Phosphatase alkaline, indicator

The chronic-duration oral MRL was derived based on the observation of increased serum levels of alkaline phosphatase (an indicator of hepatotoxicity) in dogs consuming 0.6 mg/kg/day for 1 year (Hoechst 1989c). The choice of this end point is supported by the observation of hydropic hepatic cells in rats that consumed 5 mg/kg/day for 2 years (EMC 1959b). The chronic-duration MRL of 0.002 mg/kg/day was derived by dividing the NOAEL for elevated serum alkaline phosphatase (0.18 mg/kg/day) by an uncertainty factor of 100 (10 for extrapolating from animals to humans, and 10 for human variability). 

Elevated alkaline phosphatase may indicate bone destruction. 

These results clearly indicate that the patient needs to continue with dialysis. This woman s serum calcium status should also be assessed. Hypocalcaemia should be excluded and a high serum alkaline phosphatase would indicate the presence of metabolic bone disease. Serum PTH concentrations are a very sensitive method of detecting hypocalcaemia and metabolic bone disease in patients with renal failure. 

Raised activities of the aminotransferases (AST and ALT) indicate hepatocellular damage. Increased bilirubin concentration and increased alkaline phosphatase activity indicate the presence of cholestasis, a blockage In bile flow. Serial use of LFTs is of most value in following the progress or resolution of liver disease. 

Alkaline phosphatase. The effects of food intake on plasma alkaline phosphatase in the rat have been mentioned in Chapter 2. For this species with a much larger proportion of intestinal isoenzyme in plasma, changes of plasma alkaline phosphatase can indicate gastrointestinal toxicities. 

The enzymes found in liver cells (Group I enzymes) include more than a dozen enzymes used in diagnostic laboratories, but those used most commonly are the transaminases (GOT and GPT), which continue to be the most widely used indicators of liver cell integrity. Enzymes found in the biliary cells (Group II) include alkaline phosphatase, glutamyl-transferase, leucine amniopeptidase and 3-nucleotidase. 

The Group II (biliary tract) enzymes are abnormal usually when the serum bilirubin concentration is also abnormal. Most commonly used is alkaline phosphatase which is a highly sensitive indicator of biliary tract obstruction, perhaps because the enzyme is synthesized as an induced response to obstruction of even small bile ducts. Most techniques used to identify the origin of an elevated serum alkaline phosphatase are not very useful from a clinical viewpoint (23). The simultaneous measurement of GMT activity has been found to be useful in differentiating between the hepatic and bony origin of alkaline phosphatase. An increased GMT activity in a patient with an increased ALP activity is a good indication that there is biliary biliary tract disease (62,63). 

Gao and Yamaguchi, 1999a Yamaguchi and Ma, 2001 Femoral-diaphyseal tissues from elderly female rats cultured for 24 h Daidzein or genistein (lO M, lO M) induced calcium content and alkaline phosphatase (ALP) activity indicating stimulation of bone formation. 

Another approach has been to immobilize proteins within arrays of microfabricated polyacrylamide gel pads (Arenkov et al., 2000). Nanoliters of protein solutions are transferred to 100 x 100 x 20-pM gel pads and assayed with antibodies that are labeled with a fluorescent tag. Antigen imbedded in the gel pads can be detected with high sensitivity and specificity (Arenkov et al., 2000). Furthermore, enzymes such as alkaline phosphatase can be immobilized in the gel pads and enzymatic activity is readily detected upon the addition of an indicator substrate. The main advantage of the use of the threedimensional gel pad for fixation of proteins is the large capacity for immobilized molecules. In addition, the pads in the array are separated from one another by a hydrophobic surface. Thus, each pad behaves as a small test tube for assay of protein-protein interactions and enzymatic reactions (Arenkov et al., 2000). The disadvantage of the method is the need to microfabricate the array of gel pads in that microfabrication is... 

Domestic sheep (Ovis aries) fed a low-zinc diet (2.2 mg Zn/kg DW diet) for 50 days, when compared to those fed a zinc-adequate diet (33 mg Zn/kg DW diet), excreted less zinc (<4 mg daily vs. 23 to 25), consumed less food (409 g daily vs. 898), and had lower plasma zinc concentrations (0.18 mg/L vs. 0.53 to 0.58) a reduction in plasma alkaline phosphatase activity and an increase in plasma zinc binding capacity were also noted (Khandaker and Telfer 1990). Sensitive indicators of zinc deficiency in lambs include significant reductions in plasma alkaline phosphatase activity and plasma zinc concentrations signs were clearly evident in lambs fed 10.8 mg Zn/kg DW diet for 50 to 180 days (Vergnes et al. 1990). A normal diet for lambs contains 124 to 130 mg Zn/kg DW ration vs. 33 for adults (Vergnes et al. 1990). One recommended treatment for zinc-deficient sheep is ruminal insertion of zinc-containing boluses every 40 days bolus zinc release is about 107 mg daily (Khandaker and Telfer 1990). 

The long-lived phosphorescence of the tryptophan in alkaline phosphatase is unusual. Horie and Vanderkooi examined whether its phosphorescence could be detected in E. coli strains which are rich in alkaline phosphatase.(89) They observed phosphorescence at 20°C with a lifetime of 1.3 s, which is comparable to the lifetime of purified alkaline phosphatase (1.4 s). Long-lived luminescence was not observed from strains deficient in alkaline phosphatase. The temperature dependence of tryptophan phosphorescence in the living cells was slightly different from that for the purified enzyme, indicating an environmental effect. 

If antibodies conjugated to fluorochromes are not desirable, enzyme-labeled antibodies can also be used. In this case, in the presence of a substrate and a chromagen, an enzyme provides the indicator system necessary to visuahze the location of the antibody (Carson, 1997). Horseradish peroxidase (HRP) and alkaline phosphatase (AP) are the enzymes most commonly conjugated to antibodies not labeled by... 

Enzymes have different degrees of stability after their collection. Alkaline phosphatase demonstrates up to 10% increased activity after a few hours at room temperature (B15). Most enzymes are not stable at room temperature, but can be preserved in the refrigerator for short periods or in the deep freeze for relatively long times. In Table 4 are tabulated the reported stabilities of many serum enzymes. It must be realized that the problem of enzyme stability is complicated by the fact that the isoenzymes of a particular enzyme may have different stabilities and that specimens with high activities may react differently than those with normal activities (KIO). Although it is indicated in Table 4 that serum... 

Serum alkaline phosphatase elevations have been reported following administration of salt-poor albumin (B5). Placenta is very rich in a heat-stable alkaline phosphatase, and albumin prepared from placental blood has a high activity of this enzyme. In one cirrhotic patient who received 1-6 units per day of albumin obtained from pooled human blood and/or human placenta, the alkaline phosphatase before infusion was 5 Bodansky units and by the thirteenth day of administration had reached a value of 160 units. The physician administering the albumin at first thought the patient was having a severe toxic liver reaction and stopped the therapy. The alkaline phosphatase then started to go down and within 10 days returned to normal levels. Analysis of the albumin indicated that it contained 470 units of alkaline phosphatase activity and was probably responsible for the observed elevations in the serum enzyme activity. Albumin prepared from venous blood did not cause an alkaline phosphatase elevation, but placenta-albumin caused elevations with a half-life of about 8 days (Ml). 

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