Stimulated Body Fluid

Table 12.1 Ion concentrations of human blood plasma and stimulated body fluids (SBFs) [52].

A new analytical approach involving time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to probe biomineralization process utilizing phosphoester/phosphonic acid containing polyphosphazenes (155) after exposure to stimulated body fluid. ... 

Fretting in air-saturated aqueous electrolytes, such as seawater or body fluids , produces enhanced removal of material by stimulation of electrochemical reactions, increasing the reaction rates by factors of 10 to 200 compared with air, depending on the frequency. The importance of the chemical... 

The potent antidiuretic hormone AVP orchestrates the regulation of free water absorption, body fluid osmolality, cell contraction, blood volume, and blood pressure through stimulation of three G-protein-coupled receptor subtypes Vi-vascular types a and b, V2-renal, and V3-pituitary. Increased AVP secretion is the trademark of several pathophysiological disorders, including heart failure, impaired renal function, liver cirrhosis, and SIADH. As a consequence, these patients experience excess water retention or inadequate free-water excretion, which results in the dilution of sodium concentrations, frequently manifesting as clinical hyponatremia (serum sodium concentration <135mmol/L). This electrolyte imbalance increases mortality rates by 60-fold. Selective antagonism of the AVP V2 receptor promotes water... 

The establishment of quantitative methods for the determination of vitamins in body fluids and tissues by microbiological assay techniques should stimulate the search for the significance of vitamins in disease, not only in nutritional deficiency, but in the much wider field of all metabolic disturbances. Functional vitamin deficiencies are produced by malabsorption, by inhibitors of the vitamin function through products of the body, and particularly through drugs and other toxic substances. Vitamin deficiencies may be relative deficiencies whenever an individual s metabolism is deranged so as to require enhanced quantities of a given vitamin to cure or to counteract certain symptoms as, e.g., in Darier s disease (keratosis follicularis) (P2a). 

Clinical chemistry, initiated in the 1940s. involves the biochemical testing of body fluids to provide objective information on which to base clinical diagnosis. The ever-increasing demand for high quality, routine clinical testing stimulated the development of automated techniques, and as early as the 1960s automation in the clinical laboratory was the rule rather than tlie exception. 

Neopterin. Neopterin is a low-molecular-weight substance derived from guanosine triphosphate (GTP) via the enzyme GTP-cyclohydrolase 1. Numerous investigators have demonstrated that neopterin, a product of human macrophages stimulated by y interferon and other cytokines, is a useful in vivo marker of the activation of cellular immunity (U4, Wl). Increased values of neopterin in body fluids have been reported in patients with malignancy, infections, and several inflammatory states. 

The non-specific tritiation of papaverine ha been described,13 as have methods for the detection of the alkaloid in body fluids.1415 The effects of papaverine on the biochemical fate of thymidine phosphate in the thymus,16 on cyclic AMP and the uptake of calcium in isolated pig auricle,17 on the monosynaptic reflex,18 on the L-DOPA-influenced secretion of GH and PRL,19 on cerebral blood flow,20 and on longitudinal smooth muscle21 have been studied, as have the /3-receptor-stimulant... 

Acute on top of chronic poisoning occurs in individuals who have been on a chronic lithium prescription, and who in one way or another ingest an overdose of the lithium, or are given medications that increase lithium levels. Conditions where sodium conservation is stimulated, such as low salt intake, loss of body fluid by way of vomiting, diarrhea, or use of diuretics which decrease hthium clearance (thiazides) are usually the precipitating factors. 

Concentrations of adrenal mineralocorticoids (e.g., aldosterone and DOC) and factors of the renin-angiotensin system (e.g., renin) are routinely measured in body fluids by various immunoassay and instrument-based methods. Aldosterone, like cortisol, is secreted episodically, with the highest circulating concentrations at about the time of awakening and the lowest concentrations shortly after sleep onset aldosterone concentrations, however, are only modestly stimulated by ACTH secretion.In healthy subjects, a low-sodium diet, maintaining an upright posture, and use of diuretics ail increase plasma aldosterone concentrations,... 

AVP is a pituitary peptide hormone that plays an important role in regulation of renal water and solute excretion. AVP secretion is linked directly to changes in plasma osmolality, thus attempting to maintain body fluid homeostasis. The physiologic effects of AVP are mediated through the Via and V2 receptors. Via receptors are located in vascular smooth muscle and in myocytes, where their stimulation by AVP results in vasoconstriction and increased cardiac contractility, respectively. V2 receptors are located in the collecting duct of the kidney, where AVP stimulation causes reabsorption of free water. 

Guan, Y Hao, C Cha, D.R. et al. (2005) Thiazolidinediones expand body fluid volume through PPARy stimulation of ENaC-mediated renal salt absorption. Nature Medicine, 11, 861-866. 

Heart Valves and Pacemakers. Pacemakers, which regulate the heart beat by electrical stimulation, have been used on humans since 1952, and implantable models have been used since 1958. The wires and electrodes are usually plastic coated for purposes of insulation, and the entire device is usually embedded in a plastic for protection from the body fluids. Over 60,000 of these pacemakers are placed in people each year. 

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