patients suffer restricted oral intake unnecessarily.

OBJECTIVE

we examined the predictive values of pulse oximetry and speech and language therapy bedside swallowing assessment in the detection of aspiration compared with videofluoroscopy.

DESIGN

a double-blind observational study.

SETTING

two university teaching hospitals.

SUBJECTS

we studied 53 patients whose acute strokes were confirmed by computed tomography scan.

METHODS

Each subject had initial standard bedside swallowing assessment, closely followed by simultaneous and mutually blinded pulse oximetry, swallowing assessment and videofluoroscopy.

RESULTS

15 of 53 subjects aspirated. Bedside swallowing assessment and saturation assessment at > or = 2% desaturation gave good sensitivity (80% and 87% respectively), but low positive predictive values (50% and 36% respectively). Both assessments mistook laryngeal penetration for aspiration. Re-analysis with aspiration +/- penetration as a new endpoint improved bedside swallowing assessment positive predictive values to 83% (chi2 =3.59, P=0.032). Sensitivity of saturation assessment was maintained at 86%, positive predictive values of saturation assessment improved to 69% (chi2=6.74, P=0.009). The combination of bedside swallowing assessment and saturation assessment versus aspiration + penetration gave a positive predictive value of 95%.

CONCLUSIONS

screening by saturation assessments detects 86% of aspirators/penetrators and should be followed immediately by bedside swallowing assessment, as the combination of the two assessments gives the best positive predictive value. For patients with acute stroke, we advocate a 10 ml water-swallow screening test with simultaneous pulse oximetry by suitably trained medical and nursing staff. Use of this screening test would improve dysphagia detection whilst minimizing unnecessary restriction of oral intake in stroke patients.

Perioperative antibiotic use in high-risk penetrating hollow viscus injury: a prospective randomized, double-blind, placebo-control trial of 24 hours versus 5 days

BACKGROUND

The purpose of this study was to compare the safety and therapeutic efficacy of a 24-hour versus 5-day course of ampicillin/sulbactam for the prevention of postoperative infections in high-risk patients sustaining hollow viscus injury from penetrating abdominal trauma.

METHODS

A total of 317 patients from four Level I trauma centers with penetrating abdominal injuries and at least one hollow viscus perforation each received one preoperative and three postoperative doses of ampicillin/sulbactam 3 g intravenously. After receiving 24 hours of unblinded ampicillin/sulbactam, patients were then randomized into one of two groups. Group 1 received 4 additional days of blinded ampicillin/sulbactam (5 days total of antibiotic), and Group 2 received 4 days of placebo (24 hours of antibiotic). Patients were assessed postoperatively for occurrence of deep surgical-site infections (intra-abdominal abscess, fasciitis, and peritonitis) and superficial (wound) surgical-site infections. Development of nonsurgical-site infections (e.g., pneumonia, urinary tract infection, phlebitis, and cellulitis) was also recorded. Continuous variables were analyzed by analysis of variance and discrete variables by the Cochran-Mantel-Haenszel chi2 test. Multivariate logistic regression analyses were also performed to identify independent risk factors for postoperative infection.

RESULTS

A total of 159 patients were randomized into Group 1, and 158 patients were randomized into Group 2. The Injury Severity Score and penetrating abdominal trauma index were 18+/-8 and 21+/-13, respectively, for Group 1 and 18+/-9 and 20+/-15, respectively, for Group 2. A total of 162 (51%) patients sustained one or more colon injuries (82 in Group 1 and 80 in Group 2). There were 16 (10%) surgical-site infections in Group 1 and 13 (8%) surgical-site infections in Group 2 (p = 0.74). Group 1 patients experienced 17 (11%) nonsurgical-site infections, whereas Group 2 had 32 (20%) nonsurgical-site infections. This difference, however, was not statistically significant (p = 0.16). Only the total number of blood units transfused and the presence of a PATI score greater than or equal to 25 were found to be independently associated with the development of a postoperative surgical- and nonsurgical-site infections (p = 0.001 and p = 0.003, respectively). Of note, the presence of a colon injury was not found to be an independent risk factor (p = 0.11) for either surgical or nonsurgical site postoperative infection in our study.

CONCLUSION

High-risk patients with colon or other hollow viscus injuries from penetrating abdominal trauma are at no greater risk for surgical-site or nonsurgical-site infection when treated with only a 24-hour course of a broad-spectrum antibiotic.

The role of basic sciences in a problem-based learning clinical curriculum

BACKGROUND

Very little is known about the use of problem-based learning (PBL) during the later years of the undergraduate medical course and how it influences further acquisition of basic science knowledge. Similarly to many other Faculties, the PBL approach is used at Manchester in years 1 and 2, but more unusually, the curriculum continues to be centred on PBL in the clinical modules.

OBJECTIVES

To explore whether and how basic science learning was continued in year 3 of the PBL clinical curriculum.

METHODS

10 of the weekly problems from the two core modules in year 3 were analysed to determine: (a) whether the design teams were using basic science objectives in devising the problems, and (b) whether PBL student groups were setting basic science learning objectives. The basic science knowledge of year 3 and 4 students was also measured.

RESULTS

Similar numbers of objectives were being set by the management groups for each weekly problem (Heart, lung and blood (HLB) module, median 15, range 11-20; Nutrition, metabolism and excretion (NME) module, median 13, range 9-21). In the basic sciences, there was a median of 3 objectives per problem (range 0-6) in the NME module, but only 1 objective (0-2) per problem in the HLB module. The objectives set by six PBL groups in each module were analysed. Overall, agreement was reached on 130 occasions (62%) between the design team basic science objectives and those set for themselves by the student groups. In addition, there was a median of 2 (range 1-8) new basic science objectives brought out by the PBL groups that were not listed by the HLB module design team. In the NME module, there was again a median of 2 new objectives (range 0-6). The performance of year 3 and year 4 students in the multiple-choice questions progress test was analysed. For the 65 basic science questions, the year 3 mark was 40.8 +/- 12.3% compared with 57.1 +/- 12.3% for year 4 (P < 0.0001).

CONCLUSIONS

(a) The design teams are setting basic science objectives; (b) the working problems are triggering students to set learning objectives in the basic sciences; (c) most of the objectives being set by the design teams are being triggered in the majority of group sessions; (d) the students knowledge of basic sciences increases in years 3-4.

A mechanical arthrometer to measure knee joint contracture in rats

Animal models for joint diseases are necessary for in vivo studies. Joint contractures are characterized by lack of the normal range of motion of a joint most often due to increased soft tissue stiffness. Biological and biochemical data have been obtained but biomechanical data on small animals are rare. An instrument was developed to measure rat knee angular displacement at various soft tissue loads in normal and pathological circumstances. This article describes the instrument and reports its reproducibility and accuracy. The reproducibility and accuracy of this instrument was found to be acceptable thereby validating its use for research purposes with adult rat knees.

Evaluation of an integrated curriculum using problem-based learning in a clinical environment: the Manchester experience

DESCRIPTION OF COURSE

In 1994, a new problem-based leaning (PBL) curriculum for year 1 medical students was introduced at the University of Manchester. The use of PBL has continued into the clinical clerkships. Year 3 of the curriculum is based entirely in a clinical environment with PBL groups meeting in three teaching hospitals. During this year, all students undertake two integrated 14-week modules with overarching themes. Each week, groups of eight students discuss a trigger problem connected to the relevant theme. The steps the groups use in the PBL process have been amended to encourage students to link their discussion with clinical experience.

EVALUATION

At the end of each module, all 309 students were requested to complete an evaluation questionnaire. The response rates were 80% (n=247) and 89% (n=275) for the two core modules.

RESULTS

The students have remained 'happy with the way the course is going' (83% at the end of module 2). They were also asked to rate a number of statements on a 5-point Likert scale (5=strongly agree). Concerning PBL, the students remained confident about working in a group (median 4), producing a set of learning objectives (median 4) and linking clinical experience with other knowledge (median 4). However, there were changes over the year. Fewer students agreed at the end of module 2 that 'the working problems were stimulating' (P=0.002) or 'motivated them to learn' (P < 0.001), but the clinical firms were seen as providing more appropriate experience (P=0.01) and being aware of the new curriculum and responding to it (P=0.018). We also surveyed the PBL tutors and had 65 returns from 78 people involved in the 38 PBL groups in year 3. The great majority of these are doctors employed by the National Health service. Virtually all the responders were happy to continue being a tutor (97%) and would recommend it to a colleague (93%).

CONCLUSIONS

The evaluation has been positive with PBL having been successfully implemented in a clinical environment. We have identified significant changes over the year, which we need to address as we consolidate the curriculum.

Swallowing and prevention of complications

Dysphagia occurs in up to half of patients following a stroke. In most, it is transient with only about 1 in 10 of patients having any swallowing problems at 6 months. Persistent dysphagia may be due to lack of bilateral cerebral hemisphere representation of the oral and pharyngeal musculature involved in swallowing. Thus, the unaffected hemisphere is unable to take over the function of the damaged side. Beside assessment is not a good predictor of aspiration on videofluoroscopy, but measurement of oxygen saturation may improve this. Nevertheless, clinical detection of dysphagia may be the more powerful predictor of an increased mortality and morbidity, including pneumonia, water depletion and poor nutrition. Dysphagia is also closely related to poor nutrition following stroke, but we do not know whether feeding support will improve outcome. Major trials are on-going.

Carotid disease in acute stroke: A review

This article reviews the literature about carotid disease in acute stroke. Several conclusions are drawn. First, carotid disease is an important cause of ipsilateral cortical strokes, with significant ipsilateral disease found in about one fourth of patients. Second, the role of carotid disease in lacunar stroke is less certain but probably causes a small number of lacunar infarcts. Third, the majority of infarcts that occur with severe carotid stenosis or acute carotid occlusion are caused by cerebral emboli, whereas most infarcts with preexisting occlusion are probably caused by hemodynamic factors. Fourth, the optimal timing of carotid surgery in acute stroke is uncertain. Clinical trials of endarterectomy in acute stroke are now required.

The core content of the undergraduate curriculum in Manchester

AIM

To identify the core content for the new undergraduate medical curriculum in Manchester.

METHOD

The initial step was to produce a list of 'index clinical situations' (ICSs), for which a newly graduated doctor must have a required level of competence. Using repeated consultation with consultants and general practitioners involved in medical education in the North-West of England, a list of 215 ICSs was agreed. Specialists and generalists were then asked to identify the components of the knowledge base and the performance (skills) base for each ICS. The knowledge base was divided into technical (biomedical facts/concepts) and contextual (effect/management of disease within the individual, family and society) domains. The performance base was divided into intellectual (problem solving and decision making) and interpersonal (history, examination, communication and procedural skills) domains.

RESULTS

Forty specialties were consulted and 11,021 items (defined as a piece of knowledge, a concept or a skill) were identified. There was considerable overlap in the items listed, such that when the returns for each ICS were amalgamated, the 215 ICSs contained 6434 items with a mean of 34 +/- 14.2 per situation (range 6-85). UTILISATION: We have used the defined ICSs in the design of the trigger material used in the weekly problem-based learning sessions. Over 4 years almost all (207/215, 96%) of the ICS are covered, with many being revisited at several points in the curriculum.

The effect of chronic hexarelin administration on the pituitary-adrenal axis and prolactin

OBJECTIVE

With the development of growth hormone (GH) releasing agents and their use in human subjects, it is clear that these agents are not specific for GH release. More recent studies in humans have demonstrated acute increases in adrenocorticotrophic hormone (ACTH), cortisol and prolactin (PRL) after boluses of intravenous or subcutaneous GHRPs. The potential adverse effects of repeated episodes of transient hyperprolactinaemia and hypercortisolaemia during long-term therapy with growth hormone releasing peptides (GHRPs) and similar agents have raised concern. We have therefore assessed the impact of chronic hexarelin administration on the pituitary-adrenal axis and serum prolactin levels.

DESIGN

Each subject received twice-daily subcutaneous hexarelin therapy (1.5 micrograms/kg body weight) for 16 weeks. The ACTH, cortisol and PRL responses to the morning subcutaneous injection of hexarelin were assessed. Hexarelin was administered at time 0 and blood samples were taken at -10, 0, 10, 20, 30, 40, 50, 60, 90, 120, 170 and 180 min. The ACTH and PRL responses were assessed at baseline and after 16 weeks of therapy. The cortisol response was assessed at baseline, 16 weeks and also 4 weeks after completion of hexarelin therapy. Basal levels of cortisol binding globulin (CBG), 24-h urinary free cortisol (UFC) estimations, thyroid stimulating hormone (TSH) and total thyroxine (TT4) were performed at baseline, weeks 16 and 20.

RESULTS

The mean (+/- SEM) area under the cortisol curve (AUCCORT) at baseline, week 16 and week 20 were 1506 (+/- 77) nmol/l/h, 1222 (+/- 92) nmol/l/h and 1586 (+/- 58) nmol/l/h, respectively. There was a significant change in AUCCORT over the study period (P = 0.008). Compared with baseline, AUCCOPRT had decreased significantly (P < 0.05) after 16 weeks of hexarelin therapy. Four weeks after completion of hexarelin therapy, the AUCCORT increased significantly compared with AUCCORT at week 16 (P < 0.01) and was no longer significantly different from baseline values. There were no significant changes in UFC (P = 0.3), basal cortisol measurements (P = 0.19), area under the ACTH curve (AUCACTH) (P = 0.24) or CBG (P = 0.6) over the study period. The mean (+/- SEM) area under the PRL curve (AUCPRL) at the baseline and week 16 were 624 (+/- 82) mU/l/h and 641 (+/- 83) mU/l/h, respectively. There was no significant change in AUCPRL over the study period (P = 0.35).

CONCLUSION

The present study demonstrates clearly that in this hexarelin dosage regimen, over-stimulation of the pituitary adrenal axis and prolactin secretion do not occur. In fact the impact of chronic hexarelin therapy on the pituitary-adrenal axis, i.e. decreased AUCCORT, contradict the findings reported after acute hexarelin administration and cannot be explained by changes in CBG. The lack of change in UFC, however, suggests that these changes are unlikely to be of clinical significance although the underlying mechanism requires further study.

Carotid disease in acute stroke

BACKGROUND

the Oxfordshire Community Stroke Project (OCSP) devised a simple clinical classification for acute stroke which predicted mortality, functional recovery and patterns of recurrent stroke. We aimed to determine whether this could predict the presence of carotid disease and be used to select which patients with acute stroke should be referred for carotid imaging with a view to subsequent carotid endarterectomy.

METHODS

we assessed patients with acute stroke admitted to seven hospitals over a 10-month period. Patients were classified according to the OCSP system and their carotid arteries investigated using portable continuous wave Doppler. Those with abnormal portable assessments had colour duplex Doppler imaging.

RESULTS

of 305 patients with proven or probable cerebral infarction, severe (70-99%) ipsilateral carotid stenosis was found in 16 (16%) of the 101 with partial anterior circulation infarct (PACI), four (4%) of the 100 with total anterior circulation infarct (TACI), none of the 80 with lacunar infarct (LACI) and one (4%) of the 24 with posterior circulation infarct (POCI). Complete ipsilateral carotid occlusion was found in 25 (25%) of the TACI group, 11 (11%) of the PACI group, three (4%) of the LACI group and none of the POCI group. Severe carotid stenosis or occlusion was more common in the ipsilateral than the contralateral carotid artery for the TACI and PACI groups (chi2 P< 0.05), but there was no difference between ipsilateral and contralateral carotid disease in the LACI and POCI groups. If the OCSP classification is used to detect patients with 70-99% carotid stenosis, then the sensitivity is 76% and specificity is 70%.

CONCLUSION

these findings suggest that ipsilateral carotid disease is an important cause of stroke for those with anterior circulation infarcts but not for those with LACI or POCI. Subjects with PACI should be referred for early carotid imaging to identify those with severe disease who may be suitable for elective carotid surgery.

Urinary growth hormone (GH), insulin-like growth factor I (IGF-I), and IGF-binding protein-3 measurements in the diagnosis of adult GH deficiency

The diagnosis of GH deficiency (GHD) in the elderly is based at present on the peak GH concentration during a stimulation test. We have now evaluated the performance of urinary GH (uGH), urinary insulin-like growth factor I (uIGF-I), and urinary IGF-binding protein-3 (uIGFBP-3) in the diagnosis of GHD in this group. Twenty GHD elderly patients with a history of pituitary disease and a peak GH response to arginine stimulation of less than 3 ng/mL (15 men and 5 women; age, 61.1-83.4 yr) and 19 controls (12 men and 7 women; age, 60.8-87.5 yr) were studied. GH secretion was assessed by 24-h profile and expressed as the area under the curve (AUCGH). Serum (s) IGF-I and sIGFBP-3 were measured in a single morning, fasted sample. Urinary GH, uIGF-I, and uIGFBP-3 were measured in a 24-h urine sample collected over the same interval as the GH profile, and results were expressed as total amount excreted in 24 h (tuGH24, nanograms; tuIGF-I24, nanograms; tuIGFBP-3(24), micrograms). Data are presented as the mean +/- SD, except for AUCGH, tuGH24, and tuIGFBP-3(24), which are presented as the geometric mean (-1, +1 tolerance factor). AUCGH, sIGF-I, and sIGFBP-3 were significantly lower in GHD subjects than in controls. Total uGH24 was lower in GHD subjects, but tuIGF-I24 and tuIGFBP-3(24) excretion were not different in the two groups. AUCGH provided the best separation between GHD and control subjects, whereas there was substantial overlap for sIGF-I, sIGFBP-3, and tuGH24. In both groups sIGF-I was correlated to sIGFBP-3 (GHD, r = 0.75; controls, r = 0.65; both P < 0.01), whereas tuIGF-I24 was not correlated to tuIGFBP-3(24) in either group. Moreover, tuIGF-I24 and tuIGFBP-3(24) were not related to their respective serum concentrations in either group. Total uGH24 was correlated with AUCGH only in controls (r = 0.54; P < 0.05). These data demonstrate that urinary GH and urinary and serum IGF-I and IGFBP-3 are not suitable diagnostic markers for GHD in elderly subjects.

The diagnosis of severe growth hormone deficiency in elderly patients with hypothalamic-pituitary disease

OBJECTIVE

Adults over the age of 60 years with organic disease of the hypothalamic-pituitary axis may be deficient in growth hormone (GH) to a degree that is distinct from the age-related decline in GH secretion and sufficient to cause perturbations of body composition, serum lipid profile and bone metabolism. In order to determine the best method for detecting GH deficiency in this age group we have compared spontaneous GH secretion, a provocative test of GH secretion, the arginine stimulation test (AST), and basal estimates of circulating insulin-like growth factors (IGF) and IGF-binding proteins (IGFBP).

DESIGN

Twenty-four patients (16 male) with organic hypothalamic-pituitary disease and 24 controls (17 male) were studied. The groups were matched for BMI but the patients were slightly younger than the controls, 66.0 (61.0-85.7) vs. 70.6 (60.8-87.5) years (P = 0.04). All subjects underwent a 24-h GH profile (20-minute sampling), measurement of serum IGF-I, IGF-II, IGFBP3, IGFBP2 and growth hormone binding protein (GHBP) and, after an overnight fast, an AST (intravenous arginine 20 g/m2 over 30 minutes). GH concentrations were measured using an ultrasensitive chemiluminescence assay (sensitivity 0.002 microgram/l). Normative data for serum IGF-I, IGF-II, IGFBP3 and IGFBP2 were obtained from 125 subjects aged 60-87 years.

RESULTS

None of the parameters studied was able to distinguish between all the GH deficient patients and the healthy controls. The median (range) area under the GH profile (AUCGH) and peak GH response to arginine were lower in the patients than in the controls, 310.05 (18.90-2193.36) vs. 2518.20 (526.76-12024.97) min mU/l (P < 0.00001), 1.07 (0.08-17.90) vs. 23.06 (4.60-109.98) mU/l (P < 0.00001), respectively. There was a significant relationship between AUCGH and peak GH response to arginine in the patients (r = 0.89, P < 0.0001) and in the controls (r = 0.56, P = 0.005). Serum IGF-I, IGFBP2, and IGFBP3 levels were significantly lower in the patients compared with the normal range, 102 (14-162) vs. 142 (59-298) micrograms/l (P < 0.0001), 415 (122-1868) vs. 640 (140-2585) micrograms/l (P = 0.0007) and 2.29 (0.81-3.75) vs. 2.59 (1.00-3.52) mg/l (P = 0.009), respectively. The degree of overlap between the two groups, however, was too great to make these measurements useful diagnostically. Serum IGF-II and GHBP concentrations in the patients were not significantly different from the normal range. The patients were divided into groups determined by the number of anterior pituitary hormone deficits present. There was a significant downward trend in the peak GH response to arginine with increasing severity of hypopituitarism (J = -3.04, P = 0.0012). Ninety per cent of patients with two or three additional pituitary deficiencies had a peak GH response less than 2.0 mU/l.

CONCLUSIONS

Of the indices studied the arginine stimulation test is more effective than GH markers, such as IGF-I or IGFBP3, or measurement of spontaneous GH secretion for diagnosing GH deficiency in adults over the age of 60 years. By relating the peak GH response to the degree of hypopituitarism, a GH response less than 2.0 mU/l is suggestive of severe GH deficiency in this age group under the appropriate clinical circumstances.

Growth hormone status during long-term hexarelin therapy

Hexarelin, a powerful GH-releasing peptide, is capable of causing profound GH release in normal subjects after oral, intranasal, i.v., and s.c. administration. The effect of long-term administration on GH levels in adults is unknown. We have, therefore, assessed the effects of 16 weeks of twice-daily s.c. hexarelin therapy (1.5 micrograms/kg BW) on the GH response to a single injection of hexarelin, and also the GH response to hexarelin 4 weeks after cessation of hexarelin therapy. We have also assessed the effects of chronic hexarelin therapy on serum insulin-like growth factor (IGF)-I, IGF binding protein-3, markers of bone formation (osteocalcin, procollagen-type-III-N-terminal-peptide, and C-terminal propeptide of type I collagen), and resorption (urinary deoxypyridinoline and pyridinoline), body composition, and bone mineral density. The mean (+/- SEM) area under the GH curve (AUCGH) at weeks 0, 1, 4, 16, and 20 were 19.1 +/- 2.4 micrograms/L.h, 13.1 +/- 2.3 micrograms/L.h, 12.3 +/- 2.4 micrograms/L.h, 10.5 +/- 1.8 micrograms/L.h, and 19.4 +/- 3.7 micrograms/L.h, respectively. There was a significant change in AUCGH over the study period (P = 0.0003). Further analysis showed that, compared with baseline, the decrease in AUCGH at week 4 and week 16 were significant (P < 0.05 and P < 0.01, respectively). Four weeks after completion of hexarelin therapy, the AUCGH increased significantly, compared with AUCGH at week 16 (P < 0.05), and was not significantly different from that at week 0. Serum IGF-I and IGF binding protein-3 did not change significantly over the 20-week period (P = 0.24 and P = 0.74, respectively). Of the bone markers measured, only serum C-terminal propeptide of type I collagen changed significantly and was higher at week 16, compared with baseline (P = 0.019). Total body fat, lean body mass, and bone mineral density had not changed significantly at week 16, compared with baseline (P = 0.6, P = 0.3, and P = 0.3, respectively). In summary, we have demonstrated that chronic hexarelin therapy results in a partial and reversible attenuation of the GH response to hexarelin. In the present study, the biological impact of this hexarelin schedule on the GH-IGF-I axis seems to be minimal. The therapeutic potential of chronic hexarelin requires further investigation.

Can bedside assessment reliably exclude aspiration following acute stroke?

OBJECTIVE

To investigate the ability of a bedside swallowing assessment to reliably exclude aspiration following acute stroke.

SUBJECTS

Consecutive patients admitted within 24 h of stroke onset to two hospitals.

METHODS

A prospective study. Where possible, all patients had their ability to swallow assessed on the day of admission by both a doctor and a speech and language therapist using a standardized proforma. A videofluoroscopy examination was conducted within 3 days of admission.

RESULTS

94 patients underwent videofluoroscopy; 20 (21%) were seen to be aspirating, although this was not detected at the bedside in 10. In 18 (22%) of the patients the speech and language therapist considered the swallow to be unsafe. In the medical assessment, 39 patients (41%) had an unsafe swallow. Bedside assessment by a speech and language therapist gave a sensitivity of 47%, a specificity of 86%, positive predictive value (PPV) of 50% and a negative predictive value (NPV) of 85% for the presence of aspiration. Multiple logistic regression was used to identify the optimum elements of the bedside assessments for predicting the presence of aspiration. A weak voluntary cough and any alteration in conscious level gave a sensitivity of 75%, specificity of 72%, PPV of 41% and NPV of 91% for aspiration.

CONCLUSION

Bedside assessment of swallowing lacks the necessary sensitivity to be used as a screening instrument in acute stroke, but there are concerns about the use of videofluoroscopy as a gold standard. The relative importance of aspiration and bedside assessment in predicting complications and outcome needs to be studied.

Pathology and the OSCE: insights from pilot study

Undergraduate medical education in Manchester in undergoing wholesale revision, with the introduction of problem-based learning (PBL) in each successive year of the curriculum, as the cohort of students who joined the faculty in 1994 advances through the course. This cohort has now entered year 3, which primarily hospital-based. In preparation for this, we have explored the development of an OSCE, not only to assess core interpersonal skills such as history taking, clinical examination, and the ability to explain things to patients, but also to integrate the examination of important skills relating to investigational sciences. These include the correct choice of laboratory tests, accurate interpretation of data, and appropriate selection of clinical responses to test results.

Response to dehydration in elderly patients in long-term care

Elderly patients in long-term care have a high plasma osmolality (pOSM) and associated increased mortality. In these patients, we examined pOSM, thirst (visual analogue scale, VAS) and arginine vasopressin (AVP) response to 16-hour dehydration and 2-hour rehydration. Twelve patients were randomly divided into two groups (A & B). Group A had their fluid balance monitored for two weeks, group B did not. Single measurements of VAS, pOSM and AVP were conducted on days 0, 7 and 13. Dehydration tests were conducted in both groups at the start of the study (DAY 1), and at the end of the two-week period (DAY 14). There were no significant differences between group A and B, so the results are presented for the two groups combined. There was a significant increase in both pOSM and VAS during dehydration, and a significant fall in both variables during rehydration [F (9,99) = 18.69, p < 0.001, and F(9,99) = 11.25, p < 0.001, respectively]. Plasma AVP did not change significantly during either dehydration or rehydration [F (9,99) = 0.59, p = 0.8]. There were no significant differences in response for any of the three variables between DAY 1 and DAY 14. We conclude that elderly patients in long-term care exhibit changes in thirst and osmolality during dehydration and rehydration, and that these responses are reproducible. The lack of a significant AVP response requires further investigation.

The natural history of dysphagia following a stroke

To assess the frequency and natural history of swallowing problems following an acute stroke, 121 consecutive patients admitted within 24 hours of the onset of their stroke were studied prospectively. The ability to swallow was assessed repeatedly by a physician, a speech and language therapist, and by videofluoroscopy. Clinically 51% (61/121) of patients were assessed as being at risk of aspiration on admission. Many swallowing problems resolved over the first 7 days, through 28/110 (27%) were still considered at risk by the physician. Over a 6-month period, most problems had resolved, but some patients had persistent difficulties (6, 8%), and a few (2, 3% at 6 months) had developed swallowing problems. Ninety-five patients underwent videofluoroscopic examination within a median time of 2 days; 21 (22%) were aspirating. At 1 month a repeat examination showed that 12 (15%) were aspirating. Only 4 of these were persistent; the remaining 8 had not been previously identified. This study has confirmed that swallowing problems following acute stroke are common, and it has been documented that the dysphagia may persist, recur in some patients, or develop in others later in the history of their stroke.

Relationship between growth hormone (GH) status, serum leptin and body composition in healthy and GH deficient elderly subjects

OBJECTIVE

Growth hormone (GH) secretion declines with age and is affected by body composition. The signal that mediates the latter relationship remains III-defined. Leptin, the protein product of the adipocyte specific ob gene, is thought to accurately reflect fat mass and could therefore be a candidate to influence GH secretion. We have therefore investigated the relationship between GH status, leptin and body composition in normal and GH-deficient elderly subjects.

DESIGN

GH Secretion was assessed by 20-minute sampling over 24 hours and serum leptin concentrations were measured in a single morning, fasted sample.

PATIENTS

Twenty-one GH deficient elderly patients (61-83 years) and 22 gender- and BMI-matched controls (61-88 years).

MEASUREMENTS

Body composition was assessed by dual-energy X-ray absorptiometry (DEXA). GH was measured in an ultrasensitive chemiluminescent assay and serum leptin was determined by radio-immunoassay.

RESULTS

Leptin was correlated with percentage body fat in both sexes (male r = 0.75, female r = 0.89, both P < 0.001). Male patients had increased fat mass (FM) (P < 0.01) and leptin concentrations (P < 0.05) but similar lean mass (LM) compared with controls. However, leptin concentration per unit FM was identical in both groups (P = 0.3). In contrast, female patients had lower LM (P < 0.05) but similar FM to controls, yet their leptin concentration per unit FM was twice that of the controls (P < 0.05). In multiple linear regression (MLR) leptin was determined positively by FM and negatively by LM (controls r2 = 76%; patients r2 = 73%, both P < 0.0001). When controlled for gender, GH secretion in the controls was correlated negatively with leptin (r = -0.68, P < 0.01) and negatively with percentage body fat (r = -0.73, P < 0.01). In MLR, using leptin as a marker of body composition, 66% of the variability in GH secretion in the controls could be explained by gender (38%) and by leptin (28%).

CONCLUSIONS

Both decreased lean mass and increased fat mass raise serum leptin concentrations in normal and growth hormone-deficient elderly subjects. Leptin is therefore a marker of body composition rather than fat mass alone. The influence of body composition on growth hormone secretion in the elderly may be mediated through leptin, acting as a peripheral signal from adipose tissue to decrease GH secretion.

Pilot study of carotid surgery for acute stroke

BACKGROUND

Carotid endarterectomy is usually delayed for 2 months following an acute stroke, but the stroke may progress or a further stroke may occur. A randomized pilot study of urgent carotid surgery for acute stroke was undertaken to assess the feasibility of a definitive multicentre trial.

METHODS

Seven Manchester hospitals referred patients with acute stroke (less than 7 days previously), defined according to the Oxfordshire Community Stroke Project classification The carotid arteries were examined by portable continuous-wave Doppler ultrasonography. Patients with more than 50 per cent carotid stenosis on portable Doppler ultrasonography underwent colour duplex Doppler imaging. Patients with more than 70-99 per cent carotid stenosis were randomized to urgent carotid surgery or best medical care.

RESULTS

A total of 593 patients were assessed over 2 years. Of these, 414 had acute stroke, of whom 380 had probable cerebral infarction. Complete ipsilateral internal carotid artery occlusion was most common in patients with total anterior circulation infarcts (33 (28 per cent) of 117), whereas severe ipsilateral (70-99 per cent) stenosis was most common in partial anterior circulation infarcts (25 (20 per cent) of 128). Only 16 patients (one total and 15 partial anterior circulation infarcts) were fit enough for surgery and consented to randomization.

CONCLUSION

A definitive trial of urgent carotid surgery would need to screen large numbers of patients but could focus on patients with partial anterior circulation infarcts.

A pilot exploratory study of oral electrical stimulation on swallow function following stroke: an innovative technique

This pilot study investigated the effect of oral electrical stimulation on swallow function in stroke patients with chronic dysphagia. The purpose was to determine whether an innovative technique could make an improvement in swallow function that might be developed as a potential treatment for patients with persistent dysphagia. Four stroke patients with chronic dysphagia were recruited on the basis of videofluoroscopic findings of a delayed swallow reflex. A single case design was used. Oral electrical stimulation of swallowing was carried out using a palatal prosthesis starting at an output pulse of 0.5 mA, with a fixed duration of 200 microsec, repeated at 1-sec intervals. Barium paste (1 x 5 ml) was introduced at the level of the patient's maximum tolerance of stimulation and any effect on swallow function was recorded by videofluoroscopy. The findings from the pilot study indicated that oral electrical stimulation resulted in an improvement in swallow function in 2 of the 4 patients. The stimulation was well tolerated in all cases with no serious adverse effects. These early results are promising, but further research is needed.

Preservation of growth hormone pulsatility despite pituitary pathology, surgery, and irradiation

Detailed assessment of physiological and pathophysiological GH secretion has, until recently, been limited by the poor sensitivity of the available assays. We have used an ultrasensitive chemiluminescence GH assay (sensitivity, 0.002 microgram/L) to study 24-h GH profiles (20-min sampling) from 24 patients who had been treated for hypothalamic-pituitary disease with surgery and irradiation and from 24 healthy control subjects matched for age, sex, and body mass index. Twenty-three of the 24 patients demonstrated pulsatile GH secretion, determined by Cluster. The median (range) area under the curve for GH, mean pulse area, mean pulse height, average valley mean level, and mean interpeak nadir were lower in the patients than in the controls [119.25 (7.273-843.600) vs. 968.539 (227.200-4625.000) min/microgram.L (P < 0.00001); 3.777 (0.288-30.850) vs. 61.390 (12.880-224.210) min/microgram.L (P < 0.00001), 0.107 (0.010-0.958) vs. 1.408 (0.368-5.050) micrograms/L (P < 0.00001), 0.074 (0.006-0.415) vs. 0.348 (0.048-2.350) microgram/L (P < 0.00001), and 0.066 (0.003-0.270) vs. 0.205 (0.021-1.838) microgram/L (P = 0.0004), respectively]. The median (range) number of pulses, mean pulse duration, and mean interval between pulses did not differ between the patients and controls [10 (4-15) vs. 10 (7-15; P = 0.36), 96.4 (68.0-220.0) vs. 104.0 (72.0-151.4) min (P = 0.65) and 128.0 (92.8-255.0) vs. 126.2 (90.0-180.0) min (P = 0.73), respectively]. The diurnal rhythm of GH secretion was present in the controls, but there was only limited evidence of residual diurnal rhythm in the patients. This study has demonstrated that GH secretion remains pulsatile in GH-deficient patients despite the mass effect of hypothalamic-pituitary pathology, pituitary surgery, and radiotherapy. With the development of potent GH secretagogues that are active orally, our findings may have important implications for the future management of GH-deficient subjects.

Elderly patients with adult-onset growth hormone deficiency are not osteopenic

The age-related decline in GH secretion has been implicated in the development of osteoporosis. GH-deficient adults show a significant reduction in bone mineral density (BMD), which is greater in those with childhood-onset GH deficiency than in those with GH deficiency occurring in adult life. To determine whether GH deficiency in late adult life causes a reduction in BMD beyond the decline observed with increasing age, we studied 21 patients over the age of 60 yr with GH deficiency caused by organic pituitary disease and 23 controls of similar age and sex distribution and BMI. Dual energy x-ray absorptiometry was used to determine total bone mass and BMD at the hip and in the lumbar spine. Serum osteocalcin was determined in all subjects and urinary deoxypyridinoline/creatinine ratio in 19 patients and 21 controls. The median (range) known duration of GH deficiency in the patients was 8 yr (range, 4-41 yr). The median (range) total bone mass was 2774 g (range, 1534-3734) in the patients and 2717 g (range, 1235-3549) in the controls (P = 0.42). Specific measurements of BMD made at L2-L4, the right femoral neck, the right femoral trochanter, and Ward's triangle were 1.234 (range, 0.778-1.507) vs. 1.144 g/cm2 (range, 0.809-1.466; P = 0.48), 0.921 (range, 0.605-1.372) vs. 0.96 g/cm2 (range, 0.534-1.315; P = 0.62), 0.92 (range, 0.523-1.229) vs. 0.915 g/cm2 (range, 0.353-1.313; P = 0.68), and 0.773 (range, 0.408-1.289) vs. 0.806 g/cm2 (range, 0.353-1.154; P = 0.81) in the patients and controls, respectively. The median (range) serum osteocalcin was 11.5 (range, 3.6-23.0) vs. 15.1 ng/mL (range, 0.7-40.5; P = 0.019) in the patients and controls, respectively. The median (range) deoxypyridinoline cross-links/creatinine ratio was 3.5 micromol/mol (range, 0.8-8.3) in the patients and 4.9 micromol/mol (range, 3.0-9.7) in the controls (P 0.038). There was a significant correlation between serum insulin-like growth factor I and total bone mass in the controls, but not in the patients. These data demonstrate that BMD is not significantly altered in GH-deficient adults over the age of 60 yr. Markers of bone formation and resorption are decreased, however, suggesting that bone turnover is reduced. Further studies are required to determine whether the reduction in bone turnover in these patients is of benefit.

Is there a role for carotid surgery in acute stroke?

INTRODUCTION

Carotid endarterectomy reduces the risk of stroke in patients with a history of minor ischemic stroke or transient ischaemic attacks and severe carotid stenosis, but the timing of surgery following acute stroke is controversial. Urgent carotid surgery in acute stroke may reduce the risk of early stroke recurrence due to further emboli from the diseased carotid, or may improve neurological recovery by improving cerebral blood flow to the ischaemic penumbra.

METHODS

We identified from the literature patients undergoing carotid surgery in acute stroke using a Medline search and identifying references from these sources.

RESULTS

Over 2000 patients were identified from the literature who underwent acute carotid surgery. Heterogeneous groups of patients were recruited, with no control patients treated medically in the majority of the studies. Mortality and morbidity was highly variable and depended primarily on the initial severity of the neurological deficit, with lower mortality in patients with minor neurological deficits.

CONCLUSIONS

The role of carotid surgery in acute stroke is uncertain. A multicentre randomised controlled trial is now required to assess the value of acute carotid surgery.

Aspiration following stroke: is it related to the side of the stroke?

OBJECTIVE

To investigate the relationship between the side of stroke and the presence of aspiration on videofluoroscopy.

DESIGN

Observational prospective study.

SUBJECTS

Eighty-seven patients (50% female) admitted with an acute stroke to the University Hospital of South Manchester.

METHODS

Patients admitted to the study underwent brain CT scanning and repeated videofluoroscopy.

RESULTS

CT scanning was performed within a median three days (interquartile range 2-4 days) following stroke and videofluoroscopic (VF) examination (median 2, interquartile range 1-4 days following stroke) of their swallow. Seventeen (19.5%) patients were noted to be aspirating. There were no significant relationships at this time between side or site of lesion and the presence of aspiration. A second assessment was carried out at a median time of 29 days (interquartile range 26-45) following acute stroke. Nine of 69 (13.5%) patients were noted to be aspirating, seven of whom, had right hemisphere lesions (p < 0.01).

CONCLUSIONS

Continuing aspiration may be related to the side of the cerebral lesion.

How do general practitioners manage patients at risk from stroke?

This study assessed by means of a postal questionnaire how general practitioners (GPs) manage patients at risk from stroke. Of the 640 GPs sent a questionnaire, 294 (46%) replied. In patients with a recent transient ischaemic attack or minor ischaemic stroke, 24% of responding GPs would not arrange any investigations. Sixty-one per cent refer under half of their patients for further investigation, although 99% of GPs would commence aspirin. Seventy-seven per cent of GPs were aware of the benefits of carotid surgery. For patients in atrial fibrillation, most GPs (77%) thought that warfarin reduced stroke rates, but only 20% would consider commencing warfarin, although 26% would commence aspirin. In hypertensive patients, the GPs' threshold for treatment ranged from 135 to 200mmHg systolic (median 160mmHg), and from 90 to 110mmHg diastolic (median 100mmHg). Most GPs (84%) would treat isolated systolic hypertension with a median threshold of 180mmHg (range 140-240mmHg). The results of this study suggest that some patients at risk from stroke may not receive optimal investigation and treatment in the community.