AIM: To test whether oral L-81 treatment could im-prove the condition of mice with diabetes and to investigate how L-81 regulates microsomal triglyceride transfer protein (MTP) activity in the liver. METHODS: Genetica...AIM: To test whether oral L-81 treatment could im-prove the condition of mice with diabetes and to investigate how L-81 regulates microsomal triglyceride transfer protein (MTP) activity in the liver. METHODS: Genetically diabetic (db/db) mice were fed on chow supplemented with or without L-81 for 4 wk. The body weight, plasma glucose level, plasma lipid profile, and adipocyte volume of the db/db mice were assessed after treatment. Toxicity of L-81 was also evaluated. To understand the molecular mecha-nism, HepG2 cells were treated with L-81 and the effects on apolipoprotein B (apoB) secretion and mRNA level of the MTP gene were assessed.RESULTS: Treatment of db/db mice with L-81 sig-nificantly reduced and nearly normalized their body weight, hyperphagia and polydipsia. L-81 also markedly decreased the fasting plasma glucose level, improved glucose tolerance, and attenuated the elevated levels of plasma cholesterol and triglyceride. At the effective dosage, little toxicity was observed. Treatment of HepG2 cells with L-81 not only inhibited apoB secretion, but also signif icantly decreased the mRNA level of the MTP gene. Similar to the action of insulin, L-81 exerted its effect on the MTP promoter. CONCLUSION: L-81 represents a promising candidate in the development of a selective insulin-mimetic mol-ecule and an anti-diabetic agent.展开更多
Diabetes mellitus is the most common metabolic disease and its prevalence is increasing in many countries year by year.More than 90% of diabetes patients are type 2 diabetes,which is caused by insulin resistance and b...Diabetes mellitus is the most common metabolic disease and its prevalence is increasing in many countries year by year.More than 90% of diabetes patients are type 2 diabetes,which is caused by insulin resistance and beta-cell dysfunction.In this paper,the oligomannuronate-chromium(III)complex(OM2)was prepared and its effect and mechanism on attenuating insulin resistance in diabetic C57BL/KsJ-db/db mice were studied.The results indicated that oral intake of OM2(50 mg kg-1d-1)for 42 d decreased blood glucose and lipid concentration,which was associated with the reduced serum insulin concentration and insulin resistance.According to western blot assay,OM2 could activate AMPK pathway to regulate glycogen synthesis,gluconeogenesis and lipid metabolism in the liver,and attenuate the hyperglycemic symptom in db/db mice.The effects of OM2 on attenuating insulin resistance were com-parable to that of the established antidiabetic drug metformin,and OM2 showed less adverse effect than metformin in vivo.Based on the effectiveness and low toxicity,OM2 may potentially be used for prevention and treatment of type 2 diabetes mellitus.展开更多
针对强地物杂波背景下弹载雷达目标检测与识别的技术难题,提出将高分辨距离像(high resolution range profile,HRRP)技术和多普勒波束锐化技术联合对地面进行二维高分辨成像,提高雷达在杂波下目标检测与识别的性能。该方法以线性调频步...针对强地物杂波背景下弹载雷达目标检测与识别的技术难题,提出将高分辨距离像(high resolution range profile,HRRP)技术和多普勒波束锐化技术联合对地面进行二维高分辨成像,提高雷达在杂波下目标检测与识别的性能。该方法以线性调频步进频(linear frequency modulation stepped frequency,LFM-SF)信号为基本波形,首先对平台速度产生的多普勒效应等问题进行了详细讨论并校正;然后通过距离像抽取获得各帧对应的HRRP序列,并采用方位快速傅里叶变换(fast Fourier transform,FFT)实现方位高分辨;最后对实际飞行状态下平台造成的误差进行运动补偿,完成对波束内区域的二维分辨。实测数据的处理验证了所提算法的有效性与实用性。展开更多
基金Supported by The Area of Excellence scheme of University Grants Committeethe Research Grant Council Grant, HKU 7642/05M to MCL, from Hong Kong
文摘AIM: To test whether oral L-81 treatment could im-prove the condition of mice with diabetes and to investigate how L-81 regulates microsomal triglyceride transfer protein (MTP) activity in the liver. METHODS: Genetically diabetic (db/db) mice were fed on chow supplemented with or without L-81 for 4 wk. The body weight, plasma glucose level, plasma lipid profile, and adipocyte volume of the db/db mice were assessed after treatment. Toxicity of L-81 was also evaluated. To understand the molecular mecha-nism, HepG2 cells were treated with L-81 and the effects on apolipoprotein B (apoB) secretion and mRNA level of the MTP gene were assessed.RESULTS: Treatment of db/db mice with L-81 sig-nificantly reduced and nearly normalized their body weight, hyperphagia and polydipsia. L-81 also markedly decreased the fasting plasma glucose level, improved glucose tolerance, and attenuated the elevated levels of plasma cholesterol and triglyceride. At the effective dosage, little toxicity was observed. Treatment of HepG2 cells with L-81 not only inhibited apoB secretion, but also signif icantly decreased the mRNA level of the MTP gene. Similar to the action of insulin, L-81 exerted its effect on the MTP promoter. CONCLUSION: L-81 represents a promising candidate in the development of a selective insulin-mimetic mol-ecule and an anti-diabetic agent.
基金the Program for Changjiang Scholars and Innovative Research Team in University (IRT0944)the National Natural Science Foundation of China (31070724, 30870506)+3 种基金the Special Fund for Marine Scientific Research in the Public Interest (201005024)the International Science and Technology Collaboration Program of China (2007DFA30980)the Open Research Fund of Key Laboratory of Marine Drugs of the Ministry of EducationOcean University of China (KLMD200802)
文摘Diabetes mellitus is the most common metabolic disease and its prevalence is increasing in many countries year by year.More than 90% of diabetes patients are type 2 diabetes,which is caused by insulin resistance and beta-cell dysfunction.In this paper,the oligomannuronate-chromium(III)complex(OM2)was prepared and its effect and mechanism on attenuating insulin resistance in diabetic C57BL/KsJ-db/db mice were studied.The results indicated that oral intake of OM2(50 mg kg-1d-1)for 42 d decreased blood glucose and lipid concentration,which was associated with the reduced serum insulin concentration and insulin resistance.According to western blot assay,OM2 could activate AMPK pathway to regulate glycogen synthesis,gluconeogenesis and lipid metabolism in the liver,and attenuate the hyperglycemic symptom in db/db mice.The effects of OM2 on attenuating insulin resistance were com-parable to that of the established antidiabetic drug metformin,and OM2 showed less adverse effect than metformin in vivo.Based on the effectiveness and low toxicity,OM2 may potentially be used for prevention and treatment of type 2 diabetes mellitus.
文摘针对强地物杂波背景下弹载雷达目标检测与识别的技术难题,提出将高分辨距离像(high resolution range profile,HRRP)技术和多普勒波束锐化技术联合对地面进行二维高分辨成像,提高雷达在杂波下目标检测与识别的性能。该方法以线性调频步进频(linear frequency modulation stepped frequency,LFM-SF)信号为基本波形,首先对平台速度产生的多普勒效应等问题进行了详细讨论并校正;然后通过距离像抽取获得各帧对应的HRRP序列,并采用方位快速傅里叶变换(fast Fourier transform,FFT)实现方位高分辨;最后对实际飞行状态下平台造成的误差进行运动补偿,完成对波束内区域的二维分辨。实测数据的处理验证了所提算法的有效性与实用性。
