Development of a time-resolved fluorescence immunoassay kit for detecting canine coronavirus and parvovirus through double labeling.

OBJECTIVE: Canine enteric coronavirus (CCV) and canine parvovirus type 2 (CPV-2) are the main pathogens responsible for acute gastroenteritis in dogs, and both single and mixed infections are common. This study aimed to establish a double-labeling time-resolved fluorescence immunoassay (TRFIA) to test and distinguish CCV and CPV-2 diseases. METHODS: A sandwich double-labeling TRFIA method was established and optimized using europium(III) (Eu3+)/samarium(III) (Sm3+) chelates. CCV/CPV-2 antigens were first captured by the immobilized antibodies. Then, combined with Eu3+/Sm3+-labeled paired antibodies, the Eu3+/Sm3+ fluorescence values were detected after dissociation to calculate the CCV/CPV-2 ratios. The performance, clinical performance and methodology used for laboratory (sensitivity, specificity, accuracy and stability) testing were evaluated. RESULTS: A double-label TRFIA for CCV and CPV-2 detection was optimized and established. The sensitivity of this TRFIA kit was 0.51 ng/mL for CCV and 0.80 ng/mL for CPV-2, with high specificity for CCV and CPV-2. All the accuracy data were less than 10%, and the recovery ranged from 101.21 to 110.28%. The kits can be temporarily stored for 20 days at 4 °C and can be stored for 12 months at temperatures less than - 20 °C. Based on a methodology comparison of 137 clinically suspected patients, there was no statistically significant difference between the TRFIA kit and the PCR method. Additionally, for CCV detection, the clinical sensitivity was 95.74%, and the clinical specificity was 93.33%. For CPV-2 detection, the clinical sensitivity was 92.86%, and the clinical specificity was 96.97%. CONCLUSION: In this study, a double-label TRFIA kit was prepared for CCV and CPV-2 detection with high laboratory sensitivity, specificity, accuracy, stability, clinical sensitivity and specificity. This kit provides a new option for screening/distinguishing between CCV and CPV-2 and may help improve strategies to prevent and control animal infectious diseases in the future.

Development and Validation of a Method to Quantify Flavonoids in Leaves of Lithospermum officinale (Boraginaceae).

The common gromwell Lithospermum officinale L. is a valuable medicinal plant that has been used in traditional medicine since ancient times. A method to quantify flavonoids in L. officinale leaves by differential spectrophotometry was developed taking advantage of the flavonoid reaction with aluminum chloride. The optimum duration of the reaction was determined, as well as the optimum volume-to-volume ratio between an aqueous ethanolic extract of L. officinale leaves and 2% aluminum chloride (aqueous ethanolic solution). Rutin was used as a standard. The method was validated in terms of specificity, linearity, precision, and accuracy and proved suitable for analytical purposes. The flavonoid content expressed in terms of rutin was found to exceed 2% of the absolutely dry weight in L. officinale leaves over different years of cultivation.