Kidney measurement

Concentrating ability of the kidney (measurement of urine osmolality assessed following withdrawal of food and water for 24 h free water clearance)... 

Figure 9.41 Lateral distributions of (a) , (b) Zn and (c) Pt on thin cross section of mouse kidney measured by LA-ICP-MS. (M. Zoriy, A. Matusch,...

Measurements such as creatinine clearance have been used successfully to adjust dosing regimens for drugs eliminated primarily by the kidneys. Measures of hepatic function have been sought using endogenous... 

BaumgartI H, Leichtweiss HP, Lubbers DW, Weiss C, Huland H The oxygen supply of the dog kidney measurements of intrarenal pO 2. Microvasc.Res. 4 247-257,1972... 

Cardiac nuclear imaging using Tc -red blood cells can measure the fraction of blood pumped by the heart during each beat. Tc -DTPA and sodium (9-iodohippurate, C H INNaO, are used to measure renal function of the kidney. The enhanced or diminished uptake of... 

Several hydrophilic, anionic technetium complexes can be used to perform imaging studies of the kidneys. Tc-Mertiatide (Fig. 5a) is rapidly excreted by active tubular secretion, the rate of which is a measure of kidney function. Tc-succimer (Fig. 5b), on the other hand, accumulates in kidney tissue thus providing an image of kidney morphology. 

The kidney is an important organ for the excretion of toxic materials and their metaboHtes, and measurement of these substances in urine may provide a convenient basis for monitoring the exposure of an individual to the parent compound in his or her immediate environment. The Hver has as one of its functions the metaboHsm of foreign compounds some pathways result in detoxification and others in metaboHc activation. Also, the Hver may serve as a route of elimination of toxic materials by excretion in bile. In addition to the Hver (bile) and kidney (urine) as routes of excretion, the lung may act as a route of elimination for volatile compounds. The excretion of materials in sweat, hair, and nails is usually insignificant. 

The first human kidney and bone marrow transplants using cyclosporine were reported in 1978. Oral or intravenous cyclosporine is an immunosuppressant for transplantation of these and other organs and investigations are underway for its possible use in a variety of autoimmune diseases including rheumatoid arthritis, severe psoriasis, and Crohn s disease. Dose-dependent nephrotoxicity (261—264) remains the primary limitation of the dmg and necessitates close monitoring of patients, including measurement of dmg levels in blood. Cyclosporine research has been reviewed (265—274). 

The absorption, distribution, and accumulation of lead in the human body may be represented by a three-part model (6). The first part consists of red blood cells, which move the lead to the other two parts, soft tissue and bone. The blood cells and soft tissue, represented by the liver and kidney, constitute the mobile part of the lead body burden, which can fluctuate depending on the length of exposure to the pollutant. Lead accumulation over a long period of time occurs in the bones, which store up to 95% of the total body burden. However, the lead in soft tissue represents a potentially greater toxicological hazard and is the more important component of the lead body burden. Lead measured in the urine has been found to be a good index of the amount of mobile lead in the body. The majority of lead is eliminated from the body in the urine and feces, with smaller amounts removed by sweat, hair, and nails. 

The quantification of kinins in human tissues or body fluids has been limited due to the inherent difficulties in accurately measuring the concentration of ephemeral peptides. Today HPLC-based and RIA/capture-ELA measurements are established to determine kinins in human plasma, liquor or mine. Serine protease inhibitors need to be added to prevent rapid degradation of the kinins in vitro during sample preparation. Kinins and their degradation products have been studied in various biological milieus such as plasma/ serum, urine, joint fluids, kidney, lung and skeletal muscle [2]. Under normal conditions, the concentration of kinins in these compartments is extremely low for... 

RISK FOR INEFFECTIVE TISSUE PERFUSION RENAL When the patient is taking a drag tiiat is potentially toxic to die kidneys, die nurse must carefully monitor fluid intake and output. In some instances, die nurse may need to perform hourly measurements of die urinary output. Periodic laboratory tests are usually ordered to monitor the patient s response to therapy and to detect toxic drag reactions. Seram creatinine levels and BUN levels are checked frequentiy during the course of therapy to monitor kidney function. If the BUN exceeds 40 mg dL or if the serum creatinine level exceeds 3 mg cIL, the primary health care provider may discontinue the drug therapy or reduce the dosage until renal function improves. 

The nurse must carefully monitor fluid intake and output because this drug may be nephrotoxic (harmful to the kidneys). In some instances, the nurse may need to perform hourly measurements of the urinary output. Periodic laboratory tests are usually ordered to monitor the patient s response to therapy and detect toxic drug reactions. 

The nurse measures the fluid intake and output, especially when the primary health care provider orders an increase in fluid intake or when a kidney infection is being treated. The primary health care provider may also order daily urinary pH levels when methenamine or nitrofurantoin is administered. These drugs work best in acid urine failure of the urine to remain acidic may require administration of a urinary acidifier, such as ascorbic acid. 

Following single dermal applications of 10 mg/kg of radiolabeled methyl parathion to pregnant rats, methyl parathion was found to be widely distributed to all major tissues and organs. Concentrations were highest in plasma and kidney, maximum levels measured 2 hours postapplication. Peak levels in liver, brain, fetus, and placenta, were measured 2 to 10 hours later, at which times the highest concentration of methyl parathion was in the fetus (Abu-Quare et al. 2000). 

Human erythropoietin is a glycoprotein of 166 amino acids (molecular mass about 34 kDa). Its amount in plasma can be measured by radioimmunoassay. It is the major regulator of human erythropoiesis. Erythropoietin is synthesized mainly by the kidney and is released in response to hypoxia into the bloodstream, in which it travels to the bone marrow. There it interacts with progenitors of red blood cells via a specific receptor. The receptor is a transmembrane protein consisting of two different subunits and a number of domains. It is not a tyrosine kinase, but it stimulates the activities of specific... 

The methods now used to measure 25-OH-D are competitive protein-ligand binding assays that use either serum globulin (diluted rat serum) (27)28) or a vitamin D-deficient rat kidney... 

While considerable amounts of both GOT and GPT are found in cardiac muscle, skeletal muscle and kidney, differential diagnosis is aided by the fact that the liver shows a much higher total GPT activity. An important clinical application of measurements of transaminase activity is the detection and diagnosis of viral... 

PBPK models have also been used to explain the rate of excretion of inhaled trichloroethylene and its major metabolites (Bogen 1988 Fisher et al. 1989, 1990, 1991 Ikeda et al. 1972 Ramsey and Anderson 1984 Sato et al. 1977). One model was based on the results of trichloroethylene inhalation studies using volunteers who inhaled 100 ppm trichloroethylene for 4 horns (Sato et al. 1977). The model used first-order kinetics to describe the major metabolic pathways for trichloroethylene in vessel-rich tissues (brain, liver, kidney), low perfused muscle tissue, and poorly perfused fat tissue and assumed that the compartments were at equilibrium. A value of 104 L/hour for whole-body metabolic clearance of trichloroethylene was predicted. Another PBPK model was developed to fit human metabolism data to urinary metabolites measured in chronically exposed workers (Bogen 1988). This model assumed that pulmonary uptake is continuous, so that the alveolar concentration is in equilibrium with that in the blood and all tissue compartments, and was an expansion of a model developed to predict the behavior of styrene (another volatile organic compound) in four tissue groups (Ramsey and Andersen 1984). 

The evaluation of the apparent ionization constants (i) can indicate in partition experiments the extent to which a charged form of the drug partitions into the octanol or liposome bilayer domains, (ii) can indicate in solubility measurements, the presence of aggregates in saturated solutions and whether the aggregates are ionized or neutral and the extent to which salts of dmgs form, and (iii) can indicate in permeability measurements, whether the aqueous boundary layer adjacent to the membrane barrier, Umits the transport of drugs across artificial phospholipid membranes [parallel artificial membrane permeation assay (PAMPA)] or across monolayers of cultured cells [Caco-2, Madin-Darby canine kidney (MDCK), etc.]. 

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