Calcium Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Calcium and links to relevant pages within the course.
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|Significance of Reactions at Different Phases of Testing|
Antibodies have optimum temperatures for reactivity. Reaction readings can be made at different phases: after immediate spin, after incubation at 37°C, and after the addition of antihuman globulin (AHG) and centrifugation. Reactivity in a certain phase will help to determine whether the antibody is cold reacting (IgM) or warm reacting (IgG). It will also help to distinguish between antibodies that are clinically significant and not significant. Clinically significant antibodies that are capable of causing acute and delayed hemolytic transfusion reactions (HTR) or hemolytic disease of the newborn (HDN) are usually IgG and react best in the AHG phase.Readings can be done at all three phases if a tube method is used. If a gel method is used, readings are done only at AHG. Immediate spin: Antibodies reacting in this phase tend to be cold reactive. They are usually IgM class and not clinically significant (with the exception of the A and B antibodies). 37°: Antibodies that react in this phase include strong IgM or IgG antibodies. After incubation, the tubes are examined for the presence of hemolysis. If complement was bound during incubation then hemolysis could be seen. NOTE: This reaction would only occur in serum samples. If EDTA plasma samples are used for testing, the complement cascade has been halted. Magnesium and calcium ions are not available for complement to be activated. AHG:Antibodies reacting in this phase are considered clinically significant. They are usually warm reactive and IgG.
Currently, the troponins are the definitive markers of myocyte injury. The troponins are contractile proteins that regulate muscle contractions; they work with calcium ions and another protein, tropomyosin. There are three types of troponin: Troponin C -- Calcium-Binding Component Troponin I -- Inhibitory Component Troponin T -- Tropomyosin-Binding ComponentIsoforms of the troponins are found in cardiac muscle and in slow-twitch and fast-twitch skeletal muscle. Troponin C is found in both cardiac and skeletal muscle in the same form. Troponin I has a specific form found in cardiac muscle, cTnI; cTnT is the cardiac specific form of troponin T.
|Identify the urine sediment elements shown by the arrow:||View Page|
|Which one of the following crystals is not found in normal urine:||View Page|
|Which two of the following crystalline elements are found in acid urine:||View Page|
|Which of the following forms of calcium is biologically active:||View Page|
|Which of the following anticoagulants will not produce a significant effect on calcium levels in plasma:||View Page|
|Ionized calcium is most commonly measured using which of the following method:||View Page|
|Which two of these urine elements are found exclusively in acid urine:||View Page|
No single screening test can detect all lupus anticoagulant-positive (LA-positive) patients. Several tests are available and at least two should be employed to verify the presence of LA. Before any LA screening test is done, a thrombin time (TT) should be performed to rule out therapeutic heparin or the presence of a thrombin (factor-II) inhibitor.These are some of the LA screening procedures that can then be used: Dilute Russell's Viper Venom time (DRVVT). This test utilizes a reagent containing venom from the viper Vipera russelli (which activate factor V and X), low levels of phospholipids, and calcium ions in a clotting time test. The DRVVT test principle is based on the idea that the reagents can help to identify the antibody's dependence on phospholipids . Platelet neutralization procedure. This assay will show the dependence on phospholipids for the lupus anticoagulant to take effect. This can be performed using the aPTT based technique, with the DRVVT test, or using Taipan snake venom time tests. Kaolin clotting time or silica clotting time Hexagonal Phospholipid test (HPP). This is a similar assay to the platelet neutralization procedure, but thought to be more sensitive.
|Kinetic Processes Specific to Platelets|
Adhesion When platelets adhere to exposed collagen, they take on a characteristic "spiny" shape. Their inherent stickiness, and the aforementioned spiny shape serve to compliment each other during this process. Von Willebrands Factor (vWF) is absorbed by surface receptors on both the platelet and exposed subendothelial tissue, thereby linking the platelets to the tissue.Shape change In response to chemical changes, platelets undergo shape changes from discs to spiny spheres.Release This process occurs prior to or concurrently with aggregation. Platelets dump the contents of their granules (ADP, serotonin, and calcium), which aids the upcoming aggregation process by acting as a chemical signal.Aggregation Platelets physically bind to each other, not just to the exposed subendothelial walls and collagen of the breached vessel. Platelet aggregation requires sufficient chemical signal stimulation.
|Secondary Hemostasis: The Intrinsic Pathway, continued|
2. Next, activated factor XI (XIa) catalyzes the conversion of factor IX into IXa in the presence of ionized calcium.
|Secondary Hemostasis: The Intrinsic Pathway, continued|
3. Then, activated factor IX (IXa), along with ionized calcium, platelet factor, and factor VIII, activate factor X, which is a direct precursor of thrombin in the common pathway. The activation of factor X signals the beginning of the common pathway. The activated partial thromboplastin time (aPTT) is used to monitor the intrinsic pathway and the effectiveness of heparin therapy.
|Secondary Hemostasis: The Common Pathway, continued|
Activated factor X (Xa), in the presence of factor V, ionized calcium, and platelet factor, converts prothrombin to its active form, thrombin, by cleaving the prothrombin molecule.
|Match the urine sediment or crystal to the correct description.||View Page|
|Serum calcitonin is typically elevated in which of the following conditions:||View Page|
|Choose the anticoagulant most commonly used for hemostasis testing:||View Page|
|Which of the following would be the most characteristic finding in synovial fluid in a case of pseudogout:||View Page|
|Which is the best method for examination of synovial crystals:||View Page|
|Which changes Fibrinogen into Fibrin Monomer:||View Page|
|Magnesium, Calcium, and Vitamin D|
Several studies have shown an inverse relationship between magnesium, calcium, vitamin D intake and metabolic syndrome risks, particularly insulin resistance. When dietary intake of magnesium, calcium, and vitamin D decreases, the risk of metabolic syndrome increases.Decreased magnesium concentrations occur in low grade inflammation. Milk and dairy products provide calcium and vitamin D while whole grains, green leafy vegetables, legumes, and nuts are rich in magnesium.
|Which of the following is the most suitable specimen for the isolation of Bordetella pertussis:||View Page|
|Which one of the following statements about E.coli O157:H7 is false:||View Page|
When a clinical isolate is presumptively identified as S. aureus, susceptibility testing will be performed by either the Standardized Disk Diffusion (Kirby-Bauer) or Broth Dilution (MIC) methods, using the following testing conditions as recommended by the Clinical and Laboratory Standards Institute (CLSI): Medium: MHA for disk diffusion; CAMHB + 2% NaCL for oxacillin, methicillin, and nafcillin; CAMHB supplemented up to 50 ug/ml calcium for daptomycin Inoculum: Direct colony suspension (0.5 McFarland Standard) Incubation: 35° C (Testing at temperatures above 35° C may not detect MRSA); ambient air; disk diffusion; 16to 18 hours; dilution methods; 16 to 20 hours. All methods: 24 hrs for oxacillin, methicillin, nafcillin, and vancomycin.
|Basic metabolic panel (BMP)|
Consists of an electrolyte panel, plus:
Blood urea nitrogen (BUN), which a measure of renal function.
Creatinine (Creat), which also measures renal function
Glucose, the most important blood sugar, and
Run on serum or plasma
Electrolytes are salts dissolved in water, including:Sodium (Na)
|Blood Collection Tubes|
Most blood collection tubes contain an additive that either accelerates clotting of the blood (clot activator) or prevents the blood from clotting (anticoagulant). A tube that contains a clot activator will produce a serum sample when the blood is separated by centrifugation and a tube that contains an anticoagulant will produce a plasma sample after centrifugation. Some tests require the use of serum, some require plasma, and other tests require anticoagulated whole blood. The table below lists the most commonly used blood collection tubes. Tube cap color Additive Function of Additive Common laboratory tests Light-blue 3.2% Sodium citrate Prevents blood from clotting by binding calcium Coagulation Red or gold (mottled or "tiger" top used with some tubes is not shown) Serum tube with or without clot activator or gel Clot activator promotes blood clotting with glass or silica particles. Gel separates serum from cells. Chemistry, serology, immunology Green Sodium or lithium heparin with or without gel Prevents clotting by inhibiting thrombin and thromboplastin Stat and routine chemistry Lavender or pink Potassium EDTA Prevents clotting by binding calcium Hematology and blood bank Gray Sodium fluoride, and sodium or potassium oxalate Fluoride inhibits glycolysis, and oxalate prevents clotting by precipitating calcium. Glucose (especially when testing will be delayed), blood alcohol, lactic acid
|Common crystals which can be found in ACID urine include: (Choose all that apply.)||View Page|
|What are the microscopic elements that are indicated by arrows in this image?||View Page|
|What is the identification of this crystal seen in a urine with an alkaline pH?||View Page|
|What is the identification of these crystals seen in a urine with an acid pH?||View Page|
|What is the identification of these crystals seen in urine with an alkaline pH?||View Page|
|What element is present in this slide?||View Page|
Normal crystals include uric acid, calcium oxalate, amorphous urates or phosphates, triple phosphate, ammonium biurate, and calcium carbonate.
|Calcium Carbonate Crystals|
Calcium carbonate crystals appear as tiny dumbbells or small colorless spheres.
|Crystals in Normal Acid Urine|
Crystals found in normal acid urine include uric acid, calcium oxalate and amorphous urates. This slide shows an example of uric acid crystals.
|Crystals in Normal Alkaline Urine|
Crystals found in normal alkaline urine include triple phosphate, ammonium biurate, calcium carbonate, and amorphous phosphates. This slide shows an example of triple phosphate crystals. These may appear as four to six sided prisms resembling coffin lids. They indicate either stasis of the bladder or a stale sample.
|Calcium Oxalate Crystals|
Calcium oxalate crystals in their dihydrate form have a characteristic octahedral or envelope shape, as shown in the top image on the right. Fine focusing will cause the "x" to be refractile. Size may vary from extremely small to quite large. They are associated with diets high in oxalic acid or chemical toxicity. In their monohydrate form, calcium oxalate crystals are dumbbell or oval in shape as shown in the bottom image on the right.
|Please identify these crystals.||View Page|
|Please identify these crystals.||View Page|
|Which of the following may be found in normal ACID urine?(Choose all that apply.)||View Page|