Feeding strategies of the pelagic stingray (Pteroplatytrygon violacea) in the western Mediterranean Sea.

Elasmobranchs play crucial roles as predators in marine ecosystems. Understanding their trophic strategies and interactions is necessary for comprehending food web dynamics and developing ecosystem-based management strategies. Although, feeding strategies can change depending on several factors, including fluctuations in prey availability throughout the year. In this study, we investigated the trophic ecology of the pelagic stingray, Pteroplatytrygon violacea, the only stingray inhabiting the pelagic environment in the western Mediterranean Sea. We found significant temporal differences in diet composition, mostly consuming pelagic zooplankton in spring, whereas benthopelagic teleosts in autumn. After contrasting different studies, P. violacea appears to have a generalist and opportunistic diet consisting of a broad spectrum of pelagic and benthopelagic species, and trophic plasticity in response to environmental fluctuations. Our findings suggest that P. violacea can present different feeding strategies, mainly pelagic, with a relatively low trophic position for a mesopredator compared to other batoids.

Relapse treatment with low-dose steroids in steroid-sensitive minimal change disease.

Background: The treatment of minimal change disease (MCD) consists of a high dose of steroids for several months, implying significant drug toxicity. Nevertheless, relapses of steroid-sensitive MCD usually respond to lower doses of steroids. Methods: The objective of this study was to analyze whether a low dose of steroids (LDS) is effective for the treatment of MCD relapses. Since 2018, new relapses of steroid-sensitive adult patients with MCD in three Spanish centers have been treated with LDS. The cumulative dose of steroids, the time to remission, and the relapse-free time were compared between relapses treated with LDS and previous relapses of the same patients treated with a standard dose of steroids (SDS). Results: A total of 51 relapses in 31 patients were treated with LDS and compared with 48 historical relapses of the same patients treated with SDS. The mean doses of prednisone adjusted by weight for the initial treatment were 0.45 mg/kg (0.40-0.51 mg/kg) in the relapses treated with LDS and 0.88 mg/kg (0.81-1.00 mg/kg) in those treated with SDS. The mean cumulative doses of prednisone in LDS- and SDS-treated relapses were 1,191 mg (801-1,890 mg) and 3,700 mg (2,755-5,800 mg), respectively. The duration of treatment was 63 days (42-117 days) in the LDS group and was 140 days (65-195 days) in the SDS group. All patients achieved complete remission within 1 month after steroid therapy in both groups. The times to remission of the LDS and SDS groups were 19.10 ± 12.80 and 18.93 ± 12.98 days, respectively (p = 0.95). Conclusion: Among the steroid-sensitive patients with MCD, relapse therapy with LDS (0.5 mg/kg) appears effective and allows minimization of the steroid cumulative dose.