GDF15 linked to maternal risk of nausea and vomiting during pregnancy.

GDF15, a hormone acting on the brainstem, has been implicated in the nausea and vomiting of pregnancy, including its most severe form, hyperemesis gravidarum (HG), but a full mechanistic understanding is lacking1-4. Here we report that fetal production of GDF15 and maternal sensitivity to it both contribute substantially to the risk of HG. We confirmed that higher GDF15 levels in maternal blood are associated with vomiting in pregnancy and HG. Using mass spectrometry to detect a naturally labelled GDF15 variant, we demonstrate that the vast majority of GDF15 in the maternal plasma is derived from the feto-placental unit. By studying carriers of rare and common genetic variants, we found that low levels of GDF15 in the non-pregnant state increase the risk of developing HG. Conversely, women with ß-thalassaemia, a condition in which GDF15 levels are chronically high5, report very low levels of nausea and vomiting of pregnancy. In mice, the acute food intake response to a bolus of GDF15 is influenced bi-directionally by prior levels of circulating GDF15 in a manner suggesting that this system is susceptible to desensitization. Our findings support a putative causal role for fetally derived GDF15 in the nausea and vomiting of human pregnancy, with maternal sensitivity, at least partly determined by prepregnancy exposure to the hormone, being a major influence on its severity. They also suggest mechanism-based approaches to the treatment and prevention of HG.

Predictors of type 2 diabetes remission in the Diabetes Remission Clinical Trial (DiRECT).

AIM: To identify predictors of type 2 diabetes remission in the intervention arm of DiRECT (Diabetes Remission Clinical Trial). METHODS: Participants were aged 20-65 years, with type 2 diabetes duration of <6 years and BMI 27-45 kg/m2 , and were not receiving insulin. Weight loss was initiated by total diet replacement (825-853 kcal/day, 3-5 months, shakes/soups), and weight loss maintenance support was provided for 2 years. Remissions (HbA1c <48 mmol/mol [<6.5%], without antidiabetes medications) in the intervention group (n = 149, mean age 53 years, BMI 35 kg/m2 ) were achieved by 68/149 participants (46%) at 12 months and by 53/149 participants (36%) at 24 months. Potential predictors were examined by logistic regression analyses, with adjustments for weight loss and effects independent of weight loss. RESULTS: Baseline predictors of remission at 12 and 24 months included being prescribed fewer antidiabetes medications, having lower triglyceride and gamma-glutamyl transferase levels, and reporting better quality of life with less anxiety/depression. Lower baseline HbA1c was a predictor at 12 months, and older age and male sex were predictors at 24 months. Being prescribed antidepressants predicted non-remission. Some, but not all effects were explained by weight loss. Weight loss was the strongest predictor of remission at 12 months (adjusted odds ratio per kg weight loss 1.24, 95% CI 1.14, 1.34; P < 0.0001) and 24 months (adjusted odds ratio 1.23, 95% CI 1.13, 1.35; P <0.0001). Weight loss in kilograms and percentage weight loss were equally good predictors. Early weight loss and higher programme attendance predicted more remissions. Baseline BMI, fasting insulin, fasting C-peptide and diabetes duration did not predict remission. CONCLUSIONS: Other than weight loss, most predictors were modest, and not sufficient to identify subgroups for which remission was not a worthwhile target.

Dietary fat and total energy intake modifies the association of genetic profile risk score on obesity: evidence from 48 170 UK Biobank participants.

BACKGROUND: Obesity is a multifactorial condition influenced by both genetics and lifestyle. The aim of this study was to investigate whether the association between a validated genetic profile risk score for obesity (GPRS-obesity) and body mass index (BMI) or waist circumference (WC) was modified by macronutrient intake in a large general population study. METHODS: This study included cross-sectional data from 48 170 white European adults, aged 37-73 years, participating in the UK Biobank. Interactions between GPRS-obesity and macronutrient intake (including total energy, protein, fat, carbohydrate and dietary fibre intake) and its effects on BMI and WC were investigated. RESULTS: The 93-single-nucleotide polymorphism (SNP) GPRS was associated with a higher BMI (ß: 0.57 kg m-2 per s.d. increase in GPRS (95% confidence interval: 0.53-0.60); P=1.9 × 10-183) independent of major confounding factors. There was a significant interaction between GPRS and total fat intake (P(interaction)=0.007). Among high-fat-intake individuals, BMI was higher by 0.60 (0.52, 0.67) kg m-2 per s.d. increase in GPRS-obesity; the change in BMI with GPRS was lower among low-fat-intake individuals (ß: 0.50 (0.44, 0.57) kg m-2). Significant interactions with similar patterns were observed for saturated fat intake (high ß: 0.66 (0.59, 0.73) versus low ß: 0.49 (0.42, 0.55) kg m-2, P(interaction)=2 × 10-4) and for total energy intake (high ß: 0.58 (0.51, 0.64) versus low ß: 0.49 (0.42, 0.56) kg m-2, P(interaction)=0.019), but not for protein intake, carbohydrate intake and fibre intake (P(interaction) >0.05). The findings were broadly similar using WC as the outcome. CONCLUSIONS: These data suggest that the benefits of reducing the intake of fats and total energy intake may be more important in individuals with high genetic risk for obesity.

Mallards (Anas platyrhynchos) and wastewater ponds, Part II: Developmental, physiological, morphological and behavioural effects of ingestion of secondary clarified effluent water.

Rather than migrating, mallard ducks may choose to overwinter in northern cities on open-water thermal refuges, such as municipal wastewater treatment ponds, which in Edmonton, Canada, stay ≥10°C during frigid winter months. Refuging mallards spend appreciable time daily on these ponds and hydrate using secondary clarified municipal wastewater (SCEW). We aimed to determine if SCEW ingestion affected mallard health. To this end, we gavaged newly hatched mallards (domesticated Pekin strain) over their first month with SCEW, as well as water representing negative and positive controls (municipal tap water, and the primary active ingredient from birth control pills, 17α-ethinyl estradiol (EE2), respectively). The gavage of SCEW did not affect mass of the body, liver, spleen or heart, but was associated with small increases in beak and wing chord length. In the positive control, EE2 gavage caused similar responses, but also increased tarsus and phallus length. The increases likely owed to the stimulatory effects of estrogenic substances on bone and phallus development. For the biotransformation enzyme CYP2H1, gene expression was numerically increased by both SCEW and EE2. In terms of behavior, SCEW and EE2 gavage reduced two infrequently detected behaviours, pecking and resting alone. Our results suggest that SCEW ingestion would be unlikely to cause any overt health effects in adults, but may evoke subtle, covert effects nevertheless.

Associations between weight change and biomarkers of cardiometabolic risk in South Asians: secondary analyses of the PODOSA trial.

BACKGROUND/OBJECTIVES: The association of weight changes with cardiometabolic biomarkers in South Asians has been sparsely studied. SUBJECTS/METHODS: We measured cardiometabolic biomarkers at baseline and after 3 years in the Prevention of Diabetes and Obesity in South Asians Trial. We investigated the effect of a lifestyle intervention on biomarkers in the randomized groups. In addition, treating the population as a single cohort, we estimated the association between change in weight and change in biomarkers. RESULTS: Complete data were available at baseline and after 3 years in 151 participants. At 3 years, there was an adjusted mean reduction of 1·44 kg (95% confidence interval (95% CI): 0.18-2.71) in weight and 1.59 cm (95% CI: 0.08-3.09) in waist circumference in the intervention arm as compared with the control arm. There was no clear evidence of difference between the intervention and control arms in change of mean value of any biomarker. As a single cohort, every 1 kg weight reduction during follow-up was associated with a reduction in triglycerides (-1.3%, P=0.048), alanine aminotransferase (-2.5%, P=0.032), gamma-glutamyl transferase (-2.2%, P=0.040), leptin (-6.5%, P<0.0001), insulin (-3.7%, P=0.0005), fasting glucose (-0.8%, P=0.0071), 2-h glucose (-2.3%, P=0.0002) and Homeostatic Model Assessment of insulin resistance (HOMA-IR: -4.5%, P=0.0002). There was no evidence of associations with other lipid measures, tissue plasminogen activator, markers of inflammation or blood pressure. CONCLUSIONS: We demonstrate that modest weight decrease in SAs is associated with improvements in markers of total and ectopic fat as well as insulin resistance and glycaemia in South Asians at risk of diabetes. Future trials with more intensive weight change are needed to extend these findings.

Effect of metformin therapy on circulating amino acids in a randomized trial: the CAMERA study.

AIMS: To investigate whether metformin therapy alters circulating aromatic and branched-chain amino acid concentrations, increased levels amino acid concentrations, increased levels of which have been found to predict Type 2 diabetes. METHODS: In the Carotid Atherosclerosis: Metformin for Insulin Resistance (CAMERA) study (NCT00723307), 173 individuals without Type 2 diabetes, but with coronary disease, were randomized to metformin (n=86) or placebo (n=87) for 18 months. Plasma samples, taken every 6 months, were analysed using quantitative nuclear magnetic resonance spectroscopy. Ten metabolites consisting of eight amino acids [three branched-chain (isoleucine, leucine, valine), three aromatic (tyrosine, phenylalanine, histidine) and two other amino acids (alanine, glutamine)], lactate and pyruvate were quantified and analysed using repeated-measures models. On-treatment analyses were conducted to investigate whether amino acid changes were dependent on changes in weight, fat mass or insulin resistance estimated using homeostasis model assessment (HOMA-IR). RESULTS: Tyrosine decreased [-6.1 µmol/l (95% CI -8.5, -3.7); P<0.0001], while alanine [42 umol/l (95% CI 25, 59); P<0.0001] increased in the metformin-treated group compared with the placebo-treated group. Decreases in phenylalanine [-2.0 µmol/l (95% CI -3.6, -0.3); P=0.018] and increases in histidine [2.3 µmol/l (95% CI 0.1, 4.6); P=0.045] were also observed in the metformin group, although these changes were less statistically robust. Changes in these four amino acids were not accounted for by changes in weight, fat mass or HOMA-IR values. Levels of branched-chain amino acids, glutamine, pyruvate and lactate were not altered by metformin therapy. CONCLUSIONS: Metformin therapy results in a sustained and specific pattern of changes in aromatic amino acid and alanine concentrations. These changes are independent of any effects on weight and insulin sensitivity. Any causal link to metformin's unexplained cardiometabolic benefit requires further study.

Fetally-encoded GDF15 and maternal GDF15 sensitivity are major determinants of nausea and vomiting in human pregnancy.

Human pregnancy is frequently accompanied by nausea and vomiting that may become severe and life-threatening, as in hyperemesis gravidarum (HG), the cause of which is unknown. Growth Differentiation Factor-15 (GDF15), a hormone known to act on the hindbrain to cause emesis, is highly expressed in the placenta and its levels in maternal blood rise rapidly in pregnancy. Variants in the maternal GDF15 gene are associated with HG. Here we report that fetal production of GDF15, and maternal sensitivity to it, both contribute substantially to the risk of HG. We found that the great majority of GDF15 in maternal circulation is derived from the feto-placental unit and that higher GDF15 levels in maternal blood are associated with vomiting and are further elevated in patients with HG. Conversely, we found that lower levels of GDF15 in the non-pregnant state predispose women to HG. A rare C211G variant in GDF15 which strongly predisposes mothers to HG, particularly when the fetus is wild-type, was found to markedly impair cellular secretion of GDF15 and associate with low circulating levels of GDF15 in the non-pregnant state. Consistent with this, two common GDF15 haplotypes which predispose to HG were associated with lower circulating levels outside pregnancy. The administration of a long-acting form of GDF15 to wild-type mice markedly reduced subsequent responses to an acute dose, establishing that desensitisation is a feature of this system. GDF15 levels are known to be highly and chronically elevated in patients with beta thalassemia. In women with this disorder, reports of symptoms of nausea or vomiting in pregnancy were strikingly diminished. Our findings support a causal role for fetal derived GDF15 in the nausea and vomiting of human pregnancy, with maternal sensitivity, at least partly determined by pre-pregnancy exposure to GDF15, being a major influence on its severity. They also suggest mechanism-based approaches to the treatment and prevention of HG.

B-type natriuretic peptide and glycaemia: an emerging cardiometabolic pathway?

There is emerging evidence of cross-talk between the myocardium and systemic metabolic pathways. In particular, there is interest in the potential metabolic effects of A-type and B-type natriuretic peptides (ANP and BNP), produced in the myocardial tissue in response to ventricular stretch and cardiac overload. This commentary provides an overview of the evidence that natriuretic peptides promote lipolysis and enhance adiponectin production. In addition, we review new and existing evidence that BNP may directly improve glucose control, or else lower glucose indirectly via enhanced capillary permeability or greater renal excretion. Further investigation of the links between natriuretic peptide and glycaemia would seem important given the potential to reveal novel mechanisms to treat diabetes.

SIB-DOTA: a trifunctional prosthetic group potentially amenable for multi-modal labeling that enhances tumor uptake of internalizing monoclonal antibodies.

A major drawback of internalizing monoclonal antibodies (mAbs) radioiodinated with direct electrophilic approaches is that tumor retention of radioactivity is compromised by the rapid washout of iodo-tyrosine, the primary labeled catabolite for mAbs labeled via this strategy. In our continuing efforts to develop more versatile residualizing labels that could overcome this problem, we have designed SIB-DOTA, a prosthetic labeling template that combines the features of the prototypical, dehalogenation-resistant N-succinimidyl 3-iodobenzoate (SIB) with DOTA, a useful macrocyclic chelator for labeling with radiometals. Herein we describe the synthesis of the unlabeled standard of this prosthetic moiety, its protected tin precursor, and radioiodinated SIB-DOTA. An anti-EGFRvIII-reactive mAb, L8A4 was radiolabeled with [(131)I]SIB-DOTA in 27.1±6.2% (n=2) conjugation yields and its targeting properties to the same mAb labeled with [(125)I]SGMIB both in vitro and in vivo using U87MG·ΔEGFR cells and xenografts were compared. In vitro paired-label internalization assays showed that the intracellular radioactivity from [(131)I]SIB-DOTA-L8A4 was 21.4±0.5% and 26.2±1.1% of initially bound radioactivity at 16 and 24h, respectively. In comparison, these values for [(125)I]SGMIB-L8A4 were 16.7±0.5% and 14.9±1.1%. Similarly, the SIB-DOTA prosthetic group provided better tumor targeting in vivo than SGMIB over 8 d period. These results suggest that SIB-DOTA warrants further evaluation as a residualizing agent for labeling internalizing mAbs including those targeted to EGFRvIII.

Studies on human peripheral blood lymphocytes in vitro. I. Biological and physicochemical properties of the pokeweed mitogen.

The saline extract from the roots of Phytolacca americana (pokeweed) possesses three biological properties; hemagglutinin, leukagglutinin, and mitogen. Fractionation and further purification on calcium phosphate column chromatography revealed that the biologically active substance was eluted in the front moving fraction with 0.05 M phosphate buffer pH 7.5. Analytical separation on polyacrylamide gels in disc electrophoresis yielded a single homogeneous band with an R(f) value of 0.43 containing all three biological activities. This fraction had an ultraviolet absorption spectrum similar to PHA, was stable to both periodate and mercaptoethanol treatment and gave a single band in double diffusion and immunoelectrophoretic analysis against the antibody prepared to the crude PWM saline extract. Absorption studies with red cells or stroma revealed that the hemagglutinin could be selectively removed without significantly altering the mitogen, whereas absorption with leukocytes resulted in loss of both the mitogenic and leukagglutinating activities.

Studies on human peripheral blood lymphocytes in vitro. II. Morphological and biochemical studies on the transformation of lymphocytes by pokeweed mitogen.

A study of the kinetics of RNA and DNA synthesis in PWM-stimulated lymphocytes revealed that RNA synthesis preceded the onset of DNA synthesis by approximately 24 hr and that DNA synthesis and transformation was maximal between 66 to 78 hr. Histochemical and radioautographic studies on PWM stimulated cultures indicated that at 72 hr 50 to 60% of the cell population had been transformed by PWM, and that a distinct cell type bearing cytologic resemblance to the early plasma cell had emerged. The RNA sedimentation profile for newly synthesized RNA in PWM-stimulated cells showed that a large peak of 45 to 50 S material was formed after 24 and 40 hr. PWM thus produces a distinctive transformation of human peripheral blood lymphocytes.

Are elevated circulating intercellular adhesion molecule 1 levels more strongly predictive of diabetes than vascular risk? Outcome of a prospective study in the elderly.

AIMS/HYPOTHESIS: The aim of this prospective study was to determine whether circulating intercellular adhesion molecule (ICAM) 1, as a potential surrogate of 'endothelial activation', is more strongly associated with risk of vascular events than with incident diabetes. METHODS: We related baseline ICAM-1 levels to vascular events (866 CHD and stroke events in 5,685 participants) and incident diabetes (292 in 4,945 without baseline diabetes) in the elderly over 3.2 years of follow-up. RESULTS: ICAM-1 levels correlated positively with triacylglycerol but negatively with LDL- and HDL-cholesterol. ICAM-1 levels were higher in those who developed diabetes (388.6 +/- 1.42 vs 369.4 +/- 1.39 ng/ml [mean+/-SD], p = 0.011) and remained independently associated with new-onset diabetes (HR 1.84, 95% CI 1.26-2.69, p = 0.0015 per unit increase in log[ICAM-1] after adjusting for classical risk factors and C-reactive protein). By contrast, ICAM-1 levels were not significantly (p = 0.40) elevated in those who had an incident vascular event compared with those who remained event-free, and corresponding adjusted risk associations were null (HR 0.98, 95% CI 0.80-1.22, p = 0.89) in analyses adjusted for other risk factors. CONCLUSIONS/INTERPRETATION: We show that elevated ICAM-1 levels are associated with risk of incident diabetes in the elderly at risk, despite no association with incident cardiovascular disease risk. We suggest that perturbations in circulating ICAM-1 levels are aligned more towards diabetes risk.

Approaches to defining day-one competency: a framework for learning veterinary skills.

Competency at graduation, in a variety of physical and attitudinal skills, is an essential outcome measure for courses training veterinary surgeons. The approach adopted by the Royal Veterinary College, London, to identify and define the expected skill competencies required of our veterinary undergraduates by the time of graduation is described. In addition, we demonstrate how this skill set was built into a framework that was aligned with other student learning objectives. This two-year project resulted in the publication of a day-one skills handbook, which was introduced to the college staff and students in 2007.

Associations of dietary protein intake with bone mineral density: An observational study in 70,215 UK Biobank participants.

PURPOSE: Adequate dietary protein intake is important for the maintenance of bone health; however, data in this area is ambiguous with some suggestion that high protein intake can have deleterious effects on bone health. The aim of the current study was to explore the associations of protein intake with bone mineral density (BMD). METHODS: We used baseline data from the UK Biobank (participants aged 40-69 years) to examine the association of protein intake with BMD (measured by ultrasound). These associations were examined, in women (n = 39,066) and men (n = 31,149), after adjustment for socio-demographic and lifestyle confounders and co-morbidities. RESULTS: Protein intake was positively and linearly associated with BMD in women (ß-coefficient 0.010 [95% CI 0.005; 0.015, p < 0.0001]) and men (ß-coefficient 0.008 [95% CI 0.000; 0.015, p = 0.044]); per 1.0 g/kg/day increment in protein intake, independently of socio-demographics, dietary factors and physical activity. CONCLUSIONS: The current data have demonstrated that higher protein intakes are positively associated with BMD in both men and women. This indicates that higher protein intakes may be beneficial for both men and women.

The effects of remote ischaemic preconditioning on coronary artery function in patients with stable coronary artery disease.

BACKGROUND: Remote ischaemic preconditioning (RIPC) is a cardioprotective intervention invoking intermittent periods of ischaemia in a tissue or organ remote from the heart. The mechanisms of this effect are incompletely understood. We hypothesised that RIPC might enhance coronary vasodilatation by an endothelium-dependent mechanism. METHODS: We performed a prospective, randomised, sham-controlled, blinded clinical trial. Patients with stable coronary artery disease (CAD) undergoing elective invasive management were prospectively enrolled, and randomised to RIPC or sham (1:1) prior to angiography. Endothelial-dependent vasodilator function was assessed in a non-target coronary artery with intracoronary infusion of incremental acetylcholine doses (10-6, 10-5, 10-4mol/l). Venous blood was sampled pre- and post-RIPC or sham, and analysed for circulating markers of endothelial function. Coronary luminal diameter was assessed by quantitative coronary angiography. The primary outcome was the between-group difference in the mean percentage change in coronary luminal diameter following the maximal acetylcholine dose (Clinicaltrials.gov identifier: NCT02666235). RESULTS: 75 patients were enrolled. Following angiography, 60 patients (mean±SD age 57.5±8.5years; 80% male) were eligible and completed the protocol (n=30 RIPC, n=30 sham). The mean percentage change in coronary luminal diameter was -13.3±22.3% and -2.0±17.2% in the sham and RIPC groups respectively (difference 11.32%, 95%CI: 1.2- 21.4, p=0.032). This remained significant when age and sex were included as covariates (difference 11.01%, 95%CI: 1.01- 21.0, p=0.035). There were no between-group differences in endothelial-independent vasodilation, ECG parameters or circulating markers of endothelial function. CONCLUSIONS: RIPC attenuates the extent of vasoconstriction induced by intracoronary acetylcholine infusion. This endothelium-dependent mechanism may contribute to the cardioprotective effects of RIPC.

A comparison of the associations between seven hemostatic or inflammatory variables and coronary heart disease.

BACKGROUND: While meta-analyses of prospective studies have established that plasma levels of several hemostatic variables are associated with the risk of coronary heart disease (CHD), these have been suggested to be acute-phase reactant proteins. This study examines their associations with inflammatory markers [C-reactive protein (CRP) and interleukin-6 (IL-6)] and the effect of adjustment on their associations with CHD risk. METHODS AND RESULTS: In a nested case-control study, 247 CHD cases and 473 controls were matched for age and sex from 10 529 men and women in the Fletcher Challenge cohort. Plasma levels of all hemostatic variables except von Willebrand factor (VWF) and lipoprotein (a) [Lp(a)] showed significant associations with CRP and IL-6. Fibrinogen, VWF, tissue plasminogen activator antigen (t-PA), D-dimer, Lp(a), CRP and IL-6 levels were significantly associated with risk of CHD. After adjustment for conventional risk factors, CRP, D-dimer and IL-6 levels were significantly associated with risk of CHD. On further adjustments for the other six hemostatic and inflammatory variables these associations were reduced, but remained significant for D-dimer and IL-6; odds ratios (95% CI), comparing the highest to lowest third, were 3.10 (1.25-7.67) and 2.79 (1.11-6.99), respectively. CONCLUSION: The associations of plasma levels of some hemostatic variables (fibrinogen, VWF, t-PA and Lp(a); but not fibrin D-dimer) with CHD risk are attenuated when inflammatory markers (CRP and IL-6) as well as conventional risk factors are included in multivariable analyses. D-dimer and IL-6 each have the potential to increase the prediction of CHD, in addition to conventional risk factors.

Role of arginine 180 and glutamic acid 177 of ricin toxin A chain in enzymatic inactivation of ribosomes.

The gene for ricin toxin A chain was modified by site-specific mutagenesis to change arginine 180 to alanine, glutamine, methionine, lysine, or histidine. Separately, glutamic acid 177 was changed to alanine and glutamic acid 208 was changed to aspartic acid. Both the wild-type and mutant proteins were expressed in Escherichia coli and, when soluble, purified and tested quantitatively for enzyme activity. A positive charge at position 180 was found necessary for solubility of the protein and for enzyme activity. Similarly, a negative charge with a proper geometry in the vicinity of position 177 was critical for ricin toxin A chain catalysis. When glutamic acid 177 was converted to alanine, nearby glutamic acid 208 could largely substitute for it. This observation provided valuable structural information concerning the nature of second-site mutations.

Selection and characterization of ricin toxin A-chain mutations in Saccharomyces cerevisiae.

A DNA sequence encoding the A chain of ricin toxin (RTA) from the castor bean plant, Ricinus communis, was placed under GAL1 promoter control and transformed into Saccharomyces cerevisiae. Induction of expression of RTA was lethal. This lethality was the basis for a selection of mutations in RTA which inactivated the toxin. A number of mutant alleles which encoded cross-reactive material were sequenced. Eight of the first nine mutant RTAs studied showed single-amino-acid changes involving residues located in the proposed active-site cleft.

Role of glutamic acid 177 of the ricin toxin A chain in enzymatic inactivation of ribosomes.

The gene for the A chain of ricin toxin was fused to a beta-galactosidase marker cistron via a DNA sequence encoding a short collagen linker, and the tripartite fusion protein was expressed in Escherichia coli. Site-specific mutagenesis was used to change glutamic acid residue 177 to aspartic acid or alanine. When the mutant proteins were expressed, purified, and tested quantitatively for enzymatic activity, the carboxylate function at position 177 was found not to be absolutely essential for ricin toxin A-chain catalysis.

A focused ethnography of a Child and Adolescent Mental Health Service: factors relevant to the implementation of a depression trial.

BACKGROUND: Prior to commencing a randomised controlled trial, we conducted a focused ethnography to ensure that the trial was well suited to the proposed setting. METHODS: A six-month observation of a Child and Adolescent Mental Health Service site in the North-East of England was undertaken to observe the site procedures, staff culture and patient care pathways. During this period, documentary data were collected and interviews were conducted with key informants to provide insight into staff perceptions of the proposed trial. The data were coded using thematic analysis and the resulting themes were verified by a second coder. RESULTS: Seventeen documents were collected, 158 h of observation and six formal staff interviews were undertaken. Four themes emerged from the data; non-clinically orientated variation in practice, diagnosis, capacity and staff economy. Non-clinically orientated variation in practice occurred when staff decisions were based upon resource availability rather than on clinical judgement. Diagnosis demonstrated differing staff confidence in making diagnoses and in the treatment of patients who had received a diagnosis. Capacity consisted of the time to attend training and the psychological capacity to consider or incorporate learning into practice. Staff economy was characterised by staff changes and shortages. There was significant interaction between the themes, with staff economy emerging as a central barrier to research. The results directly informed adaptations to the trial protocol. CONCLUSIONS: An ethnographic approach has provided important insights into the individual, practical and organisational boundaries into which a trial would need to be implemented.