Serum, enzyme activity levels blood

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). 

Figure 3. Schematic representation of five enzyme activity levels in blood serum as a result of various liver diseases. These data (28) do not show the large range in values among individuals. GOT, glutamate-oxaloacetate transaminase GPT, glutamate-pyruvate transaminase GlDH, glutamate dehydrogenase LDH, lactate dehydrogenase P, alkaline phosphatase.

For clinical chemistry the most important question is whether or not changes in enzyme activity will accompany defined disease states, the materials being obtainable by ways practicable in clinical medicine. The enzyme levels of G-6-PDH and 6-PGDH are assayed in serum, blood (hemolyzates), and liver homogenates yielded by biopsy. In the latter case it is necessary most of all to take account of the probable differences between the assay conditions and the steady state. Furthermore, the reference system is of decisive importance (e.g., cellularity... 

Similar results have been reported for polymorphisms at amino acid 55, with the PONl paraoxonase activity in blood serum from 55M (methionine) homozygotes reduced compared to either the 55L (leucine) homozygotes or the LM heterozygotes (Mackness et al, 1997). While it is intuitive that the rate of detoxification of a substrate would be dependent on the expression levels of these endogenous enzymes, the effects of the genetic polymorphisms suggest that catalytic efficiency is an equally important consideration. 

The neonate is at risk for kemicterus if the serum unconjugated bilirubin level is higher than 17 mg/dL. Kemicterus is characterized by yellow staining of clusters of neuronal cell bodies in the basal ganglia, cerebellum, and brain stem, leading to motor and cognitive deficits or death. Immaturity and f)erhaps hypoxia make the blood-brain barrier permeable to bilirubin and contribute to the likelihood of kemictems. The biochemical basis of bilirubin encephalopathy is due to many causes inhibition of RNA and protein synthesis, carbohydrate metabolism (both cAMP-mediated and Ca " -activated), phospholipid-dependent protein kinases, enzymes involved in the electron transport system, and impaired nerve conduction. 

Keeping in view the innumerable adverse side eflfeets eaused by the NSAIDs their clinical usefulness are restricted drastically. Therefore, patients who are taking sueh drugs for a relatively longer periods should have periodic white-blood cell counts as well as determinations of serum creatinine levels, besides hepatic enzyme activities. 

There are at least two cholinesterases acetylcholinestarase (AChE), a specific cholinesterase hydrolyzing predominantly the choline esters and occurring in high concentrations in brain, nerve and red blood cells and the other, butyrylcholinesterase (BChE), a nonspecific ( pseudo ) cholinesterase, hydrolyzing other esters as well, and found in the blood, serum, pancreas and liver. These enzymes manifest maximum catalytic activity around neutral pH and at the low levels of acetylcholine. The hydrolysis reaction of acetylcholine catalyzed by AChE is shown below ... 

Orotic acid is bound in the serum to proteins [436] and is metabolized in the liver [433]. The binding of orotic acid to serum proteins in children and adults receiving the drug orally at 80 mg/kg bodyweight per day for 28 days was less than 1% [437]. Maximal serum concentrations of orotic acid were attained 2-5 hours after intake and showed great individual variations, ranging from 0.8 to 10 xg per ml. On the other hand, the half-times for disappearance of orotic acid from the serum were about 1 hour and were more uniform [437]. The resorption of orotate was also followed in newborn infants [438], simultaneously with the level of enzyme activities in blood serum [439,440]. In connection with the anti-inflammatory effect of calcium orotate, [441] the calcium and phosphate metabolism in the treated patients was measured [442,443]. 

Glucuronyl transferase appears in the serum in patients with hepatic necrosis. Thus, even when the liver transferase level is depressed, the serum enzyme can still conjugate bilirubin in vitro. In such cases it is possible that the activity of the blood enzyme is the source of conjugated bilirubin found in the serum in patients suffering from hepatic necrosis associated with impaired hepatic glucuronyl transferase activity. 

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