Objective To investigate changes that occur in the brain when the physiological convulsive threshold becomes pathological,and to determine what differences occur in pathological and physiological convulsive thresholds...Objective To investigate changes that occur in the brain when the physiological convulsive threshold becomes pathological,and to determine what differences occur in pathological and physiological convulsive thresholds during the development of epilepsy. Methods In this study,the threshold for convulsions was determined by direct cortical stimulation in rats.The convulsive threshold was measured while recording electroencephalograms and subsequently examining histopathological changes in the hippocampus. Results At the beginning of the experiment,convulsive thresholds were all above 1 100 μA although there were significant individual variations in rats of the same group.But those thresholds quickly declined during the initial 4 weeks of repetitive electrical stimulation.The convulsive thresholds approached a constant level[TLS(430±34)μA,TGS(480±46)μA,TPS(605±70)μA]in the 10th week.There were no significant changes in thresholds when stimulation lasted for longer,the convulsive thresholds and the variations in rats of the same group were significantly lower than that at the beginning of the trial(P<0.01).An interictal discharge was also recorded in the 3rd week in heavy current group and at the 8th week in weak current group respectively which were concomitant with the neuronal da-mage and loss in the hippocampus.There was no abnormality observed in control group. Conclusion These findings indicate that the convulsion threshold in the brain should be divided into two stages:physiological convulsive threshold and pathological convulsive threshold(epileptic threshold).Epileptic threshold is created by pathological acquired factors which give rise to brain damage.The intensity of these pathological acquired factors is correlated with the formation of the pathological convulsive threshold.展开更多
BACKGROUND： Physiological convulsive thresholds degrade when the brain is in some pathologic states; thus, a level of stimulus that cannot provoke a convulsion may evoke a seizure or epileptic seizure. OBJECTIVE： To...BACKGROUND： Physiological convulsive thresholds degrade when the brain is in some pathologic states; thus, a level of stimulus that cannot provoke a convulsion may evoke a seizure or epileptic seizure. OBJECTIVE： To investigate the changes that occur in the brain when the physiological convulsive threshold becomes pathological, and to determine what differences occur in pathological and physiological convulsive thresholds during the development of epilepsy. DESIGN： A randomized controlled animal experiment. SETTING： Research Institute of Epilepsy of Shanxi Medical University; Department of Neurology, The Third Hospital of Shanxi Medical University; Research Institute of Function of Shanxi Medical University. MATERIALS： Thirty-six female Wistar rats were selected for this study. The rats were obtained from the experimental animal center of Shanxi Medical University. All laboratory procedures complied with animal ethical standards. The animals were randomly divided into three groups： a strong current group, a weak current group and a control group, with 12 rats in each group. An automatic determinator of seizure threshold was made at Shanxi Medical University and Taiyuan University of Technology. Two bipolar stainless steel stimulating electrodes and an electrode connector （diameter 1.2 ram） were made at Taiyuan University of Technology. METHODS： This study was performed in the laboratory of Research Institute of the Epilepsy of Shanxi Medical University between December 2005 and August 2006. The threshold of localized seizures was measured by performing direct cortical stimulation in rats under anesthesia. After 1 week of post-operative recovery, electric stimulation was started with three different kinds of stimulation. Seizure activity was induced by a ramp-shaped single train of biphasic pulses （50 Hz, total pulse duration of 2 ms, increasing from 0 to 2 000μ A in 15 seconds）. The threshold of localized seizures （TLS） has been defined as the minimum current intensity necessary to provoke convulsion of the forelimbs and/or facial muscles. Up to the TLS, if stimulation continued, the current intensity necessary to provoke the generalized seizures is called the threshold of generalized seizures （TGS）. If stimulation is continued for about 2 seconds when the TGS is reached, rats still showed generalized clonic activity after stimulation ceased. When seizures stopped, a short period of immobility can be observed. The current intensity is called the threshold of prolonged seizures （TPS）. The rats in the strong current group were stimulated up to the current level required to reach the TPS. In the course of stimulation, first, the TLS was recorded, then the TGS, and finally the TPS. The stimulation interval in one session was 10 minutes, repeated twice daily. The rats in the weak current group were only stimulated up to the current levels required to reach the TGS; first, the TLS was recorded and then the TGS was measured at the same time as the strong current group. Control animals were also equipped with a full electrode set and placed in the same conditions, but no stimulation took place, only electroencephalogram （EEG） recording at the same times as the experimental groups. MAIN OUTCOME MEASURES： ① Stimulation of the two experimental groups lasted for 11 weeks and then observation of their behavior and electroencephalogram recording continued for 4 weeks. The control group was also observed over a total of 15 weeks. ② Observing neuronal damage/loss in the hippocampus with a light microscope using a 250x visual field. RESULTS： All 36 Wistar rats were included in the final analysis. At the beginning of the experiment, the convulsive thresholds were all above 1 100 μA, although there were significant individual variations among rats of the same group. Those thresholds quickly declined during the initial 4 weeks of repetitive electrical stimulation. The convulsive thresholds approached a constant level in the 10^th week after commencement of stimulation. There were no significant changes in thresholds when stimulations lasted longer; the convulsive thresholds and the variations in rats of the same group were significantly lower than at the beginning of the trial （P 〈 0.01）. An interictal discharge was also recorded in the 3^rd week in the strong current group, and in the 8th week in the weak current group; these discharges were concomitant with neuronal damage and loss in the hippocampus. There was no abnormality observed in the control group. CONCLUSION： These findings indicated that the convulsion threshold in the brain should be divided into two stages： a physiological convulsive threshold and a pathological convulsive threshold （epileptic threshold） The epileptic threshold is created by pathologically acquired factors, which give rise to brain damage. The increase in the intensity of these pathologically acquired factors led to aggravation of damage.展开更多
The blood-brain barrier(BBB)is an essential component in regulating and maintaining the homeostatic microenvironment of the central nervous system(CNS).During the occurrence and development of glioblastoma(GBM),BBB is...The blood-brain barrier(BBB)is an essential component in regulating and maintaining the homeostatic microenvironment of the central nervous system(CNS).During the occurrence and development of glioblastoma(GBM),BBB is pathologically destroyed with a marked increase in permeability.Due to the obstruction of the BBB,current strategies for GBM therapeutics still obtain a meager success rate and may lead to systemic toxicity.Moreover,chemotherapy could promote pathological BBB functional restoration,which results in significantly reduced intracerebral transport of therapeutic agents during multiple administrations of GBM and the eventual failure of GBM chemotherapy.The effective delivery of intracerebral drugs still faces severe challenges.However,strategies that regulate the pathological BBB to enhance the transport of therapeutic agents across the barrier may provide new opportunities for the effective and safe treatment of GBM.This article reviews the structure and function of BBB in physiological states,the mechanisms underlying BBB pathological fenestration during the development of GBM,and the therapeutic strategies of GBM based on BBB intervention and medicinal drugs transporting across the BBB.展开更多
Fifteen apparently healthy male buffalo calves aged between 6 months to one year with body weight range of 70 - 140 Kg divided into 3 groups of 5 buffalo calves each were used in the present investigation. Endotoxic s...Fifteen apparently healthy male buffalo calves aged between 6 months to one year with body weight range of 70 - 140 Kg divided into 3 groups of 5 buffalo calves each were used in the present investigation. Endotoxic shock was produced by IV infusion of Escherichia coli endotoxin @ 5 μg/kg BW/hr for 3 hours followed by administration of three different treatment regimens comprising of intravenous infusion of hypertonic saline solution(HSS) @ 4 ml/Kg bw, flunixin meglumine @ 1.1 mg/Kg bw and blood @ 20 ml/Kg bw to group-I, HSS, Dextran-40 and Flunixin meglumine to group-II and HSS, Dextran-40, whole blood and Flunixin meglumine to group-III with the objectives to study the major physio-pathological changes during induced endotoxemia in buffalo calves and to compare the effects of different treatment options to find out the best treatment option out of the three combinations. All the animals were further observed up to day 2 or death whichever was earlier. Endotoxin infusion to all the animals caused symptoms of restlessness, respiratory distress, snoring, diarrhoea, profuse salivation along with the significant hypoproteinemia, hypoalbuminemia, hypoglobulinemia, hypokalemia and hypocalcemia. The treatment with HSS, flunixin meglumine and blood infused as one time infusion to these endotoxemic buffalo calves not only alleviated the above mentioned symptoms but also significantly raised the circulating albumin level at 5.5 hrs and day 2 and Fibrinogen level at day 2 of observation. A significant hypocalcaemia was observed at 4.5 hours along with an increase in Alkaline Phosphatase at 3.5, 4.5 and 6.5 hrs. All the endotoxemic buffalo calves which died were subjected to post mortem and histopathological studies. Epicardial and endocardial haemorrhages, haemorrhages on intestinal mucosa, congestion, haemorrhages, emphysema and fibrinous thrombi in microvasculature of lungs were salient histopathological findings. On comparison with observations of the other treatment regimens tried, it was found that the IV infusion of the combination of HSS, Flunixin meglumine, Dextran-40 and blood was found to be the most effective leading to full recovery of 3 out of 5 buffalo calves of group-III where as only 1 out of 5 animals recovered in group-II. None of the group-I animals recovered and all of these succumbed to shock after day-2.展开更多
Endotoxic shock was induced in five apparently healthy male buffalo calves by i.v infusion of Escherichia coli endotoxin at 5microgram/kilogram (μg/Kg) body weight/hour (BW/hr) for 3 hours. Endotoxin infusion caused ...Endotoxic shock was induced in five apparently healthy male buffalo calves by i.v infusion of Escherichia coli endotoxin at 5microgram/kilogram (μg/Kg) body weight/hour (BW/hr) for 3 hours. Endotoxin infusion caused clinical signs of restlessness, respiratory distress, snoring, diarrhoea, profuse salivation along with the significant hypoproteinemia, hypoalbuminemia and hypokalemia in all the animals. The animals were observed up to day 4 or death, whichever was earlier. The treatment with one time intravenous infusion of hypertonic saline solution @ 4milliliter/Kilogram body weight (ml/Kg?BW), dextran-40 @ 10 ml/Kg?BW, flunixin meglumine @ 1.1 milligram/Kg?BW (mg/Kg?BW) and blood @ 20 ml/Kg?BW to these animals alleviated the clinical signs and significantly raised the circulating glucose level at 4.5 and 5.5 hrs. The treatment led to survival of three of the five endotoxemic buffalo calves. The significant hypoproteinemia, hypoalbuminemia, hypokalemia and hypoglobulinemia continued even after treatment. Gross and histopathologic findings of congestion, haemorrhage, necrosis in vital organs viz., lungs, liver, kidneys, brain and intestines were suggestive of endotoxin induced hypoxia and multi-organ failure. Additionally, emphysema and fibrinous thrombi in microvasculature of lungs were salient histopathological findings indicating terminal respiratory failure in the remaining two dead endotoxemic buffalo calves. From clinical signs, plasma chemistry and pathological lesions, it was concluded that endotoxemia led to a disruption of critical life processes, but a timely and effective treatment could counter these deleterious effects and save precious lives.展开更多
Maillard reaction(MR)is a non-enzymatic browning reaction commonly seen in food processing,which occurs between reducing sugars and compounds with amino groups.Despite certain advantages based on Maillard reaction pro...Maillard reaction(MR)is a non-enzymatic browning reaction commonly seen in food processing,which occurs between reducing sugars and compounds with amino groups.Despite certain advantages based on Maillard reaction products(MRPs)found in some food for health and storage application have appeared,however,the MR occurring in human physiological environment can produce advanced glycation end products(AGEs)by non-enzymatic modification of macromolecules such as proteins,lipids and nucleic acid,which could change the structure and functional activity of the molecules themselves.In this review,we take AGEs as our main object,on the one hand,discuss physiologic aging,that is,age-dependent covalent cross-linking and modification of proteins such as collagen that occur in eyes and skin containing connective tissue.On the other hand,pathological aging associated with autoimmune and inflammatory diseases,neurodegenerative diseases,diabetes and diabetic nephropathy,cardiovascular diseases and bone degenerative diseases have been mainly proposed.Based on the series of adverse effects of accelerated aging and disease pathologies caused by MRPs,the possible harm caused by some MR can be slowed down or inhibited by artificial drug intervention,dietary pattern and lifestyle control.It also stimulates people's curiosity to continue to explore the potential link between the MR and human aging and health,which should be paid more attention to for the development of life sciences.展开更多
Bone is a complex biological tissue with a complicated hierarchical nanocomposite structure.The native microen-vironment of the bone tissue may be significantly disrupted by large physiological and pathological bone d...Bone is a complex biological tissue with a complicated hierarchical nanocomposite structure.The native microen-vironment of the bone tissue may be significantly disrupted by large physiological and pathological bone defects.Bone defects are often treated via complex surgical procedures that involve the application of autografts or al-lografts.While these grafting procedures often suffer from insufficient natural bone stock and immunorejection.Moreover,these traditional treatment methods fail to simulate a regenerative microenvironment,which plays a significant role in regeneration of bone tissue and repair of large bone defects.To this end,various biomimetic scaffolds have been devised to mimic the native microenvironment of bone and thereby to simultaneously re-pair bone defects and promote bone regeneration.We propose here a novel concept,in vivo bone regenerative microenvironment(BRM),which enables repair of large bone defects and enhances new bone tissue formation with external regulation.In this review,we mainly focus on materials and methods for fabrication of biomimetic scaffolds,as well as their therapeutic efficacy in modulating the BRM of large physiological and pathological bone defects.展开更多
Early embryonic development is a complex process.The zygote undergoes several rounds of division to form a blastocyst,and during this process,the zygote undergoes the maternal-to-zygotic transition to gain control of ...Early embryonic development is a complex process.The zygote undergoes several rounds of division to form a blastocyst,and during this process,the zygote undergoes the maternal-to-zygotic transition to gain control of embryonic development and makes two cell fate decisions to differentiate into an embryonic and two extra-embryonic lineages.With the use of new molecular biotechnologies and animal models,we can now further study the molecular mechanisms of early embryonic development and the pathological causes of early embryonic arrest.Here,we first summarize the known molecular regulatory mechanisms of early embryonic development in mice.Then we discuss the pathological factors leading to the early embryonic arrest.We hope that this review will give researchers a relatively complete view of the physiology and pathology of early embryonic development.展开更多
文摘Objective To investigate changes that occur in the brain when the physiological convulsive threshold becomes pathological,and to determine what differences occur in pathological and physiological convulsive thresholds during the development of epilepsy. Methods In this study,the threshold for convulsions was determined by direct cortical stimulation in rats.The convulsive threshold was measured while recording electroencephalograms and subsequently examining histopathological changes in the hippocampus. Results At the beginning of the experiment,convulsive thresholds were all above 1 100 μA although there were significant individual variations in rats of the same group.But those thresholds quickly declined during the initial 4 weeks of repetitive electrical stimulation.The convulsive thresholds approached a constant level[TLS(430±34)μA,TGS(480±46)μA,TPS(605±70)μA]in the 10th week.There were no significant changes in thresholds when stimulation lasted for longer,the convulsive thresholds and the variations in rats of the same group were significantly lower than that at the beginning of the trial(P<0.01).An interictal discharge was also recorded in the 3rd week in heavy current group and at the 8th week in weak current group respectively which were concomitant with the neuronal da-mage and loss in the hippocampus.There was no abnormality observed in control group. Conclusion These findings indicate that the convulsion threshold in the brain should be divided into two stages:physiological convulsive threshold and pathological convulsive threshold(epileptic threshold).Epileptic threshold is created by pathological acquired factors which give rise to brain damage.The intensity of these pathological acquired factors is correlated with the formation of the pathological convulsive threshold.
文摘BACKGROUND： Physiological convulsive thresholds degrade when the brain is in some pathologic states; thus, a level of stimulus that cannot provoke a convulsion may evoke a seizure or epileptic seizure. OBJECTIVE： To investigate the changes that occur in the brain when the physiological convulsive threshold becomes pathological, and to determine what differences occur in pathological and physiological convulsive thresholds during the development of epilepsy. DESIGN： A randomized controlled animal experiment. SETTING： Research Institute of Epilepsy of Shanxi Medical University; Department of Neurology, The Third Hospital of Shanxi Medical University; Research Institute of Function of Shanxi Medical University. MATERIALS： Thirty-six female Wistar rats were selected for this study. The rats were obtained from the experimental animal center of Shanxi Medical University. All laboratory procedures complied with animal ethical standards. The animals were randomly divided into three groups： a strong current group, a weak current group and a control group, with 12 rats in each group. An automatic determinator of seizure threshold was made at Shanxi Medical University and Taiyuan University of Technology. Two bipolar stainless steel stimulating electrodes and an electrode connector （diameter 1.2 ram） were made at Taiyuan University of Technology. METHODS： This study was performed in the laboratory of Research Institute of the Epilepsy of Shanxi Medical University between December 2005 and August 2006. The threshold of localized seizures was measured by performing direct cortical stimulation in rats under anesthesia. After 1 week of post-operative recovery, electric stimulation was started with three different kinds of stimulation. Seizure activity was induced by a ramp-shaped single train of biphasic pulses （50 Hz, total pulse duration of 2 ms, increasing from 0 to 2 000μ A in 15 seconds）. The threshold of localized seizures （TLS） has been defined as the minimum current intensity necessary to provoke convulsion of the forelimbs and/or facial muscles. Up to the TLS, if stimulation continued, the current intensity necessary to provoke the generalized seizures is called the threshold of generalized seizures （TGS）. If stimulation is continued for about 2 seconds when the TGS is reached, rats still showed generalized clonic activity after stimulation ceased. When seizures stopped, a short period of immobility can be observed. The current intensity is called the threshold of prolonged seizures （TPS）. The rats in the strong current group were stimulated up to the current level required to reach the TPS. In the course of stimulation, first, the TLS was recorded, then the TGS, and finally the TPS. The stimulation interval in one session was 10 minutes, repeated twice daily. The rats in the weak current group were only stimulated up to the current levels required to reach the TGS; first, the TLS was recorded and then the TGS was measured at the same time as the strong current group. Control animals were also equipped with a full electrode set and placed in the same conditions, but no stimulation took place, only electroencephalogram （EEG） recording at the same times as the experimental groups. MAIN OUTCOME MEASURES： ① Stimulation of the two experimental groups lasted for 11 weeks and then observation of their behavior and electroencephalogram recording continued for 4 weeks. The control group was also observed over a total of 15 weeks. ② Observing neuronal damage/loss in the hippocampus with a light microscope using a 250x visual field. RESULTS： All 36 Wistar rats were included in the final analysis. At the beginning of the experiment, the convulsive thresholds were all above 1 100 μA, although there were significant individual variations among rats of the same group. Those thresholds quickly declined during the initial 4 weeks of repetitive electrical stimulation. The convulsive thresholds approached a constant level in the 10^th week after commencement of stimulation. There were no significant changes in thresholds when stimulations lasted longer; the convulsive thresholds and the variations in rats of the same group were significantly lower than at the beginning of the trial （P 〈 0.01）. An interictal discharge was also recorded in the 3^rd week in the strong current group, and in the 8th week in the weak current group; these discharges were concomitant with neuronal damage and loss in the hippocampus. There was no abnormality observed in the control group. CONCLUSION： These findings indicated that the convulsion threshold in the brain should be divided into two stages： a physiological convulsive threshold and a pathological convulsive threshold （epileptic threshold） The epileptic threshold is created by pathologically acquired factors, which give rise to brain damage. The increase in the intensity of these pathologically acquired factors led to aggravation of damage.
基金supported by the National Natural Science Foundation of China(NSFC No.82104101)Jiangxi Provincial Natural Science Foundation,China(Grant No.20212BAB216003)+1 种基金the Project of Gannan Medical University(No.ZD201903)Ph.D.Start-up Fund of Gannan Medical University(QD201908).
文摘The blood-brain barrier(BBB)is an essential component in regulating and maintaining the homeostatic microenvironment of the central nervous system(CNS).During the occurrence and development of glioblastoma(GBM),BBB is pathologically destroyed with a marked increase in permeability.Due to the obstruction of the BBB,current strategies for GBM therapeutics still obtain a meager success rate and may lead to systemic toxicity.Moreover,chemotherapy could promote pathological BBB functional restoration,which results in significantly reduced intracerebral transport of therapeutic agents during multiple administrations of GBM and the eventual failure of GBM chemotherapy.The effective delivery of intracerebral drugs still faces severe challenges.However,strategies that regulate the pathological BBB to enhance the transport of therapeutic agents across the barrier may provide new opportunities for the effective and safe treatment of GBM.This article reviews the structure and function of BBB in physiological states,the mechanisms underlying BBB pathological fenestration during the development of GBM,and the therapeutic strategies of GBM based on BBB intervention and medicinal drugs transporting across the BBB.
文摘Fifteen apparently healthy male buffalo calves aged between 6 months to one year with body weight range of 70 - 140 Kg divided into 3 groups of 5 buffalo calves each were used in the present investigation. Endotoxic shock was produced by IV infusion of Escherichia coli endotoxin @ 5 μg/kg BW/hr for 3 hours followed by administration of three different treatment regimens comprising of intravenous infusion of hypertonic saline solution(HSS) @ 4 ml/Kg bw, flunixin meglumine @ 1.1 mg/Kg bw and blood @ 20 ml/Kg bw to group-I, HSS, Dextran-40 and Flunixin meglumine to group-II and HSS, Dextran-40, whole blood and Flunixin meglumine to group-III with the objectives to study the major physio-pathological changes during induced endotoxemia in buffalo calves and to compare the effects of different treatment options to find out the best treatment option out of the three combinations. All the animals were further observed up to day 2 or death whichever was earlier. Endotoxin infusion to all the animals caused symptoms of restlessness, respiratory distress, snoring, diarrhoea, profuse salivation along with the significant hypoproteinemia, hypoalbuminemia, hypoglobulinemia, hypokalemia and hypocalcemia. The treatment with HSS, flunixin meglumine and blood infused as one time infusion to these endotoxemic buffalo calves not only alleviated the above mentioned symptoms but also significantly raised the circulating albumin level at 5.5 hrs and day 2 and Fibrinogen level at day 2 of observation. A significant hypocalcaemia was observed at 4.5 hours along with an increase in Alkaline Phosphatase at 3.5, 4.5 and 6.5 hrs. All the endotoxemic buffalo calves which died were subjected to post mortem and histopathological studies. Epicardial and endocardial haemorrhages, haemorrhages on intestinal mucosa, congestion, haemorrhages, emphysema and fibrinous thrombi in microvasculature of lungs were salient histopathological findings. On comparison with observations of the other treatment regimens tried, it was found that the IV infusion of the combination of HSS, Flunixin meglumine, Dextran-40 and blood was found to be the most effective leading to full recovery of 3 out of 5 buffalo calves of group-III where as only 1 out of 5 animals recovered in group-II. None of the group-I animals recovered and all of these succumbed to shock after day-2.
文摘Endotoxic shock was induced in five apparently healthy male buffalo calves by i.v infusion of Escherichia coli endotoxin at 5microgram/kilogram (μg/Kg) body weight/hour (BW/hr) for 3 hours. Endotoxin infusion caused clinical signs of restlessness, respiratory distress, snoring, diarrhoea, profuse salivation along with the significant hypoproteinemia, hypoalbuminemia and hypokalemia in all the animals. The animals were observed up to day 4 or death, whichever was earlier. The treatment with one time intravenous infusion of hypertonic saline solution @ 4milliliter/Kilogram body weight (ml/Kg?BW), dextran-40 @ 10 ml/Kg?BW, flunixin meglumine @ 1.1 milligram/Kg?BW (mg/Kg?BW) and blood @ 20 ml/Kg?BW to these animals alleviated the clinical signs and significantly raised the circulating glucose level at 4.5 and 5.5 hrs. The treatment led to survival of three of the five endotoxemic buffalo calves. The significant hypoproteinemia, hypoalbuminemia, hypokalemia and hypoglobulinemia continued even after treatment. Gross and histopathologic findings of congestion, haemorrhage, necrosis in vital organs viz., lungs, liver, kidneys, brain and intestines were suggestive of endotoxin induced hypoxia and multi-organ failure. Additionally, emphysema and fibrinous thrombi in microvasculature of lungs were salient histopathological findings indicating terminal respiratory failure in the remaining two dead endotoxemic buffalo calves. From clinical signs, plasma chemistry and pathological lesions, it was concluded that endotoxemia led to a disruption of critical life processes, but a timely and effective treatment could counter these deleterious effects and save precious lives.
基金financially supported by grants from the National Natural Science Foundation of China (82170873,81871095)the National Natural Science Foundation of China (81974503)the Tsinghua University Spring Breeze Fund (20211080005)。
文摘Maillard reaction(MR)is a non-enzymatic browning reaction commonly seen in food processing,which occurs between reducing sugars and compounds with amino groups.Despite certain advantages based on Maillard reaction products(MRPs)found in some food for health and storage application have appeared,however,the MR occurring in human physiological environment can produce advanced glycation end products(AGEs)by non-enzymatic modification of macromolecules such as proteins,lipids and nucleic acid,which could change the structure and functional activity of the molecules themselves.In this review,we take AGEs as our main object,on the one hand,discuss physiologic aging,that is,age-dependent covalent cross-linking and modification of proteins such as collagen that occur in eyes and skin containing connective tissue.On the other hand,pathological aging associated with autoimmune and inflammatory diseases,neurodegenerative diseases,diabetes and diabetic nephropathy,cardiovascular diseases and bone degenerative diseases have been mainly proposed.Based on the series of adverse effects of accelerated aging and disease pathologies caused by MRPs,the possible harm caused by some MR can be slowed down or inhibited by artificial drug intervention,dietary pattern and lifestyle control.It also stimulates people's curiosity to continue to explore the potential link between the MR and human aging and health,which should be paid more attention to for the development of life sciences.
基金supported by the National Natural Science Foundation of China(No.31971271)。
文摘Bone is a complex biological tissue with a complicated hierarchical nanocomposite structure.The native microen-vironment of the bone tissue may be significantly disrupted by large physiological and pathological bone defects.Bone defects are often treated via complex surgical procedures that involve the application of autografts or al-lografts.While these grafting procedures often suffer from insufficient natural bone stock and immunorejection.Moreover,these traditional treatment methods fail to simulate a regenerative microenvironment,which plays a significant role in regeneration of bone tissue and repair of large bone defects.To this end,various biomimetic scaffolds have been devised to mimic the native microenvironment of bone and thereby to simultaneously re-pair bone defects and promote bone regeneration.We propose here a novel concept,in vivo bone regenerative microenvironment(BRM),which enables repair of large bone defects and enhances new bone tissue formation with external regulation.In this review,we mainly focus on materials and methods for fabrication of biomimetic scaffolds,as well as their therapeutic efficacy in modulating the BRM of large physiological and pathological bone defects.
基金the National Key Research and Development Program of China(2021YFC2700100)the National Natural Science Foundation of China(32130029,81725006,82171643,81971450,and 82101746).
文摘Early embryonic development is a complex process.The zygote undergoes several rounds of division to form a blastocyst,and during this process,the zygote undergoes the maternal-to-zygotic transition to gain control of embryonic development and makes two cell fate decisions to differentiate into an embryonic and two extra-embryonic lineages.With the use of new molecular biotechnologies and animal models,we can now further study the molecular mechanisms of early embryonic development and the pathological causes of early embryonic arrest.Here,we first summarize the known molecular regulatory mechanisms of early embryonic development in mice.Then we discuss the pathological factors leading to the early embryonic arrest.We hope that this review will give researchers a relatively complete view of the physiology and pathology of early embryonic development.
