Direct bilirubin

Recently, this problem has been approached by reverting to reading the color of the bilirubin directly. This used to be called an "Icterus Index", in which the color of the serum was compared to a dilute dichromate solution (39). However, the new approach has been to use two wavelengths. This can be used in either of two different procedures. In one procedure the reading is made at the peak for bilirubin which is at 453 nm and at an isosbestic point for hemoglobin (40). The effect on the reading due to hemoglobin is subtracted from the bilirubin value. Commercial instruments based on this principle have not been successful. 

Cholestasis (increased total bilirubin, direct bilirubin, alkaline phosphatase, and y-glutamyl transferase)... 

Liver A 27-year-old man developed jaundice and mild right upper abdominal discomfort after taking over-the-counter ranitidine for intermittent epigastric pain and heartburn for 3 days [46 ]. He had increased aspartate aminotransferase, alanine aminotransferase, and alkatine phosphatase, activities, total bilirubin, direct bilirubin, ferritin, iron saturation, and prothrombin time. Abdominal CT showed a 6-mm stone in the gallbladder. Percutaneous liver biopsy showed ntild portal inflammation with predominantly small lymphocytes and mild lobular inflammation with a few eosinophils and... 

When the amount of bilirubin produced is greater than the amount excreted, bilirubin accumulates in the blood and stains the tissue, leading to yellow discoloration called jaundice. The mechanism by which bilirubin stains tissue is not clear. It is assumed that bilirubin is transferred from plasma proteins to tissue proteins, and, as can be expected, some proteins have a greater affinity for bilirubin than others. For example, elastic tissue avidly picks up bilirubin. Direct bilirubin is more readily fixed by tissues than indirect bilirubin, except in brain of the newborn, where unconjugated bilirubin is more easily picked up by the brain than conjugated bilirubin. 

Figure 32-13. Structure of bilirubin diglucuronide (conjugated, "direct-reacting" bilirubin). Glucuronic acid is attached via ester linkage to the two propionic acid groups of bilirubin to form an acylglucuronide.

Increased total, direct, and indirect bilirubin concentrations indicate defects in transport, conjugation, or excretion of bilirubin. 

C02, chloride, direct bilirubin, triglyceride, SGPT, UE Upper extremity... 

We focus here on the use of oxygenases, particularly the blue copper oxygenases, such as laccase and bilirubin oxidase, which can biocatalytically reduce oxygen directly to water at relatively high reduction potentials under mild conditions. First, however, we will briefly consider reports on the use of hydrogen peroxide as an oxidant in biocatalytic fuel cells. 

Catalytic reduction of oxygen directly to water, while not as yet possible with traditional catalyst technology at neutral pH, is achieved with some biocatalysts, particularly by enzymes with multi-copper active sites such as the laccases, ceruloplasmins, ascorbate oxidase and bilirubin oxidases. The first report on the use of a biocatalyst... 

Conditicms that increase direct bilirubin Hepatic damage Bile duct obstruction... 

Jaundice (yellow color of skin, whites of the eyes) may occur when blood levels of bilirubin exceed normal (icterus). Jaundice may be characterized by an increase in unconjugated (indirect) bilirubin, conjugated (direct) bilirubin, or both. Accumulation of bilirubin (usually unconjugiated) in the brain (kernicterus) may result in death. When conjugated bilirubin increases, it may be excreted, giving a deep yeUow-red color to the urine. Examples of conditions associated with increased bilirubin and jaundice include the following. 

Viral hepatitis or cirrhosis produces an increase in both direct and indirect bilirubin. Aminotransferase levels will also be elevated. 

After transfer of heme to MHBP, either directly from hemopexin or from the hemopexin receptor, hemopexin and the receptor both recycle to the surface to undergo further rounds of transport. The heme inside the cell requires further intracellular trafficking to deliver heme to regulatory sites and to HO-1 for catabolism to biliverdin and iron, making intracellular transport an interesting focus of future research. The biliverdin is reduced and excreted as bilirubin, and the iron released, which can also have regulatory effects, is reutilized or stored on ferritin. 

Bilirubin effects depend on the method used for analysis. Interferences in direct serum protein methods are observed at bilirubin levels greater than 5 mg/100 ml (K7). A sample containing 20 mg of bilirubin per 100 ml increased the apparent total protein by 0.2 g/100 ml. Concentrations of bilirubin as high as 20 mg/ml do not effect albumin assays using bromocresol green binding (D12), but have a marked effect on these assays when [2-(p-hydroxyphenylazo)-benzoic acid] (HABA) dye is used (A7b). 

B21. Bratlid, D., and Winsner, A., Determination of conjugated and unconjugated bilirubin by methods based on direct spectrophotometry and chloroform-extraction. A reappraisal. Scand, J. Clin. Ijoh. Invest. 28, 41-48 (1971). 

Quantitation of synthetic, conjugated bilirubin, after its direct separation from the incubation mixtures, offers the most valid approach to the determination of conjugation rates. However, for the present, such methods are unlikely to find wide application because of instability of... 

Methods involving quantitation of conjugated azopigment directly measure the number of groups transferred and thus, by calculation, GTR. Expression of the results in function of bilirubin equivalents conjugated is equivocal. 

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