Automated particle recognition for engine soot nanoparticles

A pre-trained convolution neural network based on residual error functions (ResNet) was applied to the classification of soot and non-soot carbon nanoparticles in TEM images. Two depths of ResNet, one 18 layers deep and the other 50 layers deep, were trained using training-validation sets of increasing size (containing 100, 400 and 1400 images) and were assessed using an independent test set of 200 images. Network training was optimised in terms of mini-batch size, learning rate and training length. In all tests, ResNet18 and ResNet50 had statistically similar performances, though ResNet18 required only 25-35% of the training time of ResNet50. Training using the 100-, 400- and 1400-image training-validation sets led to classification accuracies of 84%, 88% and 95%, respectively. ResNet18 and ResNet50 were also compared for their ability to categorise soot and non-soot nanoparticles via a fivefold cross-validation experiment using the entire set of 800 images of soot and 800 images of non-soot. Cross-validation was repeated 3 times with different training durations. For all cross-validation experiments, classification accuracy exceeded 91%, with no statistical differences between any of the network trainings. The most efficient network was ResNet18 trained for 5 epochs, which reached 91.2% classification after only 84 s of training on 1600 images. Use of ResNet for classification of 1000 images, the amount suggested for reliable characterisation of soot sample, requires <4 s, compared with >30 min for a skilled operator classifying images manually. Use of convolution neural networks for classification of soot and non-soot nanoparticles in TEM images is highly promising, particularly when manually classified data sets have already been established.

Application of the PRECEDE-PROCEED model for the development of a community pharmacy ear health intervention for rural populations

Introduction

The World Health Organisation has identified ear disease to be a major public health problem in rural and remote communities, with access to services an identified barrier. (1) Rural community pharmacists are recognised as highly skilled, accessible and trusted health professionals. An innovative service “LISTEN UP” (Locally Integrated Screening and Testing Ear aNd aUral Program) has been implemented in two remote community pharmacies in Australia. The service involves patients with an ear complaint self-presenting to a participating pharmacy and receiving a clinical examination by a pharmacist, who has completed accredited training in ear health, otoscopy and tympanometry. “LISTEN UP” has been developed using the PRECEDE-PROCEED planning model.(2) The PRECEDE component of the model assesses social, epidemiological, behavioural, environmental, educational and ecological factors to inform the development of an intervention.(2) The PROCEED-component consists of pilot testing and evaluation.

Aim

To describe an ecological approach to health promotion via the application of the PRECEDE-PROCEED planning model to develop a rural community pharmacy-based ear health intervention.

Methods

PRECEDE (Predisposing, Reinforcing, and Enabling Constructs in Educational Diagnosis) provided a framework to plan and develop a locally relevant and community focused program. This included research and engagement via meetings, surveys and interviews of consumers, pharmacists, health professionals and stakeholders. PROCEED (Policy, Regulatory, and Organisational Constructs in Educational and Environmental Development) outlined the structure for implementing and evaluating the intervention that was developed in the PRECEDE process. A pilot study has been included in PROCEED segment to allow improvement before implementing and evaluating the final model. Data will be collected in the pilot study via semi-structured interviews and surveys. This will be analysed using descriptive statistics and thematic analysis of qualitative data.

Results

As part of the PRECEDE segment a social assessment was undertaken via mixed method studies of rural consumers, pharmacists and health professionals. Hearing testing was ranked as the seventh (from twenty-six) most important expanded pharmacy service by both consumer and health professional groups. An epidemiological assessment found extensive ear disease in rural and remote locations resulting in complications and hearing loss. Behavioural and environment assessments identified eleven ear health interventions which include hearing screening [3], otoscopy pilot studies [2], audiometry services [1], specific education for undergraduate pharmacy students [2] and a pharmacy-based clinic [3]. However none of the interventions described a framework for continued service provision. Policy and regulation assessment was undertaken to align the intervention within the regulatory framework. The application of this model is partially complete with the study protocol for the intervention developed and the initial pilot study in progress. This study’s strengths include its applicability to rural populations and the limited evidence base that currently exists. It is however limited by the small size of the pilot study and application of this model to a national intervention would be useful for future.

Conclusions

The application of the PRECEDE-PROCEED model demonstrates the applicability of this planning model for developing and evaluating an ear health intervention with a particular focus on community pharmacies in rural and remote locations.

References

1. World Health Organisation. Deafness and hearing loss; 2020. Available from: https://www.who.int/health-topics/hearing-loss#tab=tab_1 [Accessed: 15/9/2020]

2. Binkley CJ, Johnson KW. Application of the PRECEDE-PROCEED Planning Model in Designing an Oral Health Strategy. J Theory Pract Dent Public Health. 2013;1(3):http://www.sharmilachatterjee.com/ojs-2.3.8/index.php/JTPDPH/article/view/89

The effect of a digital training tool to aid chest image interpretation: Hybridising eye tracking technology and a decision support tool

INTRODUCTION

Eye tracking technology, checklists and search strategies have been demonstrated as useful aids in image interpretation. A training tool was developed, by the research team, which included these features. This study aimed to evaluate the effect of the training tool on participant image interpretation performance.

METHODS

The study was carried out with reporting radiographers who had either commenced training in chest image interpretation (n = 12) or were trained in musculoskeletal image interpretation (n = 23) (total n = 35). Participants were allocated to a control or intervention group. Participants completed an initial assessment at recruitment and re-attended nine months later for a follow-up assessment. The intervention group were given unlimited access to a digital training tool. During assessments participants interpreted 20 chest images whilst using eye tracking technology (total of 1400 images were interpreted). A confidence level was obtained from participants on their diagnosis and a questionnaire, to obtain demographic data, was completed following the assessment.

RESULTS

Improvements were seen in the confidence of intervention group participants (p < 0.05). False Positive (FP) scores decreased for both the control and intervention group (p < 0.05), this decrease was from 4.20 to 3.20 for the control group and from 5.87 to 3.27 for the intervention group. True Negative (TN) scores increased, from 5.13 to 6.73 for the intervention group (p < 0.05). Mean decision time decreased for both the control and intervention group.

CONCLUSION

The tool led to positive effects on participant performance and could be a useful aid in chest image interpretation learning.

IMPLICATIONS FOR PRACTICE

Improvements in performance were observed with a digital tool. The tool could improve image interpretation methods and training.

A matched comparison study of hepatitis C treatment outcomes in the prison and community setting, and an analysis of the impact of prison release or transfer during therapy

Prisoners are a priority group for hepatitis C (HCV) treatment. Although treatment durations will become shorter using directly acting antivirals (DAAs), nearly half of prison sentences in Scotland are too short to allow completion of DAA therapy prior to release. The purpose of this study was to compare treatment outcomes between prison- and community-based patients and to examine the impact of prison release or transfer during therapy. A national database was used to compare treatment outcomes between prison treatment initiates and a matched community sample. Additional data were collected to investigate the impact of release or transfer on treatment outcomes. Treatment-naïve patients infected with genotype 1/2/3/4 and treated between 2009 and 2012 were eligible for inclusion. 291 prison initiates were matched with 1137 community initiates: SVRs were 61% (95% CI 55%-66%) and 63% (95% CI 60%-66%), respectively. Odds of achieving a SVR were not significantly associated with prisoner status (P=.33). SVRs were 74% (95% CI 65%-81%), 59% (95% CI 42%-75%) and 45% (95% CI 29%-62%) among those not released or transferred, transferred during treatment, or released during treatment, respectively. Odds of achieving a SVR were significantly associated with release (P<.01), but not transfer (P=.18). Prison-based HCV treatment achieves similar outcomes to community-based treatment, with those not released or transferred during treatment doing particularly well. Transfer or release during therapy should be avoided whenever possible, using anticipatory planning and medical holds where appropriate.

BRCA1, BRCA2 and PALB2 mutations and CHEK2 c.1100delC in different South African ethnic groups diagnosed with premenopausal and/or triple negative breast cancer

Background

Current knowledge of the aetiology of hereditary breast cancer in the four main South African population groups (black, coloured, Indian and white) is limited. Risk assessments in the black, coloured and Indian population groups are challenging because of restricted information regarding the underlying genetic contributions to inherited breast cancer in these populations. We focused this study on premenopausal patients (diagnosed with breast cancer before the age of 50; n = 78) and triple negative breast cancer (TNBC) patients (n = 30) from the four South African ethnic groups. The aim of this study was to determine the frequency and spectrum of germline mutations in BRCA1, BRCA2 and PALB2 and to evaluate the presence of the CHEK2 c.1100delC allele in these patients.

Methods

In total, 108 South African breast cancer patients underwent mutation screening using a Next-Generation Sequencing (NGS) approach in combination with Multiplex Ligation-dependent Probe Amplification (MLPA) to detect large rearrangements in BRCA1 and BRCA2.

Results

In 13 (12 %) patients a deleterious mutation in BRCA1/2 was detected, three of which were novel mutations in black patients. None of the study participants was found to have an unequivocal pathogenic mutation in PALB2. Two (white) patients tested positive for the CHEK2 c.1100delC mutation, however, one of these also carried a deleterious BRCA2 mutation. Additionally, six variants of unknown clinical significance were identified (4 in BRCA2, 2 in PALB2), all in black patients. Within the group of TNBC patients, a higher mutation frequency was obtained (23.3 %; 7/30) than in the group of patients diagnosed before the age of 50 (7.7 %; 6/78).

Conclusion

This study highlights the importance of evaluating germline mutations in major breast cancer genes in all of the South African population groups. This NGS study shows that mutation analysis is warranted in South African patients with triple negative and/or in premenopausal breast cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1913-6) contains supplementary material, which is available to authorized users.

Observations of body mass index in Duchenne muscular dystrophy: a longitudinal study

BACKGROUND/OBJECTIVES

Nutritional issues that are associated with Duchenne muscular dystrophy (DMD) remain poorly understood. The aim of this analysis was to describe and explore longitudinal observations of body mass index (BMI) in a cohort of children with DMD.

SUBJECTS/METHODS

Anthropometric and clinical characteristics were collected retrospectively and longitudinally for boys with DMD seen in two large neuromuscular clinics. BMI Z-scores were determined using the Centers for Disease Control and Prevention reference values for children (2000).

RESULTS

Medical records (n=193) were examined from which 75% were included for analysis. The mean age of the cohort at the time of data collection was 11.9 years, with 72% of patients currently or previously using steroids. The highest prevalence of obesity based on the BMI Z-score was 50% at the age of 10 years. Longitudinally, BMI Z-scores from the age of 2 to 12 years plot approximately one s.d. above the mean, after which there is a marked and progressive decline. BMI gainers were identified for whom BMI Z-score increased by 1.65 units compared with the 0.09 units in non-gainers. BMI gainers were younger when they had their first BMI measurement (5.9 vs 7.2 years), and this measure was significantly lower compared with the non-gainers (BMI Z-score: 0.04 vs 1.17). In this cohort, BMI was associated with age, ambulatory status and lung function.

CONCLUSIONS

This study demonstrates that boys with DMD using steroid therapy experience shifts in BMI. A declining BMI appears to be associated with increasing age. Interpretation of growth patterns is limited here by a lack of normative growth references in DMD.

Impact of intrapancreatic or extrapancreatic bile duct involvement on survival following pancreatoduodenectomy for common bile duct cancer

BACKGROUND

The clinicopathological factors that influence survival following pancreatoduodenectomy (PD) for common bile duct (CBD) cancer are not well known. This study aimed to investigate the effect of tumour involvement of the intrapancreatic versus extrapancreatic CBD on margin status, overall (OS) and disease-free (DFS) survival.

METHODS

This was a retrospective study of patients who underwent PD for CBD cancer between 2001 and 2009. Pathological examination was performed according to a previously described standardized protocol based on axial slicing. Clinicopathological data and outcome in terms of margin status, DFS and OS were compared between cancers involving exclusively the intrapancreatic CBD (CBDin) and those involving the extrapancreatic CBD, in isolation or combined with invasion of the intrapancreatic part of the duct (CBDex).

RESULTS

A total of 66 patients were enrolled. Most CBD cancers were locally advanced (97 per cent pathological (p) T3, 76 per cent pN1). Microscopic margin involvement (R1) was more frequent in CBDex than in CBDin cancers (34 of 39 versus 13 of 27; P = 0.001), more often multifocal (P < 0.001) and more frequently affected the periductal margin (P = 0.005). Venous resection was more often required for CBDex cancers (P = 0.009). CBDex cancers were associated with worse OS (median 21 versus 28 months; P = 0.020) and DFS (14 versus 31 months; P = 0.015), but the rate and site of recurrence did not differ. Metastasis to more than two lymph nodes was an independent predictor of OS and DFS.

CONCLUSION

CBDex cancer is associated with a higher rate of R1 resection and venous resection after PD, and has a worse outcome than CBDin cancer.

Probiotic VSL#3 prevents antibiotic-associated diarrhoea in a double-blind, randomized, placebo-controlled clinical trial

BACKGROUND

Antibiotic-associated diarrhoea (AAD) is a frequent complication of systemic antibiotic therapy and Clostridium difficile-associated diarrhoea (CDAD) is its most serious form due to associated morbidity and mortality.

AIM

This trial aimed to investigate whether the probiotic VSL#3 prevents AAD and CDAD in average-risk hospital patients.

METHODS

Adult hospital inpatients exposed to systemic antibiotics were recruited to this multicentre, randomized, double-blind, placebo-controlled trial. One sachet of VSL#3 or placebo was given twice daily for the length of the antibiotics course and for seven days thereafter. Primary outcomes were AAD and CDAD.

FINDINGS

Patients randomized to active (N = 117) and placebo (N = 112) groups were well-matched for baseline demographic patient data. No cases of CDAD were detected. The rate of AAD was significantly lower in the active group on per protocol analysis (0% active vs 11.4% placebo; P = 0.006). On intention-to-treat analysis the difference in AAD incidence (4.3% active vs 8.9% placebo; P = 0.19) was not significant.

CONCLUSIONS

VSL#3 is associated with a significant reduction in the incidence of AAD in average-risk hospital inpatients exposed to systemic antibiotics. As the incidence of CDAD has fallen sharply, no cases of CDAD were found. Probiotic administration as prophylaxis for CDAD may not be indicated in average-risk hospital patients.

Bryophyte dispersal by flying foxes: a novel discovery

This research provides the first evidence of dispersal of bryophytes and associated microorganisms through ingestion by a highly mobile vertebrate vector, the spectacled flying fox (Pteropus conspicillatus). Bryophyte fragments were found in faeces collected at four P. conspicillatus' camps in the Wet Tropics bioregion, northeastern Australia. These fragments were viable when grown in culture; live invertebrates and other organisms were also present. Our study has significantly increased understanding of the role of flying foxes as dispersal vectors in tropical forests.

Musculoskeletal ultrasound training in rheumatology: the Belfast experience

OBJECTIVES

Despite the increasing use of musculoskeletal ultrasound (MSUS) as a clinical tool in rheumatology, there is no consensus yet regarding the standards required to achieve a basic level of competence in the use of this imaging technique. A number of sonographers worldwide are developing curricula and standardizing teaching methods in order to improve training in MSUS for rheumatologists. In the meantime, clinicians are devising informal means of training in order to acquire these new skills. Here we describe the informal team approach to MSUS training adopted by a group of rheumatologists from the Regional Rheumatology Centre in Belfast, UK.

METHODS

Over a 5-yr period, eight rheumatologists from Musgrave Park Hospital in Belfast used a variety of means to learn the basic skills of MSUS.

RESULTS

Seven of the team underwent a formal assessment of their competency in a practical examination devised by an experienced sonographer. All were judged to have attained a basic competency in MSU.

CONCLUSIONS

This Belfast experience shows what can be achieved despite the absence of formal MSUS training. Nevertheless, the development of recognized training programmes and international standards of competency are important goals on the way to achieving more widespread acceptance of MSUS as a useful tool in everyday clinical practice.

MRI assessment of the bony pelvis may help predict resectability of rectal cancer

OBJECTIVE

The outcome after surgical treatment of rectal cancer may be influenced by the technical difficulty of the operation, which is thought to be affected by pelvic size. The aim of this study was to examine the association between bony pelvic dimensions and CRM involvement.

PATIENTS AND METHODS

All patients with primary rectal cancer between December 1999 and January 2002 were studied. Staging was performed by pelvic MRI. Nine pelvic dimensions were measured from the MR images on a workstation. Pathology reports were obtained for all patients and the mesorectal specimen was examined. Technical difficulty was assessed by circumferential resection margin (CRM) involvement.

RESULTS

Of 126 patients with primary rectal cancer, 88 had staging MRI and rectal excision; there were significant differences between the sexes in all 9 pelvic dimensions (P < 0.05). In females, the interspinous diameter was significantly shorter in patients with CRM involvement compared with patients with a negative CRM. In female patients predicted to have a negative CRM, the anteroposterior diameter of the inlet, the anteroposterior diameter of the midplane and the transverse diameter of the midplane (interspinous distance) were significantly shorter in patients who actually had a positive CRM compared with those in whom the CRM was negative. In male patients, there was no correlation between pelvic dimensions and CRM status.

CONCLUSIONS

In certain patients with rectal cancer, CRM positivity may be predicted from pre-operative MRI pelvic measurements. This may influence the choice of adjuvant therapy.

Quantitation of intraepithelial lymphocytes in human duodenum: what is normal?

BACKGROUND

An increase in intraepithelial lymphocytes (IELs) is mandatory for the histological diagnosis of coeliac disease (CD). Currently, duodenal biopsies are used almost exclusively to establish the diagnosis, yet published work continues to cite an upper limit of 40 lymphocytes/100 epithelial cells, a figure derived from jejunal biopsies over 30 years ago.

AIM

To establish the normal range for IEL counts in distal duodenal biopsies.

MATERIALS/METHODS

Twenty subjects (seven men, 13 women; median age, 34 years; range, 20-65) with a normal sugar permeability test and concurrent distal duodenal biopsies were identified. The number of IELs and epithelial cell nuclei in an uninterrupted length of surface (villous) epithelium (> 500 cells) was counted. An image analysis system was used to assess villous architecture by calculating the villous height to crypt depth ratio.

RESULTS

The range of IEL counts in 20 subjects was 1.8-26/100 villous epithelial cells, with a mean value of 11 and SD of 6.8. The mean villous to crypt ratio was 1.82 (SD, 0.38; range, 1.22-2.46). There was no correlation between IEL counts and villous to crypt ratio (Spearman rank correlation, -0.066; p = 0.80).

CONCLUSIONS

These results suggest that 25 IELs/100 epithelial cells (mean +2 SD) should be taken as the upper limit of the normal range for duodenal mucosa.

Histological identification of Helicobacter pylori: comparison of staining methods

AIM

To determine whether two recently described staining methods (the modified McMullen's and the Helicobacter pylori silver stain HpSS methods) used for the histological identification of H pylori organisms are superior to two established techniques (the modified Giemsa and anti-H pylori antibody immunostain) in terms of availability, reproducibility, rapidity, sensitivity, and cost.

METHODS

Histological sections from 63 paired gastric biopsies from adult patients previously investigated for dyspepsia were stained with the four methods and these were assessed blindly and independently by two observers. Of the 63 patients, 30 were originally negative in all tests for H pylori infection, 30 were positive, and the remaining three cases had discordant results using a combination of five tests (rapid biopsy urease test, urea breath test, culture, serology, and histology).

RESULTS

Interobserver agreement was best with the antibody method (98%), followed by the McMullen's (90%), Giemsa (87%), and HpSS (85%). Of the 60 "gold standard" positive and negative cases, 30 were positive by the modified Giemsa stain, 29 by the McMullen's method, 29 by HpSS, and 30 by the antibody stain. However, there were two false positives with the HpSS method. The modified Giemsa is the cheapest and easiest to perform technically.

CONCLUSIONS

When H pylori are present, careful examination will almost always reveal them, whichever of these stains is used. However, the modified Giemsa stain is the method of choice because it is sensitive, cheap, easy to perform, and reproducible.

Flat and depressed colonic neoplasms: a prospective study of 1000 colonoscopies in the UK

BACKGROUND

Flat and depressed colorectal tumours were originally thought to be unique to the Japanese population. Recently there have been reports of flat and depressed lesions in western countries but they have been thought to be uncommon.

METHODS

In this prospective study, 1000 consecutive patients attending for routine colonoscopy were examined for flat or depressed lesions. The examinations were done by one European colonoscopist using methods developed in Japan.

FINDINGS

321 adenomas were found: 202 (63%) were polypoid, 36% (117) were flat and 2 (0.6%) appeared depressed. Most adenomas contained areas of mild or moderate dysplasia but 10% (31) were severely dysplastic. Six Dukes' A adenocarcinomas were identified together with 25 more advanced adenocarcinomas. The likelihood of Dukes' A cancer or severe dysplasia increased from 4% (3/70) in small flat lesions, to 6% (9/154) in small polyps, 16% (8/50) in larger polyps, 29% (14/49) in large flat lesions, and 75% (3/4) in depressed lesions. 54% (20/37) lesions containing severe dysplasia or Dukes' A carcinoma were flat or depressed.

INTERPRETATION

The polyp-carcinoma hypothesis prompts colonoscopists to search only for polypoid lesions when screening for cancer, and many early colorectal neoplasms may therefore be missed. Colonoscopists require training in the recognition of flat and depressed lesions to detect colorectal tumours in the early stages.

Primary tumours of the vestibule and inner ear

Seven primary tumours of the vestibule and inner ear are described, six schwannomas and one traumatic fibroma. Schwannomas in this situation may occur as sporadic tumours, or may be a feature of neurofibromatosis type 2 (NF-2). In the latter condition they may occur in isolation or in association with, but separate from, schwannomas arising in the internal meatus. Direct extension into the vestibule of an intrameatal vestibular schwannoma is well reported, but extension of an intravestibular tumour into the internal meatus is not described. Traumatic fibromas of the vestibule are rare and the trigger could be an attack of labyrinthitis. Intravestibular tumours, although rare, are likely to be diagnosed with increasing frequency with the widespread use of MR imaging.

Effect of the beta-agonist clenbuterol on dexamethasone-induced diaphragm dysfunction in rabbits

The present study was designed to examine whether clenbuterol (CLEN) could reduce dexamethasone (DEX)-induced diaphragm dysfunction. We studied four groups of New Zealand white (NZW) rabbits, each receiving one of the following daily injections subcutaneously for 2 wk: saline (control), DEX 3 mg/kg, DEX 3 mg/kg + CLEN 2 mg/kg, and CLEN 2 mg/kg. Diaphragm fiber cross-sectional areas (CSA) were measured. Twitch transdiaphragmatic pressure (Pdi) and tetanic Pdi were measured during bilateral phrenic stimulation both before and after 60 min of inspiratory resistive loading (IRL). DEX produced a marked atrophy of type IIa and type IIb diaphragm fibers. This diaphragm atrophy was prevented by CLEN in the DEX plus CLEN group. CLEN alone increased CSAs of all three types of diaphragm fibers. Significant reductions in twitch Pdi and tetanic Pdi at all stimulation frequencies both before and after IRL were observed similarly in the DEX group as well as in the DEX plus CLEN group compared with the control animals. We conclude that DEX produces significant diaphragm atrophy and decreases diaphragmatic contractility. CLEN produces hypertrophy of the diaphragm and minimizes diaphragm atrophy induced by DEX, but it has no demonstrable protective effect on DEX-induced diaphragm dysfunction.

Giant cell hepatitis associated with systemic lupus erythematosus

Giant hepatocytes are commonly found in several neonatal and infantile liver diseases, but are rarely found in adult liver disease. A 42 year old white woman presented with a five month history of paraesthesia and numbness of both the upper and lower limbs and with vague abdominal pain. Abnormal liver function was noted on routine screening. Ultrasound scan of the abdomen showed gallstones; barium enema, ERCP and computed tomography scan were all normal. IgG antibodies to double stranded DNA were present at a titre of 40 units. Anti-cardiolipin antibodies, anti-mitochondrial antibodies and rheumatoid factor were not detected. Serology for hepatitis A, B, C, and paramyxoviruses was negative, as was the Paul Bunnell test. A clinical diagnosis of systemic lupus erythematosus (SLE) with an axonal sensory polyneuropathy was made, the latter confirmed on biopsy of the sural nerve. Giant cells were noted on liver biopsy. The patient was treated with corticosteroids; liver function had improved after two years of follow up. When extensive giant cell transformation is noted on liver biopsy, particularly when neuropathy is also a feature, the possibility of an association with SLE should be considered.

Phrenic motoneuron firing rates during brief inspiratory resistive loads

The neural activation of the diaphragm during quiet and vigorously stimulated breathing has been hypothesized to be submaximal. In this study, we measured phrenic motoneuron firing rates during brief progressively increasing inspiratory resistive loads in anesthetized rabbits. We recorded activity in 68 phrenic motoneurons in 17 rabbits. We found that 40 of these axons were active during quiet breathing. Twenty-seven axons were silent during quiet breathing but began to fire as inspiratory loading progressed. The level of drive reflected by transdiaphragmatic pressure where silent phrenic motoneurons were recruited ranged from 5 to 45 cmH2O. Silent motoneurons showed significantly higher average rates of firing and significantly greater increases in firing rate as loading progressed (P < 0.01). The firing rate of both active and silent axons tended to plateau as rates approached 70-80 Hz. All motoneurons except for one, which may have been an afferent, were activated by inspiratory resistive loading. Inspiratory resistive loading activated phrenic motoneurons at high rates, and our results did not support the presence of significant numbers of unrecruited motoneurons.

Growth screening and urban deprivation

OBJECTIVES

To assess the effect of urban deprivation on childhood growth in a modern British society by analysing data from a regional growth survey, the Tayside growth study.

SETTING

The Tayside Region in Scotland, which has three districts with distinct socioeconomic status: Dundee (D, urban city), Angus (A, rural), and Perth (P, rural and county town).

SUBJECTS AND METHODS

Height and weight of 23,046 children (> 90% of the regional childhood population) were measured as part of a child health surveillance programme, by community health care workers at 3, 5, 7, 9, 11, and 14 years. Height standard deviation score (calculated against Tanner) and body mass index (BMI-weight (kg)/height (m)2) were calculated for each child by a central computer program; mean height standard deviation score and BMI standard deviation score were calculated for each measuring centre (school, health clinic). A deprivation score for each centre was calculated from the prevalence of single parent families; families with more than three children; unemployment rate; the number of social class V individuals; the percentage of council houses.

RESULTS

Mean height standard deviation score for Tayside was 0.11. An intraregional difference was demonstrated: mean height standard deviation score (SD) D = 0.04 (1.0); A = 0.14 (1.1); P = 0.21 (1.1); P < 0.002. There was a positive association between short stature and increasing social deprivation seen throughout Tayside (P < 0.05), with a strong association in Dundee primary school children (r = 0.6; P < 0.001). Analysis by district showed that the association was significant only above the age of 8 (P < 0.004). There was no relation between BMI and social deprivation.

CONCLUSIONS

In an industrialised developed society, urban deprivation appears to influence height mostly in late childhood, and this association should be taken into consideration in the clinical management of short stature. Height seems to be a better physical indicator of urban deprivation, and hence an index of childhood health, than BMI.

Continued prescribing of inappropriate drugs in general practice

Seven general practitioners used various methods to identify patients in their practices whom they had inherited and whose medication they regarded as inappropriate in the light of current knowledge. Information was collected in each case about the drug concerned, the patient, the original prescriber, and the reason for continued prescribing. Each patient was also interviewed. Altogether, 25 different drugs were prescribed for 40 patients: in 16 the inappropriate drug was one acting on the brain, in 13 an antihypertensive, in seven it was given for heart disease and in three, for asthma. The influence of the original prescriber, and the patient's dependence on the drug, helped to explain its continued use. Almost half the patients said that they might consider changing their medication. The study underlines the importance of reviewing long-term medication and offers a method of scrutinizing repeat prescribing in general practice. Community pharmacists could help in this process.

Stability of evoked parasternal intercostal muscle electromyogram at increased end-expiratory lung volume

The diaphragmatic electromyogram has been measured as an index of the level of diaphragmatic activation. The diaphragmatic electromyogram, however, even when measured by intramuscular electrodes, can be artifactually altered by a change in lung volume (A. Brancatisano, S. M. Kelly, A. Tully, S. H. Loring, and L. A. Engel. J. Appl. Physiol. 66: 1699-1705, 1989) or by a change in body position. The parasternal intercostal muscle may be less subject to the mechanisms that are believed to produce this artifactual change. We asked whether the parasternal intercostal electromyographic activity could be reliable when lung volume changes. Six supine rabbits were anesthetized with ketamine and xylazine. Fine bipolar copper wires, with their tips exposed, were inserted into the left parasternal intercostal muscle in the third interspace. A stimulus that was three times maximal was applied to the corresponding intercostal nerve, and the resulting action potential (AP) was photographed. Parasternal intercostal muscle length was measured by sonomicrometry over the vital capacity range. There were small nonsignificant changes in the AP from functional residual capacity (FRC) to total lung capacity. From FRC to residual volume there was variation in the AP. The AP was also quite stable when regional conductivity was altered but showed variation when the parasternal intercostal muscle length change was accentuated by traction on the rib cage. We conclude that the parasternal intercostal electromyographic activity can be reliably used to measure inspiratory motoneuron output to it over the range of lung volumes from FRC to total lung capacity.