The unicellular conifer tracheid should have greater flow resistance per length (resistivity) than the multicellular angiosperm vessel, because its high-resistance end-walls are closer together. However, tracheids and vessels had comparable resistivities for the same diameter, despite tracheids being over 10 times shorter. End-wall pits of tracheids averaged 59 times lower flow resistance on an...

Blood vessel walls are built and maintained by 2 interdependent cell types, endothelial cells and mural cells. Signals exchanged between these 2 cell types control the formation, maturation, remodeling, and function of microvascular networks. Mural cells are either pericytes in the microvasculature or smooth muscle cells (SMCs) in larger vessels. Interactions between endothelial cells and mural...

Quantitative and qualitative features are presented for 13 collections of 8 species of Ascarina. Wood anatomy is maximally primitive in most respects; moderate exception occurs in the imperforate tracheary elements, which range from tracheidlike (A. solmsiana) to fiber-tracheids (septate in two species). Perforation plates are scalariform, average more than 100 bars per plate, and have bordered...

AIMS To test the hypothesis that fragments of platelet thrombi and vascular endothelium are incorporated into the walls of small cerebral vessels in systemic lupus erythematosus (SLE). METHODS Six varied necropsy cases of central nervous system (CNS) SLE and 15 controls were studied. The controls were selected to represent a wide range of diseases in which the cerebral circulation is compromi...

Background: Angiogenesis is a key phenomenon for tumour progression, diagnosis and treatment in brain tumours and more generally in oncology. Presently, its precise, direct quantitative assessment can only be done on whole tissue sections immunostained to reveal vascular endothelial cells. But this is a tremendous task for the pathologist and a challenge for the computer since digitised whole t...

Cutaneous small-vessel vasculitis (CSVV) is a general term for diseases that present pathological features of leukocytoclastic vasculitis, i.e., diseases with pathological perivascular neutrophilic infiltration and fibrinoid degeneration of the vascular walls (Fig. 11.1). Henoch-Schönlein purpura and urticarial vasculitis are included under a broad definition of CSVV; however, they are usually ...

A 46 year old Asian male with previously treated lepromatous leprosy developed a stepwise multifocal sensory disturbance 25 years later. Neurophysiology demonstrated marked deterioration from previous studies. Sural nerve biopsy disclosed a vasculitic process superimposed on inactive lepromatous leprosy. Immunocytochemical stains for mycobacterial antigen showed deposits within nerve and vessel...

Altered expression of plasminogen activator inhibitor type-1 in vessel walls, reviewed here, might affect coronary atherogenesis. Upregulation might exacerbate vasculopathy by potentiating thrombosis and by inhibiting vascular smooth muscle cell migration, resulting in attenuation of thickness of elaborated fibrous caps implicated in the vulnerability of atheroma to rupture.

Hartley, Craig J., Anilkumar K. Reddy, Sridhar Madala, Mark L. Entman, Lloyd H. Michael, and George E. Taffet. Noninvasive ultrasonic measurement of arterial wall motion in mice. Am J Physiol Heart Circ Physiol 287: H1426–H1432, 2004; 10.1152/ajpheart. 01185.2003.—Despite the extensive use of genetically altered mice to study cardiovascular physiology and pathology, it remains difficult to quan...

Using Ulmus glabra as an example we revealed that acoustic emissions from plants do not necessarily occur in conjunction with water stress. The waveforms in the various signals show that acoustic emissions may possibly be generated by still unknown hydraulic events, more complex than cavitation. Using a special microscopic technique we established the presence of minute gas bubbles attached fir...