The Effects of Dexmedetomidine on the Cognitive Function of Mild Cognitive Impairment (MCI) Rats

Background: The study sought to investigate the effects of dexmedetomidine on cognitive function after anesthesia and to examine its actual mechanism. Methods: A total of 48 rats were randomly divided into model Groups A, B, C, or D. Rats in Groups A, B, and C received a hypodermic injection of D-gal with a concentration of 1,000 mg·kg−1·d−1 respectively for 1 week. Group D received the same volume of saline. The Morris water maze (MWM) test was performed within 6 days of the injection. After the behavior test, Group A received an inhalation dose of 2% sevoflurane. Group B received an inhalation dose of 2% sevoflurane and an intraoperative infusion of dexmedetomidine with a concentration of 10 μg·kg−1·h−1. Group C served as the control group and received no treatment. Group D received an inhalation dose of 2% sevoflurane. Results: In relation to the model establishment, we found that there was no significant difference in body weight and swimming speed before and after modeling. There was no statistically significant difference in the escape latency between Groups A, B, C, and D before modeling. After modeling, there was no statistical difference in the escape latency between Groups A, B, and C, but the difference was statistically significant when compared to Group D (P<0.05). In relation to the dexmedetomidine intervention, we found that compared to Group C, MWM test performance in Group A and B was considerably worse (longer escape latencies and fewer platform crossings within 90 seconds), and were more significant in Group A. .Compared with Group D, the levels of IL-1, IL-6, and TNF-α of the brain homogenates were elevated, and this elevation was highest in Group A, followed by Group B; The pathological changes were consistent with changes in behavioral tests. In group A, there were obvious disorders of glial cell arrangement, apoptosis and deletion. There was no significant change in group D. And the changes of vertebral cells in group B and group C were slight, with orderly arrangement and intact cell structure.Conclusions: Dexmedetomidine inhibits the apoptosis of hippocampal cells and reduces the cognitive dysfunction of rats with MCI induced by D-galactose via the inhibition of the release of inflammatory cytokines.

Radon and thoron levels in the dwellings of Buddonithanda: a village in the environs of proposed uranium mining site, Nalgonda district, Telangana state, India

Elevated levels of radon and thoron in the indoor atmosphere may cause the deleterious effects on the mankind. Mining sites and their environs attract a special interest in radon studies as higher levels are frequently reported in the habitats. In the present study, radon and thoron levels were measured in the dwellings of Buddonithanda, a village in the environs of proposed uranium mining site, with pin-hole (SSNTDs) dosimeters for the period of a year. The measured radon and thoron levels were found to vary widely from 14 to 675 Bq m−3 (geometric mean = 94 Bq m−3) and from 21 to 704 Bq m−3 (geometric mean = 121 Bq m−3), respectively. An attempt was made to understand the large spatial variation of these levels. The seasonal and diurnal variation studies were used in unraveling the behavior of the radioactive isotopes in indoor environment and the same was explained with the help of a simplified mathematical model. Quantification of inhalation dose due to radon and thoron was done with suitable occupancy factors.

Inhalation dose from exposure to radon, thoron and their progeny in indoors around a nuclear power generation facility in Uttar Pradesh, India

Radon, thoron and their progeny concentration have been measured in dwellings located within a 90 km2 area around a nuclear power plant using solid-state nuclear track detectors. Time-integrated measurements were carried out on a four-month cycle, making three measurements in each dwelling throughout the year. In total, 145 dwellings were selected for the study. The measured values of gas and their progeny concentrations were used to determine the equilibrium factor for radon and thoron indoors and annual inhalation dose. The average value of the equilibrium factor indoors was found to be 0.44 ± 0.23 for radon and 0.015 ± 0.010 for thoron. The annual inhalation dose for the public living around this plant was found to be 0.97 ± 0.55 mSv. Results were analysed for different seasons and different categories of dwellings for their construction type.

Annual effective dose from radon-222 concentration levels in underground water in bungoma south sub - county, Kenya

This research measured the concentration levels of radon in groundwater and determined the ingestion and inhalation dose. The study used RAD7 detector with RAD7-H2O accessory from Durridge Company to determine the radon levels. Thirty water samples in granitic dominated regions were collected from various areas of Bungoma County: ten from boreholes (BH), ten from hand dug wells (WL) and ten from springs (SP). The water samples were collected in 250 ml bottles which were tightly covered with lid to avoid radon leakage. The highest value was 303±4.00 KBq/m3 recorded in Kanduyi well and the lowest was 126±11.4kBq/m3 from where most of the samples recorded a high radon concentration with a mean of 269±5.25 KBq/m3 in wells, 213±7.96 KBq/m3 in boreholes and 290±7.70 KBq/m3 in springs. The average ingestion dose was found to be 1.5±0.07mSv/yr, 1.9±0.09 mSv/yr and 2.1±0.1 mSv/yr. The average annual effective dose rate for the samples collected were 2±0.1 mSv/yr for boreholes, 2.6±0.13 mSv/yr for wells and 2.7±0.14 mSv/yr for springs. The samples reported an average value of AED higher than the world average of 1.15 mSv/yr but below the exception limit of recommended action level of 10 mSv/yr hence the radon concentration levels in underground water in the study area has minimal health implications to the population.

INDOOR AND OUTDOOR RELATIONSHIPS OF PARTICLE WITH DIFFERENT SIZES IN AN APARTMENT IN HANOI: MASS CONCENTRATION AND RESPIRATORY DOSE ESTIMATION

This paper presents data on the size characterization concentration of PM0.1, PM0.5, PM1, PM2.5, PM10, TSP in indoor and outdoor air of a residential apartment in two seasons (winter and summer) in Hanoi, Vietnam. These particles with different sizes were taken by 5 stage impactors (Nano sampler 3182, KINOMAX). Daily average concentrations of coarse particles (PM10) and fine particles (PM2.5) indoors and outdoors exceeded the WHO recommended values. In winter, the concentrations of PM0.5, PM1, PM2.5 and PM10, TSP are higher than in summer. However, concentrations of PM0.1 (NP) remains negligible change between two seasons. The indoor NP accounts about 17% and 8 % of fine particle (PM2.5) and 12 % and 7% of coarse particle (PM10) in winter and summer, respectively. The indoor fraction for small sizes (NP, PM0.5, PM1 and PM2.5) have better infiltration than coarse sizes (PM10 and TSP), except for NP in summer. Moderate correlation between wind speed (Ws) and PM concentration are found, whereas precipitation (Pr), Relative humidity (RH) and temperature (T) correlate with concentration with different sizes are determined. Strong correlations between particles with different sizes are also found in indoors and outdoors (r = 0.73-0.98). Household activities like cooking, cleaning and vacuum cleaner are attributed to elevate the indoor NP. The Monte Carlo simulation shows that highest estimated dose is observed in the age group (over 60 years) and age group (0-3 years) suffers the lowest dose, which has implications in the adverse health effects for sensitive groups. Sensitive analysis find the concentration of particles to be the most influencing factor on inhalation dose estimation.

METHODOLOGY FOR SIMPLE SPOT MEASUREMENT OF EQUILIBRIUM EQUIVALENT RADON CONCENTRATION

Estimation of the effective inhalation dose of short half-life radon progeny requires the quantification of radon equilibrium equivalent activity concentrations (EEC, Ceq). The aim of the present study is to develop new methodology that focuses on spot measurements to determine EEC from single gross alpha counts and determine an optimised protocol. The core of the approach is to measure alpha particles over time when the radon progeny attached to the sampling filter are significantly disintegrated. The calibration curve of single counts to EEC is theoretically deduced and validated by a comparison test. The advantage of the present method is its minimal requirements, including the use of common instruments and simple sampling, alpha counting and analysis procedures. This approach offers an option for radon practitioners working in a variety of fields, as well as the possibility for non-experts to easily measure Ceq.