The cholinesterases: analysis by pharmacogenomics in man

We have undertaken a study on variations in cholinesterase (ChE) genes in relation to cardiovascular (CV) function and the metabolic syndrome. Peripheral and central nervous system control of cardiovascular (CV) function mediated through cholinergic pathways is critical in homeostatic maintenance of blood pressure and responsiveness to stress. For acetylcholinesterase (AChE; EC 3.1.1.7) our focus is to identify single nucleotide polymorphisms (SNPs) in the gene that are linked to cardiovascular function. For butyrylcholinesterase (BChE; EC 3.1.1.8) we examined whether BChE activity correlated with parameters of the metabolic syndrome and cardiovascular function. ChE can be found in whole blood enabling a characterization of biochemical phenotype in addition to correlating genotype with phenotypic physiologic responses. Analysis of enzymatic activity was determined spectrophotometrically in blood samples from twin and other subject registries. Correlation analysis revealed significant relationships between enzyme activity and certain CV endpoints. Linkage analysis with data from a dizygotic (DZ) twin set showed a suggestive linkage at the BChE locus, and statistical analysis revealed a high correlation between BChE activity and variables associated with cardiovascular risk and the metabolic syndrome. Pattern of within-pair twin correlations by zygosity and the ACE model-fitting findings suggest the major source of this variation (65%) is attributable to an additive genetic component. To date 19 SNPs have been identified by the re-sequencing of AChE including four nonsynonymous coding SNPs (cSNPs).

Paternal skeletal size predicts intrauterine bone mineral accrual

BACKGROUND

We have previously demonstrated that maternal body build and lifestyle factors predict neonatal bone mineral accrual. However, the paternal determinants of neonatal bone mass are not known. In this study we explored the relationship between a father's bone mass and that of his offspring.

METHODS

A total of 278 pregnancies (142 male and 136 female neonates) were recruited from the Southampton Women's Survey, a unique, well-established cohort of women, aged 20-34 yr, who had been assessed before and during pregnancy. The neonates and their fathers underwent whole body dual-x-ray absorptiometry (DXA) within 2 wk of birth using a Lunar DPX (General Electric Corp., Madison, WI) and Hologic Discovery instrument (Hologic Inc., Bedford, MA), respectively; correlation and regression methods were used to explore the parental determinants of neonatal bone mass.

RESULTS

After adjusting the paternal DXA indices for father's age and the neonatal for baby's gestational age and age at DXA scan, there were highly significant positive associations between baby's whole body bone area, bone mineral content, and bone mineral density and the corresponding indices in the father (P = 0.003, 0.0002, 0.046, respectively) among female infants. These relationships were independent of maternal height and fat stores. The associations for male infants with paternal DXA indices did not achieve statistical significance.

CONCLUSIONS

The father's skeletal size predicts skeletal size more strongly in female than male offspring, independently of the mother's body build. These data point toward the importance of considering paternal genotype in studies exploring the developmental origins of osteoporotic fracture and raise intriguing mechanistic questions about the gender specificity of influences on intrauterine bone mineral accrual.

Effect of statins on proteolytic activity in the wall of abdominal aortic aneurysms

BACKGROUND

The aim of this study was to examine the effect of statin treatment on the activity of proteases in the wall of abdominal aortic aneurysms (AAAs).

METHODS

The activities of matrix metalloproteinases (MMPs) 9 and 3, cathepsins B, H, K, L and S, and the cystatin C level were measured in extracts of AAA wall taken from 82 patients undergoing AAA repair; 21 patients were receiving statin treatment before surgery. All values were standardized against soluble protein (SP) concentration in the extract, and reported as median (interquartile range) or mean(s.e.m.).

RESULTS

The two groups had similar demographics. Reduced activity of MMP-9 (43 (34-56) versus 80 (62-110) pg per mg SP; P < 0.001), cathepsin H (183 (117-366) versus 321 (172-644) nmol 4-methylcoumarin-7-amide released per mg SP; P = 0.016) and cathepsin L (102 (51-372) versus 287 (112-816) micromol 7-amino-4-trifluoromethylcoumarin released per mg SP; P = 0.020) was found in the statin-treated aortas compared with AAAs from patients not taking a statin. The statin-treated group had lower MMP-3 activity, but this did not reach statistical significance (P = 0.053). Cystatin C levels were higher in statin-treated aortas than in controls (41.3(3.1) versus 28.9(2.1) ng per mg SP; P = 0.003).

CONCLUSION

Statins decreased the activity of proteases that have been implicated in aneurysm disease.

Should vascular surgeons be trained in endovascular techniques? An observational study

INTRODUCTION

The aim of this study was to determine if there is a satisfactory cover for interventional radiology and whether vascular surgeons have received sufficient training in endovascular techniques.

MATERIALS AND METHODS

This was an observational study based on questionnaires sent to radiology and vascular trainers and vascular trainees in England. A total of 50 NHS trusts were chosen randomly to take part in the study and 320 questionnaires were sent out with an overall consultant response rate of 57%.

RESULTS

Of vascular consultants in the study group, 53% have had experience in endovascular procedures. Overall, 87% felt that there were not enough radiologists to fulfil the demand and 64% would like further training in endovascular procedures. In addition, 69% would like to be involved in a vascular rota without the general component. Similarly, 81% of radiologists felt that the demand was not being met, as emergency interventional radiology cover was not available on most nights in 65% of the trusts. Of responders, 72% would not object to training of vascular trainees in interventional work and 43% would be happy to be involved in training. Some 33% would accept a vascular trainee for 1 year.

CONCLUSIONS

Integrated fellowship in vascular surgery and interventional radiology has been implemented and tested in a number of centres in the US. This approach could be implemented in some of the larger vascular units in the UK.

Ligand discovery and virtual screening using the program LIDAEUS

This paper discusses advances in docking and scoring approaches with examples from the high-throughput virtual screening program LIDAEUS. We describe the discovery of small molecule inhibitors for the immunophilin CypA, the cyclin-dependent kinase CDK2 and the cyclapolin series of potent Polo-like kinase inhibitors. These results are discussed in the context of advances in massively parallel computing and in the development of annotated databases.

An evaluation of infant immunization in Africa: is a transformation in progress?

OBJECTIVE

To assess the progress made towards meeting the goals of the African Regional Strategic Plan of the Expanded Programme on Immunization between 2001 and 2005.

METHODS

We reviewed data from national infant immunization programmes in the 46 countries of WHOs African Region, reviewed the literature and analysed existing data sources. We carried out face-to-face and telephone interviews with relevant staff members at regional and subregional levels.

FINDINGS

The African Region fell short of the target for 80% of countries to achieve at least 80% immunization coverage by 2005. However, diphtheria-tetanus-pertussis-3 coverage increased by 15%, from 54% in 2000 to 69% in 2004. As a result, we estimate that the number of nonimmunized children declined from 1.4 million in 2002 to 900,000 in 2004. In 2004, four of seven countries with endemic or re-established wild polio virus had coverage of 50% or less, and some neighbouring countries at high risk of importation did not meet the 80% vaccination target. Reported measles cases dropped from 520,000 in 2000 to 316,000 in 2005, and mortality was reduced by approximately 60% when compared to 1999 baseline levels. A network of measles and yellow fever laboratories had been established in 29 countries by July 2005.

CONCLUSION

Rates of immunization coverage are improving dramatically in the WHO African Region. The huge increases in spending on immunization and the related improvements in programme performance are linked predominantly to increases in donor funding.

Open-label study of pemetrexed alone for chemonaive patients and pre-treated patients with malignant pleural mesothelioma: Outcomes of the International Expanded Access Program (EAP)

7709

Background: In a previous phase II study of chemonaive malignant pleural mesothelioma (MPM) patients (pts), single-agent pemetrexed (P) resulted in a 14.1% response rate (RR) and median survival of 10.7 mos (95% CI 7.7–14.5) (Scagliotti 2003). Likewise, the P arm in a phase III study of pre-treated MPM pts yielded an 18.7% RR (40.7% with stable disease, SD) and median survival of 8.4 mos (95% CI 6.2–10.5) (Jassem 2006). The EAP provided 3311 MPM pts with access to P alone, P plus cisplatin, or P plus carboplatin in 13 countries. In this abstract we report on the safety and efficacy data of those MPM pts treated with P alone. Methods: Eligible pts had histologic or cytologic diagnosis of MPM and were either chemonaïve or previously treated with =1 line(s) of chemotherapy. Pts pre-treated with P were allowed if they had experienced clinical benefit from the prior P. Treatment consisted of P (500 mg/m2) once (day 1) every 21 days with standard pre-medication of vitamin B12, folic acid, and dexamethasone. Investigator-determined response (RR) and survival data (with censoring) were recorded at the end of study participation. Myelosuppression data (CTC) were also collected. Results: 812 MPM pts (319 chemonaïve; 493 pre-treated) received =1 dose of P and were evaluated for safety, and 643 pts (247 chemonaïve; 396 pre-treated) were evaluated for efficacy (RR and survival). In chemonaïve pts with MPM, the median age was 69 yrs (range: 39–87 yrs), 78.1% were male, and 71.6% had a KPS ≥80 (of the 93% who had PS evaluated). In pre-treated pts with MPM, the median age was 63 yrs (range: 31–85 yrs), 75.9% were male, and 74.5% had a KPS ≥80 (of the 95% who had PS evaluated). Both groups received a median of 4 cycles (chemonaive group range 1–18; pretreated group range 1–23). See the table for efficacy and safety data. Conclusions: Results of the EAP confirm earlier phase II and phase III studies.

No significant financial relationships to disclose.

[Table: see text]

Learning movement sequences with a delayed reward signal in a hierarchical model of motor function

A key problem in reinforcement learning is how an animal is able to learn a sequence of movements when the reward signal only occurs at the end of the sequence. We describe how a hierarchical dynamical model of motor function is able to solve the problem of delayed reward in learning movement sequences using associative (Hebbian) learning. At the lowest level, the motor system encodes simple movements or primitives, while at higher levels the system encodes sequences of primitives. During training, the network is able to learn a high level motor program composed of a specific temporal sequence of motor primitives. The network is able to achieve this despite the fact that the reward signal, which indicates whether or not the desired motor program has been performed correctly, is received only at the end of each trial during learning. Use of a continuous attractor network in the architecture enables the network to generate the motor outputs required to produce the continuous movements necessary to implement the motor sequence.

Efficacy and plasma levels of ropivacaine for children: controlled regional analgesia following lower limb surgery

BACKGROUND

Continuous regional analgesia (CRA) is considered a safe and efficacious technique for postoperative pain relief in children after lower limb surgery. We recently evaluated the feasibility of patient-controlled regional analgesia (PCRA) in a similar acute pain situation and we concluded that PCRA might be advantageous over CRA in terms of lower costs, risk of systemic toxicity while producing similarly adequate analgesia. We therefore prospectively compared both techniques in the paediatric population.

METHODS

In total, 30 children undergoing lower limb orthopaedic surgery were randomized to receive PCRA or CRA with ropivacaine 0.2%. Visual analogue scale scores, rescue analgesia, overall satisfaction, motor blockade and plasma ropivacaine concentrations were recorded for 48 h.

RESULTS

Adequate analgesia was achieved with both techniques. No significant difference was noted for rescue analgesia, overall satisfaction and motor blockade. In contrast, children in the PCRA group received significantly less local anaesthetics than those in the CRA group. In addition, total plasma concentrations of ropivacaine were significantly reduced in the PCRA group as compared with the CRA group during the 48 h postoperative period.

CONCLUSIONS

Both techniques are efficacious and satisfactory. However, PCRA with ropivacaine 0.2% can provide adequate postoperative analgesia for paediatric orthopaedic procedures with smaller doses of ropivacaine than CRA.

Growth of gold nanoparticle films driven by the coalescence of particle-stabilized emulsion drops

We have investigated the mechanism of the spontaneous growth of a gold nanoparticle film on a container wall when an aqueous dispersion of gold nanoparticles is shaken with an oil phase containing octadecylamine, as first described by Mayya and Sastry (Mayya, K. S.; Sastry, M. Langmuir 1999, 15, 1902.). Experimental evidence is described, which shows that the film growth is driven by the coalescence of particle-coated emulsion drops with the flat oil-water interface separating the oil and water phases.

Double masked randomised controlled trial to assess the effectiveness of paracetamol in reducing pain in panretinal photocoagulation

AIM

To assess the effectiveness of pre-emptive analgesia with paracetamol in reducing pain associated with panretinal photocoagulation (PRP) in a prospective, double masked, randomised controlled trial.

METHOD

60 patients undergoing PRP for the first time were enrolled and randomised to paracetamol or placebo, taken for 2 days starting 24 hours before the laser treatment. The laser treatment was performed following a standardised protocol. Pain during and after treatment was assessed using the McGill pain questionnaire (MPQ) and visual analogue scales (VAS).

RESULTS

The statistical analysis looked for differences between the two study groups immediately after the laser surgery and 24 hours later. There was no statistically significant difference in the primary outcome measure of perception of pain during and 24 hours after PRP, between the paracetamol and placebo group. However, none of the patients in the paracetamol group reported increased total pain at 24 hours, whereas six patients in the placebo group reported increased pain; this difference (21%) was significant to p = 0.01.

CONCLUSIONS

Pre-emptive analgesia with paracetamol did not significantly reduce pain associated with PRP. This study has described for the first time the type of pain associated with PRP, which is perceived mainly as a discomfort. The main attributes of the pain that patients described, were sharp, flashing, tiring, intense, piercing, intermittent, and brief.

Botrytis grey mould of chickpea: a review of biology, epidemiology, and disease management

Botrytis grey mould (BGM), caused by Botrytis cinerea Pers. ex. Fr., is an economically important disease of chickpea (Cicer arietinum L.), especially in areas where cool, cloudy, and humid weather persists. Several epidemics of BGM causing complete crop loss in the major chickpea-producing countries have been reported. The pathogen B. cinerea mainly survives between seasons on infected crop debris and seeds. Despite extensive investigations on pathological, physiological, and molecular characteristics of B. cinerea causing grey mould type diseases on chickpea and several other hosts, the nature of infection processes and genetic basis of pathogen variability have not been clearly established. This lack of information coupled with the need for repeated application of chemical fungicides forced the deployment of host plant resistance (HPR) as a major option for BGM management. Effective and repeatable controlled-environment and field-screening techniques have been developed for identification of HPR. Of the selected portion of chickpea germplasm evaluated for BGM resistance, only few accessions belonging to both cultivated and wild Cicer spp. were tolerant to BGM, and the search for higher levels of disease resistance continues. Fungicide application based on disease predictive models is helpful in precision-based fungicide application. Integrated disease management (IDM) of BGM has proved more effective than any of the individual disease management components in large-scale, on-farm studies conducted in India, Nepal, and Bangladesh. Further information on the biology of B. cinerea and epidemiology of the disease is needed to strengthen the IDM programs. In this paper the biology of B. cinerea including its variability, epidemiology of BGM, identified sources of resistance, and other management options, and available information on biochemical and genetic basis of disease resistance have been reviewed with a mention of future research priorities.

112 LLAMA LAMA GLAMA PREGNANCIES FROM VITRIFIED/WARMED BLASTOCYSTS USING A NOVEL COAXIAL CRYOPROTECTANT MICROINJECTION SYSTEM

There has been only limited progress in efforts to cryopreserve llama embryos, and no live offspring have been reported to date. The main obstacle is the large diameter of in vivo-recovered llama embryos that results in high embryo volume to surface ratio. First, a novel coaxial microinjection device was designed and constructed to allow the injection of a cryoprotectant (CPA) solution directly into the cavity of hatched llama blastocysts in an effort to reduce the exposure time to toxic CPAs. The coaxial device consisted of a holding borosilicate pipette (120-μm OD; 60-μm ID) and an injection pipette (20-μm OD; 17-μm ID) placed inside the holding pipette for injection of CPAs and for aspiration of aqueous fluids from the blastocele cavity. In this preliminary study, two methods of cryopreservation were evaluated. Treatment (Trt) A consisted of injection of a CPA solution using the coaxial microinjection system followed by a vitrification (VITC) protocol. Day 7 in vivo-derived, hatched llama blastocysts (>500-μm diameter) were held in PBS during injection with an equilibration solution (EQUL) consisting of 15% glycerol, 10% butanediol, 1% polyethylene glycol, 20% fetal bovine serum (FBS) and 0.5 m sucrose in ViGro Holding Plus medium (Bioniche Animal Health, Melleville, Ontario, Canada). Embryos were immobilized with the holding pipette and EQUL solution was injected until the embryos were hyperinflated. The contents of the blastocele cavity were then aspirated and the embryos were released and held in EQUL solution for 8 min. After equilibration, embryos were transferred to a 3 step VITC solution (20% glycerol, 20% ethylene glycol, 0.3 m sucrose, 0.375 m glucose, 3% polyethylene glycol in three steps; Aller et al. 2002 Anim. Reprod. Sci. 73, 121–127), loaded into 0.25-mL plastic straws, and plunged into LN2. Trt B consisted of VITC only, without microinjection of CPAs. After 60 days, the straws containing the vitrified embryos in Trt A were removed from the LN2 and placed in a water bath at 32°C for 10 s. Embryos were injected with diluent medium (0.3 m sucrose in ViGro Holding Plus) into the blastocele cavity using the coaxial system until re-inflated to their original spherical shape. The warming of embryos in Trt B was performed without injection of diluent medium. Embryos from both treatments were held in diluent medium for 7 min and then placed in ViGro culture medium. Randomly chosen, VITC-thawed hatched blastocysts were nonsurgically transferred (1 or 2/female) to GnRH-treated llama recipients. Two pregnancies resulted from the transfer of three embryos (67%) from Trt A, with normal heart beats confirmed by ultrasonography 24 days post-transfer (Table 1). No pregnancies resulted from the transfer of embryos from Trt B. The pregnancies remain ongoing (60 and 210 days) at the time of this submission. These preliminary results demonstrate the successful use of a novel microinjection system in the cryopreservation of llama embryos. Research is now underway to determine the optimal VITC solutions and embryo exposure time. Table 1. Comparison of two vitrification methods for hatched llama blastocysts

Maternal and seasonal predictors of change in calcaneal quantitative ultrasound during pregnancy

BACKGROUND

During pregnancy, mineralization of the fetal skeleton and obligate urinary losses require adaptation of maternal calcium homeostasis, such as increased intestinal calcium absorption and bone resorption. However, the environmental determinants of maternal bone resorption during pregnancy in healthy adult mothers have not been previously described.

SUBJECTS AND METHODS

We conducted a population-based longitudinal study of 307 term pregnancies using a cohort of 307 pregnant women living in Southampton, United Kingdom. During early and late pregnancy, skeletal status was measured at the left calcaneus using quantitative ultrasound (QUS).

RESULTS

There was a significant (P < 0.001) decline in both speed of sound and broadband ultrasound attenuation during pregnancy. Those women who were pregnant for the first time (P = 0.001), had low milk intake prepregnancy (P = 0.01), and reduced measures of fat mass (P = 0.01) showed the greatest decline in calcaneal bone measurements. Furthermore, those women who were pregnant over winter months had greater losses in calcaneal QUS (P = 0.02).

CONCLUSION

Maternal lifestyle, fat stores, and seasonality of early pregnancy influence maternal calcaneal QUS loss during pregnancy; the findings support a role for vitamin D supplementation of women pregnant during winter, especially those with low calcium intakes who are pregnant for the first time.

Evidence-based practice of photopheresis 1987-2001: a report of a workshop of the British Photodermatology Group and the U.K. Skin Lymphoma Group

Photopheresis or extracorporeal photochemotherapy (ECP) is a novel immunomodulatory therapy which involves separation of the patient's leucocyte-rich plasma, followed by ex vivo administration of a photosensitizer and ultraviolet A radiation, before reinfusion. ECP has been used successfully for the treatment of cutaneous T-cell lymphoma (CTCL: Sézary syndrome), graft-versus-host disease (GVHD) and cardiac transplant rejection. ECP has a dose-sparing effect on concurrent immunosuppressive therapy. The procedure induces apoptosis of the irradiated lymphocytes, but the exact mechanism by which ECP exerts its therapeutic effect in these different conditions is uncertain. The treatment has very few adverse effects and in particular is not associated with an increased incidence of opportunistic infections. The evidence for the efficacy of ECP has been appraised by a combined British Photodermatology Group and U.K. Skin Lymphoma Group workshop on the basis of evidence published up to the end of 2001 and on the consensus of best practice. There is fair evidence for the use of ECP in erythrodermic CTCL and steroid-refractory GVHD, but randomized controlled studies are needed. There is good evidence supporting the use of ECP in preventing cardiac rejection following transplantation. Randomized controlled trials have also shown a therapeutic benefit in type 1 diabetes mellitus, but the inconvenience associated with the procedure outweighed the clinical benefit. There is fair evidence not to use ECP for the treatment of systemic sclerosis and multiple sclerosis, and good evidence not to use ECP for other forms of CTCL.

Umbilical cord leptin predicts neonatal bone mass

Evidence is accumulating that the risk of osteoporosis in later life may be determined in part by environmental influences on bone development during intrauterine and early postnatal life. A potential role for fetal leptin in mediating these effects is suggested by animal studies showing that leptin influences prenatal osteoblast growth and development, and that fetal leptin concentrations are altered by changes in maternal nutrition. In a group of term human infants we reported previously that maternal birthweight, smoking, fat mass, and exercise during late pregnancy independently predict neonatal bone mass. To investigate the potential role of leptin in mediating these effects, we now relate leptin concentrations in umbilical venous serum to neonatal bone mass and body composition in 117 infants. There were strong positive associations between umbilical venous leptin concentration and each of whole body bone mineral contents (BMC) (r = 0.42, P < or = 0.001) and estimated volumetric bone density (r = 0.21, P = 0.02); whole body lean mass (r = 0.21, P < or = 0.024); and whole body fat mass (r = 0.60, P < 0.001). The associations with neonatal BMC and fat mass, but not with lean mass, were independent of associations that we have reported previously between cord serum insulin-like growth factor 1 (IGF-1) concentrations and neonatal body composition. Among the maternal determinants of neonatal bone mass, cord leptin explained the relationship with maternal fat stores, but not those with the mother's own birthweight, smoking, or physical activity. We conclude that umbilical venous leptin predicts both the size of the neonatal skeleton and its estimated volumetric mineral density. In addition, among previously documented maternal determinants of neonatal bone mass in healthy pregnancies, maternal fat stores may mediate their effect on fetal bone accrual through variation in fetal leptin concentrations.

Measuring Friedreich ataxia: Interrater reliability of a neurologic rating scale

Measuring the severity of neurologic dysfunction in patients with inherited ataxias, including Friedreich ataxia (FA), is difficult because of the variable rate of progression, the variable age at onset and the variety of neural systems that may be affected. The authors discuss the problems related to rating scales in the ataxias, report a neurologic rating scale for FA, and demonstrate acceptable interrater reliability of the instrument.

Human auditory steady state responses to binaural and monaural beats

OBJECTIVE

Binaural beat sensations depend upon a central combination of two different temporally encoded tones, separately presented to the two ears. We tested the feasibility to record an auditory steady state evoked response (ASSR) at the binaural beat frequency in order to find a measure for temporal coding of sound in the human EEG.

METHODS

We stimulated each ear with a distinct tone, both differing in frequency by 40Hz, to record a binaural beat ASSR. As control, we evoked a beat ASSR in response to both tones in the same ear. We band-pass filtered the EEG at 40Hz, averaged with respect to stimulus onset and compared ASSR amplitudes and phases, extracted from a sinusoidal non-linear regression fit to a 40Hz period average.

RESULTS

A 40Hz binaural beat ASSR was evoked at a low mean stimulus frequency (400Hz) but became undetectable beyond 3kHz. Its amplitude was smaller than that of the acoustic beat ASSR, which was evoked at low and high frequencies. Both ASSR types had maxima at fronto-central leads and displayed a fronto-occipital phase delay of several ms.

CONCLUSIONS

The dependence of the 40Hz binaural beat ASSR on stimuli at low, temporally coded tone frequencies suggests that it may objectively assess temporal sound coding ability. The phase shift across the electrode array is evidence for more than one origin of the 40Hz oscillations.

SIGNIFICANCE

The binaural beat ASSR is an evoked response, with novel diagnostic potential, to a signal that is not present in the stimulus, but generated within the brain.

Impact of computer-aided detection prompts on the sensitivity and specificity of screening mammography

OBJECTIVES

To determine the value of computer-aided detection (CAD) for breast cancer screening.

DESIGN

Two sets of mammograms with known outcomes were used in two studies. Participants in both studies read the films with and without the benefit of a computer aid. In both studies, the order of reading sessions was randomised separately for each reader. The first set of 180 films, used in study 1, included 20 false-negative interval cancers and 40 screen-detected cancers. The second set of 120 films, used in study 2, was designed to be favourable to CAD: all 44 cancer cases had previously been missed by a film reader and cancers prompted by CAD were preferentially included.

SETTING

The studies were conducted at five UK screening centres between January 2001 and April 2003.

PARTICIPANTS

Thirty radiologists, five breast clinicians and 15 radiographers participated.

INTERVENTIONS

All cases in the trial were digitised and analysed using the R2 ImageChecker version 2.2. Participants all received training on the use of CAD. In the intervention condition, participants interpreted cases with a prompt sheet on which regions of potential abnormality were indicated.

MAIN OUTCOME MEASURES

The sensitivity and specificity of participants were measured in both intervention and control conditions.

RESULTS

No significant difference was found for readers' sensitivity or specificity between the prompted and unprompted conditions in study 1 [95% confidence index (CI) for sensitivity with and without CAD is 0.76 to 0.80, for specificity it is 0.81 to 0.86 without CAD and 0.81 to 0.87 with CAD]. No statistically significant difference was found between the sensitivity and specificity of different groups of film reader (95% CI for unprompted sensitivity of radiologists was 0.75 to 0.81, for radiographers it was 0.71 to 0.81, prompted sensitivity was 0.76 to 0.81 for radiologists and 0.69 to 0.79 for radiographers). Thirty-five readers participated in study 2. Sensitivity was improved in the prompted condition (0.81 from 0.78) but the difference was slightly below the threshold for statistical significance (95% CI for the difference -0.003 to 0.064). Specificity also improved (0.87 from 0.86); again, the difference was not significant at 0.05 (95% CI -0.003 to 0.034). A cost-effectiveness analysis showed that computer prompting increases cost.

CONCLUSIONS

No significant improvement in film readers' sensitivity or specificity or gain in cost-effectiveness was established in either study. This may be due to the system's low specificity, its relatively poor sensitivity for subtle cancers or the fact the prompts cannot serve as aids to decision-making. Readers may have been better able to make use of the prompts after becoming more accustomed to working with them. Prompts may have an impact in routine use that is not detectable in an experimental setting. Although the case for CAD as an element of the NHS Breast Screening Programme is not made here, further research is required. Evaluations of new CAD tools in routine use are underway and their results should be given careful attention.

Assessing the impact of CAD on the sensitivity and specificity of film readers

AIM

To assess the impact of computer-aided detection (CAD) prompts on film readers' sensitivity and specificity.

MATERIAL AND METHODS

Thirty-five readers read 120 films, including 44 cancers, 40 of which were prompted. All readers looked at all cases with and without prompts. The sensitivity and specificity were calculated for each reader under each condition.

RESULTS

The sensitivity improved when CAD prompts were used (0.80 from 0.77). The difference was slightly below the threshold for statistical significance (95% CI for the difference is -0.0027-0.064). The specificity also improved (0.86 from 0.85), but not significantly. There was a significant improvement in sensitivity when readers' judgements were combined to simulate double reading, from 0.77 to 0.81. (95% CI for the difference is 0.014-0.077).

CONCLUSIONS

Analysis of prompted cancers that readers did and did not recall, found that cases were more likely to be correctly recalled if there were emphasized prompts, more prompts or if the case was harder. There was no statistically significant effect for type of abnormality or tumour size or for the performance, attitude or experience of the reader.

Evaluation of computer-aided detection (CAD) devices

We present a review of three major UK studies of computer-aided detection (CAD) for mammography. A short account of the motivation, methods and results is given for each of the three. A number of conclusions are drawn, particularly about the merits and difficulties of research in the field. The first two studies measured the impact of CAD on the sensitivity and specificity of film readers interpreting cases with known outcomes displayed on rollers with an artificially high frequency of cancers. In the first study 50 film readers each read 180 cases, including 60 cancers (40 screen-detected and 20 interval). In the second study 35 film readers viewed 120 cases including 44 cancers, of which 40 were selected to be difficult cases that CAD prompted correctly. The third study was carried out prospectively. 6111 films were independently double read by film readers who recorded a judgement before and after viewing CAD prompts. In addition to this, intraobserver measure of the impact of CAD, we compared the cancer detection rate in these cases with that in 1339 cases read over the same period without the benefit of CAD. None of the three studies showed a statistically significant effect attributable to CAD. There is evidence that a high proportion of missed cancers are prompted and that "emphasised" prompts, which have a greater positive predictive value, have a stronger impact on decision-making that other prompts.

The cost-effectiveness of technology transfer using telemedicine

The high burden of disease in developing countries often makes it difficult for health systems in these countries to attain the same level of specialist skills as industrialized countries. Technology transfer is one way to improve specialist skills whilst at the same time reducing the burden of disease. This paper describes the use of teleophthalmology, a form of telemedicine, as a mode of technology transfer between the United Kingdom and South Africa. As the burden of eye disease in South Africa is high, the country cannot afford the level of ophthalmic specialization achieved in the UK. The paper estimates the cost-effectiveness of the technology transfer project in terms of a cost per Disability Adjusted Life Year (DALY) averted. We found the technology transfer project to be cost-effective in reducing the burden of eye disease, and that practitioners in South Africa also learned novel procedures that could help future patients and improve cost-effectiveness. Technology transfer using telemedicine is a cost-effective method that richer countries can employ to aid capacity building in the health care systems of poorer countries.

Can early infection explain the sibling effect in adult atopy?

Atopy is strongly and inversely related to family size, a pattern which is plausibly assumed to reflect a protective effect of early infection. The current study tested this hypothesis by case-referent analysis of an adult cohort in the UK. The study established that atopy, defined by prick tests to common aeroallergens, was less common among those from larger families after adjustment for potentially confounding factors. In particular, a higher number of brothers appeared to offer protection. The current authors attempted to explain this distribution by examining contemporary family-doctor records of early childhood infections; and by a number of other indirect indices of early-life "hygiene". The sibling effect was unexplained by evidence of infection with either hepatitis A or Helicobacter pylori, or by counts of infections or antibiotic prescriptions in early life. There was a significant and independent negative association between the number of gastrointestinal infections before the age of 5 yrs and the odds of atopy. Dog ownership and home moving in early life also displayed potentially protective associations. Although the current study replicates the finding that atopy is inversely associated with family size this could not be explained by documentary or serological evidence of early infection. The findings support the suggestion that the "sibling effect" in atopy may not simply reflect protection by early infection.

Ostwald ripening in emulsions: estimation of solution thermodynamics of the disperse phase

The rate of Ostwald ripening has been measured for small emulsions prepared by the dilution of O/W microemulsions containing a range of n-alkanes. The rates were determined as a function of temperature for decane, undecane, dodecane and tri-decane using photon correlation spectroscopy. The aqueous solubilities of these oils were estimated from the rates of ripening using the Lifshitz, Slyozov and Wagner theory of Ostwald ripening. These solubilities were used to calculate the free energy, enthalpy and entropy of solution for the 4 alkanes. Values obtained were in good agreement with literature values. The free energy of solution of hexadecane and octadecane were also determined from the rate of ripening of mixed oil phase emulsions with dodecane using the treatment suggested by Kabalnov. The values obtained agreed well with extrapolated values of the free energy from lower alkanes, suggesting that coiling or aggregation of the longer chain molecules in solution was not affecting the solubility.