Lymphatic flow clearance

Conjunctiva and Tenon s capsule 1) Diffusion across these tissues 2) Clearance via conjunctival blood and lymphatic flow 1) In vitro permeability of rabbit conjunctiva and Tenon s capsule 2) Limited data on blood and lymphatic flow and on capillary permeabiUty... 

Both the epidermal flux and the viable epidermal concentrations of topically applied solutes are dependent on clearance from the dermis and binding in the dermis. Factors deflning this clearance and binding have been considered in this chapter. In addition, examples of altered percutaneous absorption fluxes or tissue levels as a consequence of changes in blood flow, lymphatic flow, and altered binding have been summarized. 

The osteopathic treatment of sinusitis has several goals to relieve obstruction and pain to improve venous and lymphatic flow from the area to affect reflex changes and to improve mucociliary clearance. Several manual techniques have been designed to aid in achieving these goals. Although only one set of sinuses may produce pain, the entire series of techniques should be performed to assist drainage of all the sinus areas. 

Once an antibody has egressed into the interstitial space, its movement is somewhat more complicated than simple diffusion around the interstitial space (until it binds to epitope) or flow into lymphatics for mononuclear phagocytic clearance. There are a number of mechanisms by which antibodies (that are not bound via CDR to target or a cross-reactive epitope) are transported across and to a variety of cell types. Below are discussed several specialized and/or tissue-specific mechanisms of IgG transport and/or clearance. 

Whether an increase in vascular permeability results in mucosal edema depends on the balance between the amount of leakage into the mucosa and the rate of clearance from the mucosa, either through the lymphatics or across the epithelium into the airway lumen. The increase of vascular permeability produced by inflammatory stimuli can result in the bulk flow of plasma into the airway mucosa (Renkin, 1992). The amount of plasma leakage depends upon the number of gaps that form in the endothelium of the leaky vessels, the duration of the gaps and the intravascular pressure that drives the extravasation (Clough, 1991 Taylor and Ballard, 1992). The movement of plasma proteins and other osmotically active solutes into the mucosa can increase the interstitial oncotic pressure, which favors the net movement of fluid out of vessels and further increases the amount of leakage (Taylor and Ballard, 1992). 

Dermal Blood Flow, Lymphatics, and Binding as Determinants of Topical Absorption, Clearance, and Distribution... 

Most studies on percutaneous absorption emphasize the penetration of drugs, toxins, and other solutes into and through the skin as described in this book. Percutaneous absorption is also dependent on the clearance of solutes from the skin and transport into deeper layers of the skin (Figure 13.1). Clearance mechanisms in the avascular viable epidermis, diffusion in the dermis, and export from/within the dermis include solute diffusion and physiological transport by the dermal blood and lymphatic systems. This chapter focuses on the nature of these clearance mechanisms and how they affect the rates of percutaneous absorption and the levels of solute in skin and tissue. We consider first the role of blood flow, followed by the role of binding, transport to deeper tissues, and then the role of lymphatics. 

Static barriers (different layers of cornea, sclera, and retina, including blood aqueous and blood-retinal barriers), dynamic barriers (choroidal and conjunctival blood flow, lymphatic clearance, and tear dilution), and efflux pumps in conjunction pose a significant challenge for delivery of a drug alone or in dosage form, especially to the posterior segment. 

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