Normal Plasma Constituents

HSA is the single most abundant protein in blood (Table 12.7). Its normal concentration is approximately 42 g 1 1, representing 60 per cent of total plasma protein. The vascular system of an average adult thus contains in the region of 150 g of albumin. HSA is responsible for over 80 per cent of the colloidal osmotic pressure of human blood. More than any other plasma constituent, HSA is thus responsible for retaining sufficient fluid within blood vessels. It has been aptly described as the protein that makes blood thicker than water. 

Pharmacokinetics Sodium bicarbonate in water dissociates to provide sodium and bicarbonate ions. Sodium is the principal cation of extracellular fluid. Bicarbonate is a normal constituent of body fluids and normal plasma level ranges from 24 to 31 mEq/L. Plasma concentration is regulated by the kidney. Bicarbonate anion is considered labile because, at a proper concentration of hydrogen ion, it may be converted to carbonic acid, then to its volatile form, carbon dioxide, excreted by lungs. Normally, a ratio of 1 20 (carbonic acid bicarbonate) is present in extracellular fluid. In a healthy adult with normal kidney function, almost all the glomerular filtered bicarbonate ion is reabsorbed less than 1% is excreted in urine. 

As an alternate approach to separating these can-nabinoids from endogenous plasma constituents, some bonded phase columns operated in a normal phase mode were investigated. Prior experience in our laboratory (13) had demonstrated the dependability of silica gel when used to process numerous plasma samples. That is, resolution was unaffected by the numerous endogenous plasma constituents continually placed on the column. 

Both normal phase and reverse phase HPLC methods were studied as analytical techniques for analysis of I and VI in human plasma. Normal phase was found to be more satisfactory for separation of I from plasma constituents whereas reverse phase was the choice for VI. Although reverse phase HPLC could be used to simultaneously assay for both I and VI when placed directly on the instrument, it was not practical for analysis of plasma extracts. 

The only nonbone condition in which elevated activities of TR-ACP are found in serum is Gaucher s disease of spleen, a lysosomal storage disorder. Its source in this disease is the abnormal macrophages in spleen and other tissues, which overexpress this normal macrophage constituent. The hairy cells of hairy-ceU leukemia (leukemic reticuloendotheliosis) also express the osteoclast-type AGP, providing a useful histological marker. However, in this condition, the isoenzyme does not enter the plasma in increased amounts. 

However, a number of studies have identified heparin as a trace constituent of normal plasma . The least concentration of free heparin which... 

Bannon, P. D., and G. H. EriedeU. 1966. Values for plasma constituents in normal and tumor bearing golden hamsters. Laboratory Animal Care 16 417 20. 

The current concept of atherosclerosis fonnation postulates that arterial injury occurs first followed by a sequence of events culminating in plaque deposits. The two prevalent theories of plaque pathogenesis are the infiltration concept and the thrombogenic theory. They involve different mechanisms and are not easily reconcilable. The filtration theory presumes that the plasma constituents which normally diffuse into the vessel wall from the luminal surface are localized at the injury site initiating plaque formation. In the other major theory, mural thrombi adhere to the injury surface and become incorporated into the wall by an overgrowth of endothelium. The type of plaque formed is dependent upon the ratio of the adhering materials, platelets and fibrin. 

Lipids circulate in blood as constituents of the lipoproteins or bound to albumin (free fatty acids). Electrophoretic separation of plasma proteins on paper is a relatively easy and convenient method for the semi-quantitative analysis of lipoproteins. Staining the strips with dyes which only respond to lipids reveals three well-defined bands when normal plasma or serum is analyzed. The a-lipoprotein migrates the farthest from the origin. The pre-j8, previously called the a-2-hpoprotein, and the jS-Hpoprotein, are closer to the origin. In the post-prandial normal serum, and in some hyperlipemic sera, after fasting, a fourth band can be seen at the origin. This band is due to neutral fat particles with a small protein content (i.e. chylomicron fraction). 

To examine a sample by inductively coupled plasma mass spectrometry (ICP/MS) or inductively coupled plasma atomic-emission spectroscopy (ICP/AES) the sample must be transported into the flame of a plasma torch. Once in the flame, sample molecules are literally ripped apart to form ions of their constituent elements. These fragmentation and ionization processes are described in Chapters 6 and 14. To introduce samples into the center of the (plasma) flame, they must be transported there as gases, as finely dispersed droplets of a solution, or as fine particulate matter. The various methods of sample introduction are described here in three parts — A, B, and C Chapters 15, 16, and 17 — to cover gases, solutions (liquids), and solids. Some types of sample inlets are multipurpose and can be used with gases and liquids or with liquids and solids, but others have been designed specifically for only one kind of analysis. However, the principles governing the operation of inlet systems fall into a small number of categories. This chapter discusses specifically substances that are normally liquids at ambient temperatures. This sort of inlet is the commonest in analytical work. 

Several of the neurotransmitters are small-molecule amines such as dopamine, serotonin, epinephrine, and norepinephrine. These neurotransmitters are synthesized in the cytoplasm of the axon terminal and subsequently transported into and stored within the synaptic vesicles. The amino acids glycine and glutamic acid are normal constituents of proteins and are present in abundance in the axons. These are also stored in synaptic vesicles. Each electrical impulse that arrives at the presynaptic side of a synapse will cause only a small minority of the synaptic vesicles to fuse with the plasma membrane and discharge their contents. The remaining synaptic vesicles remain, waiting for subsequent electrical impulses. At the same time, neurotransmitter synthesis continues, as does their storage in synaptic vesicles. This tends to restore the full complement of amine neurotransmitters at the axon terminal. 

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