Microvasculature abnormalities

Microvasculature abnormal Blood vessels dilated, twisted... 

Grenz zone prominent, elastogenesis, elastosis, collagen degeneration, loss of anchoring fibrils Microvasculature abnormal Blood vessels dilated, twisted later stages - sparse, perivenular lymphohistiocytic infiltrates... 

There is a long-standing hypothesis that the microvasculature plays a pathological role in forms of chronic inflammatory polyarthritis, particularly RA (Rothschild and Masi, 1982). One of the proposed mechanisms of vascular damage in connective tissue disease is the direct action of a cytotoxic serum factor inducing endothelial cell damage. Blake et al. (1985) have su ested that the vascular abnormalities associated with RA may be linked to oxidized lipoproteins because they are cytotoxic to endothelial cells. 

As discussed in Section 3.3, few histopathological studies of asthma have focused specifically on the microvasculature. Nonetheless, there is evidence that neovascularization is one of the changes in the airways of asthmatics (Kuwano et al., 1991). This observation in potentially important because newly formed blood vessels may be abnormally leaky (Schoefl, 1967) or abnormally responsive to inflammatory mediators (McDonald, 1992). The plasma leakage that occurs in the airway mucosa of asthmatics could result from the heightened response of the mucosal blood vessels to inflammatory mediators. 

Women with sickle cell disease are predisposed to occlusion of the microvasculature (because of abnormal, inflexible red blood cells). Studies of women with sickle cell disease have shown no significant differences between OC users and non-users with regard to coagulation studies, blood viscosity measurements, or incidence or severity of painful sickle cell crisis. 

There is an increase in serum creatine kinase concentration and electromyography abnormalities. Other serum enzymes, such as the alanine transaminase, aspartate transaminase, and lactate dehydrogenase, also may be increased. Muscle biopsies show a necrotizing inflammatory process. The skin lesions of dermatomyositis show an immune-complex-mediated necrosis of the microvasculature. PM... 

Scleroderma (systemic sclerosis) is a disease of unknown etiology characterized by abnormally increased collagen deposition in the skin and visceral organs, alterations in the microvasculature, and numerous cellular and humoral immune abnormalities. A recent study in the United States estimated the disease prevalence to be approximately 25 per 100 000 (Mayes et al., 2003). Besides a racial... 

Fig. 4.2. Flow chart describing the mechanisms responsible for the increase in geometric and viscous resistance to flow caused by structural and functional abnormalities of the tumor microvasculature, which lead to a hostile tumor microenvironment...

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