The brachiopod <i>Eoobolus</i> from the early cambrian mural formation (Canadian Rocky Mountains)

The Early Cambrian brachiopod, Eoobolus, is one of the first representatives of the superfamily, Linguloidea, the defining characteristics of which include the classical morphology of oval shells and a pedicle that emerges from between the two valves. The material described here from the Mural Formation (Jasper National Park, Canadian Rocky Mountains) provides well-preserved muscle scars and larval shells that allow a discussion of the muscle system and the larval morphology of Eoobolus. The dorsal larval shell exhibits a morphology similar to other Cambrian linguloids, but also to paterinids, Mickwitzia muralensis, and some rhynchonelliforms. This suggests that there was a lesser degree of disparity among brachiopod larvae in the Cambrian than there is today. The muscle system of Eoobolus is similar to other linguloids, but differs from that of Recent lingulids and discinids by having one or two more pairs of oblique muscles. New data on the distribution of features characteristic of the family Eoobolidae question the validity of this family

Coronary microvascular dysfunction in cardiovascular disease:Lessons from large animal models

The coronary microvasculature is responsible for maintaining local matching of myocardial blood flow to myocardial demand of oxygen and nutrients. Long term adjustment of myocardial blood flow involves structural changes in microvascular density and diameter while fine-tuning of flow is achieved via adaptations in vascular smooth muscle tone in the coronary microvasculature.In the past several decades, considerable research efforts have been directed at understanding structural and functional microvascular adaptations involved in matching myocardial oxygen supply and demand and how these mechanisms are affected by various diseases. In this review we will discuss our current understanding of the mechanisms underlying the regulation of coronary microvascular tone under healthy physiological conditions, and the role of microvascular dysfunction in obstructive and non-obstructive coronary artery disease, as studied in large animal (particularly swine) models and confirmed in human studies. Future studies should be directed at further unraveling the mechanisms of coronary microvascular dysfunction in different disease entities in order to, and ultimately directed at improving microvascular function as a therapeutic target in patients with ischemic heart disease