Introduction: Given the ongoing coronavirus disease 2019 (COVID-19) pandemic and the consequent global healthcare crisis, there is an urgent need to better understand risk factors for symptom deterioration and mortality among patients with COVID-19. This systematic review aimed to meet the need by determining the predictive value of chronic diseases for COVID-19 severity and mortality.Methods: We searched PubMed, Embase, Web of Science, and Cumulative Index to Nursing and Allied Health Complete to identify studies published between December 1, 2019, and December 31, 2020. Two hundred and seventeen observational studies from 26 countries involving 624,986 patients were included. We assessed the risk of bias of the included studies and performed a cumulative meta-analysis.Results: We found that among COVID-19 patients, hypertension was a very common condition and was associated with higher severity, intensive care unit (ICU) admission, acute respiratory distress syndrome, and mortality. Chronic obstructive pulmonary disease was the strongest predictor for COVID-19 severity, admission to ICU, and mortality, while asthma was associated with a reduced risk of COVID-19 mortality. Patients with obesity were at a higher risk of experiencing severe symptoms of COVID-19 rather than mortality. Patients with cerebrovascular disease, chronic liver disease, chronic renal disease, or cancer were more likely to become severe COVID-19 cases and had a greater probability of mortality.Conclusions: COVID-19 patients with chronic diseases were more likely to experience severe symptoms and ICU admission and faced a higher risk of mortality. Aggressive strategies to combat the COVID-19 pandemic should target patients with chronic diseases as a priority.
The delivery of drugs across the blood–brain barrier (BBB) effectively and safely is one of the major challenges in the treatment of neurodegenerative diseases.
At
present, the complex pathogenesis, the difficult-to-overcome
blood–brain barrier (BBB), the development of the disease course
which cannot be prevented, and other problems are serious challenges
in the treatment of Alzheimer’s disease (AD). In order to enhance
the therapeutic effect of drugs through BBB, we synthesized simple
and easy-to-obtain selenium quantum dots (SeQDs), with a multitarget
therapeutic effect. This new type of SeQDs has an ultrasmall size
and can quickly penetrate the BBB. According to the fluorescence characteristics
of SeQDs, we can diagnose and track AD. The experimental results show
that SeQDs have strong free-radical scavenging activity, protect cells
from oxidative stress induced by different stimuli, and show broad-spectrum
antioxidant activity. The SeQDs can not only effectively inhibit Aβ
aggregation and significantly reduce Aβ-mediated cytotoxicity,
thus preventing AD cascade reaction, but also effectively reduce tau
protein phosphorylation by down-regulating PHF1 and CP13 and further
reduce oxidative stress, restore mitochondrial functions, and maintain
nerve cell stability and protect nerve cells from oxidative stress.
In vivo studies demonstrate that SeQDs can continuously accumulate
in the brain after rapid passage of BBB and can quickly alleviate
AD, significantly improve the memory impairment of AD mice, and improve
their learning and memory ability. Therefore, the use of SeQDs in
the treatment of AD has great advantages compared with traditional
single-target drugs and provides a new direction for the combination
of prevention and treatment of neurodegenerative diseases.
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