Objective To study the relationship between cartilage end plate calcification and intervertebral disc degeneration Methods An experimental model of cervical disc degeneration in rabbits was established by resecti...Objective To study the relationship between cartilage end plate calcification and intervertebral disc degeneration Methods An experimental model of cervical disc degeneration in rabbits was established by resection of the cervical supraspinous and interspinous ligaments and detachment of the posterior paravertebral muscles from the cervical vertebrae Mechanical instability in the cervical spine elicited by this surgical intervention accelerated the process of intervertebral disc degeneration The extent of intervertebral disc degeneration was graded in morphologically, and the thicknesses of the calcified layer and the uncalcified layer of the cartilage end plate were measured in each degenerated cervical disc Results In less severely degenerative cervical discs, the morphology of the cartilage end plate showed nearly normal construction, and the tidemark was clear In severely degenerative discs, the matrix and cells showed fibrosis, the tidemark advanced, and the calcified cartilage thickened There exists a positive correlation between the thickness of the calcified layer of the cartilage end plate and the degree of cervical disc degeneration Conclusion The calcification of the cartilage end plate is the key factor that initiates and promotes cervical disc degeneration展开更多
Objective：The rapid expansion of knowledge regarding the functional anatomy of hand and wrist,increasing functional demands of senior citizens and improved methodologies of achieving and maintaining anatomic restorat...Objective：The rapid expansion of knowledge regarding the functional anatomy of hand and wrist,increasing functional demands of senior citizens and improved methodologies of achieving and maintaining anatomic restoration of distal radius fractures has generated a renewed interest in addressing these fractures in a more precise manner.The purpose of our study was to evaluate the difference in patients function among those treated by 1） closed reduction and Plaster of Paris cast,2） distractor application,or 3） open reduction and internal fixation with a volar plate,and to assess the treatment choice for each particular fracture type.Methods：A prospective study was carried out on 60 patients with fractures of the distal end radius.Fractures were classified according to the AO classification into type A （extra-articular）,type B （partial articular） and type C （complete articular）.After initial evaluation patients were taken up for either conservative or operative treatment and were followed up for two years.Results：Anatomical results were evaluated according to the Sarmiento＇s modification of Lindstrom Criteria,which showed that excellent results were more frequent with open reduction and internal fixation using the plating technique.Clinical and functional results were evaluated according to the demerit point system of Gartland and Werley with Sarmiento modification,which was revealed to relate with the type of treatment techniques.Conclusion：There is no customized solution for all the fractures of the distal radius.The choice of treatment should be based on the fracture type,the patient＇s characteristics,the patient＇s demands and the treating surgeon＇s experience and preference.展开更多
During the development of the nervous system,there is an overproduction of neurons and synapses.Hebbian competition between neighboring nerve endings and synapses performing different activity levels leads to their el...During the development of the nervous system,there is an overproduction of neurons and synapses.Hebbian competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or strengthening.We have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase B receptor neurotrophic retrograde pathway,at the neuromuscular junction,in the axonal development and synapse elimination process versus the synapse consolidation.The purpose of this review is to describe the neurotrophic influence on developmental synapse elimination,in relation to other molecular pathways that we and others have found to regulate this process.In particular,we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors,coupled to downstream serine-threonine protein kinases A and C(PKA and PKC)and voltage-gated calcium channels,at different nerve endings in developmental competition.The dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site,influence each other,and require careful studies to individualize the mechanisms of specific endings.We describe an activity-dependent balance(related to the extent of transmitter release)between the presynaptic muscarinic subtypes and the neurotrophin-mediated TrkB/p75NTR pathways that can influence the timing and fate of the competitive interactions between the different axon terminals.The downstream displacement of the PKA/PKC activity ratio to lower values,both in competing nerve terminals and at postsynaptic sites,plays a relevant role in controlling the elimination of supernumerary synapses.Finally,calcium entry through L-and P/Q-subtypes of voltage-gated calcium channels(both channels are present,together with the N-type channel in developing nerve terminals)contributes to reduce transmitter release and promote withdrawal o展开更多
文摘Objective To study the relationship between cartilage end plate calcification and intervertebral disc degeneration Methods An experimental model of cervical disc degeneration in rabbits was established by resection of the cervical supraspinous and interspinous ligaments and detachment of the posterior paravertebral muscles from the cervical vertebrae Mechanical instability in the cervical spine elicited by this surgical intervention accelerated the process of intervertebral disc degeneration The extent of intervertebral disc degeneration was graded in morphologically, and the thicknesses of the calcified layer and the uncalcified layer of the cartilage end plate were measured in each degenerated cervical disc Results In less severely degenerative cervical discs, the morphology of the cartilage end plate showed nearly normal construction, and the tidemark was clear In severely degenerative discs, the matrix and cells showed fibrosis, the tidemark advanced, and the calcified cartilage thickened There exists a positive correlation between the thickness of the calcified layer of the cartilage end plate and the degree of cervical disc degeneration Conclusion The calcification of the cartilage end plate is the key factor that initiates and promotes cervical disc degeneration
文摘Objective：The rapid expansion of knowledge regarding the functional anatomy of hand and wrist,increasing functional demands of senior citizens and improved methodologies of achieving and maintaining anatomic restoration of distal radius fractures has generated a renewed interest in addressing these fractures in a more precise manner.The purpose of our study was to evaluate the difference in patients function among those treated by 1） closed reduction and Plaster of Paris cast,2） distractor application,or 3） open reduction and internal fixation with a volar plate,and to assess the treatment choice for each particular fracture type.Methods：A prospective study was carried out on 60 patients with fractures of the distal end radius.Fractures were classified according to the AO classification into type A （extra-articular）,type B （partial articular） and type C （complete articular）.After initial evaluation patients were taken up for either conservative or operative treatment and were followed up for two years.Results：Anatomical results were evaluated according to the Sarmiento＇s modification of Lindstrom Criteria,which showed that excellent results were more frequent with open reduction and internal fixation using the plating technique.Clinical and functional results were evaluated according to the demerit point system of Gartland and Werley with Sarmiento modification,which was revealed to relate with the type of treatment techniques.Conclusion：There is no customized solution for all the fractures of the distal radius.The choice of treatment should be based on the fracture type,the patient＇s characteristics,the patient＇s demands and the treating surgeon＇s experience and preference.
基金supported by Catalan Government,Nos.2014SGR344(to JT),2017SGR704(to JT),2021SGR01214(to MAL)MCIN/AEI/10.13039/501100011033/by“ERDF A way of making Europe,”Nos.SAF2015-67143(to JT),PID2019-106332GB-I00(to JT and MAL)and PID2022-141252NB-I00(to MAL).
文摘During the development of the nervous system,there is an overproduction of neurons and synapses.Hebbian competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or strengthening.We have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase B receptor neurotrophic retrograde pathway,at the neuromuscular junction,in the axonal development and synapse elimination process versus the synapse consolidation.The purpose of this review is to describe the neurotrophic influence on developmental synapse elimination,in relation to other molecular pathways that we and others have found to regulate this process.In particular,we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors,coupled to downstream serine-threonine protein kinases A and C(PKA and PKC)and voltage-gated calcium channels,at different nerve endings in developmental competition.The dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site,influence each other,and require careful studies to individualize the mechanisms of specific endings.We describe an activity-dependent balance(related to the extent of transmitter release)between the presynaptic muscarinic subtypes and the neurotrophin-mediated TrkB/p75NTR pathways that can influence the timing and fate of the competitive interactions between the different axon terminals.The downstream displacement of the PKA/PKC activity ratio to lower values,both in competing nerve terminals and at postsynaptic sites,plays a relevant role in controlling the elimination of supernumerary synapses.Finally,calcium entry through L-and P/Q-subtypes of voltage-gated calcium channels(both channels are present,together with the N-type channel in developing nerve terminals)contributes to reduce transmitter release and promote withdrawal o
