ADAM12-directed ectodomain shedding of E-cadherin potentiates trophoblast fusion.

Trophoblasts, placental cells of epithelial lineage, undergo extensive differentiation to form the cellular components of the placenta. Trophoblast progenitor cell differentiation into the multinucleated syncytiotrophoblast is a key developmental process required for placental function, where defects in syncytiotrophoblast formation and turnover associate with placental pathologies and link to poor pregnancy outcomes. The cellular and molecular processes governing syncytiotrophoblast formation are poorly understood, but require the activation of pathways that direct cell fusion. The protease, A Disintegrin and Metalloproteinase 12 (ADAM12), controls cell fusion in myoblasts and is highly expressed in the placenta localizing to multiple trophoblast populations. However, the importance of ADAM12 in regulating trophoblast fusion is unknown. Here, we describe a function for ADAM12 in regulating trophoblast fusion. Using two distinct trophoblast models of cell fusion, we show that ADAM12 is dynamically upregulated and is under the transcriptional control of protein kinase A. siRNA-directed loss of ADAM12 impedes spontaneous fusion of primary cytotrophoblasts, whereas overexpression of the secreted variant, ADAM12S, potentiates cell fusion in the Bewo trophoblast cell line. Mechanistically, both ectopic and endogenous levels of ADAM12 were shown to control trophoblast fusion through E-cadherin ectodomain shedding and remodeling of intercellular boundaries. This study describes a novel role for ADAM12 in placental development, specifically highlighting its importance in controlling the differentiation of villous cytotrophoblasts into multinucleated cellular structures. Moreover, this work identifies E-cadherin as a novel ADAM12 substrate, and highlights the significance that cell adhesion molecule ectodomain shedding has in normal development.

Activation of endocrine-related gene expression in placental choriocarcinoma cell lines following DNA methylation knock-down.

Increasingly, placental DNA methylation is assessed as a factor in pregnancy-related complications, yet the transcriptional impact of such findings is not always clear. Using a proliferative in vitro placental model, the effect of DNA methylation loss on gene activation was evaluated at a number of genes selected for being differentially methylated in pre-eclampsia-associated placentae in vivo. We aimed to determine whether reduced DNA methylation at specific loci was associated with transcriptional changes at the corresponding gene, thus providing mechanistic underpinnings for previous clinical findings and to assess the degree of transcriptional response amongst our candidate genes. BeWo and JEG3 choriocarcinoma cells were exposed to 1 µM 5-Aza-2'-deoxycytidine (5-Aza-CdR) or vehicle control for 48 h, and re-plated and cultured for a further 72 h in normal media before cells were harvested for RNA and DNA. Bisulphite pyrosequencing confirmed that DNA methylation was reduced by ∼30-50% points at the selected loci studied in both cell lines. Gene activation, measured by qRT-PCR, was highly variable and transcript specific, indicating differential sensitivity to DNA methylation. Most notably, loss of DNA methylation at the leptin (LEP) promoter corresponded to a 200-fold and 40-fold increase in LEP expression in BeWo and JEG3 cells, respectively (P < 0.01). Transcripts of steroidogenic pathway enzymes CYP11A1 and HSD3B1 were up-regulated ∼40-fold in response to 5-Aza-CdR exposure in BeWo cells (P < 0.01). Other transcripts, including aromatase (CYP19), HSD11B2, inhibin (INHBA) and glucocorticoid receptor (NR3C1) were more moderately, although significantly, affected by loss of associated DNA methylation. These data present a mixed effect of DNA methylation changes at selected loci supporting cautionary interpretation of DNA methylation results in the absence of functional data.

Prenatal and perinatal environmental influences on the human fetal and placental epigenome.

Drug, hormonal, and nutritional exposures in pregnancy can cause birth defects, or have more subtle influences that may affect adult health through epigenetic developmental programming. Characterizing these epigenetic changes may provide valuable insight into the mechanism by which our health is influenced by the environment and provide biomarkers of exposure; however, currently there are few data from human studies directly addressing this. We review data on three types of exposures-nutritional, glucocorticoid, and endocrine-disrupting chemicals-and discuss how these may be associated with epigenetic changes in the fetus and the placenta, a key mediator of in utero environment. In addition, we outline some considerations for investigation of epigenetic effects in the fetus and placenta that are important to consider in the design of studies for the future.

Limited clinical utility of CT coronary angiography in a district hospital setting.

BACKGROUND: Studies have demonstrated considerable accuracy of multi-slice CT coronary angiography (MSCT-CA) in comparison to invasive coronary angiography (I-CA) for evaluating coronary artery disease (CAD). The extent to which published MSCT-CA accuracy parameters are transferable to routine practice beyond high-volume tertiary centres is unknown. AIM: To determine the accuracy of MSCT-CA for the detection of CAD in a Scottish district general hospital. DESIGN: Prospective study of diagnostic accuracy. METHOD: One hundred patients with suspected CAD recruited from two Glasgow hospitals underwent both MSCT-CA (Philips Brilliance 40 × 0.625 collimation, 50-200 ms temporal resolution) and I-CA. Studies were reported by independent, blinded radiologists and cardiologists and compared using the AHA 15-segment model. RESULTS: Of 100 patients [55 male, 45 female, mean (SD) age 58.0 (10.7) years], 59 and 41% had low-intermediate and high pre-test probabilities of significant CAD, respectively. Mean (SD) heart rate during MSCT-CA was 68.8 (9.0) bpm. Fifty-seven per cent of patients had coronary artery calcification and 35% were obese. Patient prevalence of CAD was 38%. Per-patient sensitivity, specificity, positive and negative (NPV) predictive values for MSCT-CA were 92.1, 47.5, 52.2 and 90.6%, respectively. NPV was reduced to 75.0% in the high pre-test probability group. Specificity was compromised in patients with sub-optimally controlled heart rates, calcified arteries and elevated BMI. CONCLUSION: Forty-Slice MSCT-CA has a high NPV for ruling out significant CAD when performed in a district hospital setting in patients with low-intermediate pre-test probability and minimal arterial calcification. Specificity is compromised by clinically appropriate strategies for dealing with unevaluable studies. Effective heart rate control during MSCT-CA is imperative. National guidelines should be utilized to govern patient selection and direct MSCT-CA reporter training to ensure quality control.

Balsalazide-induced myocarditis.

A 38 year-old man with ulcerative colitis recently treated with balsalazide was admitted with chest pain. Investigations demonstrated myocardial necrosis, ECG changes, echocardiographic wall motion abnormalities but normal epicardial coronary arteries and no LV scar on cardiac MRI. Myocarditis was diagnosed and balsalazide therapy was withdrawn, resulting in a full recovery and resolution of abnormalities.

Diagnosis of pulmonary embolism with CT pulmonary angiography: a systematic review.

OBJECTIVE: To appraise the evidence on the diagnostic accuracy of CT pulmonary angiography and the prognostic value of a negative CT pulmonary angiogram in the diagnosis of pulmonary embolism. METHODS: Medline, EMBASE, and grey literature were systematically searched by two researchers. Any study which compared CT pulmonary angiography to an acceptable reference standard or prospectively followed up a cohort of patients with a normal CT pulmonary angiogram was included. Study methods were appraised independently by two researchers, and data were extracted independently by three researchers. RESULTS: Thirteen diagnostic and 11 follow up studies were identified. Studies varied in prevalence of pulmonary embolism (19-79%), patient groups, and method quality. Few studies recruited unselected emergency department patients. There was heterogeneity in the analysis of sensitivity (53 to 100%), specificity (79 to 100%), and false negative rate (1.0 to 10.7%). The pooled false negative rate of combined negative CT pulmonary angiography and negative deep vein thrombosis testing was 1.5% (95% CI 1.0 to 1.9%). CONCLUSION: Diagnostic studies give conflicting results for the diagnostic accuracy of CT pulmonary angiography. Follow up studies show that CT pulmonary angiography can be used in combination with investigation for deep vein thrombosis to exclude pulmonary embolism.

Investigating pulmonary embolism in the emergency department with lower limb plethysmography: the Manchester Investigation of Pulmonary Embolism Diagnosis (MIOPED) study.

OBJECTIVES: To measure the diagnostic accuracy of computerised strain gauge plethysmography in the diagnosis of pulmonary embolism (PE). METHODS: Two researchers prospectively recruited 425 patients with pleuritic chest pain presenting to the emergency department (ED). Lower limb computerised strain gauge plethysmography was performed in the ED. All patients underwent an independent reference standard diagnostic algorithm to establish the presence or absence of PE. A low modified Wells' clinical probability combined with a normal D-dimer excluded PE. All others required diagnostic imaging with PIOPED interpreted ventilation perfusion scanning and/or computerised tomography (CT) pulmonary angiography. Patients with a nondiagnostic CT had digital subtraction pulmonary angiography. All patients were followed up clinically for 3 months. RESULTS: The sensitivity of computerised strain gauge plethysmography was 33.3% (95% confidence interval (CI) 16.3 to 56.2%) and specificity 64.1% (95% CI 59.0 to 68.8%). The negative likelihood ratio was 1.04 (95% CI 0.68 to 1.33) and positive likelihood ratio 0.93 (95% CI 0.45 to 1.60). CONCLUSIONS: Lower limb computerised strain gauge plethysmography does not aid in the diagnosis of PE.

Outpatient diagnosis of pulmonary embolism: the MIOPED (Manchester Investigation Of Pulmonary Embolism Diagnosis) study.

BACKGROUND AND OBJECTIVES: Pleuritic chest pain, a symptom of pulmonary embolism, is a common presenting symptom in the emergency department. The aim of this study was to validate an algorithm for the diagnosis of pulmonary embolism in emergency department patients with pleuritic chest pain. METHODS: This was a prospective, diagnostic cohort study conducted in a large UK city centre emergency department. A total of 425 patients with pleuritic chest pain presenting to the emergency department between February 2002 and June 2003 were recruited. Patients scoring a low modified Wells clinical probability of pulmonary embolism, who had a normal latex agglutination D-dimer, were discharged. All others followed a diagnostic imaging protocol to exclude and diagnose pulmonary embolism using PIOPED interpreted ventilation-perfusion scanning, CT pulmonary angiography, and digital subtraction pulmonary angiography. All patients were followed up for three months for evidence of pulmonary embolism or deep vein thrombosis. An independent adjudication committee reviewed all deaths. RESULTS: A total of 408 patients completed the diagnostic algorithm; 86.5% (353/408) were investigated as outpatients, 5.4% (22/408) were diagnosed as having pulmonary embolism, and 98.8% (403/408) were followed up for three months. Of the 381 patients without pulmonary embolism who completed follow up, the incidence of thromboembolic disease was 0.8% (95% CI 0.3% to 2.3%): two patients had pulmonary embolism and one had a deep vein thrombosis. CONCLUSIONS: The MIOPED (Manchester Investigation Of Pulmonary Embolism Diagnosis) diagnostic protocol can safely exclude pulmonary embolism in outpatients with pleuritic chest pain.

Heart failure with preserved left ventricular systolic function: a hospital cohort study.

OBJECTIVE: To investigate how patients with heart failure with preserved left ventricular systolic function (LVSF) compare with patients with reduced LVSF. DESIGN: Cohort study. SETTING: Urban university hospital. PATIENTS: 528 index emergency admissions with heart failure during the year 2000. Information on LVSF and follow up was available for 445 (84%) of these patients. RESULTS: 130 (29%) patients had preserved LVSF (defined as an ejection fraction > 40%). The median follow up was 814 days (range 632-978 days). The average (SD) age was 72 (13) years. Women accounted for 62% and 45% of patients with preserved and reduced LVSF, respectively (p = 0.001). Patients with preserved LVSF (compared with those with reduced LVSF) had a higher prevalence of left ventricular hypertrophy (56% v 29%) and aortic valve disease (mean gradient > 20 mm Hg; 31% v 9%). Fewer patients with preserved LVSF received an angiotensin converting enzyme inhibitor (65% v 78%, p = 0.008) or spironolactone (12% v 21%, p = 0.027). Anaemia tended to occur more often in patients with preserved LVSF than in those with reduced LVSF (43% v 33% for women, p = 0.12; 59% v 49% for men, p = 0.22). There was a similarly high prevalence of significant renal dysfunction in both groups (estimated glomerular filtration rate < 60 ml/min/1.73 m2 in 68% with preserved and 64% with reduced LVSF, p = 0.40). Mortality was similar in both groups (preserved versus reduced 51 (39%) v 132 (42%), p = 0.51). Compared with patients with reduced LVSF, patients with preserved LVSF tended to have a lower risk of death or hospital admission for heart failure (56 (42%) v 165 (53%), p = 0.072) but a similar rate of death or readmission for any reason. CONCLUSION: Patients with preserved LVSF had more co-morbid problems than those with reduced LVSF; however, prognosis was similar for both groups.

Comparison of survival following coronary artery bypass grafting vs. percutaneous coronary intervention in diabetic and non-diabetic patients: retrospective cohort study of 6320 procedures.

AIM: To determine whether mortality following percutaneous coronary intervention vs. coronary bypass grafting varies according to whether or not patients have diabetes. METHODS: We used the Scottish Coronary Revascularization Register to identify all patients undergoing revascularization in Scottish NHS hospitals since 1997. We excluded single-vessel disease, left main stem stenosis, and bypass grafting performed at the same time as other operations. We used death certificate data from the Registrar General to identify all subsequent deaths. RESULTS: Of the 6320 eligible procedures, 5042 (80%) were bypass grafts and 1278 (20%) angioplasties. Overall 831 (13%) patients had diabetes with no significant difference by procedure (13% vs. 12%). A total of 382 deaths occurred over a mean follow-up of 2.3 years. Diabetic patients had a poorer prognosis following both surgery (adjusted hazards ratio (HR) 1.43, 95% confidence interval (CI) 1.08, 1.89) and percutaneous intervention (adjusted HR 2.58, 95% CI 1.43, 4.63). Among non-diabetic patients, no significant differences in mortality were detected between the two procedures. Among diabetic patients, no significant difference was detected in those with two-vessel disease. In those with impaired left ventricular function and triple-vessel disease, angioplasty was associated with a significantly higher risk of death (adjusted HR 3.58, 95% CI 1.40, 9.19). CONCLUSIONS: This is the first study to demonstrate statistically significant results that support the BARI trial findings. Our study demonstrated a significant difference for triple-vessel disease but not two-vessel disease. The former may be due to incomplete revascularization using percutaneous intervention. Our results require corroboration from randomized trials.

Poor concordance of commonly used echocardiographic measures of left ventricular diastolic function in patients with suspected heart failure but preserved systolic function: is there a reliable echocardiographic measure of diastolic dysfunction?

OBJECTIVE: To determine the concordance of different Doppler echocardiographic criteria for "diastolic dysfunction" in patients with suspected heart failure but preserved left ventricular systolic function. DESIGN: Prospective, descriptive study. SETTING: Outpatient based direct access echocardiography service. PATIENTS: Consecutive patients referred with suspected heart failure but preserved left ventricular systolic function. MEASUREMENTS: Echocardiographic measurements of systolic and diastolic function. Eight published studies giving age and sex specific ranges for measures of diastolic function in healthy subjects were reviewed and the proportion of patients outside the normal limits for each of these published ranges was calculated. RESULTS: There was very poor concordance between measures with up to a 16-fold difference in the prevalence of diastolic dysfunction in the overall patient cohort. Even for a given measure, there was relatively poor agreement between the published reference ranges. In subsets likely to include patients at high risk of having diastolic dysfunction, an increased prevalence of diastolic dysfunction was not evident with any measure in any patient subset. CONCLUSIONS: Our findings challenge the use of the diagnosis of diastolic heart failure based on the most commonly used echocardiographic criteria. Physicians should be cautious about echocardiographic reports describing diastolic dysfunction and only apply the diagnosis of diastolic heart failure with great care.

Towards evidence based emergency medicine: best BETs from the Manchester Royal Infirmary. Glucagon in tricyclic overdose.

A short cut review was carried out to establish whether the addition of glucagon to standard treatments improves clinical outcome in patients who have taken an overdose of tricyclic antidepressants. Altogether 31 papers were found using the reported search, of which three presented the best evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses of these best papers are tabulated. A clinical bottom line is stated.

Towards evidence based emergency medicine: best BETs from the Manchester Royal Infirmary. Colourimetric CO(2) detector compared with capnography for confirming ET tube placement.

A short cut review was carried out to establish whether colourimetric carbon dioxide detectors are as reliable as capnometry at verifying tracheal placement of endotracheal tubes after emergency intubation. A total of 69 papers were found using the reported search, of which four presented the best evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses of these best papers are tabulated. A clinical bottom line is stated.

Rapid access chest pain clinics--can they be justified?

Rapid access chest pain clinics are expanding across the country with marked resource implications despite a paucity of data regarding their efficacy. Early assessment of patients in this manner potentially delays review of patients referred via the traditional route. We conducted a prospective observational study of patients referred with chest pain to the Cardiology Outpatient Department over a four-week period in a District General Hospital to compare demographics and outcomes in patients referred to the rapid access with those referred to the general cardiology clinics. There were no significant differences in baseline demographics, exercise test result or clinic outcome. Both populations were low risk. Discussion is needed between primary and secondary care to achieve a consensus as to the purpose of a rapid access system and how best to utilise the service appropriately. Further studies are required to assess the efficacy and health economics of this system.

The utilisation of a day-surgery unit for direct-current (DC) cardioversion of atrial fibrillation.

Atrial fibrillation (AF) is a common arrhythmia associated with increased morbidity and mortality. Current practice aims to restore sinus rhythm (SR), although the question of whether rate or rhythm control is the optimal approach for these patients remains unanswered. The most established method of restoring SR in patients with AF of duration greater than 48 hours is external direct-current cardioversion (DCC). This is a descriptive paper summarising how we utilised the hospital's day surgery unit for the provision of DCC for patients with AF in order to provide a more efficient service and allow an increased number of procedures to be conducted. We describe the reasons for setting up the service and the methods involved. We also summarise the advantages associated with this new system.