Adeno-associated virus gene therapy prevents progression of kidney disease in genetic models of nephrotic syndrome

Gene therapy for kidney diseases has proven challenging. Adeno-associated virus (AAV) is used as a vector for gene therapy targeting other organs, with particular success demonstrated in monogenic diseases. We aimed to establish gene therapy for the kidney by targeting a monogenic disease of the kidney podocyte. The most common cause of childhood genetic nephrotic syndrome is mutations in the podocyte gene NPHS2, encoding podocin. We used AAV-based gene therapy to rescue this genetic defect in human and mouse models of disease. In vitro transduction studies identified the AAV-LK03 serotype as a highly efficient transducer of human podocytes. AAV-LK03-mediated transduction of podocin in mutant human podocytes resulted in functional rescue in vitro, and AAV 2/9-mediated gene transfer in both the inducible podocin knockout and knock-in mouse models resulted in successful amelioration of kidney disease. A prophylactic approach of AAV 2/9 gene transfer before induction of disease in conditional knockout mice demonstrated improvements in albuminuria, plasma creatinine, plasma urea, plasma cholesterol, histological changes, and long-term survival. A therapeutic approach of AAV 2/9 gene transfer 2 weeks after disease induction in proteinuric conditional knock-in mice demonstrated improvement in urinary albuminuria at days 42 and 56 after disease induction, with corresponding improvements in plasma albumin. Therefore, we have demonstrated successful AAV-mediated gene rescue in a monogenic renal disease and established the podocyte as a tractable target for gene therapy approaches.

Podocyte protease activated receptor 1 stimulation in mice produces focal segmental glomerulosclerosis mirroring human disease signaling events

About 30% of patients who have a kidney transplant with underlying nephrotic syndrome (NS) experience rapid relapse of disease in their new graft. This is speculated to be due to a host-derived circulating factor acting on podocytes, the target cells in the kidney, leading to focal segmental glomerulosclerosis (FSGS). Our previous work suggests that podocyte membrane protease receptor 1 (PAR-1) is activated by a circulating factor in relapsing FSGS. Here, the role of PAR-1 was studied in human podocytes in vitro, and using a mouse model with developmental or inducible expression of podocyte-specific constitutively active PAR-1, and using biopsies from patients with nephrotic syndrome. In vitro podocyte PAR-1 activation caused a pro-migratory phenotype with phosphorylation of the kinase JNK, VASP protein and docking protein Paxillin. This signaling was mirrored in podocytes exposed to patient relapse-derived NS plasma and in patient disease biopsies. Both developmental and inducible activation of transgenic PAR-1 (NPHS2 Cre PAR-1Active+/-) caused early severe nephrotic syndrome, FSGS, kidney failure and, in the developmental model, premature death. We found that the non-selective cation channel protein TRPC6 could be a key modulator of PAR-1 signaling and TRPC6 knockout in our mouse model significantly improved proteinuria and extended lifespan. Thus, our work implicates podocyte PAR-1 activation as a key initiator of human NS circulating factor and that the PAR-1 signaling effects were partly modulated through TRPC6.

Abstract P5-03-06: Effect of Sleep Traits on Subtype Specific Breast Cancer Survival: a Mendelian Randomization Analysis

Background There is increasing interest in the relationship between sleep traits and both quality of life and survival in breast cancer. Recent work has found that oestrogen receptor positive (ER+) tumour cells are more likely to spread, via the circulation, at night than in the morning, providing support for a potential role of sleep characteristics influencing metastasis and therefore survival from breast cancer. The aim of this study was to investigate causal effects of sleep traits on subtype-specific breast cancer survival. Methods Single-nucleotide polymorphisms (SNPs) identified from GWAS associated with sleep traits with were used as a genetic instruments for Chronotype (N=697,828), Insomnia (N=1,331,010), Sleep Duration (N=446,118), Napping (N=452,633), Daytime sleepiness(N=452,071) and Ease of Getting up (N=461,658). All instruments were identified in data from UK Biobank, except chronotype and insomnia, which were identified in meta-analyses of UK Biobank and 23andme. For all instruments female-specific effect estimates were used. For these SNPs, summary statistics of their association with breast cancer survival were obtained from GWAS meta-analyses of European women from the Breast Cancer Association Consortium (BCAC), (N=91,686, with 7531 breast cancer specific deaths over a median follow-up of 8.1 years). To estimate the causal effect of the sleep traits on breast cancer survival, we applied two-sample MR for both overall and subtype-specific breast cancer (Luminal A-like, Luminal B-like, Human Epidermal Growth Factor 2 (Her2) positive, Her2 negative and triple negative (TNBC)). Further stratification by tumour characteristics at diagnosis and treatment received was also used. Sensitivity analyses were used to assess the robustness of main analyses to MR assumptions. Results For every hour increase in sleep duration, we observed worsening 5-year breast cancer specific survival in patients with ER+ tumours who received endocrine therapy (HR: 2.55, 95% CI: 1.10, 5,82) and for all patients receiving aromatase inhibitors (HR: 9.57, 95% CI: 1.61, 57.10). Conversely, improved 5-year survival was observed in patients with ER- tumours who received chemotherapy (HR: 0.30, 95% CI: 0.10, 0.87) and all patients receiving taxanes (HR: 0.23, 95% CI: 0.05, 0.98). We also observed that an increase in daytime sleepiness improved 15-year survival in patients both overall (HR: 0.34, 95% CI: 0.14, 0.80) and with lymph node negative tumours at diagnosis (HR: 0.12, 95% CI: 0.02, 0.64). Detailed sensitivity analyses are ongoing. Conclusions The current study uses a causal approach to identify potential effects between sleep patterns and breast cancer survival and confirms the previously observed relationships with increased sleep duration and worse survival in ER+ breast cancer. The reasons for opposite effects seen in those with ER- and those receiving taxanes needs further mechanistic work. Although the improved survival in relation to increased daytime sleepiness appears to be in-keeping with previous findings, this may largely reflect shorter sleep duration. Further work accurately characterising sleep quality, rather than duration in those with breast cancer, examining the effects on quality of life and survival and establishing mechanisms are needed.

Citation Format: Bryony Hayes, Richard Martin, Deborah Lawlor, Rebecca Richmond, Tim Robinson. Effect of Sleep Traits on Subtype Specific Breast Cancer Survival: a Mendelian Randomization Analysis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-03-06.

IGFBP-1 expression is reduced in human type 2 diabetic glomeruli and modulates β1-integrin/FAK signalling in human podocytes

AIMS/HYPOTHESIS

Podocyte loss or injury is one of the earliest features observed in the pathogenesis of diabetic kidney disease (DKD), which is the leading cause of end-stage renal failure worldwide. Dysfunction in the IGF axis, including in IGF binding proteins (IGFBPs), is associated with DKD, particularly in the early stages of disease progression. The aim of this study was to investigate the potential roles of IGFBPs in the development of type 2 DKD, focusing on podocytes.

METHODS

IGFBP expression was analysed in the Pima DKD cohort, alongside data from the Nephroseq database, and in ex vivo human glomeruli. Conditionally immortalised human podocytes and glomerular endothelial cells were studied in vitro, where IGFBP-1 expression was analysed using quantitative PCR and ELISAs. Cell responses to IGFBPs were investigated using migration, cell survival and adhesion assays; electrical cell-substrate impedance sensing; western blotting; and high-content automated imaging.

RESULTS

Data from the Pima DKD cohort and from the Nephroseq database demonstrated a significant reduction in glomerular IGFBP-1 in the early stages of human type 2 DKD. In the glomerulus, IGFBP-1 was predominantly expressed in podocytes and controlled by phosphoinositide 3-kinase (PI3K)-forkhead box O1 (FoxO1) activity. In vitro, IGFBP-1 signalled to podocytes via β1-integrins, resulting in increased phosphorylation of focal-adhesion kinase (FAK), increasing podocyte motility, adhesion, electrical resistance across the adhesive cell layer and cell viability.

CONCLUSIONS/INTERPRETATION

This work identifies a novel role for IGFBP-1 in the regulation of podocyte function and that the glomerular expression of IGFBP-1 is reduced in the early stages of type 2 DKD, via reduced FoxO1 activity. Thus, we hypothesise that strategies to maintain glomerular IGFBP-1 levels may be beneficial in maintaining podocyte function early in DKD.

Abstract GS2-06: Exploring the causal role of the human gut microbiome in breast cancer risk using mendelian randomization

Background: Variation in the human gut microbiome may influence cancer progression and therapy response through various mechanisms including modulation of both immune and cell signalling pathways. Whilst observational epidemiological studies have provided evidence that the gut microbiome may play a role in cancer risk, such studies are prone to residual confounding, reverse causation, and other forms of bias. Therefore, the nature of these associations still remains unclear. Mendelian randomization (MR) is a causal methodology that uses genetic variants as instruments (“proxies”) for risk factors to eliminate such biases when questioning causality in observational epidemiological associations. The statistical power and precision of MR analyses can be increased by employing a “two-sample MR” (2SMR) framework in which summary data – usually from large, independent, genome-wide association studies (GWASs) reporting associations of genetic variants with exposures (here, the gut microbiome) and outcomes (here, cancer) – are synthesised to estimate causal effects of each exposure on each outcome of interest. In this study, we utilised 2SMR to interrogate causal relationships between the gut microbiome and breast cancer (BC) risk using the largest published GWASs of the gut microbiome and of clinically utilised subtypes of BC.

Methods: We performed 2SMR using summary-level data from the GWAS of the host genetic contribution to gut microbiome variation amongst European individuals (the Flemish Gut Flora Project and two German cohorts (n=3890)) combined with summary-level data from the GWAS of BC risk (Breast Cancer Association Consortium (133,384 cases stratified by Luminal A, Luminal B, Human Epidermal Growth Factor 2 (Her2) positive, Her2 negative and triple negative status and 113,789 controls, plus 18,908 BRCA1 mutation carriers (9,414 with BC)). Sensitivity analyses were also conducted to assess pleiotropy of genetic variants on BC risk, independent of gut microbiota. Analyses were conducted in R Studio using the TwoSampleMR and the MR-TRYX packages.

Results: Of the 14 microbial traits (MTs) with evidence for a host genetic contribution in the GWAS of the gut microbiome, we found evidence that abundance of a genus within a certain bacterial order decreased the risk of triple negative BC (odds ratio per standard deviation increase: 0.84; 95% CI: 0.71, 0.9; p=0.03). In addition, we demonstrated that the risk of all molecular subtypes of BC may be altered by variation in these MTs, and that these relationships differed according to subtype. Sensitivity analyses demonstrated that pleiotropy was unlikely to explain these relationships

Conclusions: In our study, we utilised two recent and novel GWASs in an MR context to appraise causality in relationships between the gut microbiome and BC risk and found evidence that certain bacteria may alter BC risk, effects of which vary according to molecular subtype. These important results generate hypotheses about mechanisms underlying the causal biology of BC subtypes and potentially facilitate the design of BC risk-reducing interventions and prevention strategies.

Citation Format: Tim Robinson, Grace Edmunds, Bryony Hayes, Kaitlin Wade. Exploring the causal role of the human gut microbiome in breast cancer risk using mendelian randomization [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr GS2-06.

Basal ganglia echogenicity in preterm infants: A case series

BACKGROUND

Damage to the basal ganglia and thalamus (BGT) can be caused by multiple perinatal factors and may be associated with movement disorders, cognitive delay and visual difficulties. Changes in BGT structure, seen as echogenicity on ultrasound, are difficult to objectively quantify. The aetiology, clinical relevance and developmental outcomes of BGT echogenicity are poorly understood. We aimed to gain a better understanding of the natural history of BGT echogenicity in a preterm population.

METHODS

Retrospective review of clinical course, neuroimaging and development in infants born <32weeks gestation over 5 years with evidence of BGT echogenicity.

RESULTS

BGT echogenicity was reported in 18/650 infants (2.7%). Echogenicity appeared at a median of 8 days (2-45 days) and resolved on pre-discharge ultrasound in 50%. Thirteen infants had a term corrected MRI brain with abnormal BGT signal seen in 3 infants (23%). All 3 infants had persisting echogenicity on discharge ultrasound. No infant with echogenicity resolution on ultrasound had changes on term MRI. 14 infants had developmental progress available at 1 year corrected. Abnormal development was reported in four children of whom one had BGT changes on term MRI. Two children with persistent BGT changes but an otherwise normal MRI had reported normal neurodevelopment.

CONCLUSION

BGT echogenicity is relatively common on routine ultrasound and resolves in the majority of infants by term corrected. This review suggests that at term corrected, normal cranial ultrasound may obviate the need for MRI where no other concerns exist. BGT echogenicity did not appear to independently influence neurodevelopment.

Detection of first gammaherpesvirus sequences in Central African bats

Herpesviruses have been identified in many species; however, relatively few bat herpesvirus are known, considering the enormous diversity of bats. We used consensus PCR to test bats from the Republic of the Congo and found DNA of two different novel bat herpesviruses. One was detected in a Pipistrellus nanulus, the other in a Triaenops persicus bat and both resemble gammaherpesviruses. On the amino acid level, the amplified sequences differ by 55% from each other, and by 27% and 25% from the next closest known viruses. The findings point towards the diversity of herpesviruses in Central African bats.

Developments in Point-of-Care Diagnostic Technology for Cancer Detection

Cancer is the cause of death for one in seven individuals worldwide. It is widely acknowledged that screening and early diagnosis are of vital importance for improving the likelihood of recovery. However, given the costly, time-consuming, and invasive nature of the many methods currently in use, patients often do not take advantage of the services available to them. Consequently, many researchers are exploring the possibility of developing fast, reliable, and non-invasive diagnostic tools that can be used directly or by local physicians at the point-of-care. Herein, we look at the use of established biomarkers in cancer therapy and investigate emerging biomarkers exhibiting future potential. The incorporation of these biomarkers into point-of-care devices could potentially reduce the strain currently experienced by screening programs in hospitals and healthcare systems. Results derived from point-of-care tests should be accurate, sensitive, and generated rapidly to assist in the selection of the best course of treatment for optimal patient care. Essentially, point-of-care diagnostics should enhance the well-being of patients and lead to a reduction in cancer-related deaths.

Detection and assessment of copy number variation using PacBio long-read and Illumina sequencing in New Zealand dairy cattle

Single nucleotide polymorphisms have been the DNA variant of choice for genomic prediction, largely because of the ease of single nucleotide polymorphism genotype collection. In contrast, structural variants (SV), which include copy number variants (CNV), translocations, insertions, and inversions, have eluded easy detection and characterization, particularly in nonhuman species. However, evidence increasingly shows that SV not only contribute a substantial proportion of genetic variation but also have significant influence on phenotypes. Here we present the discovery of CNV in a prominent New Zealand dairy bull using long-read PacBio (Pacific Biosciences, Menlo Park, CA) sequencing technology and the Sniffles SV discovery tool (version 0.0.1; https://github.com/fritzsedlazeck/Sniffles). The CNV identified from long reads were compared with CNV discovered in the same bull from Illumina sequencing using CNVnator (read depth-based tool; Illumina Inc., San Diego, CA) as a means of validation. Subsequently, further validation was undertaken using whole-genome Illumina sequencing of 556 cattle representing the wider New Zealand dairy cattle population. Very limited overlap was observed in CNV discovered from the 2 sequencing platforms, in part because of the differences in size of CNV detected. Only a few CNV were therefore able to be validated using this approach. However, the ability to use CNVnator to genotype the 557 cattle for copy number across all regions identified as putative CNV allowed a genome-wide assessment of transmission level of copy number based on pedigree. The more highly transmissible a putative CNV region was observed to be, the more likely the distribution of copy number was multimodal across the 557 sequenced animals. Furthermore, visual assessment of highly transmissible CNV regions provided evidence supporting the presence of CNV across the sequenced animals. This transmission-based approach was able to confirm a subset of CNV that segregates in the New Zealand dairy cattle population. Genome-wide identification and validation of CNV is an important step toward their inclusion in genomic selection strategies.

The effect of antenatal magnesium sulfate on left ventricular afterload and myocardial function measured using deformation and rotational mechanics imaging

OBJECTIVE

Assess the effect of antenatal magnesium sulfate (MgSO4) on left ventricular function measured using deformation and rotational mechanics imaging.

STUDY DESIGN

Infants who received MgSO4 were matched for gestation, birth weight and mode of delivery with controls. Echocardiography was carried out on days 1 and 2 to measure left ventricle longitudinal strain (LV LS), twist, untwist rate, ejection fraction (EF), and systemic vascular resistance (SVR).

RESULTS

Thirty-eight infants with a median gestation and birth weight of 27.1 weeks and 923 g were included. On day 1, the MgSO4 group (n=19) had a lower SVR and higher LV LS, EF, twist and untwist rate than the Control group (n=19) (all P<0.05). There were no differences between the groups on day 2.

CONCLUSION

Antenatal MgSO4 administration is associated with a lower SVR and higher myocardial function on day 1 in preterm infants <29 weeks gestation.

The Goals of Patient Care project: implementing a proactive approach to patient-centred decision-making

BACKGROUND

Patients in the later stages of their lives risk being harmed by futile or unwanted interventions if realistic care goals and patient values are not recognised. Doctors have difficulty discussing and informing patients' healthcare goals.

AIMS

To review implementation of a Goals of Patient Care (GOPC) summary in medical inpatients and its applicability in emergency medical response (EMR) situations.

METHODS

Single-centre cross-sectional study of adult medical inpatients and adult inpatients requiring EMR at a Victorian general hospital.

MEASURES

presence and content of GOPC summary, secondary review of decision-making and discussion documentation, patient characteristics; EMR precipitants and outcomes.

RESULTS

GOPC were documented for 82 of 101 patients. One had an existing advance directive, and six had records of a patient-appointed substitute decision-maker. For patients with GOPC, 80 had life-prolonging treatment aims, with a varying degree of treatment limitation in 48. Discussion with patient or substitute decision-maker was evident in 43 cases. GOPC were documented prior to nine of 23 EMR. The EMR triggered a GOPC modification in three instances.

CONCLUSIONS

Introduction of a routine GOPC summary encourages consideration of goals of care for most medical inpatients. Few have pre-existing records of their wishes, and there are opportunities for improvement in this regard. Doctors may still have difficulty determining goals of care, and discussion of GOPC with patients and families may not be clearly documented. Most patients requiring EMR do not have prior GOPC review, and the role of the summary in these situations remains unclear.

Attitudes of Hospital Healthcare Workers towards Influenza Vaccination in a Tertiary Hospital Setting

The rate of uptake of seasonal influenza vaccination worldwide by healthcare workers (HCWs) has been suboptimal. Nationally, uptake among hospital HCWs was less than 20% prior to 2014. Indeed in our hospital following the 2010/2011 influenza season, a significant number of staff chose to have their vaccinations after the usual campaign period. The Occupational Health Department (OHD) undertook a questionnaire survey to determine the reason(s) for their late presentation. This was not anonymised, with a 21.7% participation rate (119 replied out of 548). We found 86(72.3%) HCWs believed influenza to be a serious illness, 84(70.6%) wanted to protect their family members and friends, and 64(53.8%) their patients from the infection. Nevertheless, 77(64.7%) were influenced by the recent media attention on the H1N1 influenza pandemic. We conclude external factors such as the arrival of the H1N1 pandemic continue to play an important role in influencing HCWs' attitudes towards receiving the vaccine.

Sharps injuries in a teaching hospital: changes over a decade

BACKGROUND

Sharps injuries create a high volume of occupational health (OH) workload in the health care setting. The deadline for implementation of the European Sharps Directive was 11 May 2013.

AIMS

To compare the epidemiology of sharps injuries reported in a large Irish teaching hospital in 2008-10 with those reported between 1998 and 2000.

METHODS

We compared data from electronic and paper OH records of sharps injuries reported between 1 January 2008 and 31 December 2010 with those from a previous study of sharps injuries reported between 1 January 1998 and 31 December 2000.

RESULTS

A total of 325 sharps injuries were reported in 2008-10, compared with 332 in 1998-2000 (P = 0.568). Hepatitis B immunity in sharps injury recipients in 2008-10 was 87% compared to 86% in 1998-2000 (P = 0.32). Glove use was reported in 80% of reported injuries in 2008-10 compared with 74% in 1998-2000 (P = 0.32). In 2008-10, 49% of injuries occurred during disposal or following improper disposal of sharps, compared with 42% in 1998-2000.

CONCLUSIONS

There was no significant change in the epidemiology of sharps injuries reported between 2008 and 2010 compared with 1998-2000. Further education in standard precautions, safe disposal of sharps, the use of safety-engineered devices and the benefits of hepatitis B immunization is needed.

Evaluation of spinosad for the oral treatment and control of flea infestations on cats in Europe

METHODS

An ectoparasiticide containing spinosad was evaluated as an oral formulation for cats. Two European laboratory studies and a European multicentre field efficacy and safety study assessed the use of a chewable tablet formulation of spinosad at a dose range of 50-75 mg/kg for treatment and control of flea infestations on cats.

RESULTS

The studies with experimentally infested cats consistently demonstrated persistent activity against Ctenocephalides felis with >98 per cent efficacy at four weeks post-treatment. In the field study with naturally infested client-owned cats from 18 clinics across Germany and Italy, two monthly doses of spinosad were administered; selamectin was the comparator product. Safety was evaluated in 226 cats, each receiving at least one dose of spinosad or selamectin; both products were well tolerated. 113 spinosad-treated cats and 71 selamectin-treated cats showed >97 per cent reductions in geometric mean flea counts within 14 days post-treatment and at 60 days post-treatment efficacy was >98 per cent in both groups. Analysis of success rates showed 96 per cent in spinosad-treated cats compared with 90.9 per cent in selamectin-treated cats at day 60. The spinosad tablets were successfully administered to over 98 percent of cats. These studies indicate that this formulation of spinosad is safe and efficacious for treatment and prevention of flea infestations in cats.

Clinical model for ethical cardiopulmonary resuscitation decision-making

BACKGROUND

Decisions to withhold cardiopulmonary resuscitation (CPR) for future cardiac arrest continue to be problematic, with a lack of consistency in how doctors approach this decision.

AIMS

To develop a clinical model that can be used in education to improve consistency in CPR decision-making.

METHODS

A qualitative study, using semistructured interviews with a total of 33 senior doctors, junior doctors and nurses from two Melbourne hospitals explored how decisions to withhold CPR are made. Interviews explored: issues arising; how doctors learn to make these decisions; how they deal with disagreement and their experiences of performing CPR. The transcripts were coded and analysed thematically.

RESULTS

Three major themes were identified: CPR as a life-and-death decision; good and bad dying; and trust. The research also defined the two elements to a CPR decision: (i) technical and (ii) ethical.

CONCLUSIONS

Applying ethical principles commonly used in medicine, a model for ethical CPR decision-making has been developed that identifies four patient groups, each with a different discussion aim. This approach simplifies the complexities of the CPR decision, providing a structured way to teach CPR decision-making to doctors and thereby achieve greater consistency in the decisions made.

The Houdini effect--an unusual case of blunt abdominal trauma resulting in perforative appendicitis

We present a unique case of perforative appendicitis that occurred in an adult following blunt abdominal trauma. This case represents the first such reported case from Ireland. It also represents a modern practical example of Laplace's theory of the effect of increased pressure on colonic wall tension leading to localized perforation, and serves to highlight not only the importance in preoperative imaging for blunt abdominal trauma, but also the importance of considering appendiceal perforation.

Evaluation of spinosad for the oral treatment and control of flea infestations on dogs in Europe

The novel ectoparasiticide spinosad is a naturally occurring mixture of spinosyns A and D formed during a fermentation process. The spinosyns are tetracyclic macrolides with a unique ring system. Their mode of action differs from that of other commercially available insecticides. Laboratory and field trials were conducted to evaluate the use of spinosad in a chewable tablet at a dose range of 45 to 70 mg/kg for the treatment and control of flea infestations on dogs in Europe. Laboratory studies with artificially infested dogs confirmed persistent activity against Ctenocephalides felis of higher than 99 per cent at three weeks post-treatment with values of 96.5 to 97.8 per cent at four weeks. Two multicentric field trials with naturally infected client-owned animals in five European countries used selamectin as comparator. Monthly doses were given during the summer when many homes were heavily infested. Households with spinosad-treated dogs showed cumulative benefits with flea burdens reduced by about 97 per cent at 14 and 30 days and by 99.6 per cent at 60 and 90 days. Corresponding figures for selamectin were significantly lower (P<0.05) at all time points: between 88.5 and 91 per cent at 14 and 30 days, then 97.8 and 98.2 per cent at 60 and 90 days. Thus, the performance of spinosad compared favourably with that of the established reference product.

Remote and rural: do mentors enhance the value of distance learning continuing medical education?

CONTEXT

Experts suggest that distance learning continuing medical education (CME) is only effective when there is the opportunity for two-way discussion and reflection. The value of on-line mentoring has been mainly studied in the West.

OBJECTIVES

We examined the benefits and practical implications of providing mentors for distance learning CME in a low technology setting.

METHODS

We conducted a randomized controlled trial with qualitative and quantitative analysis of the impact of mentoring on completion of CME and quality of reflective learning.

RESULTS

Twenty-six of 64 doctors completed all four CME modules. Non-completers were interviewed by telephone. Odds ratio analysis suggested that mentored doctors were three times more likely to complete their CME; however, this did not reach statistical significance (p = 0.07, 95% CI 0.89-10.57). Being in rural practice (p = 0.05) and younger in age (p = 0.005) were significantly associated with completion of CME. Mentored doctors seemed to show a higher quality of reflection on learning. Contact between mentors and mentees was difficult. Both mentors and mentees felt that optimal use of the system was not made.

DISCUSSION

Despite mentors' perceptions that they had little impact, mentored doctors did appear to be more likely to complete CME. Work is needed to increase the quality of interpersonal and educational interaction between mentors and mentees.

Hepatocellular carcinoma complicating cystic fibrosis related liver disease

Early diagnosis and treatment of the respiratory and gastrointestinal complications of cystic fibrosis (CF) have led to improved survival with many patients living beyond the fourth decade. Along with this increased life expectancy is the risk of further disease associated with the chronic manifestations of their condition. We report a patient with documented CF related liver disease for which he was under routine surveillance that presented with histologically proven hepatocellular carcinoma (HCC). It is important that physicians are aware of this association as increased vigilance may lead to earlier diagnosis and perhaps, a better outcome.

Clinicopathologic features of sentinel node metastases predictive of positive axillary clearance in grade 1 invasive breast carcinoma

BACKGROUND

Sentinel node (SN) biopsy is widely used to stage breast carcinoma and, when positive, typically leads to axillary clearance (AC).

AIMS

This study assesses clinicopathologic features of grade 1 breast carcinoma SNs with the aim of identifying a group of patients, who are likely to have a negative AC and can, therefore, safely be spared further surgery.

RESULTS

Two hundred and forty-seven patients with grade 1 invasive carcinoma were identified, of whom 29 had a positive SN. Four patients (13.8%) had a positive AC. Positive AC occurred in 3 of 6 (50%) patients whose SN showed extranodal extension (EE), but in only 1 of 23 (4.3%) patients without EE. All patients were staged as pN1(sn) following SN biopsy: only one, who had a 5.27 mm metastasis with EE, was pN2 following AC.

CONCLUSIONS

Extranodal extension is a significant predictor of a positive AC in this group. In its absence, AC did not alter the post-SN biopsy pN stage.

Detection of QTL for growth rate in the blacklip abalone (Haliotis rubra Leach) using selective DNA pooling

The objective of this study was to identify QTL for growth rate in the blacklip abalone Haliotis rubra using selective DNA pooling. Three full-sibling families of H. rubra derived from crosses of wild broodstock were used. DNA was extracted from the largest and smallest 10% of progeny and combined into two pools for each phenotypic tail. The DNA pools were typed with 139 microsatellites, and markers showing significant differences between the peak height ratios of alleles inherited from the parents were individually genotyped and analysed by interval mapping. A strong correlation (r = 0.94, P < 0.001) was found between the t-values from the analysis of pools and the t-values from the analysis of individual genotypes. Based on the interval mapping analysis, QTL were detected on nine linkage groups at a chromosome-wide P < 0.01 and one linkage group at a chromosome-wide P < 0.05. The study demonstrated that selective DNA pooling is efficient and effective as a first-pass screen for the discovery of QTL in an aquaculture species.

Construction of a dense SNP map for bovine chromosome 6 to assist the assembly of the bovine genome sequence

A linkage map was constructed for bovine chromosome 6 (BTA6), using 399 single nucleotide polymorphisms (SNPs) detected primarily from PCR-resequencing. The efficiency of SNP detection was highly dependent on the source of sequence information chosen for primer design (BAC-end sequences, introns or promoters). The SNPs were used to build a linkage map comprising 104 cM on BTA6. The SNP order in the linkage map corresponded very well with radiation hybrid (RH) maps available for BTA6 as well as with expected positions in the human comparative map, but diverged significantly from the current assembly of the bovine genome (Btau_3.1). When performing linkage analysis with the marker order suggested from the Btau_3.1 we observed an expansion of the genetic map from 104 cM to 137 cM, strongly suggesting a reordering of scaffolds in the current version of the bovine genome assembly. The extent of LD on BTA6 was evaluated by calculating the average r(2) for SNP pairs separated by given distances. The decline of LD was rapid with distance, such that r(2) was 0.1 at 100 kb. Our results indicate that linkage mapping will be a valuable source of information for correcting errors in the current bovine assembly. These errors were sufficiently frequent to be of concern for the accuracy of mapping QTL with panels of SNPs whose positions are based on the current assembly.

Cerebral palsy after maternal trauma in pregnancy

Ten children (six males, four females) with spastic (n=9) and mixed spastic-dyskinetic (n=1) cerebral palsy were born at term to mothers who earlier in the pregnancy had been involved in accidents without suffering overt abdominal injury, placental abruption, or premature onset of labour. At follow-up (at ages 2-24y), Gross Motor Function Classification System levels were II (n=7) and V (n=3). Cognitive level was normal in five patients, while learning disability was mild to moderate in two and severe in three. Magnetic resonance imaging of the brain in all children, assessed blind to the dates of maternal trauma in pregnancy, showed lesions consistent with prenatal vascular insult at the time of the trauma. Feasible mechanisms of brain injury include reduced placental blood flow and/or placental embolization.

Long chain fatty acid oxidation defects in children: importance of detection and treatment options

BACKGROUND

Mitochondrial beta oxidation plays a major role in energy production. Long chain fatty acid oxidation defects include deficiency of the trifunctional protein (rare) or more commonly defects of the long chain 3-hydroxy acyl-CoA dehydrogenase enzyme (LCHAD). These long chain defects have variable presentations, they may present in the neonate or infant with sudden death, hepatopathy (Reyes disease), hypoketotic hypoglycaemia, rhabdomyolysis, myopathy, cardiomyopathy and with late complications such as peripheral neuropathy, pigmentary retinopathy, retinal degeneration and progressive visual loss. The correct diagnosis at presentation is not only life saving but also allows for the appropriate dietary and other intervention, which may have major effects on outcome.

AIM

Three case reports of patients with long chain fatty acid oxidation defects who have shown significant benefits from treatment are reported.

CONCLUSIONS

These paediatric presentations illustrate the clinical heterogeneity of long chain fatty acid oxidation defects and opportunities for effective management if correctly diagnosed.

Impact of education on women with perinatal depression

OBJECTIVE

To assess the impact that education through participation in a depression screening program has on mental health literacy and help seeking behavior in perinatal women.

METHODS

Responses to a hypothetical case of depression, help seeking behavior, and screening levels for risk of depression using the Edinburgh Postnatal Depression Scale were compared between two groups of postnatal women; one group who had participated in a screening program and the other who had not. Those who participated in the screening program were also asked to evaluate the educational material they had received.

RESULTS

A total of 1309 women, broadly representative of postnatal women, answered one or more questionnaires. Those who had participated in the screening program were better able to recognize depression in a hypothetical case, and also assess their own mental state more appropriately. Those women who had been part of the program and did not score high on the EPDS were less likely to seek help, were more satisfied when they did and tended to benefit more from the educational booklet.

CONCLUSIONS

Participation in a screening program with educational material had significant benefits for mental health literacy and the health service use for perinatal women at risk for depression.

Ischaemic stroke in children secondary to post varicella angiopathy

Varicella in childhood is a self-limiting disease, which usually follows a benign course. However, complications, although rare, may have serious consequences. Ischaemic stroke secondary to post varicella angiopathy is a well-described complication and is estimated to account for up to a third of all strokes in infants. We present three previously healthy children who presented to our centre with ischaemic cerebrovascular infarction due to varicella angiopathy. All three children first presented within six weeks after onset of varicella infection and had MRI changes characteristic of ischaemic stroke secondary to post varicella angiopathy. While one child made an excellent recovery being left with only a minor deficit, the remaining two children were left with considerable morbidity severely affecting quality of life. The varicella vaccine has been proven to be well tolerated, safe and effective. We conclude that varicella vaccination should be considered for inclusion in the vaccination schedule to prevent serious complications which while rare may have devastating consequences.

Health professional's knowledge and awareness of perinatal depression: results of a national survey

INTRODUCTION

Postnatal depression affects 14% of women, occurring also antenatally, with potential long-term consequences, making it an important disorder to detect and manage early. In this study we sought to examine knowledge and awareness of perinatal depression in health professionals involved in perinatal care throughout Australia prior to the implementation of a comprehensive screening program, aimed at improving detection and access to appropriate management.

METHODS

A random sample of General Practitioners (GPs) and Maternal Child Health Nurses (MCHNs) and Midwives, in regions throughout Australia to be subsequently targeted by a screening and education program, were invited to participate. Responses to a hypothetical vignette and a knowledge questionnaire, as well as details of experience were completed.

FINDINGS

Questionnaires were completed by 246 GPs, 338 MCHNs and 569 midwives, with overall response rates; GP's 23%; MCHN's 55% and midwives 57%. Although knowledge level was similar among professional groups, MCHNs had higher levels of awareness of perinatal depression. Both GPs and MCHNs were more likely than midwives to recognize the need for providing help to women with emotional distress. Depression was more likely to be considered postnatally than antenatally in all groups, with GPs most likely to provide this diagnosis. GPs had a significant propensity to recommend antidepressants, and midwives to select non-specific medications.

CONCLUSIONS

Health professionals responding to this survey had a high awareness and similar knowledge base. Further education on antenatal depression and the safety risks and alternatives to medication is important for all groups, but particularly important for midwives and GPs. The latter is especially relevant given the preference for women with perinatal depression not to use pharmacological interventions to treat their emotional distress.

Determinants of influenza vaccination uptake among hospital healthcare workers

Influenza vaccination of health care workers is recommended for their own protection and that of their patients. There is serendipitous protection for their contacts outside of work. Influenza vaccination uptake has been historically poor. A questionnaire study of healthcare staff at a tertiary referral hospital was carried out to evaluate knowledge of and attitudes to influenza and its vaccine. There was a 36% response rate to the questionnaire, but with reasonably proportionate representation of the various occupational groups. The mean acceptance of vaccine in respondents was 30%; however the vaccination rate for the hospital in 2003 was 16.2% indicating that non-vaccinees were under represented in the study sample.. Vaccine uptake increased with age. Occupationally, doctors, clerical and catering/household staff had higher than mean reported uptake of vaccine. Nurse respondents reported vaccine uptake of 22%. The role of these factors is examined in determining vaccine acceptance. A strong belief in the effectiveness of influenza vaccine was shown to be the strongest predictor of vaccine uptake with 66% of this group taking vaccine. A maximum score in an 8-question knowledge test was only associated with a 51% vaccine uptake. Implications for campaigns to improve uptake are discussed.

Modelling skin permeability in risk assessment--the future

The modelling of skin permeability is important for transdermal drug delivery, in the cosmetic industry and for risk assessment attendant on dermal exposure to toxic substances. The two principal methods currently used are quantitative structure-activity relationships (QSARs), used in the main to predict permeability coefficients, and mathematical modelling based on analytical or numerical solutions to the relevant partition and transport equations and used to predict the amount of a substance permeating through the skin. This paper will assess recent progress in this area and suggest what will be needed for future advancements. The considerable effort invested in the development of QSARs during the past decade has resulted in only rather modest progress. Further significant improvement in our ability to predict percutaneous permeability is likely to require the measurement of new data under carefully controlled conditions and its fitting to new QSAR equations. Reliable assessments of risks following dermal exposures will demand new integrated mathematical models that include the variables associated with the exposure and penetration processes as well as the factors that control the subsequent passage of the penetrant into the systemic system.

Occupational sharps injuries in a Dublin teaching hospital

Contaminated sharps injuries pose a risk of infection to health care workers and represent a major workload for hospital occupational health departments (OHDs). The aim of this study was to review the epidemiology and management of sharps injuries in an Irish tertiary referral centre, which has not been previously described. Occupational health records of sharps injuries occurring between January 1998 and December 2000 inclusive were reviewed from the hospital OHD. A total of 332 sharps injuries were reported to the OHD in this period. More than two-thirds of injuries involved medical or nursing staff. Support staff such as cleaners and porters accounted for 13.5% of injuries. The majority of sharps injury recipients (86%) were immune to hepatitis B. Of those injured, 22% were not wearing gloves at the time of their injury. Eight source patients were hepatitis C antibody positive, two were HIV antibody positive and one was hepatitis B surface antigen positive. No instances of occupational acquisition of blood borne viruses were documented. The results of this study confirm that health care workers need further education to prevent sharps injuries, and that the risk of blood borne virus acquisition through an occupational sharps injury is low but not negligible.