Bajiaolian, one of the species in the Mayapple family ( Podophyllum pelatum ), has been widely used as a traditional Chinese herbal medicine for the remedies of snake bites, general weakness, poisons, condyloma accumi...Bajiaolian, one of the species in the Mayapple family ( Podophyllum pelatum ), has been widely used as a traditional Chinese herbal medicine for the remedies of snake bites, general weakness, poisons, condyloma accuminata, lymphadenopathy, and certain tumors in China. In Western medicine, Podophyllum was first used medically as a laxative in the early 19th century. Since 1940, the resin of podophyllum has also been used topically for various skin lesions, such as warts and condyloma. Human poisonings have been reported.An animal model was established to investigate the neurotoxic effects of Bajiaolian. Podophyllotoxin, the major active ingredient in Podophyllum, was injected (ip) to young adult male rats at doses of 0, 5, 10, or 15 mg-kg-1 b.w.. The animals were sacrificed 72 h after injection.Neuronal changes were readily observable in animals treated with 10 or 15 mg-kg-1 of the toxin. Edematous changes of the anterior horn motoneurons were observed in the spinal cord. No neuronal necrosis was found. The type of neuronal swelling is believed to be only a transient change and would probably subside with time if no further assaults occur. More serious and perhaps longer term of changes were found in the dorsal ganglion neurons and the nerve fibers (axons) in the central and peripheral nervous system. Severe depletion of the Nissl substance (RNA/polyribosomes) was observed in the dorsal root ganglion neurons. Alterations in these sensory neurons would give rise to and correlate with the sensory disturbances experienced by the patients. Bodian staining also revealed a dose-related increase in the coarseness (thickness) of the nerve fibers (axons) in the cerebellum, cerebral cortex, brainstem, and spinal cord.This is the first scientific study showing the neurotoxicity of Bajiaolian, a commonly used Chinese herbal medicine. Toxicities on other organ systems by this drug certainly exist. Caution should be exercised in the dispensing and usage of this medicine.展开更多
Vascular endothelial growth factor(VEGF)in neurodevelopment and regeneration:VEGF is a well-known factor that promotes vascularization and angiogenesis.Besides this it participates in the pathogenesis of several di...Vascular endothelial growth factor(VEGF)in neurodevelopment and regeneration:VEGF is a well-known factor that promotes vascularization and angiogenesis.Besides this it participates in the pathogenesis of several diseases,such as colorectal carcinoma,lung cancer or diabetic retinopathy.Within the last decade,VEGF has been successfully integrated into the treatment of such diseases,for example as a therapy for colorectal cancer with the VEGF-receptor (VEGFR)-inhibitor axitinib.展开更多
Traumatic brain injury (TBI) is a mechanical injury to brain tissue that leads to an impairment of function and a broad spectrum of symptoms and disabilities; often, it is followed by diffuse axonal injury, which ca...Traumatic brain injury (TBI) is a mechanical injury to brain tissue that leads to an impairment of function and a broad spectrum of symptoms and disabilities; often, it is followed by diffuse axonal injury, which causes denaturation of the white matter and axon retraction, leaving patients with severe brain damage or even in a persistent vegetative state.展开更多
Following injury in central nervous system(CNS),there are pathological changes in the injured region,which include neuronal death,axonal damage and demyelination,inflammatory response and activation of glial cells.T...Following injury in central nervous system(CNS),there are pathological changes in the injured region,which include neuronal death,axonal damage and demyelination,inflammatory response and activation of glial cells.The proliferation of a large number of astrocytes results in the formation of glial scar.展开更多
To apply electrical stimulation to the specific phase position of electroencephalogram (EEG) waveform, a nervous electrical stimulation system was developed using general data acquisition card and LabVIEW virtual in...To apply electrical stimulation to the specific phase position of electroencephalogram (EEG) waveform, a nervous electrical stimulation system was developed using general data acquisition card and LabVIEW virtual instrument environment. The hippocampal field potential signal in the brain of rat was sampled using the acquisition card' s A/D channel, and the amplitude and cycle characteristics were analyzed and the wave peak or trough of the coming field potential ( 0 ) rhythm was predicted using LabVIEW program. Meanwhile, the needed stimulus signal was output at the specified phase position via the digital port or D/A channel of the acquisition card, so as to implement the nerve stimulation. The experimental result showed that the prediction accuracies of 0 -rhythm wave peak and trough were up to 92% and 86%, respectively. The electrical stimulation system can be applied to predicting a variety of nervous rhythm wave phases and other signal characteristics because of its universality and flexibility. Thus, a new loop control stimulation method is provided for the nerve electrophysiology study and the electrical stimulation treatment of brain diseases.展开更多
The nature of saltatory conduction in myelinated axon described by equivalent circuit and circuit theory is still contentious. Recent experimental observations of action potentials transmitting through disjointed nerv...The nature of saltatory conduction in myelinated axon described by equivalent circuit and circuit theory is still contentious. Recent experimental observations of action potentials transmitting through disjointed nerve fibers strongly suggest an electromagnetic wave propagation mechanism of the nerve signals. In this paper, we employ the electromagnetic wave model of the myelinated axon to describe action potential signal propagation. We use the experimental frequency-dependent conductivity and permittivity values of the nerve tissues in order to reliably calculate the electromagnetic modes by using electromagnetic mode solvers. We find that the electromagnetic waves above 10 kHz can be well confined in extracellular fluid–myelin sheath–intracellular fluid waveguide and propagate a distance of 7 mm without much attenuation. Our study may serve as one of the fundamental researches for the better understanding of the nervous system.展开更多
文摘Bajiaolian, one of the species in the Mayapple family ( Podophyllum pelatum ), has been widely used as a traditional Chinese herbal medicine for the remedies of snake bites, general weakness, poisons, condyloma accuminata, lymphadenopathy, and certain tumors in China. In Western medicine, Podophyllum was first used medically as a laxative in the early 19th century. Since 1940, the resin of podophyllum has also been used topically for various skin lesions, such as warts and condyloma. Human poisonings have been reported.An animal model was established to investigate the neurotoxic effects of Bajiaolian. Podophyllotoxin, the major active ingredient in Podophyllum, was injected (ip) to young adult male rats at doses of 0, 5, 10, or 15 mg-kg-1 b.w.. The animals were sacrificed 72 h after injection.Neuronal changes were readily observable in animals treated with 10 or 15 mg-kg-1 of the toxin. Edematous changes of the anterior horn motoneurons were observed in the spinal cord. No neuronal necrosis was found. The type of neuronal swelling is believed to be only a transient change and would probably subside with time if no further assaults occur. More serious and perhaps longer term of changes were found in the dorsal ganglion neurons and the nerve fibers (axons) in the central and peripheral nervous system. Severe depletion of the Nissl substance (RNA/polyribosomes) was observed in the dorsal root ganglion neurons. Alterations in these sensory neurons would give rise to and correlate with the sensory disturbances experienced by the patients. Bodian staining also revealed a dose-related increase in the coarseness (thickness) of the nerve fibers (axons) in the cerebellum, cerebral cortex, brainstem, and spinal cord.This is the first scientific study showing the neurotoxicity of Bajiaolian, a commonly used Chinese herbal medicine. Toxicities on other organ systems by this drug certainly exist. Caution should be exercised in the dispensing and usage of this medicine.
基金the Heinrich and Alma Vogelsang Foundation for financial support in the form of a graduation scholarship
文摘Vascular endothelial growth factor(VEGF)in neurodevelopment and regeneration:VEGF is a well-known factor that promotes vascularization and angiogenesis.Besides this it participates in the pathogenesis of several diseases,such as colorectal carcinoma,lung cancer or diabetic retinopathy.Within the last decade,VEGF has been successfully integrated into the treatment of such diseases,for example as a therapy for colorectal cancer with the VEGF-receptor (VEGFR)-inhibitor axitinib.
基金supported by grants from the Spanish Ministry of Economy and Competitivenessthe European Regional Development Fund 2007-2013(BFU2014-56300-P)+4 种基金the Xunta de Galicia(GPC2014/030)supported by a grant from the Xunta de Galicia(2016-PG008)a grant from the crowdfunding platform Precipita(FECYTSpanish Ministry of Economy and Competitivenessgrant number 2017-CP081)
文摘Traumatic brain injury (TBI) is a mechanical injury to brain tissue that leads to an impairment of function and a broad spectrum of symptoms and disabilities; often, it is followed by diffuse axonal injury, which causes denaturation of the white matter and axon retraction, leaving patients with severe brain damage or even in a persistent vegetative state.
基金supported by National Basic Research Program of China(973 Program,2014CB542205)Hong Kong RGC grant+2 种基金Hong Kong Health and Medical Research Fundfoundation for Distinguished Young Talents in Higher Education of Guangdong(Yq2013023)the Leading Talents of Guangdong Province(87014002)
文摘Following injury in central nervous system(CNS),there are pathological changes in the injured region,which include neuronal death,axonal damage and demyelination,inflammatory response and activation of glial cells.The proliferation of a large number of astrocytes results in the formation of glial scar.
文摘To apply electrical stimulation to the specific phase position of electroencephalogram (EEG) waveform, a nervous electrical stimulation system was developed using general data acquisition card and LabVIEW virtual instrument environment. The hippocampal field potential signal in the brain of rat was sampled using the acquisition card' s A/D channel, and the amplitude and cycle characteristics were analyzed and the wave peak or trough of the coming field potential ( 0 ) rhythm was predicted using LabVIEW program. Meanwhile, the needed stimulus signal was output at the specified phase position via the digital port or D/A channel of the acquisition card, so as to implement the nerve stimulation. The experimental result showed that the prediction accuracies of 0 -rhythm wave peak and trough were up to 92% and 86%, respectively. The electrical stimulation system can be applied to predicting a variety of nervous rhythm wave phases and other signal characteristics because of its universality and flexibility. Thus, a new loop control stimulation method is provided for the nerve electrophysiology study and the electrical stimulation treatment of brain diseases.
基金Project supported by the National Key Research and Development Program of China (Grant No. 2017YFA0701302)the Xiamen University Malaysia Research Fund, Malaysia (Grant No. XMUMRF/2020-C5/IMAT/0012)。
文摘The nature of saltatory conduction in myelinated axon described by equivalent circuit and circuit theory is still contentious. Recent experimental observations of action potentials transmitting through disjointed nerve fibers strongly suggest an electromagnetic wave propagation mechanism of the nerve signals. In this paper, we employ the electromagnetic wave model of the myelinated axon to describe action potential signal propagation. We use the experimental frequency-dependent conductivity and permittivity values of the nerve tissues in order to reliably calculate the electromagnetic modes by using electromagnetic mode solvers. We find that the electromagnetic waves above 10 kHz can be well confined in extracellular fluid–myelin sheath–intracellular fluid waveguide and propagate a distance of 7 mm without much attenuation. Our study may serve as one of the fundamental researches for the better understanding of the nervous system.