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1.  From muscle research to clinical applications: Do glutamate antagonists aid muscle recovery? 
Summary
It has been shown in the rat, that during the first five postnatal days, motoneurons are particularly vulnerable to excitotoxic cell death and glutamate receptors play a significant role in this time-dependent process. Various categories of glutamate blockers (MK-801, Mg, PNQX, DAP-5) have various actions on the respective receptors. Furthermore, the different response between mature and immature motoneurons following injury is attributed to the quantity of glutamate receptors on the cell membrane. The effect of these substances on the recovery of fast and slow muscles after sciatic nerve crush, at critical developmental stages, shows a variable but impressive reversal of the devastating effects on rat muscle properties, which is different between fast and slow muscles. In addition, blocking of NMDA receptors by various substances rescues motoneurons and increases the number of motor units surviving into adulthood.
In this way, glutamate receptor blockers may represent a promising therapeutic approach to retain nerve and muscle function during neurodegenerative events.
PMCID: PMC3666501  PMID: 23738276
excitotoxicity; glutamate antagonists; muscle plasticity; reinnervation; NMDA; AMPA
2.  Contractile properties and movement behaviour in neonatal rats with axotomy, treated with the NMDA antagonist DAP5 
BMC Physiology  2012;12:5.
Background
It is well known that axotomy in the neonatal period causes massive loss of motoneurons, which is reflected in the reduction of the number of motor units and the alteration in muscle properties. This type of neuronal death is attributed to the excessive activation of the ionotropic glutamate receptors (glutamate excitotoxicity). In the present study we investigated the effect of the NMDA antagonist DAP5 [D-2-amino-5-phosphonopentanoic acid] in systemic administration, on muscle properties and on behavioural aspects following peripheral nerve injury.
Methods
Wistar rats were subjected to sciatic nerve crush on the second postnatal day. Four experimental groups were included in this study: a) controls (injection of 0.9% NaCl solution) b) crush c) DAP5 treated and d) crush and DAP5 treated. Animals were examined with isometric tension recordings of the fast extensor digitorum longus and the slow soleus muscles, as well as with locomotor tests at four time points, at P14, P21, P28 and adulthood (2 months).
Results
1. Administration of DAP5 alone provoked no apparent adverse effects. 2. In all age groups, animals with crush developed significantly less tension than the controls in both muscles and had a worse performance in locomotor tests (p < 0.01). Crush animals injected with DAP5 were definitely improved as their tension recordings and their locomotor behaviour were significantly improved compared to axotomized ones (p < 0.01). 3. The time course of soleus contraction was not altered by axotomy and the muscle remained slow-contracting in all developmental stages in all experimental groups. EDL, on the other hand, became slower after the crush (p < 0.05). DAP5 administration restored the contraction velocity, even up to the level of control animals 4. Following crush, EDL becomes fatigue resistant after P21 (p < 0.01). Soleus, on the other hand, becomes less fatigue resistant. DAP5 restored the profile in both muscles.
Conclusions
Our results confirm that contractile properties and locomotor behaviour of animals are severely affected by axotomy, with a differential impact on fast contracting muscles. Administration of DAP5 reverses these devastating effects, without any observable side-effects. This agent could possibly show a therapeutic potential in other models of excitotoxic injury as well.
doi:10.1186/1472-6793-12-5
PMCID: PMC3395568  PMID: 22551202
3.  Volumetric and MGMT parameters in glioblastoma patients: Survival analysis 
BMC Cancer  2012;12:3.
Background
In this study several tumor-related volumes were assessed by means of a computer-based application and a survival analysis was conducted to evaluate the prognostic significance of pre- and postoperative volumetric data in patients harboring glioblastomas. In addition, MGMT (O6-methylguanine methyltransferase) related parameters were compared with those of volumetry in order to observe possible relevance of this molecule in tumor development.
Methods
We prospectively analyzed 65 patients suffering from glioblastoma (GBM) who underwent radiotherapy with concomitant adjuvant temozolomide. For the purpose of volumetry T1 and T2-weighted magnetic resonance (MR) sequences were used, acquired both pre- and postoperatively (pre-radiochemotherapy). The volumes measured on preoperative MR images were necrosis, enhancing tumor and edema (including the tumor) and on postoperative ones, net-enhancing tumor. Age, sex, performance status (PS) and type of operation were also included in the multivariate analysis. MGMT was assessed for promoter methylation with Multiplex Ligation-dependent Probe Amplification (MLPA), for RNA expression with real time PCR, and for protein expression with immunohistochemistry in a total of 44 cases with available histologic material.
Results
In the multivariate analysis a negative impact was shown for pre-radiochemotherapy net-enhancing tumor on the overall survival (OS) (p = 0.023) and for preoperative necrosis on progression-free survival (PFS) (p = 0.030). Furthermore, the multivariate analysis confirmed the importance of PS in PFS and OS of patients. MGMT promoter methylation was observed in 13/23 (43.5%) evaluable tumors; complete methylation was observed in 3/13 methylated tumors only. High rate of MGMT protein positivity (> 20% positive neoplastic nuclei) was inversely associated with pre-operative tumor necrosis (p = 0.021).
Conclusions
Our findings implicate that volumetric parameters may have a significant role in the prognosis of GBM patients. Furthermore, volumetry could help not only to improve the prediction of outcome but also the outcome itself by identifying patients at high risk of treatment failure and, thus, seek alternative treatment for these patients. In this small series, MGMT protein was associated with less aggressive tumor characteristics.
doi:10.1186/1471-2407-12-3
PMCID: PMC3264493  PMID: 22214427

Results 1-3 (3)