Prevalence of the ABCB1-1Δ gene mutation in a sample of New Zealand Huntaway dogs

AIMS

To determine the prevalence of the ATP Binding Cassette Subfamily B Member 1-1Δ mutation (ABCB1-1Δ; previously Multidrug Resistance 1 (MDR1) mutation) in a cohort of New Zealand Huntaway dogs.

MATERIALS AND METHODS

Samples were opportunistically collected from Huntaway dogs (n = 189) from throughout New Zealand. Buccal swabs were collected from 42 Huntaways from the Wairarapa region and 147 blood samples from Huntaways from the Gisborne, Waikato, Manawatū/Whanganui, Hawkes Bay, Canterbury and Otago regions. DNA was extracted from all samples and tested for the presence of the ABCB1-1Δ allele.

RESULTS

Of 189 Huntaway dogs that were tested, two were found to be heterozygous carriers of the ABCB1-1Δ allele and the remaining 187/189 dogs were homozygous for the wild type allele. No dogs homozygous for the mutation were identified.

CONCLUSIONS AND CLINICAL RELEVANCE

The results of this study show that the ABCB1-1Δ allele is present in Huntaway dogs. The low prevalence in this convenience sample suggests that the prevalence of this allele in the Huntaway population is likely to be low. We recommend that veterinary clinicians discuss the potential for this mutation in Huntaways with dog owners including the clinical implications for dogs that are homozygous for the mutated allele and the potential for testing for the mutation, as they would do for other known mutations.

136 GameteGuard in maturation medium improves bovine embryo quality and quantity

The number of invitro-produced (IVP) bovine embryos generated in the United States increased 11% from 2017 to 2018, demonstrating a demand for new technology to rapidly and efficiently improve herd genetics. Unfortunately, embryo production on a per oocyte basis remains low, limiting the number of high-quality commercial embryos available for transfer or freezing. Reactive oxygen species (ROS) are a major contributor to low embryo production rates of invitro gametes and are especially problematic in maturation media. This is due to high numbers of mitochondria in the bovine oocyte producing ROS exacerbated by the invitro environment. GameteGuard® is an organic plant-based additive that provides protection against reactive oxygen species. The aims of this research were to evaluate the effects of GameteGuard addition to invitro bovine embryo production media to (1) mitigate the impact of ROS on oocyte maturation and competence, and (2) increase the production of high-quality embryos in our IVP system. Four rounds of invitro embryo production (Colorado State University protocol and media) with or without maturation medium supplemented with GameteGuard were performed (n=1175 total oocytes). Oocytes were aspirated from abattoir ovaries; those with homogeneous ooplasm and multiple layers of even cumulus cells were matured using control (n=585) or GameteGuard-supplemented (n=590) maturation medium. Oocytes were fertilized with frozen/thawed semen from proven IVF bulls (n=4) and then cultured in a two-step media system to Day 7. Blastocysts were evaluated on Day 7 according to IETS embryo grading standards. A subset of 80 blastocysts were fixed and stained after grading using an In Situ Cell Death Detection Kit (Fluorescein; Millipore Sigma) and Hoechst 33342 (Invitrogen) as apoptotic and counter-stains, respectively. Stained blastocysts were assessed by immunofluorescence microscopy to obtain the percentage of apoptotic cells and total cell count. Because multiple bulls were used, a linear mixed model was required for data analysis. Treatment was considered the fixed effect and bulls as a random effect to determine the impact of the treatment on stage and quality of blastocysts. Cleavage rates were not different (P>0.5) but GameteGuard supplementation of maturation medium resulted in a 22% increase in grade-1 embryos per total blastocysts produced (P<0.01; n=79/106 control vs. n=120/137 GameteGuard grade 1 blastocysts). Additionally, the percent of grade 2 and 3 embryos per total blastocysts decreased, (P<0.01; 27%, n=27/106 control and 11%, n=14/137 GameteGuard grade 2 and 3 blastocysts), suggesting that supplementation with GameteGuard promoted development of better-quality embryos overall. The percentage of apoptotic cells was also significantly higher in control blastocysts compared with treated blastocysts (P<0.02; 11.4%, n=38 control and 12.8%, n=42 GameteGuard). GameteGuard supplementation of the maturation medium significantly increased the production of high-quality IVP bovine embryos, thereby providing potential marketable gain for embryo producers.

Long-term follow-up of a randomized controlled trial of a text-message diabetes self-management support programme, SMS4BG

AIMS

To determine the long-term effectiveness of an individually tailored text-message diabetes self-management support programme, SMS4BG, on glycaemic control at 2 years in adults with diabetes with an HbA_1c concentration > 64 mmol/mol (8%).

METHODS

We conducted a 2-year follow-up of a two-arm, parallel, randomized controlled trial across health services in New Zealand. Participants were English-speaking adults with type 1 or 2 diabetes and with an HbA_1c >64 mmol/mol (8%). In the main trial participants randomized to the intervention group (N=183) received up to 9 months of an automated tailored text-message programme in addition to usual care. Participants in the control group (N=183) received usual care for 9 months. In this follow-up study, 293 (80%) of 366 randomized participants in the main trial were included. The primary outcome measure was change in glycaemic control (HbA_1c ) from baseline to 2 years. Mixed-effect models were used to compare the group differences at 3, 6, 9 and 24 months, adjusted for baseline HbA_1c and stratification factors (health district category, diabetes type and ethnicity).

RESULTS

The decrease in HbA_1c at 2 years was significantly greater in the intervention group [mean (sd) -10 (18) mmol/mol or -0.9 (1.6)%] compared with the control group [mean (sd) -1 (20) mmol/mol or -0.1 (1.8)%], with an adjusted mean difference of -9 mmol/mol (95% CI -14, -5) or -0.8% (95% CI -1.2, -0.4; P<0.0001).

CONCLUSIONS

Improvements in glycaemic control resulting from a text-message diabetes self-management support programme were sustained at 2 years after randomization. These findings support the implementation of SMS4BG in current practice.

Reaching out to reduce health inequities for Māori youth

AIM

This paper describes an initiative facilitating comprehensive assessment and delivery of brief interventions for Māori youth in Northland, New Zealand.

BACKGROUND

The population in Northland is predominantly Māori and is one of New Zealand's most deprived populations. Māori youth have the highest youth suicide rate in the developed world and elevated numbers of youth displaying mental health issues and/or risk behaviours are of grave national concern. Like Indigenous peoples worldwide, inequities persist for Māori youth accessing and engaging with healthcare services.

DESCRIPTION

Taking services out to Māori youth in remote and isolated areas, Northland's youth specialist nurses are reducing some barriers to accessing health care. The youth version of the Case-finding and Help Assessment Tool is a New Zealand-developed, e-screening tool for youth psychosocial issues, facilitating comprehensive assessment and brief intervention delivery.

DISCUSSION

Early detection of, and timely intervention for, mental health and risk behaviours can significantly improve health outcomes in youth. However, for this to happen barriers preventing youth from accessing appropriate care need to be overcome.

CONCLUSION

Youth specialist nurses could improve access to care for youth from ethnic minorities, rural and isolated regions, and areas of high deprivation without overwhelming the medical profession.

IMPLICATIONS FOR NURSING POLICY

Specialist nurses are trained and empowered to practice at the top of their scope. With general practitioner oversight and standing order sign off specialist nurses can work autonomously to improve access to health services, without increasing the workload of doctors.

IMPLICATIONS FOR NURSING PRACTICE

Encouraging continuous self-reflection of the nurse's effectiveness in meeting patient needs, holistically and culturally, facilitates the provision of accessible care that is patient-centred and culturally safe.

A single-cell hematopoietic landscape resolves 8 lineage trajectories and defects in Kit mutant mice

Hematopoietic stem and progenitor cells (HSPCs) maintain the adult blood system, and their dysregulation causes a multitude of diseases. However, the differentiation journeys toward specific hematopoietic lineages remain ill defined, and system-wide disease interpretation remains challenging. Here, we have profiled 44 802 mouse bone marrow HSPCs using single-cell RNA sequencing to provide a comprehensive transcriptional landscape with entry points to 8 different blood lineages (lymphoid, megakaryocyte, erythroid, neutrophil, monocyte, eosinophil, mast cell, and basophil progenitors). We identified a common basophil/mast cell bone marrow progenitor and characterized its molecular profile at the single-cell level. Transcriptional profiling of 13 815 HSPCs from the c-Kit mutant (W41/W41) mouse model revealed the absence of a distinct mast cell lineage entry point, together with global shifts in cell type abundance. Proliferative defects were accompanied by reduced Myc expression. Potential compensatory processes included upregulation of the integrated stress response pathway and downregulation of proapoptotic gene expression in erythroid progenitors, thus providing a template of how large-scale single-cell transcriptomic studies can bridge between molecular phenotypes and quantitative population changes.

What services are available for the treatment of transsexuals in Great Britain?

AIMS AND METHOD

We conducted a questionnaire survey of all 120 health authorities and boards responsible for the commissioning of services for the assessment and treatment of transsexual people in England, Scotland and Wales, in order to identify the nature of the input offered and assess conformity to current international standards of care.

RESULTS

Eighty-two per cent of the commissioning authorities responded and confirmed that most health authorities/boards provide a full service for the treatment of transsexuals, although this would be delivered at a local level in only 20% of cases. However, 11 commissioning authorities gave confused and inaccurate responses and three other health authorities appear to hold views on the commissioning of these specialist services that are not in keeping with the current legal situation and a recent High Court ruling, which establishes the right of transsexual people to NHS assessment and treatment.

CLINICAL IMPLICATIONS

There are discrepancies in prioritisation and provision of clinical services for this group that are not standard across Great Britain.

Management of sulfonylurea-treated monogenic diabetes in pregnancy: implications of placental glibenclamide transfer

The optimum treatment for HNF1A/HNF4A maturity-onset diabetes of the young and ATP-sensitive potassium (K_ATP ) channel neonatal diabetes, outside pregnancy, is sulfonylureas, but there is little evidence regarding the most appropriate treatment during pregnancy. Glibenclamide has been widely used in the treatment of gestational diabetes, but recent data have established that glibenclamide crosses the placenta and increases risk of macrosomia and neonatal hypoglycaemia. This raises questions about its use in pregnancy. We review the available evidence and make recommendations for the management of monogenic diabetes in pregnancy. Due to the risk of stimulating increased insulin secretion in utero, we recommend that in women with HNF1A/ HNF4A maturity-onset diabetes of the young, those with good glycaemic control who are on a sulfonylurea per conception either transfer to insulin before conception (at the risk of a short-term deterioration of glycaemic control) or continue with sulfonylurea (glibenclamide) treatment in the first trimester and transfer to insulin in the second trimester. Early delivery is needed if the fetus inherits an HNF4A mutation from either parent because increased insulin secretion results in ~800-g weight gain in utero, and prolonged severe neonatal hypoglycaemia can occur post-delivery. If the fetus inherits a K_ATP neonatal diabetes mutation from their mother they have greatly reduced insulin secretion in utero that reduces fetal growth by ~900 g. Treating the mother with glibenclamide in the third trimester treats the affected fetus in utero, normalising fetal growth, but is not desirable, especially in the high doses used in this condition, if the fetus is unaffected. Prospective studies of pregnancy in monogenic diabetes are needed.

Comparative genomics of Eucalyptus and Corymbia reveals low rates of genome structural rearrangement

BACKGROUND

Previous studies suggest genome structure is largely conserved between Eucalyptus species. However, it is unknown if this conservation extends to more divergent eucalypt taxa. We performed comparative genomics between the eucalypt genera Eucalyptus and Corymbia. Our results will facilitate transfer of genomic information between these important taxa and provide further insights into the rate of structural change in tree genomes.

RESULTS

We constructed three high density linkage maps for two Corymbia species (Corymbia citriodora subsp. variegata and Corymbia torelliana) which were used to compare genome structure between both species and Eucalyptus grandis. Genome structure was highly conserved between the Corymbia species. However, the comparison of Corymbia and E. grandis suggests large (from 1-13 MB) intra-chromosomal rearrangements have occurred on seven of the 11 chromosomes. Most rearrangements were supported through comparisons of the three independent Corymbia maps to the E. grandis genome sequence, and to other independently constructed Eucalyptus linkage maps.

CONCLUSIONS

These are the first large scale chromosomal rearrangements discovered between eucalypts. Nonetheless, in the general context of plants, the genomic structure of the two genera was remarkably conserved; adding to a growing body of evidence that conservation of genome structure is common amongst woody angiosperms.

Balancing water-quality threats from nutrients and production in Australian and New Zealand dairy farms under low profit margins

The loss of nitrogen (N) and phosphorus (P) from dairy-farmed land can impair water quality. Efforts to curtail these losses in Australia and New Zealand (Australasia) have involved a mixture of voluntary and regulatory approaches. In the present paper, we summarise the losses of N and P from Australasian dairy farms, examine the policy drivers used for mitigating losses and evaluate the effectiveness of contrasting approaches to implementing mitigations. Median losses for N and P were 27 and 1.6 kg/ha.year respectively, with a wide range of variation (3–153 kg N/ha.year and 0.3–69 kg P/ha.year) caused by a complex array of climate, soil types, flow paths, nutrient surpluses and land management factors. This complexity, coupled with the variable implementation of measures to mitigate losses, means that many voluntary programs to decrease losses have had uncertain or limited success. Although there is little or no formal regulation in Australia, regulation exists in New Zealand that requires regional authorities to implement the best strategy to improve water quality according to regional-specific characteristics. In testing a generalised approach to mitigation (priority given to those that are easy to implement) in four regions in New Zealand, we found that P could be mitigated quite cheaply, but N reductions required more measures, some of which are costly. Conversely, prioritising on the basis of mitigation cost-effectiveness for a specific nutrient will lead to more rapid reductions in losses of the target nutrient, but with fewer co-benefits for the non-target nutrient or other water pollutants, such as faecal microorganisms and sediment. This information will assist farmers in deciding how to meet a catchment target at least cost.

Identification of novel regulators of developmental hematopoiesis using Endoglin regulatory elements as molecular probes

Enhancers are the primary determinants of cell identity, and specific promoter/enhancer combinations of Endoglin (ENG) have been shown to target blood and endothelium in the embryo. Here, we generated a series of embryonic stem cell lines, each targeted with reporter constructs driven by specific promoter/enhancer combinations of ENG, to evaluate their discriminative potential and value as molecular probes of the corresponding transcriptome. The Eng promoter (P) in combination with the -8/+7/+9-kb enhancers, targeted cells in FLK1 mesoderm that were enriched for blast colony forming potential, whereas the P/-8-kb enhancer targeted TIE2+/c-KIT+/CD41- endothelial cells that were enriched for hematopoietic potential. These fractions were isolated using reporter expression and their transcriptomes profiled by RNA-seq. There was high concordance between our signatures and those from embryos with defects at corresponding stages of hematopoiesis. Of the 6 genes that were upregulated in both hemogenic mesoderm and hemogenic endothelial fractions targeted by the reporters, LRP2, a multiligand receptor, was the only gene that had not previously been associated with hematopoiesis. We show that LRP2 is indeed involved in definitive hematopoiesis and by doing so validate the use of reporter gene-coupled enhancers as probes to gain insights into transcriptional changes that facilitate cell fate transitions.

Type 1 Diabetes Genetic Risk Score: A Novel Tool to Discriminate Monogenic and Type 1 Diabetes

Distinguishing patients with monogenic diabetes from those with type 1 diabetes (T1D) is important for correct diagnosis, treatment, and selection of patients for gene discovery studies. We assessed whether a T1D genetic risk score (T1D-GRS) generated from T1D-associated common genetic variants provides a novel way to discriminate monogenic diabetes from T1D. The T1D-GRS was highly discriminative of proven maturity-onset diabetes of young (MODY) (n = 805) and T1D (n = 1,963) (receiver operating characteristic area under the curve 0.87). A T1D-GRS of >0.280 (>50th T1D centile) was indicative of T1D (94% specificity, 50% sensitivity). We then analyzed the T1D-GRS of 242 white European patients with neonatal diabetes (NDM) who had been tested for all known NDM genes. Monogenic NDM was confirmed in 90, 59, and 8% of patients with GRS <5th T1D centile, 50-75th T1D centile, and >75th T1D centile, respectively. Applying a GRS 50th T1D centile cutoff in 48 NDM patients with no known genetic cause identified those most likely to have a novel monogenic etiology by highlighting patients with probable early-onset T1D (GRS >50th T1D centile) who were diagnosed later and had less syndromic presentation but additional autoimmune features compared with those with proven monogenic NDM. The T1D-GRS is a novel tool to improve the use of biomarkers in the discrimination of monogenic diabetes from T1D.

Ten years of the national genetic diabetes nurse network: a model for the translation of genetic information into clinical care

Increasing technological advances have resulted in the recognition of a range of genetic conditions not traditionally seen by clinical genetics teams. This has implications for the education of other healthcare professionals who may have insufficient knowledge to identify or support families with these conditions. The national genetic diabetes nurse (GDN) project, which trains diabetes specialist nurses (DSNs), was started in 2002 to increase awareness of monogenic diabetes among healthcare professionals across the UK. This paper describes the development and evaluation of the first 10 years of this project, indicating that GDNs have increased diagnostic referral rates and supported local families through diagnosis and treatment changes across the UK. The GDN project has proved an effective, innovative means of disseminating new genetic information from a centre of excellence and is suggested as a model for the successful and rapid dissemination of genetic information into routine clinical care in other conditions.

Urinary C-peptide creatinine ratio detects absolute insulin deficiency in Type 2 diabetes

AIMS

To determine the prevalence and clinical characteristics of absolute insulin deficiency in long-standing Type 2 diabetes, using a strategy based on home urinary C-peptide creatinine ratio measurement.

METHODS

We assessed the urinary C-peptide creatinine ratios, from urine samples taken at home 2 h after the largest meal of the day, in 191 insulin-treated subjects with Type 2 diabetes (diagnosis age ≥45 years, no insulin in the first year). If the initial urinary C-peptide creatinine ratio was ≤0.2 nmol/mmol (representing absolute insulin deficiency), the assessment was repeated. A standardized mixed-meal tolerance test with 90-min stimulated serum C-peptide measurement was performed in nine subjects with a urinary C-peptide creatinine ratio ≤ 0.2 nmol/mmol (and in nine controls with a urinary C-peptide creatinine ratio >0.2 nmol/mmol) to confirm absolute insulin deficiency.

RESULTS

A total of 2.7% of participants had absolute insulin deficiency confirmed by a mixed-meal tolerance test. They were identified initially using urinary C-peptide creatinine ratio: 11/191 subjects (5.8%) had two consistent urinary C-peptide creatinine ratios ≤ 0.2 nmol/mmol; 9 of these 11 subjects completed a mixed-meal tolerance test and had a median stimulated serum C-peptide of 0.18 nmol/l. Five of these 9 had stimulated serum C-peptide <0.2 nmol/l and 9/9 subjects with urinary C-peptide creatinine ratio >0.2 had endogenous insulin secretion confirmed by the mixed-meal tolerance test. Compared with subjects with a urinary C-peptide creatinine ratio >0.2 nmol/mmol, those with confirmed absolute insulin deficiency had a shorter time to insulin treatment (median 2.5 vs. 6 years, P=0.005) and lower BMI (25.1 vs. 29.1 kg/m(2) , P=0.04). Two out of the five patients with absolute insulin deficiency were glutamic acid decarboxylase autoantibody-positive.

CONCLUSIONS

Absolute insulin deficiency may occur in long-standing Type 2 diabetes, and cannot be reliably predicted by clinical features or autoantibodies. Absolute insulin deficiency in Type 2 diabetes may increase the risk of hypoglycaemia and ketoacidosis, as in Type 1 diabetes. Its recognition should help guide treatment, education and management. The urinary C-peptide creatinine ratio is a practical non-invasive method to aid detection of absolute insulin deficiency, with a urinary C-peptide creatinine ratio > 0.2 nmol/mmol being a reliable indicator of retained endogenous insulin secretion.

Improved genetic testing for monogenic diabetes using targeted next-generation sequencing

AIMS/HYPOTHESIS

Current genetic tests for diagnosing monogenic diabetes rely on selection of the appropriate gene for analysis according to the patient's phenotype. Next-generation sequencing enables the simultaneous analysis of multiple genes in a single test. Our aim was to develop a targeted next-generation sequencing assay to detect mutations in all known MODY and neonatal diabetes genes.

METHODS

We selected 29 genes in which mutations have been reported to cause neonatal diabetes, MODY, maternally inherited diabetes and deafness (MIDD) or familial partial lipodystrophy (FPLD). An exon-capture assay was designed to include coding regions and splice sites. A total of 114 patient samples were tested--32 with known mutations and 82 previously tested for MODY (n = 33) or neonatal diabetes (n = 49) but in whom a mutation had not been found. Sequence data were analysed for the presence of base substitutions, small insertions or deletions (indels) and exonic deletions or duplications.

RESULTS

In the 32 positive controls we detected all previously identified variants (34 mutations and 36 polymorphisms), including 55 base substitutions, ten small insertions or deletions and five partial/whole gene deletions/duplications. Previously unidentified mutations were found in five patients with MODY (15%) and nine with neonatal diabetes (18%). Most of these patients (12/14) had mutations in genes that had not previously been tested.

CONCLUSIONS/INTERPRETATION

Our novel targeted next-generation sequencing assay provides a highly sensitive method for simultaneous analysis of all monogenic diabetes genes. This single test can detect mutations previously identified by Sanger sequencing or multiplex ligation-dependent probe amplification dosage analysis. The increased number of genes tested led to a higher mutation detection rate.

Islet autoantibodies can discriminate maturity-onset diabetes of the young (MODY) from Type 1 diabetes

AIM

Maturity-onset diabetes of the young is a monogenic form of familial, young-onset diabetes. It is rare (∼1% diabetes) and may be misdiagnosed as Type 1 diabetes and inappropriately treated with insulin. Type 1 diabetes is characterized by the presence of islet autoantibodies, including glutamate decarboxylase (GAD) and islet antigen-2 (IA-2) antibodies. The prevalence of islet autoantibodies is unknown in maturity-onset diabetes of the young and may have the potential to differentiate this form of diabetes from Type 1 diabetes. The aim of this study was to determine the prevalence of GAD and IA-2 antibodies in patients with maturity-onset diabetes of the young and Type 1 diabetes.

METHODS

We measured plasma GAD and IA-2 antibodies in 508 patients with the most common forms of maturity-onset diabetes of the young (GCK: n = 227; HNF1A: n = 229; HNF4A: n = 52) and 98 patients with newly diagnosed Type 1 diabetes (diagnosed < 6 months). Autoantibodies were considered positive if ≥ 99th centile of 500 adult control subjects.

RESULTS

GAD and/or IA-2 antibodies were present in 80/98 (82%) patients with Type 1 diabetes and 5/508 (< 1%) patients with maturity-onset diabetes of the young. In the cohort with Type 1 diabetes, both GAD and IA-2 antibodies were detected in 37.8% of patients, GAD only in 24.5% and IA-2 only in 19.4%. All five patients with maturity-onset diabetes of the young with detectable antibodies had GAD antibodies and none had detectable IA-2 antibodies.

CONCLUSION

The prevalence of GAD and IA-2 antibodies in maturity-onset diabetes of the young is the same as in control subjects (< 1%). The finding of islet autoantibodies, especially IA-2 antibodies, makes the diagnosis of maturity-onset diabetes of the young very unlikely and genetic testing should only be performed if other clinical characteristics strongly suggest this form of diabetes rather than Type 1 diabetes. This supports routine islet autoantibody testing before proceeding to more expensive molecular genetic testing.

Neutral metallated and meso-substituted porphyrins as antimicrobial agents against gram-positive pathogens

Staphylococcus aureus is a bacterial pathogen that causes severe infections among humans. The increasing emergence of antibiotic resistance necessitates the development of new strategies to combat the spread of disease. One approach is photodynamic inactivation using porphyrin photosensitizers, which generate superoxide and other radicals in the presence of light, causing cell death via the oxidation of proteins and lipids. In this study, we analyzed a novel library of meso-substituted and metallated porphyrins for activity against multidrug-resistant S. aureus. From a library of 251 compounds, 51 showed antimicrobial activity, in three discrete classes of activity: those that functioned only in light, those that had toxicity only in darkness, and those that displayed activity regardless of illumination. We further demonstrated the broad-spectrum activity of these compounds against a variety of pathogens, including Bacillus anthracis, Enterococcus faecalis, and Escherichia coli. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) analyses of lead compounds (XPZ-263 and XPZ-271) revealed strong activity and killing towards methicillin-resistant S. aureus (MRSA) strains. An analysis of mutation frequencies revealed low incidences of resistance to lead compounds by E. coli and MRSA. Finally, an exploration of the underlying mechanism of action suggests that these compounds do not depend solely upon light-induced radical generation for toxicity, highlighting their potential for clinical applications.

Peripheral blood dendritic cell subtypes are significantly elevated in subjects with asthma

BACKGROUND

Dendritic cells (DCs) are crucial for the processing of antigens, T lymphocyte priming and the development of asthma and allergy. Smokers with asthma display altered therapeutic behaviour and a reduction in endobronchial DC CD83 expression compared with non-smokers with asthma. No information is available on the impact of smoking on peripheral blood DC profiles.

OBJECTIVE

Determine peripheral blood DC profiles in subjects with and without asthma with differing smoking histories.

METHODS

Forty-three asthmatics (17 smokers, nine ex-smokers and 17 never-smokers) and 16 healthy volunteers (nine smokers and seven never-smokers) were recruited. Spirometry, exhaled nitric oxide and venesection was performed. DC elution was by flow cytometry via the expression of DC surface markers [plasmacytoid (pDC) (BDCA-2, CD303), type 1 conventional (cDC) (BDCA-1, CD1c), and type 2 cDC (BDCA-3, CD141)].

RESULTS

Subjects with asthma displayed increases in all DC subtypes compared with normal never-smokers: [type 1 cDCs - asthma [median% (IQR)]: 0.59% (0.41, 0.74), normal never-smokers: 0.35% (0.26, 0.43), P=0.013]; type 2 cDCs - asthma: 0.04% (0.02, 0.06), normal never-smokers: 0.02% (0.01, 0.03), P=0.008 and pDCs - asthma: 0.32% (0.27, 0.46), normal never-smokers: 0.22% (0.17, 0.31), P=0.043, and increased pDC and type 1 cDCs compared with normal smokers. Smoking did not affect DC proportions in asthma. Cigarette smoking reduced pDC proportions in normal subjects [normal never-smokers: 0.22% (0.17, 0.31); normal smokers: 0.09% (0.08, 0.15), P=0.003].

CONCLUSIONS AND CLINICAL RELEVANCE

This study shows for the first time that subjects with asthma display a large increase in peripheral blood DC proportions. Cigarette smoking in asthma did not affect the peripheral blood DC profile but did suppress pDC proportions in non-asthmatic subjects. Asthma is associated with a significant increase in circulating DCs, reflecting increased endobronchial levels and the importance of DCs to the development and maintenance of asthma. (Clinical trials.gov identifier: NCT00411320)

Stopping insulin injections following genetic testing in diabetes: impact on identity

BACKGROUND

Identification of genes causing monogenic diabetes has led to treatment change, from insulin to sulphonylureas for many previously considered insulin dependent. Changing treatment has led to improved glycaemic control and quality of life; however, the impact of a genetic diagnosis and consequent treatment change on identity has not been explored.

METHODS

This paper examines the experiences of patients and their families using Bury's theory of biographical disruption in chronic illness to offer insight and comparison with the disruption caused by treatment change following genetic testing. This qualitative study is a longitudinal follow-up using in-depth interviews over time. Thirty-one individuals were interviewed following genetic testing and again 12 months later.

RESULTS

Key themes identified were: (i) embodied practices of diabetes; (ii) perceived identity on insulin; (iii) 'holding on' to insulin treatment; (iv) challenges and benefits of treatment change; (v) identity reconstruction. Participants were categorized into 'Transferers' who successfully transferred to sulphonylureas, 'Attempters' who attempted transfer but recommenced insulin and 'Decliners' who declined treatment change.

CONCLUSIONS

Injecting insulin was integral to participants' lives and fundamental to their identity. Embodied practices of diabetes were deeply embedded in self identity; the possibility of stopping insulin injections was a major challenge contradicting previous beliefs and led to identity reconstruction.

Clinical audit: management of acute severe asthma in west Glasgow

BACKGROUND

The U.K. has 75,000 hospital admissions and over 1500 deaths from asthma annually. The British Thoracic Society (BTS) guidelines represent the recognised standard for acute asthma management. We assessed the degree of conformity with these guidelines in an acute medical unit.

METHODOLOGY

Data from consecutive admissions were collected prospectively. Practice was audited in October December 2005 and October 2006 - January 2007. Between cycles an educational programme was instigated,

RESULTS

Fifty-eight patients were included. Clinical parameters were well recorded in both cycles. Peak expiratory flow was consistently under-recorded (72% at admission; 67% in monitoring). in monitoring). Severity assessment was documented at 55% and 66% in cycle one and two respectively. Of these, the assessment was incorrect in 33% in cycle one and 21% in cycle two. All misclassifications of severity were underestimates. All life-threatening attacks were not identified. No improvement occurred between cycles. Overall, 60% of patients were inappropriately treated according to BTS guidelines, 40% due to under-treatment. Under-treatment occurred more frequently in cycle two compared with cycle one (57% vs. 24%, p = 0.007), predominantly due to inadequate treatment of life-threatening asthma.

CONCLUSION

Management of acute asthma in a large, urban teaching hospital is suboptimal. Educational intervention failed to improve care; more comprehensive strategies are required.

Increased all-cause and cardiovascular mortality in monogenic diabetes as a result of mutations in the HNF1A gene

AIMS

To investigate all-cause and cardiovascular mortality in subjects with diabetes caused by a mutation in the hepatocyte nuclear factor 1alpha gene (HNF1A).

METHODS

We identified 39 British families with HNF1A mutations. Consenting individuals were asked details of age and cause of death of parents and siblings. Copies of death certificates were requested from the family or were obtained via the Offices for National Statistics.

RESULTS

Data were collated on 241 control subjects and 153 mutation carriers. Of those who died, 66% of mutation carriers died from a cardiovascular-related illness compared with 43% of control subjects (P = 0.02). Family members with HNF1A mutations died at a younger age than familial control subjects [all-cause hazard ratio, adjusting for sex and smoking status: 1.9 (95% confidence interval 1.2, 2.9, P = 0.006; cardiovascular hazard ratio: 2.3, confidence interval 1.3, 4.2, P = 0.006)].

CONCLUSIONS

We have shown that individuals known to have diabetes caused by a mutation in the HNF1A gene have an increased risk of cardiovascular mortality compared with their unaffected family members. As with other forms of diabetes, consideration should be given to early statin therapy despite a seemingly protective lipid profile.

A genetic diagnosis of HNF1A diabetes alters treatment and improves glycaemic control in the majority of insulin-treated patients

BACKGROUND AND AIMS

Hepatocyte nuclear factor-1 alpha (HNF1A) gene mutations are the commonest cause of monogenic diabetes, but patients are often misdiagnosed as having Type 1 diabetes and started on insulin treatment. Patients with HNF1A diabetes are particularly sensitive to the glucose-lowering effect of sulphonylureas, which are the pharmacological treatment of choice. We aimed to assess if patients do change from insulin to sulphonylurea treatment when HNF1A diabetes is confirmed and the impact of this treatment change on long-term glycaemic control.

METHODS

We investigated the clinical course of 43 patients who were insulin treated from diagnosis for a median 4 years (range 1-14) before an HNF1A gene mutation was identified.

RESULTS

Thirty-four patients (79%) stopped insulin following genetic testing and transferred to sulphonylureas. Twenty-four of them (71%) remained off insulin at a median 39 months (range 17-90) post-transfer. The 10 patients who recommenced insulin had a trend towards a longer duration of diabetes (18 vs. 7 years, P = 0.066) compared with those remaining on tablets. The median glycated haemoglobin (HbA(1c)) was good (6.9%; interquartile range 6.3-8.0%) in the patients who remained off insulin and 19/24 patients (79%) achieved HbA(1c) < 7.5% or improved their pre-genetic diagnosis HbA(1c) by > 1.0%. Transfer off insulin was not attempted in eight patients: one of these was planning pregnancy and two chose to remain on insulin.

CONCLUSION

In this observational study we found that a molecular genetic diagnosis of HNF1A diabetes does alter treatment in clinical practice, with 79% attempting transfer to sulphonylureas. Transfer to sulphonylureas was successful in the majority of patients without deterioration in glycaemic control.

Peroxidase activity of cytochrome C facilitates the protoporphyrinogen oxidase reaction

Protoporphyrinogen oxidase (PPO) catalyzes the penultimate reaction in heme biosynthesis. The 'oxygen dependent' form of this enzyme can utilize three molecules of oxygen as electron acceptors in the reaction. In the current study, the ability of cytochrome c to serve as an electron acceptor for PPO was examined. Cytochrome c was found to enhance the catalytic rate of Drosophila melanogaster PPO under reduced oxygen conditions, and cytochrome c became reduced during PPO catalysis. Further kinetic analysis under anaerobic conditions revealed that hydrogen peroxide, a byproduct of the PPO reaction, is required for this rate enhancement to occur. This suggests that the generation of free radicals via the peroxidase activity of cytochrome c plays a part in this rate enhancement, rather than cytochrome c acting as an electron acceptor for the PPO reaction. Given the abundance of cytochrome c in the intermembrane space of mitochondria, the cellular location of PPO, this process may potentially impact on the synthesis of heme in vivo particularly in conditions of low oxygen or hypoxia.

Pregnancy outcome in patients with raised blood glucose due to a heterozygous glucokinase gene mutation

AIM

To assess determinants of fetal growth in the offspring of pregnant women with hyperglycaemia due to a heterozygous glucokinase (GCK) gene mutation.

METHODS

Details of gestational age at delivery, fetal birth weight and maternal antenatal treatment were collected from patients and retrospective case note review of 82 offspring born to 42 women with GCK gene mutations and 31 offspring born to 13 unaffected normoglycaemic women with an affected partner. Fetal genotype was determined using direct sequencing from either a mouth swab or a blood sample.

RESULTS

In mothers with GCK mutations, non-mutation-carrying offspring were heavier than mutation-carrying offspring (corrected birth weight 3.9 +/- 0.6 vs. 3.2 +/- 0.8 kg; P < 0.001) and more likely to be macrosomic (> 4.0 kg; 39% vs. 7%, P = 0.001). There was no difference in corrected birth weight between offspring of insulin- and diet-treated women (3.7 +/- 0.7 vs. 3.8 +/- 0.6 kg; P = 0.1), although insulin-treated mothers delivered earlier (37.5 +/- 1.7 vs. 38.9 +/- 2.3 weeks; P < 0.001) due to increased obstetric intervention.

CONCLUSIONS

Offspring of women with GCK mutations are at increased risk of macrosomia and its obstetric consequences. Fetal birth weight is predominantly altered by fetal genotype and not treatment of maternal hyperglycaemia with insulin. This probably reflects the large effect of a fetal GCK mutation on fetal insulin secretion and the difficulty in reducing the regulated maternal glycaemia caused by a glucose sensing defect in people with GCK mutations.

Assessing the effectiveness of actions to mitigate nutrient loss from agriculture: a review of methods

Diffuse nutrient loss from agriculture is degrading surface and groundwater quality throughout Europe, leaving water bodies at risk of not reaching targets set by the Water Framework Directive (WFD). Mitigation methods to reduce diffuse agricultural nutrient loss need to be implemented where water bodies have been identified as at risk of not reaching good status by 2015. Though the effectiveness of individual mitigation methods has usually been assessed in controlled experiments, it is necessary to quantify impact under a wider range of environmental and agricultural conditions and at the catchment scale to ensure that action taken now will be sufficient to meet WFD targets. Due to catchment buffering and long transit times (>50 years), it is unlikely that responses to intervention will be observed by 2015 in many water bodies. In this review, we compare the attributes and usefulness of different approaches (direct measurement, nutrient budgeting, risk assessment and modelling) to assess the efficacy of actions to mitigate sources and transport of nitrogen (N) and phosphorus (P) from agricultural land to water. Modelling and 'measured changes in farm activity' through budgeting avoid the time lags associated with direct measurement and enable rapid evaluations of different options before implementation. Budgeting approaches using on-farm data also provide a simpler, more communicable means of assessment but currently fail to consider the timing and transport aspects of mitigation and assume a direct causal relationship between potential and actual nutrient loss. Risk assessment and modelling applications are potentially more comprehensive and able to better reflect choice of mitigation at a range of scales, but assessments demand increased availability of data, and there is a large degree of uncertainty associated with their spatial and temporal dimensions which is difficult to validate adequately. The failings of individual approaches suggest that these assessment methods should be integrated to maximise their potential usefulness and positive attributes. This will enable nutrient inputs to be utilised most efficiently at broad scales and site specific actions to reduce nutrient transport and delivery can be targeted most cost-effectively at smaller scales. Such an integrated approach will also more effectively engage and involve the farmer in what must be an iterative process.

Equine herpesvirus-1-specific interferon gamma (IFNgamma) synthesis by peripheral blood mononuclear cells in thoroughbred horses

REASONS FOR PERFORMING STUDY

An assay has been developed that measures EHV-1 specific interferon gamma synthesis (IFNgamma), a cytokine produced following the activation of memory T lymphocytes and therefore a measure of cell mediated immunity. The method requires validation in the field.

OBJECTIVES

To measure the frequency of EHV-1 specific, IFNgamma synthesising peripheral blood mononuclear cells (PBMC) in a population of Thoroughbred horses, and examine its relationship with age, gender, premises and history of vaccination or field infection with EHV-1.

METHODS

Lymphocytes from 200 Thoroughbred horses were stimulated with EHV-1 in vitro, and IFNgamma detected using a monoclonal antibody and indirect immunofluorescence. Percent positive cells were enumerated by flow cytometric analysis and the results described and compared statistically between groups.

RESULTS

The frequency of IFNgamma+ PBMC was significantly higher in animals age >5 years compared with 2-4 years, in females vs. males, on stud farms vs. training yards and following vaccination of 2-year-olds with inactivated virus compared with nonvaccinates. Age strongly confounded all these associations and care must therefore be taken interpreting these results. Mares exposed to a field infection with EHV-1 also had higher frequencies of IFNgamma+ PBMC than other vaccinated horses.

CONCLUSIONS

The frequency of EHV-1 specific, IFNgama+ PBMC among the sample Thoroughbred population was diverse but lowest in young, unvaccinated horses-in-training.

POTENTIAL RELEVANCE

The frequency of EHV-1 specific lymphocytes synthesising IFNgamma in this population may be associated with its susceptibility to infection with this virus. This easy technique may be applied to monitor the antigenicity of vaccines and their effectiveness at stimulating cellular immunity.