Comparison of the incidence of vancomycin-associated nephrotoxicity following the change from trough-guided dosing to AUC-guided doing using trough-only data.

OBJECTIVES: Although use of AUC-guided vancomycin dosing was recommended in the revised 2020 consensus guideline, collection of multiple vancomycin serum samples to calculate AUC may cause clinical complications. AUC calculated from trough-only data (one-point AUC-guided dosing) has not been sufficiently validated. The aim of the present study was to compare the incidence of nephrotoxicity following the change from trough-guided to one-point AUC-guided dosing. METHODS: We conducted a single-centre, prospective cohort study to compare the incidence of nephrotoxicity between a trough-guided dosing group and one-point AUC-guided dosing group. RESULTS: One-point AUC-guided dosing significantly decreased the incidence of acute kidney injury (AKI) compared with trough-guided dosing (2.8% versus 17.4%, P = 0.002). Further, Kaplan-Meier plots for cumulative incidence of the AKI-free rate indicated that the onset of AKI was significantly longer in the one-point AUC-guided dosing group than in trough-guided dosing (HR, 6.5; 95% CI, 1.5-27.4; P = 0.011). Moreover, multivariate Cox proportional hazard analysis indicated that implementation of one-point AUC-guided dosing was a significant protective factor against the incidence of AKI (age-adjusted HR, 0.164; 95% CI, 0.04-0.69; P = 0.014). CONCLUSIONS: Compared with trough concentration-guided dosing, AUC-guided dosing using one-point sampling markedly reduced the incidence of AKI, without additional serum sampling.

Histological Properties of Main and Accessory Olfactory Bulbs in the Common Hippopotamus.

The olfactory system of mammals comprises a main olfactory system that detects hundreds of odorants and a vomeronasal system that detects specific chemicals such as pheromones. The main (MOB) and accessory (AOB) olfactory bulbs are the respective primary centers of the main olfactory and vomeronasal systems. Most mammals including artiodactyls possess a large MOB and a comparatively small AOB, whereas most cetaceans lack olfactory bulbs. The common hippopotamus (Hippopotamus amphibius) is semiaquatic and belongs to the order Cetartiodactyla, family Hippopotamidae, which seems to be the closest extant family to cetaceans. The present study evaluates the significance of the olfactory system in the hippopotamus by histologically analyzing the MOB and AOB of a male common hippopotamus. The MOB comprised six layers (olfactory nerve, glomerular, external plexiform, mitral cell, internal plexiform, and granule cell), and the AOB comprised vomeronasal nerve, glomerular, plexiform, and granule cell layers. The MOB contained mitral cells and tufted cells, and the AOB possessed mitral/tufted cells. These histological features of the MOB and the AOB were similar to those in most artiodactyls. All glomeruli in the AOB were positive for anti-Gαi2, but weakly positive for anti-Gαo, suggesting that the hippopotamus vomeronasal system expresses vomeronasal type 1 receptors with a high affinity for volatile compounds. These findings suggest that the olfactory system of the hippopotamus is as well developed as that of other artiodactyl species and that the hippopotamus might depend on its olfactory system for terrestrial social communication.

Histological features of the vomeronasal organ in the giraffe, Giraffa camelopardalis.

The vomeronasal organ (VNO) that preferentially detects species-specific substances is diverse among animal species, and its morphological properties seem to reflect the ecological features of animals. This histological study of two female reticulated giraffes (Giraffa camelopardalis reticulata) found that the VNO is developed in giraffes. The lateral and medial regions of the vomeronasal lumen were covered with sensory and nonsensory epithelia, respectively. The vomeronasal glands were positive for periodic acid-Schiff and alcian blue (pH 2.5) stains. The VNO comprises several large veins like others in the order Cetartiodactyla, suggesting that these veins function in a pumping mechanism in this order. In addition, numerous thin-walled vessels located immediately beneath the epithelia covering the lumen entirely surrounded the vomeronasal lumen. This sponge-like structure might function as a specific secondary pump in giraffes.