The rapid spread of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) in recent years not only caused a global pandemic but resulted in enormous social,economic,and health burdens worldwide.Despite considera...The rapid spread of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) in recent years not only caused a global pandemic but resulted in enormous social,economic,and health burdens worldwide.Despite considerable efforts to combat coronavirus disease 2019(COVID-19),various SARS-CoV-2 variants have emerged,and their underlying mechanisms of pathogenicity remain largely unknown.Furthermore,effective therapeutic drugs are still under development.Thus,an ideal animal model is crucial for studying the pathogenesis of COVID-19 and for the preclinical evaluation of vaccines and antivirals against SARS-CoV-2 and variant infections.Currently,several animal models,including mice,hamsters,ferrets,and nonhuman primates(NHPs),have been established to study COVID-19.Among them,ferrets are naturally susceptible to SARS-CoV-2 infection and are considered suitable for COVID-19 study.Here,we summarize recent developments and application of SARS-CoV-2 ferret models in studies on pathogenesis,therapeutic agents,and vaccines,and provide a perspective on the role of these models in preventing COVID-19 spread.展开更多
Background： Early embryonic developmental arrest is the most commonly understudied adverse outcome of pregnancy. The relevance of intrauterine infection to spontaneous embryonic death is rarely studied and remains un...Background： Early embryonic developmental arrest is the most commonly understudied adverse outcome of pregnancy. The relevance of intrauterine infection to spontaneous embryonic death is rarely studied and remains unclear. This study aimed to investigate the relationship between intrauterine bacterial infection and early embryonic developmental arrest. Methods： Embryonic chorion tissue and uterine swabs for bacterial detection were obtained from 33 patients who underwent artificial abortion （control group） and from 45 patients who displayed early embryonic developmental arrest （trial group）. Results： Intrauterine bacterial infection was discovered in both groups. The infection rate was 24.44% （11/45） in the early embryonic developmental arrest group and 9.09% （3/33） in the artificial abortion group. Classification analysis revealed that the highest detection rate for Micrococcus luteus in the early embryonic developmental arrest group was 13.33% （6/45）, and none was detected in the artificial abortion group. M. luteus infection was significantly different between the groups （P 〈 0.05 as shown by Fisher＇s exact test）. In addition, no correlation was found between intrauterine bacterial infection and history of early embryonic developmental arrest. Conelusions： IV/. luteus infection is related to early embryonic developmental arrest and might be one of its causative factors.展开更多
Temperature is one of the abiotic factors limiting growth and productivity of plants. In the present work, the effect of low non-freezing temperature, as an inducer of ＂chilling resistance＂, was studied in three cul...Temperature is one of the abiotic factors limiting growth and productivity of plants. In the present work, the effect of low non-freezing temperature, as an inducer of ＂chilling resistance＂, was studied in three cultivars of rice （Oryza sativa L.）, japonica cv. 9516 （j-9516）, the two parental lines of superhigh-yield hybrid rice between subspecies, Peiai/E32 （ji-PE）, and the traditional indica hybrid rice Shanyou 63 （i-SY63）. Leaves of chill-treated rice showed chilling-induced resistance, as an increase of their low-temperature tolerance was measured using chlorophyll fluorescence measurements, revealing a change in photosystem II （PSII） efficiency. After 5 d of exposure to 11 ~C under low light （100 pmol·m^-2·s^-1）, levels of unsaturated fatty acids in PSII thylakoid membrane lipids decreased during the initial 1-2 d, then increased slowly and reached 99.2%, 95.3% and 90.1% of the initial value （0 d） in j-9516, ji-PE and i-SY63, respectively, on the fifth day. However, under medium light （600 μmol·m^-2·s^-1）, all cultivars experienced similar substantial photoinhibition, which approached steady state levels after a decline in levels of unsaturated fatty acids in PSII thylakoid membrane lipids to about 57.1%, 53.8% and 44.5% of the initial values （0 d） in j-9516, ji-PE and i-SY63 on the fifth day. Under either chilling-induced resistance （the former） or low temperature photoinhibition （the latter） conditions, the changes of other physiological parameters such as D1 protein contents, electron transport activities of PSII （ETA）, Fv/Fm, xanthophyl cycle activities expressed by DES （deepoxide state） were consistent with that of levels of unsaturated fatty acids in PSII thylakoid membrane lipids. So there were negative correlations between saturated levels of fatty acids （16：1（3t）, 16：0, 18：0）, especially the 16：1（3t） fatty acid on thylakoid membrane and other physiological parameters, such as D1 protein contents, ETA and （A＋Z）/（A＋V＋Z）. A specific role of desaturation of fatty acids and the photoprotective pigments of the xanthophyl cycle, leading to an acclimation response in thylakoid membrane lipids may be involved. We conclude that chilling-induced resistance is accelerated by the unsaturation of thylakoid membranes, and the ability of rice plants to cold-harden can be enhanced by genetic engineering.展开更多
To the Editor:Anemia is a common finding among patients admitted to intensive care units(ICUs),nearly 60%of ICU patients had serum hemoglobin levels<12 g/dL at baseline,30%of whom had serum hemoglobin levels<9 g...To the Editor:Anemia is a common finding among patients admitted to intensive care units(ICUs),nearly 60%of ICU patients had serum hemoglobin levels<12 g/dL at baseline,30%of whom had serum hemoglobin levels<9 g/dL,over 95%of critically ill patients were anemic within 3 days of ICU admission.[1]Moreover,anemia may be aggravated or newly developed in critically ill patients during their ICU stay.展开更多
基金supported by the S&T Program of Hebei(20277705D and 20372601D)Natural Science Foundation of Hebei Province,China (H2020206352)+2 种基金Science and Technology Project of Hebei Education Department (QN2018150)Hebei Medical Science Research Project (20220973)Chinese Medicine Research Program of Hebei Province (2021119)。
文摘The rapid spread of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) in recent years not only caused a global pandemic but resulted in enormous social,economic,and health burdens worldwide.Despite considerable efforts to combat coronavirus disease 2019(COVID-19),various SARS-CoV-2 variants have emerged,and their underlying mechanisms of pathogenicity remain largely unknown.Furthermore,effective therapeutic drugs are still under development.Thus,an ideal animal model is crucial for studying the pathogenesis of COVID-19 and for the preclinical evaluation of vaccines and antivirals against SARS-CoV-2 and variant infections.Currently,several animal models,including mice,hamsters,ferrets,and nonhuman primates(NHPs),have been established to study COVID-19.Among them,ferrets are naturally susceptible to SARS-CoV-2 infection and are considered suitable for COVID-19 study.Here,we summarize recent developments and application of SARS-CoV-2 ferret models in studies on pathogenesis,therapeutic agents,and vaccines,and provide a perspective on the role of these models in preventing COVID-19 spread.
文摘Background： Early embryonic developmental arrest is the most commonly understudied adverse outcome of pregnancy. The relevance of intrauterine infection to spontaneous embryonic death is rarely studied and remains unclear. This study aimed to investigate the relationship between intrauterine bacterial infection and early embryonic developmental arrest. Methods： Embryonic chorion tissue and uterine swabs for bacterial detection were obtained from 33 patients who underwent artificial abortion （control group） and from 45 patients who displayed early embryonic developmental arrest （trial group）. Results： Intrauterine bacterial infection was discovered in both groups. The infection rate was 24.44% （11/45） in the early embryonic developmental arrest group and 9.09% （3/33） in the artificial abortion group. Classification analysis revealed that the highest detection rate for Micrococcus luteus in the early embryonic developmental arrest group was 13.33% （6/45）, and none was detected in the artificial abortion group. M. luteus infection was significantly different between the groups （P 〈 0.05 as shown by Fisher＇s exact test）. In addition, no correlation was found between intrauterine bacterial infection and history of early embryonic developmental arrest. Conelusions： IV/. luteus infection is related to early embryonic developmental arrest and might be one of its causative factors.
基金Supported by the National Natural Science Foundation of China （30270794） and the Jiangsu Provincial Natural Science Foundation of China （BK2005041）.
文摘Temperature is one of the abiotic factors limiting growth and productivity of plants. In the present work, the effect of low non-freezing temperature, as an inducer of ＂chilling resistance＂, was studied in three cultivars of rice （Oryza sativa L.）, japonica cv. 9516 （j-9516）, the two parental lines of superhigh-yield hybrid rice between subspecies, Peiai/E32 （ji-PE）, and the traditional indica hybrid rice Shanyou 63 （i-SY63）. Leaves of chill-treated rice showed chilling-induced resistance, as an increase of their low-temperature tolerance was measured using chlorophyll fluorescence measurements, revealing a change in photosystem II （PSII） efficiency. After 5 d of exposure to 11 ~C under low light （100 pmol·m^-2·s^-1）, levels of unsaturated fatty acids in PSII thylakoid membrane lipids decreased during the initial 1-2 d, then increased slowly and reached 99.2%, 95.3% and 90.1% of the initial value （0 d） in j-9516, ji-PE and i-SY63, respectively, on the fifth day. However, under medium light （600 μmol·m^-2·s^-1）, all cultivars experienced similar substantial photoinhibition, which approached steady state levels after a decline in levels of unsaturated fatty acids in PSII thylakoid membrane lipids to about 57.1%, 53.8% and 44.5% of the initial values （0 d） in j-9516, ji-PE and i-SY63 on the fifth day. Under either chilling-induced resistance （the former） or low temperature photoinhibition （the latter） conditions, the changes of other physiological parameters such as D1 protein contents, electron transport activities of PSII （ETA）, Fv/Fm, xanthophyl cycle activities expressed by DES （deepoxide state） were consistent with that of levels of unsaturated fatty acids in PSII thylakoid membrane lipids. So there were negative correlations between saturated levels of fatty acids （16：1（3t）, 16：0, 18：0）, especially the 16：1（3t） fatty acid on thylakoid membrane and other physiological parameters, such as D1 protein contents, ETA and （A＋Z）/（A＋V＋Z）. A specific role of desaturation of fatty acids and the photoprotective pigments of the xanthophyl cycle, leading to an acclimation response in thylakoid membrane lipids may be involved. We conclude that chilling-induced resistance is accelerated by the unsaturation of thylakoid membranes, and the ability of rice plants to cold-harden can be enhanced by genetic engineering.
文摘To the Editor:Anemia is a common finding among patients admitted to intensive care units(ICUs),nearly 60%of ICU patients had serum hemoglobin levels<12 g/dL at baseline,30%of whom had serum hemoglobin levels<9 g/dL,over 95%of critically ill patients were anemic within 3 days of ICU admission.[1]Moreover,anemia may be aggravated or newly developed in critically ill patients during their ICU stay.
