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Auditory event-related potentials to speech and acoustic stimulus in premature infants with periventricular leukomalacia
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Poster Session 1 Abstracts 2 June 2008 / Int. J. Devl Neuroscience 26 (2008) 841–866
in 5FU treated rats compared to controls and a non significant decrease in the exploration time of objects in a new location. Also the number of Ki67 positive cells in the 5-FU treated group was significantly lower than the control group. From these findings we conclude that 5-FU has an effect on hippocampal dependent behaviour which is associated with a reduction in cell proliferation. This animal model confirms the reports of cognitive deficits made by patients taking this drug.
[P1.57] Auditory event-related potentials to speech and acoustic stimulus in premature infants with periventricular leukomalacia G.N. Avecilla-Ramı´rez *, T. Harmony, E. Porras-Kattz, J. Ricardo-Garcell, A. Ferna´ndez-Bouzas, E. Santiago Instituto de Neurobiologı´a, UNAM, Mexico *Corresponding author. Keywords: Periventricular leukomalacia; Event-related potentials; Infants; Speech
doi: 10.1016/j.ijdevneu.2008.09.105 [P1.56] p75NTR-mediated axon degeneration is involved in myelin inhibition K.J. Park 2,*, D.R. Kaplan 1, F.D. Miller 1 1
Hospital for Sick Children, Canada University of Toronto, Canada *Corresponding author.
2
Keywords: Myelin; p75; Degeneration; Axon
Inhibition of axon growth is regulated by p75NTR during CNS myelin inhibition. Peripheral axons lacking p75NTR will grow onto CNS myelin in vivo and in culture. Furthermore, myelin derived proteins that inhibit growth bind to NogoR, and NogoR requires p75NTR as a co-receptor in order to mediate its inhibitory effects. We have recently shown that p75NTR signals to cause axon degeneration during pruning in vivo and in culture. Although it is assumed that inhibition of axon growth onto myelin is a consequence of repulsion and/or retraction mechanisms, we asked whether myelin inhibition might be due to local axon degeneration as mediated by p75NTR. In order to address this question, we grew dorsal root ganglia explants as well as sympathetic neuron cultures (SCG) onto varying concentrations of myelin. Cultures from WT and p75/ animals were analyzed using live imaging, phase photomicrographs, and immunofluorescence for alpha-tubulin. Degeneration, as evidenced by axon blebbing and beading, as well as decreased mitochondrial activity, was observed in WT axons grown onto the myelin substrate. This degeneration was not observed in p75/ neurons, but could be rescued by reintroducing p75, indicating that myelin induced axon degeneration is p75NTR dependent. To ask whether this myelin-dependent degeneration required neurotrophin binding to p75, we blocked BDFN using a function blocking antibody. This treatment completely rescued the degeneration. Previous work has shown that p75 mediates myelin inhibition by activating Rho, we therefore asked whether myelin-dependent degeneration required interactions between p75NTR and RhoGDI. Specifically, we blocked the interaction of p75NTR with RhoGDI using a previously defined blocking peptide, TAT-Pep5, in sympathetic neuron cultures where the axons were grown over a myelin substrate. These cultures exhibited less degeneration, indicating that myelin induced axon degeneration requires interactions between RhoGDI and p75NTR. Thus, one way that myelin inhibits axonal growth is by triggering p75NTR-dependent axon degeneration. doi: 10.1016/j.ijdevneu.2008.09.106
Periventricular Leukomalacia (PVL) is the predominant form of brain white matter lesion in preterm and newborn infants, and represents the major cause of long-term neurological and cognitive disabilities in surviving infants. The aim of this work is to correlate the event-related potentials recorded at early age with the posterior development of language in infants with PVL antecedents and in healthy infants. In a first stage, we examined recordings of PREs in 15 infants with PVL (1.5 months) and 14 healthy control infants (1.5 months) listening phonetic and acoustic changes. The obligatory components for the standard stimulus in both conditions (phonetic and acoustic) were smaller in amplitude in the PVL group than in the control group. In response to the deviant syllable, the PVL group showed a difference in positivity with low amplitude, as well as in response to the deviant harmonic tones. In contrast, the control group presented a difference in negativity in response to the deviant syllables and harmonic tones. These results may suggest an abnormal cortical auditory processing of speech and acoustic stimulus in the PVL group and an increase in their risk to develop language impairments or delays. In the second stage, we correlate latency and amplitude of P350 component in response to syllables in every infant with their results in language comprehension and production at 14 months. We found a positive linear correlation between amplitude and comprehension and production, and a negative linear correlation between latency and comprehension. These results show that ERPs in response to syllables could be used as a predictive factor of language development in infants at risk of cognitive impairments. doi: 10.1016/j.ijdevneu.2008.09.107 [P1.58] Hybrid synaptogenesis formed between the somatic neurons and the automatic neurons B.Y. Su 1,*, C. Wen 2, C.G. Xiao 3,** 1
Chengdu Medical College, China Third Military Medical University, China 3 Huazhong University of Science and Technology, China *Corresponding author. Tel.: +86 28 68289158. **Corresponding author. Tel.: +86 27 85726303. 2
Keywords: Spinal motoneuron; Superior cervical ganglion neuron; Co-culture; Synaptogenesis
Visceral organs are usually denervated by spinal cord injuries or other diseases, which cause a series of dysfunction. Unfortunately, so far there is no idea therapy available although some clinic trials are now in use. From a scientific perspective, reinnervation of the organs is the most potential strategy to reconstruct their functions, which involving establish the somatic-autonomic reflexes by surgery. Accumulating evidence indicates that synaptogenesis can be formed between somatic neurons and autonomic neurons in vivo by surgery. In this study, Spinal neurons were co-cultured with the labeled superior cervical ganglion neurons (SCGNs) on microislandized coverslips with complete medium. The synaptogenesis between spinal motoneurons (SMNs) and SCGNs were
Poster Session 1 Abstracts 2 June 2008 / Int. J. Devl Neuroscience 26 (2008) 841–866
in 5FU treated rats compared to controls and a non significant decrease in the exploration time of objects in a new location. Also the number of Ki67 positive cells in the 5-FU treated group was significantly lower than the control group. From these findings we conclude that 5-FU has an effect on hippocampal dependent behaviour which is associated with a reduction in cell proliferation. This animal model confirms the reports of cognitive deficits made by patients taking this drug.
[P1.57] Auditory event-related potentials to speech and acoustic stimulus in premature infants with periventricular leukomalacia G.N. Avecilla-Ramı´rez *, T. Harmony, E. Porras-Kattz, J. Ricardo-Garcell, A. Ferna´ndez-Bouzas, E. Santiago Instituto de Neurobiologı´a, UNAM, Mexico *Corresponding author. Keywords: Periventricular leukomalacia; Event-related potentials; Infants; Speech
doi: 10.1016/j.ijdevneu.2008.09.105 [P1.56] p75NTR-mediated axon degeneration is involved in myelin inhibition K.J. Park 2,*, D.R. Kaplan 1, F.D. Miller 1 1
Hospital for Sick Children, Canada University of Toronto, Canada *Corresponding author.
2
Keywords: Myelin; p75; Degeneration; Axon
Inhibition of axon growth is regulated by p75NTR during CNS myelin inhibition. Peripheral axons lacking p75NTR will grow onto CNS myelin in vivo and in culture. Furthermore, myelin derived proteins that inhibit growth bind to NogoR, and NogoR requires p75NTR as a co-receptor in order to mediate its inhibitory effects. We have recently shown that p75NTR signals to cause axon degeneration during pruning in vivo and in culture. Although it is assumed that inhibition of axon growth onto myelin is a consequence of repulsion and/or retraction mechanisms, we asked whether myelin inhibition might be due to local axon degeneration as mediated by p75NTR. In order to address this question, we grew dorsal root ganglia explants as well as sympathetic neuron cultures (SCG) onto varying concentrations of myelin. Cultures from WT and p75/ animals were analyzed using live imaging, phase photomicrographs, and immunofluorescence for alpha-tubulin. Degeneration, as evidenced by axon blebbing and beading, as well as decreased mitochondrial activity, was observed in WT axons grown onto the myelin substrate. This degeneration was not observed in p75/ neurons, but could be rescued by reintroducing p75, indicating that myelin induced axon degeneration is p75NTR dependent. To ask whether this myelin-dependent degeneration required neurotrophin binding to p75, we blocked BDFN using a function blocking antibody. This treatment completely rescued the degeneration. Previous work has shown that p75 mediates myelin inhibition by activating Rho, we therefore asked whether myelin-dependent degeneration required interactions between p75NTR and RhoGDI. Specifically, we blocked the interaction of p75NTR with RhoGDI using a previously defined blocking peptide, TAT-Pep5, in sympathetic neuron cultures where the axons were grown over a myelin substrate. These cultures exhibited less degeneration, indicating that myelin induced axon degeneration requires interactions between RhoGDI and p75NTR. Thus, one way that myelin inhibits axonal growth is by triggering p75NTR-dependent axon degeneration. doi: 10.1016/j.ijdevneu.2008.09.106
Periventricular Leukomalacia (PVL) is the predominant form of brain white matter lesion in preterm and newborn infants, and represents the major cause of long-term neurological and cognitive disabilities in surviving infants. The aim of this work is to correlate the event-related potentials recorded at early age with the posterior development of language in infants with PVL antecedents and in healthy infants. In a first stage, we examined recordings of PREs in 15 infants with PVL (1.5 months) and 14 healthy control infants (1.5 months) listening phonetic and acoustic changes. The obligatory components for the standard stimulus in both conditions (phonetic and acoustic) were smaller in amplitude in the PVL group than in the control group. In response to the deviant syllable, the PVL group showed a difference in positivity with low amplitude, as well as in response to the deviant harmonic tones. In contrast, the control group presented a difference in negativity in response to the deviant syllables and harmonic tones. These results may suggest an abnormal cortical auditory processing of speech and acoustic stimulus in the PVL group and an increase in their risk to develop language impairments or delays. In the second stage, we correlate latency and amplitude of P350 component in response to syllables in every infant with their results in language comprehension and production at 14 months. We found a positive linear correlation between amplitude and comprehension and production, and a negative linear correlation between latency and comprehension. These results show that ERPs in response to syllables could be used as a predictive factor of language development in infants at risk of cognitive impairments. doi: 10.1016/j.ijdevneu.2008.09.107 [P1.58] Hybrid synaptogenesis formed between the somatic neurons and the automatic neurons B.Y. Su 1,*, C. Wen 2, C.G. Xiao 3,** 1
Chengdu Medical College, China Third Military Medical University, China 3 Huazhong University of Science and Technology, China *Corresponding author. Tel.: +86 28 68289158. **Corresponding author. Tel.: +86 27 85726303. 2
Keywords: Spinal motoneuron; Superior cervical ganglion neuron; Co-culture; Synaptogenesis
Visceral organs are usually denervated by spinal cord injuries or other diseases, which cause a series of dysfunction. Unfortunately, so far there is no idea therapy available although some clinic trials are now in use. From a scientific perspective, reinnervation of the organs is the most potential strategy to reconstruct their functions, which involving establish the somatic-autonomic reflexes by surgery. Accumulating evidence indicates that synaptogenesis can be formed between somatic neurons and autonomic neurons in vivo by surgery. In this study, Spinal neurons were co-cultured with the labeled superior cervical ganglion neurons (SCGNs) on microislandized coverslips with complete medium. The synaptogenesis between spinal motoneurons (SMNs) and SCGNs were