Subject assay methods

Egawa et al. [103] by using a microbial assay method reported that miconazole was not detected in the blood after human subjects were given 100 mg tablets of miconazole intravaginally for 14 days. Six species of 12 strains of human vaginal Lactobacillus were insensitive to miconazole. 

The chemistry, metabolism, and clinical importance of folic acid have been the subject of many excellent reviews (A7, Gil, H14, H20, Rl). Folic acid deficiency leads to a macrocytic anemia and leucopenia. These symptoms are due to inadequate synthesis of nucleic acid. The synthesis of purine bases and of thymine, required for nucleic acid synthesis, is impaired in folic acid deficiency. Detection of folic acid activity in biologic fluids and tissues is of the utmost importance it distinguishes between the various anemias, e.g., those due to vitamin Bi2 or folic acid deficiency. Because morphology of the abnormal red cell does not help in diagnosing vitamin deficiency, one must rely on assay methods for differential diagnosis. Treatment of pernicious anemia with folic acid has led to subacute combined degeneration of the spinal cord despite... 

The subject of impurity analysis of pharmaceutical compounds has been insufficiently addressed in the scientific literature. Many monographs in die U.S. Pharmacopeia have nonspecific assay methods. An attempt has been made to address this problem by focusing on specific methodologies and delineating origination and concentration of impurities found in pharmaceutical compounds. 

None of the methods developed thus far can be considered ideal, especially for routine quality control purposes. Among their disadvantages are subjective readout methods, time-consuming separations, questionable specificity, and limited applicability. Recent work showing that taste thresholds for limonin are lower than had previously been assumed for significant proportions of the population emphasizes the need for a better assay method. The use of a protein specific for limonin, such as an enzyme or antibody, could provide the basis for an improved assay." (9)... 

It is reasonable to question whether the distribution of the estimates of a drug concentration in a blood specimen might be approximated by the normal distribution. Table 1 presents the results of repeated analyses of a specimen of interference-free plasma spiked to contain a known amount of drug. These data are taken from a comparative bioavailability study in which single doses of an unmarketed generic product and the marketed brand product of a drug were administered on separate occasions to healthy males. The values presented are the first of duplicate determinations of a quality control (QC) specimen that was included with each batch of subject specimens. This was done to verify that the in-process accuracy and precision of the assay method were consistent with the values observed during the assay validation. 

One of the aims of endocrinologists is to develop assay methods that will enable them to obtain quantitative estimates of FSH and LH in body fluids and glandular extracts. A major object of this review is to examine the basic principles underlying immunological assay methods for these hormones with a view to determining whether or not the results obtained by such procedures will be meaningful. Little or no mention is made of biological assays for these hormones because such techniques have been the subject of numerous reviews over the past two decades (A11,L5, L6). 

Because dependence upon circulating CH levels is one of the definitive characteristics of the somatomedins (see Section 1.2), new assays have generally been characterized by their ability to distinguish somatomedin levels in patients with CH disorders from those in healthy subjects. Several studies have compared values in GH-deficient children with those in healthy adults and, while an assay method that could not make this distinction would be invalid, dependence upon CH cannot be established by such comparisons, since somatomedin levels (particularly SM-C/ICF-I) in children without CH deficiency are lower than adult values. 

In studies directly comparing different assay methods, RIA methods invariably show somewhat better discrimination than do other radioligand methods or bioassays. In one such study (B14), 5 out of 13 samples from hyposomatotropic subjects, all of which were clearly low by SM-C/IGF-I RIA, were not distinguishable from samples from healthy subjects by placental membrane RRA using SM-C/IGF-I tracer. The rather poor correlation (r=0.836) between RIA and RRA results for 69 healthy, GH-deficient, or... 

There are large numbers of assay methods differing from one another in types of substrates employed, substrate concentrations, buffer types, buffer strengths, pH values, and temperatures of incubation. Some methods have been officially recommended by national institutes (Gll, S7) and the entire subject is reviewed in detail in a recent book (Mc3). 

If the automated assay method is sufficiently different from the manual method, then the differences between the two methods must be carefully examined to determine the best testing approach. This may result in the need to partially revalidate each assay on the automated system. Once this is done, a decision must be made about whether both the methods can be used to generate data for the same subject/study/ project. This involves quite a lot of work and serves as an example of why standardizing the manual and automated methods is so important. 

There are several in vivo assay models for angiogenesis, including the shell-less chicken chorioallantoic membrane (CAM) assay, the cornea assay, and the endothelial cell assay. The CAM assay is most frequently used assay method because it is easy to use and less costly. In this assay, an inhibitor s effect on the shell-less chicken embryo culture can be observed directly, although quantitating the result is subjective. The mouse cornea assay is widely favored because the cornea is an avascular tissue, any blood vessel development unequivocally demonstrates the lack of antiangiogensis activity [77-79]. However, all of these in vivo assay... 

A very important observation at this point is that an IDMS assay is in principle a physical measurement since it is a measurement of ratio of isotopes and not of a ratio of elements (as in classical analytical chemistry). Indeed two numbers of atoms are compared in a ratio determination and these atoms belong to the same element. Hence ail the chemical interferences, normal in a chemical assay, do not affect the result anymore. Combined with the fact that the requirement of being quantitative - essential and difficult in classical chemistry assay - must not be fulfilled (after spiking), this means that IDMS ranks higher in the hierarchy of methods than normal elemental assay methods since it is far less subject to potential chemical error sources. In other words its inherent potential for good precision and accuracy (i.e. small overall uncertainty) and - at least as important -the transparency of the uncertainty propagation in (Eqs. 4 and 5) give it the character of what some have called a "reference method" or even a definitive method". 

A review on the subject of immobilized enzymes in biochemical analysis covers preparation and properties of immobilized enzymes assay methods using immobilized enzymes (spectrophotomatic assays, automated methods in biochemical analysis, enzyme electrodes, and colorimetric analyses using immobilized enzymes) and applications of immobilized enzymes in biochemical analysis. ... 

The number of existing empirical units for hyaluronidase activity nearly equals the number of workers in the field. The correlation of units obtained by different physicochemical with biological assay methods is of great theoretical and practical interest and has been the subject of several studies. 

The prevalence of antibodies was much higher in our study may be due to used the highly sensitive assay method and case selection of the subjects. 

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