The effects of living in an outdoor enclosure on hippocampal plasticity and anxiety‐like behavior in response to nematode infection

The hippocampus of rodents undergoes structural remodeling throughout adulthood, including the addition of new neurons. Adult neurogenesis is sensitive to environmental enrichment and stress. Microglia, the brain's resident immune cells, are involved in adult neurogenesis by engulfing dying new neurons. While previous studies using laboratory environmental enrichment have investigated alterations in brain structure and function, they do not provide an adequate reflection of living in the wild, in which stress and environmental instability are common. Here, we compared mice living in standard laboratory settings to mice living in outdoor enclosures to assess the complex interactions among environment, gut infection, and hippocampal plasticity. We infected mice with parasitic worms and studied their effects on adult neurogenesis, microglia, and functions associated with the hippocampus, including cognition and anxiety regulation. We found an increase in immature neuron numbers of mice living in outdoor enclosures regardless of infection. While outdoor living prevented increases in microglial reactivity induced by infection in both the dorsal and ventral hippocampus, outdoor mice with infection had fewer microglia and microglial processes in the ventral hippocampus. We observed no differences in cognitive performance on the hippocampus‐dependent object location task between infected and uninfected mice living in either setting. However, we found that infection caused an increase in anxiety‐like behavior in the open field test but only in outdoor mice. These findings suggest that living conditions, as well as gut infection, interact to produce complex effects on brain structure and function.     

Impact of COVID-19 Pandemic on Organ Donation in Hong Kong: A Single-Center Observational Study

IntroductionThe coronavirus disease 2019 (COVID-19) pandemic was expected to have a negative impact on organ donation. With the differences in health care systems and lockdown policies in various regions, the pandemic's effect on organ donation and transplant service may vary. Most of the deceased donor organ referrals in our hospital came from non–intensive care units (ICUs). The objective of this study is to report our experience and quantify the effects of the COVID-19 pandemic on deceased donor organ donation in our center.MethodsThis was a retrospective observational study comparing the deceased donor organ donation activity during the period January 23 to November 30, 2020 with the same period in 2018 in Queen Elizabeth Hospital, Hong Kong.ResultsThere was a 26.9% reduction in deceased donor organ donor referral in 2020 compared with 2018. No significant difference in the proportion of referrals from ICU or non-ICU areas between the 2 time periods was observed. The brain death confirmation rate was significantly higher in 2020 (40.8% vs 20.2%, P = .003). Nine patients had family consent for organ donation in 2020 (vs 7 patients in the same period in 2018). There were no significant differences in consent rate and number of recovered organs between the 2 periods.ConclusionsWith effective measures to limit the spread of COVID-19 in a community, it is possible to support the needs of both patients with COVID-19 and deceased donor organ donation services.     

Osteoporotic Vertebral Fracture Prevalence in Elderly Chinese Men and Women: A Comparison of Endplate/Cortex Fracture–Based and Morphometrical Deformity–Based Methods

This study aims to evaluate endplate/cortex fracture (ECF)-based method for detecting osteoporotic vertebral fracture (VF) in elderly Chinese population (age ≥ 65 years). The radiographs of 1954 elderly Chinese men (mean: 72.3 years) and 1953 elderly Chinese women (mean: 72.5 years) were evaluated according to Genant's morphometrical vertebral deformity (VD) severity criteria, as well as identified VF according to ECF without necessary requirement of VD. According to ECF, grade-1, -2, and -3 VF prevalence was 1.89%, 1.74%, and 2.25% in men, and 3.33%, 3.07%, and 5.89% in women, respectively. In men and women, 15.7% (35 of 223) and 34.5% (48 of 139) of vertebrae with VD grade-1 deformity were ECF(+, with fracture), respectively. In men and women, 89.7% (35 of 39) and 66.7% (48 of 72) of vertebrae with ECF grade-1 fracture had VD grade-1 deformity. For grade-1 change, ECF(+) subjects tended to have a lower BMD than the VD(+) subjects. In subjects with VD grade-2 deformity, those who were also EC (+) tended to have a lower BMD than those were ECF(?). In all grades, VD(?) and ECF(?) subjects tended to have highest BMD, whereas VD(+) and ECF(+) subjects tended to have lowest BMD. ECF may be more specific for assessing mild VF than the criteria based on vertebral deformity.