The Uptake and Distribution Evidence of Nano-and Microplastics in vivo after a Single High Dose of Oral Exposure

Objective Tissue uptake and distribution of nano-/microplastics was studied at a single high dose by gavage in vivo.Methods Fluorescent microspheres(100 nm,3μm,and 10μm)were given once at a dose of 200 mg/(kg∙body weight).The fluorescence intensity(FI)in observed organs was measured using the IVIS Spectrum at 0.5,1,2,and 4 h after administration.Histopathology was performed to corroborate these findings.Results In the 100 nm group,the FI of the stomach and small intestine were highest at 0.5 h,and the FI of the large intestine,excrement,lung,kidney,liver,and skeletal muscles were highest at 4 h compared with the control group(P<0.05).In the 3μm group,the FI only increased in the lung at 2 h(P<0.05).In the 10μm group,the FI increased in the large intestine and excrement at 2 h,and in the kidney at 4 h(P<0.05).The presence of nano-/microplastics in tissues was further verified by histopathology.The peak time of nanoplastic absorption in blood was confirmed.Conclusion Nanoplastics translocated rapidly to observed organs/tissues through blood circulation;however,only small amounts of MPs could penetrate the organs.

Relationship between Road Network Density and Cognitive Function: Results from a Cross-Sectional Study among Adults Aged 60 Years and Older in Liaoning, China

A good built environment is a basic element for supporting active and healthy aging.The built environment can change individual behaviors,stimulate cognitive activities,and potentially affect cognitive health.A growing number of studies have explored many features of the built environment,such as land use mix and destination accessibility.

Evidence on Invasion of Blood,Adipose Tissues,Nervous System and Reproductive System of Mice After a Single Oral Exposure:Nanoplastics versus Microplastics

Objective This study was designed to provide the evidences on the toxicokinetics of microplastics(MPs)and nanoplastics(NPs)in the bodies of mammals.Methods 100 nm,3μm,and 10μm fluorescent polystyrene(PS)beads were administered to mice once by gavage at a dose of 200 mg/kg body weight.The levels and change of fluorescence intensity in samples of blood,subcutaneous fat,perirenal fat,peritesticular fat,cerebrum,cerebellum,testis,and epididymis were measured at 0.5,1,2,and 4 h after administration using an IVIS Spectrum small-animal imaging system.Histological examination,confocal laser scanning,and transmission electron microscope were performed to corroborate the findings.Results After confirming fluorescent dye leaching and impact of pH value,increased levels of fluorescence intensity in blood,all adipose tissues examined,cerebrum,cerebellum,and testis were measured in the 100 nm group,but not in the 3 and 10μm groups except in the cerebellum and testis at 4 h for the 3μm PS beads.The presence of PS beads was further corroborated.Conclusion After a single oral exposure,NPs are absorbed rapidly in the blood,accumulate in adipose tissues,and penetrate the blood-brain/testis barriers.As expected,the toxicokinetics of MPs is significantly size-dependent in mammals.

An Epidemic of Hepatitis A--Liaoning Province,2020

What is already known about this topic?Hepatitis A(HA)is caused by acute hepatitis A virus(HAV)infection and was once very common in China.Following the 2008 introduction of the HA vaccine into the national Expanded Program on Immunization(EPI),the incidence of reported HA in China decreased markedly.However,HA epidemics still occur in Liaoning Province every 3–5 years,although with far fewer cases than in the pre-HA-vaccination era.What is added by this report?Between January 1,2020 and March 18,2020,the number of reported cases of HA in Dalian and Dandong cities of Liaoning Province increased significantly compared with the same period in previous years.All cases were sporadic,and cases were seen in nearly every township.The increase in HA occurred one month after local fresh seafood became available with most cases being among adults.A casecontrol study showed that consuming raw or undercooked seafood,clams,snapping shrimp,and oysters were significantly associated with the increase in HA.What are the implications for public health practices?Strengthening health education for residents to avoid consumption of raw seafood and encouraging HAV vaccination of adults aged 20 to 54 years are important to prevent periodic HAV endemic outbreaks.Further multisectoral cooperation must be emphasized on HA surveillance in areas with a high prevalence of HA.