Vascular system peripheral

Blood Access Devices. An investigational device called the Osteoport system allows repeated access to the vascular system via an iatraosseous iafusion directiy iato the bone marrow. The port is implanted subcutaneously and secured iato a bone, such as the iUac crest. Medications are adrninistered as ia any conventional port, but are taken up by the venous sinusoids ia the marrow cavity, and from there enter the peripheral circulation (8). 

Cramping sensation in the leg or buttock precipitated reproducibly by walking or exercise that occurs as a result of decreased oxygen supply due to severe atherosclerotic disease of the peripheral vascular system. It typically subsides after a brief rest. 

The pathophysiologic mechanisms of portal hypertension and of cirrhosis itself are entwined with the mechanisms of ascites (Fig. 19-3). Cirrhotic changes and the subsequent decrease in synthetic function lead to a decrease in production of albumin (hypoalbuminemia). Albumin is the major intravascular protein involved in maintaining oncotic pressure in the vascular system low serum albumin levels and increased capillary permeability allow fluid to leak from the vascular space into body tissues. This can result in peripheral edema, ascites, and fluid in the pulmonary system. The obstruction of hepatic sinusoids and... 

It is found in many cellular complexes, such as the CNS, the peripheral nervous system and the cardio vascular system, but it also appears in blood cells. 

Most types of smooth muscle are dependent on transmembrane calcium influx for normal resting tone and contractile responses. These cells are relaxed by the calcium channel blockers (Figure 12-3). Vascular smooth muscle appears to be the most sensitive, but similar relaxation can be shown for bronchiolar, gastrointestinal, and uterine smooth muscle. In the vascular system, arterioles appear to be more sensitive than veins orthostatic hypotension is not a common adverse effect. Blood pressure is reduced with all calcium channel blockers. Women may be more sensitive than men to the hypotensive action of diltiazem. The reduction in peripheral vascular resistance is one mechanism by which these agents may benefit the patient with angina of effort. Reduction of coronary artery tone has been demonstrated in patients with variant angina. 

The u.se of agents that directly affect the peripheral component of the sympathetic nervous system represents an important approach to the treatment of hypertension. A second approach to modifying sympathetic influence on the conllo-vascular. system is through inhibition or reduction of CNS control of blixxl pressure. Several widely used medicalirss act by stimulating receptors, which in the CNS reducer sympathetic outflow to the cardiovascular system and produces a hypotensive effect. 

Interest in thrombolytic therapy for acute ischemic stroke re-emerged with reports of successful thrombolysis for arterial thrombosis in the peripheral vascular system. Local lA infusion was found to have higher rates of recanalization compared with systemic IV delivery of thrombolytics without increased levels of hemorrhagic complications IV use of UK and SK was found to provide clinical benefit in patients with pulmonary embolism [5, 6]. In the early 1980s, lA infusion of UK or SK for acute MI was shown to be highly effective [5, 6]. At the same time, technical advances in endovascnlar microcatheter and microguidewire design made access to the intracranial vessels safer... 

Brakkee, A.J. and Vendrik, A.J., Arterio-venous shunts in peripheral vascular systems, Pflugers Arch., 1970, 314, 170. 

The chemistry and biochemistry of the tocopherylquinones and tocopherols has been recently reviewed in some detail. The first recognized function of vitamin E was as an antisterility factor for the laboratory rat. However, it is now known to have multiple functions in vivo. For example, it is required for the maintenance of structural and functional integrity of skeletal, cardiac, and smooth muscle and, in some animals, the peripheral vascular system. Tocopherols also function as intracellular antioxidants, particularly with respect to the stabilization of ingested fats and perhaps products arising in the metabolic synthesis and degradation of lipids. It has also been proposed that the tocopherylquinones may have some functional role in electron transport systems. 

The presence of hyperphosphatemia for extended periods of time may lead to additional manifestations. Calcium deposits in vascular cells may leadtoateriosclerosis (hardened arterial walls), which, in turn, will cause increased systolic blood pressure, widening pulse pressure, and eventually hypertrophy of the left ventricle of the heart. When the calcium deposits occur in the peripheral vascular system, the person may develop ulcerations and gangrene in the affected extremities. 

Cardiovascular system symptoms—If the thiamin deficiency persists, the heart muscles weaken and heart failure may result Also, the smooth muscles of the vascular system may be involved, causing peripheral vasodilation. As a result of cardiac failure, peripheral ema may be observed in the extremities. 

Many toxic substances also affect the peripheral vascular system (e.g. ergo-tamine and several toxins). These effects tend to he chroiuc, however, and outside the remit of the discussion of toxic trauma as an acute phenomenon. 

In essential hypertension there is an increase in peripheral resistance of the vascular system due to constriction of the peripheral arterioles and, as a compensatory mechanism, the diastolic and systolic blood pressures become elevated. However, the nature of the disturbances that cause this t3rpe of vasoconstriction in the absence of recognizable structural disease is not known. 

---