Other Serum Determinants

Especially in Al bone disease hypercalcemia, suppressed PTH levels, and normal or slightly elevated alkaline phosphates have been reported. Hypercalcemia may develop in some hemodialysis patients with acute Al encephalopathy when they are also exposed to oral calcium and vitamin D preparations in combination with the available calcium from the dialysate [17], It is not known whether PTH levels and serum alkaline levels change during acute Al encephalopathy. 

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C13. Cryer, P. E., and Daughady, W. H., Diabetic ketosis Elevated serum glutamic oxaloacetic transaminase (SCOT) and other findings determined by multichannel chemical analysis. Diabetes 18, 781-785 (1969). 

Purines, pyrimidines, and the corresponding nucleosides have been separated in reversed phase systems. The five mqior nucleosides as well as inosine and xanthosine and the corresponding seven bases were separated by Hartwick and Brown (405). The selective determination of adenosine in the presence of other serum components has been reported (406). 

An intravenous line should be placed and blood drawn for serum glucose and other routine determinations. 

In determining cortisol in serum, most of the cortisol is bound to corticosteroid-binding globulin and other serum proteins. How then is cortisol released for detection [1006] (2 marks)... 

A variety of electrochemical methods have been incorporated into automated systems. The most widely used Mec-trochemical approach involves ion-selective electrodes. These electrodes have replaced flame photometry for the determination of sodium and potassium in many analyzers and have lately found direct application in the measurement of other electrolytes and indirect application in the analysis of several other serum constituents. The operating principle of ion-selective electrodes is given in some detail in Chapter 4. The relationship between ion activity and the concentration of ions in the specimens must be established with calibrating solutions, and frequent recalibration must be done to compensate for alterations of electrode response. 

Absence of serum alkaline phosphatase elevation, however, does not necessarily imply absence of disease (SI7). The same general rule applies to other serum enzyme determinations, so that there is at present no single biochemical test which can be relied on to exclude hepatic disease. 

When antibodies are being purified, an assay for antibody activity and a method for determining the purity of the antibody are required. Contamination with other serum proteins can easily be checked by SDS-PAGE and staining the gels with Coomassie Blue. The activity of the antibodies can be determined by immunoassays such as any one of the methods that are described in this book. 

Chu et al. used an activated copolymer of methacrylate for antibody im-mobihsation to develop a Pz immimosensor for the detection of a-fetoprotein in serum [140]. The analyte was measured Unearly from 100 to 800ngmL and no interferences from other serum components were observed. Valent values and affinity constants of the immunoreaction were also determined. Comparable results to RIA were obtained. 

The patients, whether on Allopurinol or placebo, received identical-looking tablets. The study was not a double-blind one, as the doctors who were following the patients knew the group to which eveiy patient belonged. No special dietary restrictions were imposed on the patients. The patients were seen at least once a month. Each time, in addition to body weight and blood pressure, blood was drawn for plasma uric acid, electrolytes, and plasma urea. The patients collected, for every monthly visit, a 24-hour urine collection for creatinine clearance. Once every three months, maximal urine osmolality was determined, and blood drawn for determination of plasma cholesterol, glucose, Hb., serum iron, total iron binding capacity, in addition to the other monthly determined parameters. 

Of particular interest will be the iron and calcium data. However, other nutrients must also be carefully considered. Unfortunately, data on the zinc content of food is as yet unavailable and will have to wait for later analysis. Regression analysis between serum ferritin levels and blood lead concentrations will be performed as well as a comparison with other hematological determinations such as free erythrocyte protoporphyrins, hemoglobin, hematocrit, and serum iron, which are all indicators of iron status. 

Apparently related observations were made by Hannestad et al. (24) who investigated two IgM monotypic proteins with different electrophoretic mobilities, isolated from the serum of a single patient. Both proteins reacted specifically with a trinitrophenyl derivative of hemo-cyanin. The IgM proteins were not, however, identical in specificity since only one of them reacted with a Klebsiella polysaccharide. Each protein had individual, unrelated idiotypic determinants but also held in common other antigenic determinants that were not found in 99 other serums from patients with Waldenstrom s macroglobulinemia or rheumatoid arthritis. This appears, then, to be another example of cross-idiotypic specificity. 

The analysis of clinical samples is often complicated by the complexity of the sample matrix, which may contribute a significant background absorption at the desired wavelength. The determination of serum barbiturates provides one example of how this problem is overcome. The barbiturates are extracted from a sample of serum with CHCI3, and extracted from the CHCI3 into 0.45 M NaOH (pH 13). The absorbance of the aqueous extract is measured at 260 nm and includes contributions from the barbiturates as well as other components extracted from the serum sample. The pH of the sample is then lowered to approximately 10 by adding NH4CI, and the absorbance remeasured. Since the barbiturates do not absorb at this pH, the absorbance at pH 10 is used to correct the absorbance at pH 13 thus... 

Today, however, GC-GC coupling is seldom used to determine pesticides in environmental samples (2), although comprehensive MDGC has been applied to determine pesticides in more complex samples, such as human serum (19). On the other-hand, new trends in the pesticide market, which is now moving towards the production of optically active enantiomers and away from racemic mixtures, may make this area suitable for GC-GC application. The coupling of non-chiral columns to chiral columns appears to be a suitable solution to the separation problems that such a trend might cause. 

The two examples of sample preparation for the analysis of trace material in liquid matrixes are typical of those met in the analytical laboratory. They are dealt with in two quite different ways one uses the now well established cartridge extraction technique which is the most common the other uses a unique type of stationary phase which separates simultaneously on two different principles. Firstly, due to its design it can exclude large molecules from the interacting surface secondly, small molecules that can penetrate to the retentive surface can be separated by dispersive interactions. The two examples given will be the determination of trimethoprim in blood serum and the determination of herbicides in pond water. 

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