Capillary isoelectric focusing with whole column imaging detection (iCIEF): A new approach to the characterization and quantification of salivary α-amylase.

Saliva is an easily collected biological fluid with potentially important diagnostic value. While gel electrophoresis is generally used for salivary analysis, we employed the capillary isoelectric focusing technique to allow for a rapid, automated mode of electrophoresis. Capillary isoelectric focusing coupled with UV whole column imaging detection (iCIEF) was used to develop a robust protocol to characterize salivary α-amylase collected from various glands. Notably, three sample preparation methods were examined: ultrafiltration, gel-filtration, and starch affinity interaction with salivary amylase. Salivary α-amylase separated into two major peaks before sample treatment; while both filtration methods and starch affinity interaction of salivary amylase enhanced the resolution of isozymes, desalting with gel-filtration displayed the best recovery and the highest resolution of isozymes. Good agreement existed between the observed isoelectric points and the values reported in the literature. In addition, a high level of precision was apparent, and the relative standard deviation for replicates was less than 0.5% for pIs (peak positions) and below 10% for peak area. Furthermore, saliva secreted from the parotid gland proved to have a higher amylase content compared to either secretions from the submandibular/sublingual complex, or whole saliva, as well as amylase enhancement under stimulation. The results suggest that the iCIEF technique can be used to accurately resolve and quantitate amylase isozymes in a rapid and automated fashion, and that gel-filtration should be applied to saliva samples beforehand to allow for optimal purification and characterization.

Assessing agreement between salivary alpha amylase levels collected by passive drool and eluted filter paper in adolescents with cancer.

PURPOSE/OBJECTIVES: To assess the validity of filter paper (FP) against the gold standard of passive drool (PD) for collecting salivary alpha amylase as a surrogate biomarker of psychological stress in adolescents with cancer. DESIGN: Part of a longitudinal, descriptive study of symptoms in adolescents with cancer during chemotherapy. SETTING: A pediatric hematology/oncology treatment center. SAMPLE: 33 saliva sample pairs from nine adolescents with cancer, aged 13-18 years. METHODS: Salivary alpha amylase was collected by PD and FP at four time points during a cycle of chemotherapy: days 1 (time 1) and 2 (time 2) of chemotherapy, day 7-10 (time 3), and day 1 of the next cycle (time 4). A random effects regression was used to assess the correlation between PD and FP values, and a Bland Altman analysis was conducted to assess agreement between the values. MAIN RESEARCH VARIABLES: Salivary alpha amylase. FINDINGS: The estimated correlation between PD and FP values was r = 0.91, p < 0.001. Regression results were also used to rescale FP values to the levels of the PD values because the FP values were on a different scale than the PD values. The Bland Altman analysis revealed that the agreement between the rescaled FP values and PD values was not satisfactory. CONCLUSIONS: Eluted FP may not be a valid method for collecting salivary alpha amylase in adolescents with cancer. IMPLICATIONS FOR NURSING: Psychological stress in adolescents with cancer may be linked to negative outcomes, such as greater symptom severity and post-traumatic stress disorder. Nurses need valid, efficient, biobehavioral measures to assess psychological stress in the clinical setting.

Differences in saliva collection location and disparities in baseline and diurnal rhythms of alpha-amylase: a preliminary note of caution.

Identified in the early 1980s as a surrogate marker of the sympathetic nervous system component of the stress response, there has been renewed interest in measuring salivary alpha-amylase (sAA) to test biosocial models of stress vulnerability. This brief report presents studies that document that oral fluids from the parotid and submandibular gland areas had higher sAA values than did whole saliva specimens, and sAA values in whole saliva were higher than levels measured in oral fluids from the sublingual gland area. sAA in oral fluids from the parotid and submandibular gland areas showed the highest and more pronounced diurnal variation than levels in whole saliva, and sAA in sublingual saliva showed the lowest and shallowest diurnal variation. When this source of inherent variability in sAA activity levels is not controlled for by collecting oral fluids consistently from specific gland areas, the detection of individual differences, associations between sAA and "behavioral" variables, and intra-individual change in sAA levels may be compromised. Awareness, and management, of this ubiquitous source of measurement error in sAA are essential to ensure the success of future research on the correlates and concomitants of sAA levels, stress-related reactivity and recovery, and diurnal variation.