Diagnostic value of electrocardiogram in cardiac tamponade.

INTRODUCTION: We aim to study the diagnostic value of electrocardiogram (ECG) in cardiac tamponade. METHODS: This study was a single centre, retrospective casecontrol study. We recruited 42 patients diagnosed with cardiac tamponade of various aetiologies confirmed by transthoracic echocardiography and 100 controls between January 2011 and December 2015. The ECG criteria of cardiac tamponade we adopted was as follows: 1) Low QRS voltage in a) the limb leads alone, b) in the precordial leads alone or, c) in all leads, 2) PR segment depression, 3) Electrical alternans, and 4) Sinus tachycardia. RESULTS: Malignancy was the most common causes of cardiac tamponade, the two groups were of similar proportion of gender and ethnicity. We calculated the sensitivity (SN), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV) of each ECG criteria. Among the ECG abnormalities, we noted the SN of 'low voltage in all chest leads' (69%), 'low voltage in all limb leads' (67%) and 'sinus tachycardia' (69%) were higher as compared to 'PR depression' (12%) and 'electrical alternan' (5%). On the other hand, 'low voltage in all chest leads' (98%), 'low voltage in all leads' (99%), 'PR depression' (100%) and 'electrical alternans' (100%) has highest SP. CONCLUSION: Our study reaffirmed the findings of previous studies that electrocardiography cannot be used as a screening tool for diagnosing cardiac tamponade due to its low sensitivity. However, with clinical correlation, electrocardiography is a valuable adjuvant test to 'rule in' cardiac tamponade because of its high specificity.

Acute myocarditis mimicking ST-elevation myocardial infarction: A diagnostic challenge for frontline clinicians.

The clinical presentation of acute myocarditis is highly variable ranging from no symptoms to cardiogenic shock. Despite considerable progress, it remains a challenge for frontline physicians to discriminate between acute myocarditis and myocardial infarction, especially in the early phase. Our case serves as a reminder that acute presentation of myocarditis could resemble ST elevation myocardial infarction potentially misdirecting the therapeutic decision. The clinical presentation, electrocardiographic and laboratory findings of the patient are not specific enough to distinguish acute myocarditis from myocardial infarction. The gold standard tests such coronary angiography and cardiovascular magnetic resonance (CMR) can reliably differentiate the two entities.

Gender differences for growth in North American Atlantic salmon.

An assumption in aquaculture of Atlantic salmon is that male and female growth within families is perfectly genetically correlated. That is, families would rank identically if based on male growth only or female growth only. Also, growth in freshwater and sea water is assumed to be highly correlated between males and females within families. However, structural analysis of the DNA of Atlantic salmon has found that the linkage maps of females differ significantly from that of males. Genetic variability for any trait measured on females could be greater or lesser than on males. Thus, male and female growth might be considered as separate traits giving rise to families ranking differently depending on gender. A multiple trait family model for weight and length at 3 years of age in Atlantic salmon according to gender was applied to data on North American Atlantic salmon obtained from the Oak Bay Hatchery in New Brunswick, Canada. Genetic correlations between male and female growth in both freshwater and sea water were estimated by Bayesian methods. The estimates support the possible existence of gender dimorphism in North American Atlantic salmon for growth traits.

Parasitism perturbs the mucosal microbiome of Atlantic Salmon.

Interactions between parasite, host and host-associated microbiota are increasingly understood as important determinants of disease progression and morbidity. Salmon lice, including the parasitic copepod Lepeophtheirus salmonis and related species, are perhaps the most important problem facing Atlantic Salmon aquaculture after feed sustainability. Salmon lice parasitize the surface of the fish, feeding off mucus, scales and underlying tissue. Secondary bacterial infections are a major source of associated morbidity. In this study we tracked the diversity and composition of Salmo salar skin surface microbiota throughout a complete L. salmonis infection cycle among 800 post-smolts as compared to healthy controls. Among infected fish we observed a significant reduction in microbial richness (Chao1, P = 0.0136), raised diversity (Shannon, P < 7.86e-06) as well as highly significant destabilisation of microbial community composition (Pairwise Unifrac, beta-diversity, P < 1.86e-05; P = 0.0132) by comparison to controls. While undetectable on an individual level, network analysis of microbial taxa on infected fish revealed the association of multiple pathogenic genera (Vibrio, Flavobacterium, Tenacibaculum, Pseudomonas) with high louse burdens. We discuss our findings in the context of ecological theory and colonisation resistance, in addition to the role microbiota in driving primary and secondary pathology in the host.

Filtration of sea louse, Lepeophtheirus salmonis, copepodids by the blue mussel, Mytilus edulis, and the Atlantic sea scallop, Placopecten magellanicus, under different flow, light and copepodid-density regimes.

Population management of Lepeophtheirus salmonis in Canada currently relies on chemotherapeutants to remove attached stages of the ectoparasite. However, some populations of L. salmonis are developing resistance to chemotherapeutants making alternate management measures necessary. This article explores the ability of filter-feeding shellfish [i.e. blue mussels (Mytilus edulis) and Atlantic sea scallops (Placopecten magellanicus)] to consume the copepodid stages of L. salmonis in the laboratory under static and flowing water conditions, with variable copepodid densities, and with the aid of a light attractant. Mytilus edulis consumed copepodids under both static and flowing water conditions, and the proportion of individuals ingested was similar at low and high copepodid densities, suggesting that M. edulis was not saturated at the concentrations tested. Also, M. edulis consumed more copepodids when a light attractant was present, suggesting that lights may be useful to concentrate widely dispersed copepodids around cultured shellfish in the field. Finally, P. magellanicus consumed the same number of copepodids as an equivalent total wet weight of M. edulis. During each of the four separate experiments, shellfish consumed between 18 and 38% of the copepodids presented per hour, suggesting that both species are well suited for low level removal of copepodids over time.

The distribution of polynuclear aromatic hydrocarbons in ambient air particulates in Singapore.

Ambient air particulates were collected using high volume samplers at seven locations throughout Singapore. The particulates were analyzed for eleven polynuclear aromatic hydrocarbons (PAH) using high performance liquid chromatography (HPLC) with fluorescence detection. Several sample preparation techniques were used to determine which method would yield the most PAHs from the bulk sample matrix. PAH profiles (standardised against the concentration of benzo(a)pyrene) were obtained to characterise the different sampling sites chosen.

Determination of oestriol in pregnancy urine by normal-phase high-performance liquid chromatography with electrochemical detection.

A method for the determination of oestriol in pregnancy urine by normal-phase high-performance liquid chromatography with electrochemical detection is described. A large-volume wall-jet cell with an Ag-Ag+ reference electrode was used as the detector system. The limit of detection obtained is comparable to that of electrochemical detection following reversed-phase liquid chromatography. One of the advantages of electrochemical detection with normal-phase systems is that adsorption problems are minimized.