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Urea Breath Test
The urea breath test is a rapid diagnostic procedure used to identify infections by ''Helicobacter pylori'', a spiral bacterium implicated in gastritis, gastric ulcer, and peptic ulcer disease. It is based upon the ability of ''H. pylori'' to convert urea to ammonia and carbon dioxide. Urea breath tests are recommended in leading society guidelines as a preferred non-invasive choice for detecting ''H. pylori'' before and after treatment. Principles and mechanism Patients swallow urea labelled with an uncommon isotope, either radioactive carbon-14 or non-radioactive carbon-13. In the subsequent 10–30 minutes, the detection of isotope-labelled carbon dioxide in exhaled breath indicates that the urea was split; this indicates that urease (the enzyme that ''H. pylori'' uses to metabolize urea) is present in the stomach, and hence that ''H. pylori'' bacteria are present. For the two different forms of urea, different instrumentation is required. Carbon-14 is normally measured by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medical Diagnosis
Medical diagnosis (abbreviated Dx, Dx, or Ds) is the process of determining which disease or condition explains a person's symptoms and signs. It is most often referred to as diagnosis with the medical context being implicit. The information required for diagnosis is typically collected from a history and physical examination of the person seeking medical care. Often, one or more diagnostic procedures, such as medical tests, are also done during the process. Sometimes posthumous diagnosis is considered a kind of medical diagnosis. Diagnosis is often challenging because many signs and symptoms are nonspecific. For example, redness of the skin (erythema), by itself, is a sign of many disorders and thus does not tell the healthcare professional what is wrong. Thus differential diagnosis, in which several possible explanations are compared and contrasted, must be performed. This involves the correlation of various pieces of information followed by the recognition and differentiat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metabolism
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the conversion of food to building blocks for proteins, lipids, nucleic acids, and some carbohydrates; and the elimination of metabolic wastes. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. The word metabolism can also refer to the sum of all chemical reactions that occur in living organisms, including digestion and the transportation of substances into and between different cells, in which case the above described set of reactions within the cells is called intermediary (or intermediate) metabolism. Metabolic reactions may be categorized as ''catabolic'' – the ''breaking down'' of compounds (for example, of glucose to pyruvate by ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breath Tests
A breath test is a type of test performed on air generated from the act of exhalation. Types include: *Breathalyzer – by far the most common usage of this term relates to the legal breath test to determine if a person is driving under the influence of alcohol (drug), alcohol. *Hydrogen breath test – it is becoming more and more common for people to undertake a medical test for clinical medical diagnosis, diagnosis of dietary disabilities such as Hereditary fructose intolerance, fructose intolerance, fructose malabsorption, lactose intolerance and lactulose, lactulose intolerance. *The presence of ''Helicobacter pylori'' (in peptic ulcer disease) can be tested for with the urea breath test. *Exhaled nitric oxide is a breath test that might signal airway inflammation such as in asthma. *Breath tests for diseases have been developed for early detection of lung cancer, breast cancer, Tuberculosis, pulmonary tuberculosis and many others, to serve as an adjunct to existing medical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breath Test
A breath test is a type of test performed on air generated from the act of exhalation. Types include: *Breathalyzer – by far the most common usage of this term relates to the legal breath test to determine if a person is driving under the influence of alcohol (drug), alcohol. *Hydrogen breath test – it is becoming more and more common for people to undertake a medical test for clinical medical diagnosis, diagnosis of dietary disabilities such as Hereditary fructose intolerance, fructose intolerance, fructose malabsorption, lactose intolerance and lactulose, lactulose intolerance. *The presence of ''Helicobacter pylori'' (in peptic ulcer disease) can be tested for with the urea breath test. *Exhaled nitric oxide is a breath test that might signal airway inflammation such as in asthma. *Breath tests for diseases have been developed for early detection of lung cancer, breast cancer, Tuberculosis, pulmonary tuberculosis and many others, to serve as an adjunct to existing medical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Endoscopy
Esophagogastroduodenoscopy (EGD) or oesophagogastroduodenoscopy (OGD), also called by various other names, is a diagnostic endoscopic procedure that visualizes the upper part of the gastrointestinal tract down to the duodenum. It is considered a minimally invasive procedure since it does not require an incision into one of the major body cavities and does not require any significant recovery after the procedure (unless sedation or anesthesia has been used). However, a sore throat is common. Alternative names The words ''esophagogastroduodenoscopy'' (EGD; American English) and ''oesophagogastroduodenoscopy'' (OGD; British English; see spelling differences) are both pronounced . It is also called ''panendoscopy'' (PES) and ''upper GI endoscopy''. It is also often called just ''upper endoscopy'', ''upper GI'', or even just ''endoscopy''; because EGD is the most commonly performed type of endoscopy, the ambiguous term ''endoscopy'' is sometimes informally used to refer to EGD by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biopsy
A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a disease. The tissue is then fixed, dehydrated, embedded, sectioned, stained and mounted before it is generally examined under a microscope by a pathologist; it may also be analyzed chemically. When an entire lump or suspicious area is removed, the procedure is called an excisional biopsy. An incisional biopsy or core biopsy samples a portion of the abnormal tissue without attempting to remove the entire lesion or tumor. When a sample of tissue or fluid is removed with a needle in such a way that cells are removed without preserving the histological architecture of the tissue cells, the procedure is called a needle aspiration biopsy. Biopsies are most commonly performed for insight into possible cancerous or inflammatory conditions. History T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rapid Urease Test
Rapid urease test, also known as the CLO test (Campylobacter-like organism test), is a rapid diagnostic test for diagnosis of ''Helicobacter pylori''. The basis of the test is the ability of ''H. pylori'' to secrete the urease enzyme, which catalyzes the conversion of urea to ammonia and carbon dioxide. Process The test is performed at the time of gastroscopy. A biopsy of mucosa is taken from the antrum of the stomach, and is placed into a medium containing urea and an indicator such as phenol red. The urease produced by ''H. pylori'' hydrolyzes urea to ammonia, which raises the pH of the medium, and changes the color of the specimen from yellow (NEGATIVE) to red (POSITIVE). Among different kinds of rapid urease tests (liquid-based, gel-based, dry cool) there is a design type with single-layer sensitive element — a layer impregnated simultaneously with urea and an indicator composition. Such a design bears the risk of false-positive result due to the pH value of the gastric biop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proton Pump Inhibitor
Proton-pump inhibitors (PPIs) are a class of medications that cause a profound and prolonged reduction of stomach acid production. They do so by irreversibly inhibiting the stomach's H+/K+ ATPase proton pump. They are the most potent inhibitors of acid secretion available. Proton-pump inhibitors have largely superseded the H2-receptor antagonists, a group of medications with similar effects but a different mode of action, and antacids. PPIs are among the most widely sold medications in the world. The class of proton-pump inhibitor medications is on the World Health Organization's List of Essential Medicines. Omeprazole is the specific listed example. Medical uses These medications are used in the treatment of many conditions, such as: * Dyspepsia * Peptic ulcer disease including after endoscopic treatment for bleeding * As part of ''Helicobacter pylori'' eradication therapy * Gastroesophageal reflux disease (GERD or GORD) including symptomatic endoscopy-negative reflux disea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Specificity (tests)
''Sensitivity'' and ''specificity'' mathematically describe the accuracy of a test which reports the presence or absence of a condition. Individuals for which the condition is satisfied are considered "positive" and those for which it is not are considered "negative". *Sensitivity (true positive rate) refers to the probability of a positive test, conditioned on truly being positive. *Specificity (true negative rate) refers to the probability of a negative test, conditioned on truly being negative. If the true condition can not be known, a " gold standard test" is assumed to be correct. In a diagnostic test, sensitivity is a measure of how well a test can identify true positives and specificity is a measure of how well a test can identify true negatives. For all testing, both diagnostic and screening, there is usually a trade-off between sensitivity and specificity, such that higher sensitivities will mean lower specificities and vice versa. If the goal is to return the ratio at w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensitivity (tests)
''Sensitivity'' and ''specificity'' mathematically describe the accuracy of a test which reports the presence or absence of a condition. Individuals for which the condition is satisfied are considered "positive" and those for which it is not are considered "negative". *Sensitivity (true positive rate) refers to the probability of a positive test, conditioned on truly being positive. *Specificity (true negative rate) refers to the probability of a negative test, conditioned on truly being negative. If the true condition can not be known, a " gold standard test" is assumed to be correct. In a diagnostic test, sensitivity is a measure of how well a test can identify true positives and specificity is a measure of how well a test can identify true negatives. For all testing, both diagnostic and screening, there is usually a trade-off between sensitivity and specificity, such that higher sensitivities will mean lower specificities and vice versa. If the goal is to return the ratio at w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isotope Ratio Mass Spectrometry
Isotope-ratio mass spectrometry (IRMS) is a specialization of mass spectrometry, in which mass spectrometric methods are used to measure the relative abundance of isotopes in a given sample. This technique has two different applications in the earth and environmental sciences. The analysis of ' stable isotopes' is normally concerned with measuring isotopic variations arising from mass-dependent isotopic fractionation in natural systems. On the other hand, radiogenic isotope analysis involves measuring the abundances of decay-products of natural radioactivity, and is used in most long-lived radiometric dating methods. Introduction The isotope-ratio mass spectrometer (IRMS) allows the precise measurement of mixtures of naturally occurring isotopes. Most instruments used for precise determination of isotope ratios are of the magnetic sector type. This type of analyzer is superior to the quadrupole type in this field of research for two reasons. First, it can be set up for multiple- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scintillation (physics)
Scintillation is the physical process where a material, called scintillator, emits UV or visible light under excitation from high energy photons (X-rays or γ-rays) or energetic particles,(such as electrons, alpha particles, neutrons or ions). See scintillator and scintillation counter for practical applications. Overview The process of scintillation is one of luminescence whereby light of a characteristic spectrum is emitted following the absorption of radiation. The scintillation process can be summarized in three main stages (A) conversion, (B) transport and energy transfer to the luminescence center, and (C) luminescence. The emitted radiation is usually less energetic than the absorbed radiation, hence generally scintillation is a down-conversion process. Conversion processes The first stage of scintillation, conversion, is the process where the energy from the incident radiation is absorbed by the scintillator and highly energetic electrons and holes are created in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
