Subchronic Oral Toxicity Evaluation of Lanthanum： A 90-day, Repeated Dose Study in Rats

Objective The present study was undertaken to evaluate the subchronic toxicity of lanthanum and to determine the no observed adverse effect level（NOAEL）,which is a critical factor in the establishment of an acceptable dietary intake（ADI）.Methods In accordance with the Organization for Economic Co-operation and Development（OECD） testing guidelines,lanthanum nitrate was administered once daily by gavage to Sprague-Dawley（SD） rats at dose levels of 0,1.5,6.0,24.0,and 144.0 mg/kg body weight（BW） per day for 90 days,followed by a recovery period of 4 weeks in the 144.0 mg/kg BW per day and normal control groups.Outcome parameters were mortality,clinical symptoms,body and organ weights,serum chemistry,and food consumption,as well as ophthalmic,urinary,hematologic,and histopathologic indicators.The benchmark dose（BMD） approach was applied to estimate a point of departure for the hazard risk assessment of lanthanum.Results Significant decreases were found in the 144.0 mg/kg BW group in the growth index,including body weight,organ weights,and food consumption.This study suggests that the NOAEL of lanthanum nitrate is 24.0 mg/kg BW per day.Importantly,the 95% lower confidence value of the benchmark dose（BMDL） was estimated as 9.4 mg/kg BW per day in females and 19.3 mg/kg BW per day in males.Conclusion The present subchronic oral exposure toxicity study may provide scientific data for the risk assessment of lanthanum and other rare earth elements（REEs）.

Quasi-90-day oscillation observed in the MLT region at low latitudes from the Kunming meteor radar and SABER

Observations of a quasi-90-day oscillation in the mesosphere and lower thermosphere(MLT) region from April 2011 to December 2014 are presented in this study. There is clear evidence of a quasi-90-day oscillation in temperatures obtained from the Kunming meteor radar(25.6°N, 103.8°E) and Sounding of the Atmosphere using Broadband Emission Radiometry(SABER), as well as in wind observed by the Kunming meteor radar. The quasi-90-day oscillation appears to be a prominent feature in the temperatures and meridional wind tides and presents quite regular cycles that occur approximately twice per year. The amplitudes and phases of the quasi-90-day oscillation in the SABER temperature show a feature similar to that of upward-propagated diurnal tides, which have a vertical wavelength of ～20 km above 70 km. In the lower atmosphere, a similar 90-day variability is presented in the surface latent heat flux and correlates with the temperature in the MLT region. Similar to the quasi-90-day oscillation in temperature, a 90-day variability of ozone(O3) is also present in the MLT region and is considered to be driven by a similar variability in the upwardly-propagated diurnal tides generated in the lower atmosphere. Moreover, the 90-day variability in the absorption of ultraviolet(UV) radiation by daytime O3 in the MLT region is an in situ source of the quasi-90-day oscillation in the MLT temperature.

Subchronic Oral Toxicity Evaluation of Sodium Dehydroacetate: A 90-day Repeated Dose Study in Rats

Objective The present study was undertaken to evaluate the subchronic oral toxicity of sodium dehydroacetate(DHA-Na)and to determine the point of departure(POD),which is a critical factor in the establishment of an acceptable dietary intake.Methods DHA-Na was administered once daily by gavage to Sprague–Dawley rats at dose levels of 0.0,31.0,62.0,and 124.0 mg/kg BW per day for 90 days,followed by a recovery period of 4 weeks in the control and 124.0 mg/kg BW per day groups.The outcome parameters were mortality,clinical observations,body weights,food consumption,hematology and clinical biochemistry,endocrine hormone levels,and ophthalmic,urinary,and histopathologic indicators.The benchmark dose(BMD)approach was applied to estimate the POD.Results Significant decreases were found in the 62.0 and 124.0 mg/kg BW groups in terms of the body weight and food utilization rate,whereas a significant increase was found in the thyroid stimulating hormone levels of the 124.0 mg/kg BW group.Importantly,the 95%lower confidence limit on the BMD of 51.7 mg/kg BW was modeled for a reduction in body weight.Conclusion The repeated-dose study indicated the slight systemic toxicity of DHA-Na at certain levels(62.0 and 124.0 mg/kg BW)after a 90-day oral exposure.

The effects of 90-day feeding of D-psicose syrup in male wistar rats

D-Psicose is a rare sugar present in small quantities in natural products. In a previous study, we showed that D-psicose suppresses increase in plasma glucose and reduces body fat accumulation in rats. Based on acute and chronic toxicity testing in rats, D-psicose is classified as an ordinary and safe substance. Recently, we developed a high D-psicose syrup (PS) made from high fructose corn syrup (HFCS) by the alkaline isomerization method. However, the safety of PS as a food additive has not been demonstrated. In this study, we investigated the effects of 90-day feeding of PS in male Wistar rats. The rats were fed diets containing 3% D-psicose (control) or 4.3% PS for 90 days. The body weight gain and intra-abdominal adipose tissue weight did not differ between the control and PS group. The weights of the tissues did not differ between the two dietary groups. In clinical chemistry and hematological analyses, no differences were found between the control and PS groups. No gross pathological findings were evident at dietary doses of 4.3% PS. Therefore, the present study found no adverse effects of PS in rats fed a diet containing 4.3% PS for 90 days.