ABSTRACT
ß-Glucosidase activity assays constitute an important indicator for the early diagnosis of neonatal necrotizing enterocolitis and qualitative changes in medicinal plants. The drawbacks of the existing methods are high consumption of both time and reagents, complexity in operation, and requirement of expensive instruments and highly trained personnel. The present study provides a simplified, highly selective, and miniaturized glucometer-based strategy for the detection of ß-glucosidase activity. Single-factor experiments showed that optimum ß-glucosidase activity was exhibited at 50 °C and pH 5.0 in a citric acid-sodium citrate buffer when reacting with 0.03 g/mL salicin for 30 min. The procedure for detection was simplified without the need of a chromogenic reaction. Validation of the analytical method demonstrated that the accuracy, precision, repeatability, stability, and durability were good. The linear ranges of ß-glucosidase in a buffer solution and rat serum were 0.0873-1.5498 U/mL and 0.4076-2.9019 U/mL, respectively. The proposed method was free from interference from ß-dextranase, snailase, ß-galactosidase, hemicellulase, and glucuronic acid released by baicalin. This demonstrated that the proposed assay had a higher selectivity than the conventional dinitrosalicylic acid (DNS) assay because of the specificity for salicin and unique recognition of glucose by a personal glucose meter. Miniaturization of the method resulted in a microassay for ß-glucosidase activity. The easy-to-operate method was successfully used to detect a series of ß-glucosidases extracted from bitter almonds and cultured by Aspergillus niger. In addition, the simplified and miniaturized glucometer-based assay has potential application in the point-of-care testing of ß-glucosidase in many fields, including medical diagnostics, food safety, and environmental monitoring.
Subject(s)
Chemistry, Clinical/instrumentation , Glucose/analysis , beta-Glucosidase/analysis , Animals , Aspergillus niger , Calibration , Cellulase/analysis , Chemistry, Clinical/methods , Dextranase/analysis , Enterocolitis, Necrotizing/blood , Enterocolitis, Necrotizing/diagnosis , Equipment Design , Flavonoids/analysis , Glucuronic Acid/analysis , Glucuronidase/analysis , Glycoside Hydrolases/analysis , Hydrogen-Ion Concentration , Linear Models , Multienzyme Complexes/analysis , Plants, Medicinal , Polygalacturonase/analysis , Rats , Reproducibility of Results , beta-Galactosidase/analysisABSTRACT
This prospective study was conducted to evaluate the accuracy of transcutaneous bilirubinometry in preterm newborns less than 32 weeks of gestation. Serum bilirubin values measured by direct spectrophotometry were considered as standard, the range was 2.2-12.5 mg/dL. 32 jaundiced infants of less than 32 weeks of gestation without phototherapy, including 10 ELBW neonates, were enrolled. Close correlation (R=0.933) existed between total serum bilirubin and transcutaneous bilirubin values measured over sternum.
Subject(s)
Hyperbilirubinemia, Neonatal/diagnosis , Infant, Premature , Blood Specimen Collection/instrumentation , Chemistry, Clinical/instrumentation , Female , Humans , Hyperbilirubinemia, Neonatal/blood , Hyperbilirubinemia, Neonatal/therapy , Infant, Extremely Low Birth Weight , Infant, Newborn , Infant, Very Low Birth Weight , Male , Neonatal Screening/instrumentation , Neonatal Screening/methods , Spectrophotometry/instrumentation , Statistics as TopicABSTRACT
An experimental clinical chemistry analyzer system was designed and built to demonstrate the feasibility of clinical chemistry as part of a medical-care system at NASA's planned space station Freedom. We report the performance of the experimental analyzer, called a medical development unit (MDU), for selected analytes in a laboratory setting in preparation for a preliminary clinical trial at patients' bedsides in an intensive-care unit. Within-run CVs ranged from 0.7% for sodium to 7.1% for phosphorus; day-to-day CVs ranged from 1.0% for chloride to 23.4% for calcium. Correlation of patients' blood sample analyses compared well with those by Ektachem E700 and other high-volume central laboratory analyzers (r ranged from 0.933 for creatine kinase MB isoenzyme to 0.997 for potassium), except for hemoglobin (r = 0.901) and calcium (r = 0.823). Although several CVs obtained in this study exceeded theoretical desired precision limits based on biological variations, performance was adequate for clinical laboratory diagnosis. We examined the effect of potentially interfering concentrations of hemoglobin, bilirubin, and lipids: the only effect was negative interference with calcium analyses by high concentrations of bilirubin. We also examined the effects of preanalytical variables and the performance of experimental sample-transfer cups designed to retain sample and reference liquid in microgravity. Continued development of the MDU system is recommended, especially automation of sample processing.