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PAH Clearance
Para-aminohippurate (PAH) clearance is a method used in renal physiology to measure renal plasma flow, which is a measure of renal function. PAH is completely removed from blood that passes through the kidneys (PAH undergoes both glomerular filtration and tubular secretion), and therefore the rate at which the kidneys can clear PAH from the blood reflects total renal plasma flow. The concentration of PAH is measured in one arterial blood sample (PPAH) and one urine sample(UPAH). The urine flow (V) is also measured. Renal perfusion flow is then calculated by: :RPF = \frac V What is calculated is the effective renal plasma flow (eRPF). However, since the renal extraction ratio of PAH almost equals 1, then eRPF almost equals RPF. Precision The renal extraction ratio of PAH in a normal individual is approximately 0.92, and thus not exactly 1.0. Thus, this method usually underestimates RPF by approximately 10%. This margin of error is generally acceptable considering the ease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Para-aminohippurate
Aminohippuric acid or ''para''-aminohippuric acid (PAH), a derivative of hippuric acid, is a diagnostic agent useful in medical tests involving the kidney used in the measurement of renal plasma flow. It is an amide derivative of the amino acid glycine and para-aminobenzoic acid, ''para''-aminobenzoic acid that is not naturally found in humans; it needs to be IV infused before diagnostic use. Uses Diagnostics PAH is useful for the measurement of renal plasma flow. The renal extraction ratio of PAH in a normal individual is approximately 0.92. This means that unlike inulin and creatinine, which are filtered in the glomerulus and ignored by the rest of the kidney, aminohippuric acid is both filtered and secreted, being almost entirely removed from the bloodstream in a normal kidney. Pharmaceuticals Aminohippuric acid is often used as the sodium salt (chemistry), salt sodium ''para''-aminohippurate. During World War II, ''para''-aminohippurate was given along with penicillin in o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Renal Physiology
Renal physiology (Latin ''rēnēs'', "kidneys") is the study of the physiology of the kidney. This encompasses all functions of the kidney, including maintenance of acid-base balance; regulation of fluid balance; regulation of sodium, potassium, and other electrolytes; clearance of toxins; absorption of glucose, amino acids, and other small molecules; regulation of blood pressure; production of various hormones, such as erythropoietin; and activation of vitamin D. Much of renal physiology is studied at the level of the nephron, the smallest functional unit of the kidney. Each nephron begins with a filtration component that filters the blood entering the kidney. This filtrate then flows along the length of the nephron, which is a tubular structure lined by a single layer of specialized cells and surrounded by capillaries. The major functions of these lining cells are the reabsorption of water and small molecules from the filtrate into the blood, and the secretion of wastes f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Renal Plasma Flow
In the physiology of the kidney, renal blood flow (RBF) is the volume of blood delivered to the kidneys per unit time. In humans, the kidneys together receive roughly 25% of cardiac output, amounting to 1.2 - 1.3 L/min in a 70-kg adult male. It passes about 94% to the cortex. RBF is closely related to renal plasma flow (RPF), which is the volume of blood plasma delivered to the kidneys per unit time. While the terms generally apply to arterial blood delivered to the kidneys, both RBF and RPF can be used to quantify the volume of venous blood exiting the kidneys per unit time. In this context, the terms are commonly given subscripts to refer to arterial or venous blood or plasma flow, as in RBFa, RBFv, RPFa, and RPFv. Physiologically, however, the differences in these values are negligible so that arterial flow and venous flow are often assumed equal. Renal plasma flow Renal plasma flow is the volume of plasma that reaches the kidneys per unit time. Renal plasma flow is given ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Renal Function
Assessment of kidney function occurs in different ways, using the presence of symptoms and signs, as well as measurements using urine tests, blood tests, and medical imaging. Functions of a healthy kidney include maintaining a person's fluid balance, maintaining an acid-base balance; regulating electrolytes including sodium, potassium, and other electrolytes; clearing toxins; regulating blood pressure; and regulating hormones, such as erythropoietin; and activation of vitamin D. Introduction The functions of the kidney include maintenance of acid-base balance; regulation of fluid balance; regulation of sodium, potassium, and other electrolytes; clearance of toxins; absorption of glucose, amino acids, and other small molecules; regulation of blood pressure; production of various hormones, such as erythropoietin; and activation of vitamin D. Much of renal physiology is studied at the level of the nephron, the smallest functional unit of the kidney. Each nephron begins w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arterial Blood Sample
In medicine, sampling is gathering of matter from the body to aid in the process of a medical diagnosis and/or evaluation of an indication for treatment, further medical tests or other procedures. In this sense, the sample is the gathered matter, and the sampling tool or sampler is the person or material to collect the sample. Sampling is a prerequisite for many medical tests, but generally not for medical history, physical examination and radiologic tests. By sampling technique *Obtaining excretions or materials that leave the body anyway, such as urine, stool, sputum, or vomitus, by direct collection as they exit. A sample of saliva can also be collected from the mouth. Excision (cutting out), a surgical method for the removal of solid or soft tissue samples. *Puncture (also called ''centesis'') followed by aspiration is the main method used for sampling of many types of tissues and body fluids. Examples are thoracocentesis to sample pleural fluid, and amniocentesis to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urine Flow Rate
Urine flow rate or urinary flow rate is the volumetric flow rate of urine during urination. It is a measure of the quantity of urine excreted in a specified period of time (per second or per minute). It is measured with uroflowmetry, a type of flow measurement. The letters "V" (for volume) and "Q" (a conventional symbol for flow rate) are both used as a symbol for urine flow rate. The V often has a dot (overdot), that is, V̇ ("V-dot"). Qmax indicates the maximum flow rate. Qmax is used as an indicator for the diagnosis of enlarged prostate. A lower Qmax may indicate that the enlarged prostate puts pressure on the urethra, partially occluding it. Uroflowmetry is performed by urinating into a special urinal, toilet, or disposable device that has a measuring device built in. The average rate changes with age. Clinical usage Changes in the urine flow rate can be indicative of kidney, prostate or other renal disorders. Similarly, by measuring urine flow rate, it is possible to calcu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Effective Renal Plasma Flow
Effective renal plasma flow (eRPF) is a measure used in renal physiology to calculate renal plasma flow (RPF) and hence estimate renal function. Because the extraction ratio of PAH is high, it has become commonplace to estimate the RPF by dividing the amount of PAH in the urine by the plasma PAH level, ignoring the level in renal venous blood. The value obtained in this way is called the effective renal plasma flow (eRPF) to indicate that the level in renal venous plasma was not measured. The actual RPF can be calculated from eRPF as follows: : \text = \frac where extraction ratio is the ratio of compound entering the kidney that is excreted into the final urine. When using a compound with an extraction ratio near 1, such as para-aminohippurate Aminohippuric acid or ''para''-aminohippuric acid (PAH), a derivative of hippuric acid, is a diagnostic agent useful in medical tests involving the kidney used in the measurement of renal plasma flow. It is an amide derivative of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extraction Ratio
Extraction ratio is a measure in renal physiology, primarily used to calculate renal plasma flow in order to evaluate renal function. It measures the percentage of the compound entering the kidney that was excreted into the final urine. Texas Tech University Health Sciences Center Measured in concentration in , it may thus be expressed as: : , where Pa is the concentration in , and Pv is the concentration in the |
Renal Blood Flow
In the physiology of the kidney, renal blood flow (RBF) is the volume of blood delivered to the kidneys per unit time. In humans, the kidneys together receive roughly 25% of cardiac output, amounting to 1.2 - 1.3 L/min in a 70-kg adult male. It passes about 94% to the cortex. RBF is closely related to renal plasma flow (RPF), which is the volume of blood plasma delivered to the kidneys per unit time. While the terms generally apply to arterial blood delivered to the kidneys, both RBF and RPF can be used to quantify the volume of venous blood exiting the kidneys per unit time. In this context, the terms are commonly given subscripts to refer to arterial or venous blood or plasma flow, as in RBFa, RBFv, RPFa, and RPFv. Physiologically, however, the differences in these values are negligible so that arterial flow and venous flow are often assumed equal. Renal plasma flow Renal plasma flow is the volume of plasma that reaches the kidneys per unit time. Renal plasma flow is given ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Renal Physiology
Renal physiology (Latin ''rēnēs'', "kidneys") is the study of the physiology of the kidney. This encompasses all functions of the kidney, including maintenance of acid-base balance; regulation of fluid balance; regulation of sodium, potassium, and other electrolytes; clearance of toxins; absorption of glucose, amino acids, and other small molecules; regulation of blood pressure; production of various hormones, such as erythropoietin; and activation of vitamin D. Much of renal physiology is studied at the level of the nephron, the smallest functional unit of the kidney. Each nephron begins with a filtration component that filters the blood entering the kidney. This filtrate then flows along the length of the nephron, which is a tubular structure lined by a single layer of specialized cells and surrounded by capillaries. The major functions of these lining cells are the reabsorption of water and small molecules from the filtrate into the blood, and the secretion of wastes f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
