Butylated hydroxytoluene (BHT) is a synthetic phenolic antioxidant widely used in food additives, pharmaceuticals, personal care products, and other industries. It has been frequently detected in various environmental media, including oceans, soils, and the atmosphere. Human exposure to BHT can occur through multiple routes, and it has the potential to accumulate in the body while being readily transformed into several metabolites that are often more toxic than the parent compound. In recent years, numerous studies have investigated the levels of BHT and its metabolites in human populations and their potential health risks. Most current research on BHT exposure and its metabolites has focused on vulnerable groups such as pregnant women and children. These compounds have been detected in various biological samples—including human serum, urine, cerebrospinal fluid, and placenta—with relatively high frequencies.The metabolites of BHT demonstrate greater toxicity than BHT itself and have been implicated in pathological processes such as diminished ovarian reserve and miscarriage. Potential mechanisms include endocrine disruption, oxidative stress, and DNA damage. This article reviews current research on human exposure to BHT and its metabolites, as well as their potential health effects, aiming to provide a scientific basis for establishing usage standards and assessing health risks associated with BHT.

Butylated hydroxytoluene (BHT) is a synthetic phenolic antioxidant widely used in food additives, pharmaceuticals, personal care products, and other industries. It has been frequently detected in various environmental media, including oceans, soils, and the atmosphere. Human exposure to BHT can occur through multiple routes, and it has the potential to accumulate in the body while being readily transformed into several metabolites that are often more toxic than the parent compound. In recent years, numerous studies have investigated the levels of BHT and its metabolites in human populations and their potential health risks. Most current research on BHT exposure and its metabolites has focused on vulnerable groups such as pregnant women and children. These compounds have been detected in various biological samples—including human serum, urine, cerebrospinal fluid, and placenta—with relatively high frequencies.The metabolites of BHT demonstrate greater toxicity than BHT itself and have been implicated in pathological processes such as diminished ovarian reserve and miscarriage. Potential mechanisms include endocrine disruption, oxidative stress, and DNA damage. This article reviews current research on human exposure to BHT and its metabolites, as well as their potential health effects, aiming to provide a scientific basis for establishing usage standards and assessing health risks associated with BHT.

Objective:To examine the effects of preimplantation genetic testing for aneuploidies (PGT-A) using blastocyst biopsy on maternal and perinatal outcomes for women of advanced age.Methods:A retrospective cohort study was conducted during January 2016 to December 2018 at Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital. Women who were aged ≥35 years, underwent intracytoplasmic sperm injection (ICSI, control group) or PGT-A after ICSI (PGT-A group) with single frozen-thawed blastocyst transferred were eligible in this study. They were further divided into 35-37 years old subgroup and ≥38 years old subgroup according to age. The primary outcome was live birth, and the secondary outcomes were human chorionic gonadotropin (hCG) positivity, clinical pregnancy, pregnancy loss, hypertension in pregnancy, gestational diabetes mellitus, gestational age, preterm birth, caesarean section, low birth weight, small gestational age, and large gestational age.Results:For women aged ≥35 years, the live birth rate in PGT-A group was significantly higher than that in control group [38.0% (89/234) vs. 26.8% (237/885), OR(95% CI)=1.49(1.13-1.97), P=0.047], the miscarriage rate was significantly lower than that in control group [17.6% (19/108) vs. 29.0% (116/443), OR(95% CI)=0.45(0.24-0.85), P=0.013]. We found that for women who aged ≥38 years, the live birth rate [ OR(95% CI)=3.01(1.67-5.44), P<0.001], hCG positivity rate [ OR(95% CI)=2.08(1.25-3.47), P=0.005], clinical pregnancy rate [ OR(95% CI)=2.39(1.40-4.07), P=0.001] in PGT-A group were significantly higher than those in control group, and the miscarriage rate in PGT-A group was significantly lower than that in control group [ OR(95% CI)=0.34(0.13-0.85), P=0.022]; for women aged 35-37 years, there were no statistically significant differences in pregnancy outcomes between the two groups (all P>0.05). Moreover, there were no statistically significant differences in the rates of obstetric complications and perinatal outcomes for women aged ≥35 years between PGT-A group and control group (all P>0.05), and similar results were found in the subgroup analyses for women who aged 35-37 years or ≥38 years. Conclusion:PGT-A using blastocyst stage biopsy strategy in single blastocyst thaw transferred cycles could significantly improve the rates of hCG positivity, clinical pregnancy, and live birth, and significantly reduce the miscarriage rate for women aged ≥38 years, but could not improve the pregnancy outcomes for women aged 35-37 years. In addition, the use of PGT-A does not increase the risk of obstetric complications and perinatal outcomes for women of advanced age.

Objective:To examine the effects of preimplantation genetic testing for aneuploidies (PGT-A) using blastocyst biopsy on maternal and perinatal outcomes for women of advanced age.Methods:A retrospective cohort study was conducted during January 2016 to December 2018 at Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital. Women who were aged ≥35 years, underwent intracytoplasmic sperm injection (ICSI, control group) or PGT-A after ICSI (PGT-A group) with single frozen-thawed blastocyst transferred were eligible in this study. They were further divided into 35-37 years old subgroup and ≥38 years old subgroup according to age. The primary outcome was live birth, and the secondary outcomes were human chorionic gonadotropin (hCG) positivity, clinical pregnancy, pregnancy loss, hypertension in pregnancy, gestational diabetes mellitus, gestational age, preterm birth, caesarean section, low birth weight, small gestational age, and large gestational age.Results:For women aged ≥35 years, the live birth rate in PGT-A group was significantly higher than that in control group [38.0% (89/234) vs. 26.8% (237/885), OR(95% CI)=1.49(1.13-1.97), P=0.047], the miscarriage rate was significantly lower than that in control group [17.6% (19/108) vs. 29.0% (116/443), OR(95% CI)=0.45(0.24-0.85), P=0.013]. We found that for women who aged ≥38 years, the live birth rate [ OR(95% CI)=3.01(1.67-5.44), P<0.001], hCG positivity rate [ OR(95% CI)=2.08(1.25-3.47), P=0.005], clinical pregnancy rate [ OR(95% CI)=2.39(1.40-4.07), P=0.001] in PGT-A group were significantly higher than those in control group, and the miscarriage rate in PGT-A group was significantly lower than that in control group [ OR(95% CI)=0.34(0.13-0.85), P=0.022]; for women aged 35-37 years, there were no statistically significant differences in pregnancy outcomes between the two groups (all P>0.05). Moreover, there were no statistically significant differences in the rates of obstetric complications and perinatal outcomes for women aged ≥35 years between PGT-A group and control group (all P>0.05), and similar results were found in the subgroup analyses for women who aged 35-37 years or ≥38 years. Conclusion:PGT-A using blastocyst stage biopsy strategy in single blastocyst thaw transferred cycles could significantly improve the rates of hCG positivity, clinical pregnancy, and live birth, and significantly reduce the miscarriage rate for women aged ≥38 years, but could not improve the pregnancy outcomes for women aged 35-37 years. In addition, the use of PGT-A does not increase the risk of obstetric complications and perinatal outcomes for women of advanced age.

Aim To establish a set of apparatus and method for the continued measurement of the oxygen consumption in mice. Methods The apparatus consists of a bottle with broad-neck for mice, basic burette, beaker containing water and some tubes for connection. Twenty mice were divided randomly into two groups and administered intragestrically propranolol 20 mg?kg -1 or equal volume of normal saline, respectively. The survival time and oxygen consumption were measured in mice subjected to normobaric and hypoxia.Results The survival time was prolonged by 43.35% (P