Characteristics of azole-resistant Aspergillus fumigatus attached to agricultural products imported to Japan.

Due to the increase in the number of azole-resistant Aspergillus fumigatus, there is an urgent need of data to predict future trends and prevent further spreading. The intercountry transfer of resistant A. fumigatus on plant bulbs have been reported. We investigated existence and characteristics of resistant isolates attached to agricultural products imported to Japan. We purchased 292 samples in Japan. All samples were screened for the existence of azole-resistant A. fumigatus. For positive isolates, minimum inhibitory concentrations of the drugs were determined. We also analyzed Cyp51A, Hmg1, and Erg6 mutations of these isolates and conducted microsatellite genotyping. Fourteen azole-resistant isolates were detected, of which 13 were cultured from flower bulbs imported from the Netherlands. Among them 5 were from 11 bulbs of Hippeastrum (45.5%), 5 were from 24 bulbs of Gladiolus (20.8%), 2 were from 4 bulbs of Ixia (50.0%), and 1 was from 22 bulbs of Tulipa (4.5%). Only 1 resistant isolate was cultured from the 10 bulbs of Narcissus (10.0%) originating in Japan. Various novel mutations including Y121F/T289A in Cyp51A with no tandem repeat in promoter region were discovered from imported strains. Our study provides important data showing that agricultural imports provide a possible route for their intercontinental spread and raises the concern that strains harboring highly diverse Cyp51A mutations might increase in clinical settings in the future.

Inhibition of the Hepatic Uptake of 99mTc-Tetrofosmin Using an Organic Cation Transporter Blocker.

The accumulation of high levels of 99mTc-tetrofosmin (99mTc-TF) in the hepatobiliary system can lead to imaging artifacts and interference with diagnosis. The present study investigated the transport mechanisms of 99mTc-TF and attempted to apply competitive inhibition using a specific inhibitor to reduce 99mTc-TF hepatic accumulation. In this in vitro study, 99mTc-TF was incubated in HEK293 cells expressing human organic anion transporting polypeptide 1B1 (OATP1B1), OATP1B3, OATP2B1, organic anion transporter 2 (OAT2), organic cation transporter 1 (OCT1), OCT2, and Na+-taurocholate cotransporting polypeptide with or without each specific inhibitor to evaluate the contribution of each transporter to 99mTc-TF transportation. In vivo studies, dynamic planar imaging, and single photon emission computed tomography (SPECT) experiments with rats were performed to observe alterations to 99mTc-TF pharmacokinetics using cimetidine (CMT) as an OCT1 inhibitor. Time-activity curves in the liver and heart were acquired from dynamic data, and the 99mTc-TF uptake ratio was calculated from SPECT. From the in vitro study, 99mTc-TF was found to be transported by OCT1 and OCT2. When CMT-preloaded rats and control rats were compared, the hepatic accumulation of the 99mTc-TF was reduced, and the time to peak heart count shifted to an earlier stage. The hepatic accumulation of 99mTc-TF was markedly suppressed, and the heart-to-liver ratio increased 1.6-fold. The pharmacokinetics of 99mTc-TF were greatly changed by OCT1 inhibitor. Even in humans, the administration of OCT1 inhibitor before cardiac SPECT examination may reduce 99mTc-TF hepatic accumulation and contribute to the suppression of artifacts and the improvement of SPECT image quality.

A newly developed enzyme-immunoassay for measuring the tissue contents of PACAP in fish.

We have developed a novel and easy enzyme-immunoassay (EIA) for pituitary adenylate cyclase-activating polypeptide (PACAP). We used it to determine immunoreactive PACAP levels in the central nervous system (CNS) and peripheral tissues of two fishes, a teleost (the stargazer) and an elasmobranch (a stingray). An antiserum was raised in a white rabbit immunized with a conjugate of synthetic stargazer PACAP27 plus keyhole limpet hemocyanin. The EIA system used an antiserum/biotin-labeled PACAP/avidin/biotin-conjugated enzyme complex, and a double antibody method was used to precipitate the immune complexes. We call the system the avidin-biotin complex detectable EIA (ABCDEIA) for PACAP. ABCDEIA with biotin-labeled PACAP27 detected only PACAP27, recognizing neither the longer forms of PACAP nor any other peptides. PACAPs with 27, 38, and 44 residues cross-reacted in another ABCDEIA with biotin-labeled PACAP38 or PACAP44. Whole brains of both fishes contained much higher levels of PACAP, 6-30 times as high as the levels in the mammalian brain, but unexpectedly, no immunoreactive PACAP27 was found in any CNS or peripheral tissue in either fish. The gastrointestinal tracts of fish also contained lower, but significant amounts of PACAP.