Memorial University of Newfoundland

About: Memorial University of Newfoundland is a education organization based out in St. John's, Newfoundland and Labrador, Canada. It is known for research contribution in the topics: Population & Gadus. The organization has 13818 authors who have published 27785 publications receiving 743594 citations. The organization is also known as: Memorial University & Memorial University of Newfoundland and Labrador.

Lipid and Phenolic Biomarkers in Marine Ecosystems: Analysis and Applications

Abstract: Biomarkers are compounds or groups of compounds that can be used as signatures of individual organisms or groups of organisms, or of certain environmental processes Lipid and phenolic biomarkers can be used to assess the health of an ecosystem and the degree to which it has been influenced by terrestrial and anthropogenic inputs Lipid classes and fatty acids can be used to determine production of marine biogenic material of dietary value to pelagic and benthic organisms Polycyclic aromatic hydrocarbons and 5β-stanols such as coprostanol can be used to determine pollutant loading from oil spillage or sewage and the phenanthrene/methylphenanthrene ratio can be used specifically as an indicator of wood burning N-alkanes and thermochemolysis products in cores can show the sensitivity of sediments to changes in land use patterns near the land margin The relationship between marine and terrestrially derived products in sediment cores can be used to indicate the degree to which land use changes have impacted the pattern of marine biogenic productivity in the area Stable isotope and multivariate analyses are particularly useful for biomarker validation

Cardiac plasticity in fishes: environmental influences and intraspecific differences

Abstract: Fish cardiac physiology and anatomy show a multiplicity of intraspecific modifications when exposed to prolonged changes in environmentally relevant parameters such as temperature, hypoxia and food availability, and when meeting the increased demands associated with training/increased activity and sexual maturation. Further, there is evidence that rearing fish under intensive aquaculture conditions significantly alters some, but not all, aspects of cardiac anatomy and physiology. This review focuses on the responses of cardiac physiology and anatomy to these challenges, highlighting where applicable, the importance of hyperplastic (i.e. the production of new cells) vs hypertrophic (the enlargement of existing cells) growth to the adaptive response of the heart. In addition, we summarize recent studies that have explored the relationship between the myocardial protection afforded by preconditioning and myocardial hypoxia tolerance. This latter research clearly demonstrates the capacity of the fish heart to adjust to short-term perturbations, and shows that it can be difficult to predict how short-term and long-term alterations in cardiac physiology will interact.

Prolonged but delayed postischemic hypothermia: a long-term outcome study in the rat middle cerebral artery occlusion model.

Abstract: Delayed but prolonged hypothermia persistently decreases cell death and functional deficits after global cerebral ischemia in rodents. Postischemic hypothermia also reduces infarction after middle cerebral artery occlusion (MCAO) in rat. Because initial neuroprotection is sometimes transient and may not subserve functional recovery, especially on demanding tasks, the authors examined whether postischemic cooling would persistently reduce infarction and forelimb reaching deficits after MCAO. Male spontaneously hypertensive rats were trained to retrieve food pellets in a staircase test that measures independent forelimb reaching ability. Later, rats underwent 90 minutes of normothermic MCAO, through a microclip, or sham operation. In some rats, prolonged cooling (33 degrees C for 24 hours and then 35 degrees C for 24 hours) began 2.5 hours after the onset of ischemia (60 minutes after the start of reperfusion; n = 17 with subsequently 1 death) or sham procedures (n = 4), whereas untreated sham (n = 4) and ischemic (n = 16 with subsequently 1 death) rats maintained normothermia. An indwelling abdominal probe continually measured core temperature, and an automated fan and water spray system was used to produce hypothermia. One month later rats were reassessed in the staircase test over five days and then killed. The contralateral limb impairment in food pellet retrieval was completely prevented by hypothermia (P = 0.0001). Hypothermia reduced an infarct volume of 67.5 mm3 after untreated ischemia to 35.8 mm3 (P < 0.0001). These findings of persistent benefit encourage the clinical assessment of hypothermia.