Perivascular connective tissu

Rats exposed to 1.9mg/m for 4 hours/day, 6 days/week for 5 months showed inflammatory changes in the peribronchial and perivascular connective tissues. Long-term studies have shown no carcinogenic potential. Most mutagenicity data suggest that diquat is not mutagenic. ... 

The term stroma comprises the interstitial connective tissue of an organ. In the liver, four types of tissue structure are differentiated (7.) capsule of the liver, (2.) perivascular connective tissue, (S.) Glisson s portal tract, and (4.) reticular network. 

The perivascular fibrous capsule (R Glisson, 1654) commences in the hepatic porta as a tree-like branching framework of connective tissue surrounding the interlobular vessels. It also surrounds the central hepatic vein and its small tributaries, which are joined to the parenchyma by radial fibres as well as being established in the portal tracts. This prevents a suction-induced collapse of the venous vessels as a result of respiration-dependent negative pressure in the pleural cavity. The perivascular connective tissue, known as Glisson s capsule, extends fine secondary trabeculae into the parenchyma. They contain the intralobular biliary, lymphatic and blood capillaries. 

In the portal tract (= Glisson s triangle, portal field) (E Glisson, 1659), the perivascular connective tissue with its enclosed (and protected) radicles of the portal veins, the hepatic arterioles, bile ducts, lymph vessels and nerve fibres terminates in the connective tissue covering of the... 

Fig. 34.1 Chronic persistent hepatitis smooth liver surface with spotted, brick-red coloured pattern. Clearly pronounced blood vessels with perivascular connective tissue, fine perilobular fibrosis...

Lymphoid Elements. The thymus plays a central role in the differentiation of T lymphocytes (Cantor and Weissman, 1976), and although much recent emphasis has focused on the thymic epithelial cells, it must be emphasized that the thymus is a lymphoid structure composed predominantly of thymic lymphocytes or thyntocytes. The thymus can be viewed as a solid epithelial organ, penetrated by blood vessels and infiltrated with thymocytes in four discrete areas the subcapsular cortex, the inner cortex, the medulla, and the perivascular connective tissue. 

Generalized vascular changes in most monkeys were congestion swollen endothelial cells, with many intravascular large lymphocytes or lymphoblasts and inconsistent widening of perivascular connective tissue spaces (by edema). Hepatic lesions were portal infiltrates of lymphocytes, lymphoblasts, macrophages, and occasional neutrophils. The choroid plexus was slightly thickened (by edema). 

Azar et al. (1970) studied a chancre measuring 3 cm at its base and 2 cm in height. Electron microscopy revealed that Treponema pallidum organisms were principally located in intercellular spaces in the direct vicinity of small blood vessels. These organisms were, furthermore, observed within the cytoplasm of neutrophils, macrophages, endothelial and perivascular connective tissue cells, and within plasma cells. 

Muscle biopsy is usually undertaken to confirm the provisional clinical diagnosis. Because the skin lesions normally precede those in muscle, biopsies of muscle taken early may show little abnormality. Inflammatory foci may be scanty or absent and muscle fiber diameters may be normal. However typical biopsies show discrete foci of inflammatory cells, with a predominance of B-lymphocytes (see Figure 18). These cells are situated in perimysial connective tissue rather than in the en-domysium and are often also perivascular in location. Muscle fiber necrosis occurs in JDM but muscle fibers do not appear to be the primary target of the disordered immune process. Rather, it is the micro vasculature of the muscle which appears to degenerate first and muscle necrosis is preceded by capillary necrosis, detectable at the ultrastructural level. 

In some sections more or less extended epidermal necrosis and detachment of the epidermis are seen, in others intra-epidermal abcesses may be observed. In the upper dermis, the small vessels are dilated and there are extravasations. The infiltrate is very extensive, being composed of small round cells, connective tissue cells, and eosinophils. The eosinophils are intra- and perivascular. We cannot say, as we did in the sensitization with CA, that the infiltrate is largely composed of eosinophils, but we can affirm that these are much more numerous than in the sensitization with DNCB. 

De novo expression of eNOS was noted in mast cells located in the perivascular and peribronchial connective tissue of the rat limg in response to Upo-polysaccharide (Ermert et al. 2002). 

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