Chemotropic guidance facilitates axonal regeneration and synapse formation after spinal cord injury.

A principal objective of spinal cord injury (SCI) research is the restoration of axonal connectivity to denervated targets. We tested the hypothesis that chemotropic mechanisms would guide regenerating spinal cord axons to appropriate brainstem targets. We subjected rats to cervical level 1 (C1) lesions and combinatorial treatments to elicit axonal bridging into and beyond lesion sites. Lentiviral vectors expressing neurotrophin-3 (NT-3) were then injected into an appropriate brainstem target, the nucleus gracilis, and an inappropriate target, the reticular formation. NT-3 expression in the correct target led to reinnervation of the nucleus gracilis in a dose-related fashion, whereas NT-3 expression in the reticular formation led to mistargeting of regenerating axons. Axons regenerating into the nucleus gracilis formed axodendritic synapses containing rounded vesicles, reflective of pre-injury synaptic architecture. Thus, we report for the first time, to the best of our knowledge, the reinnervation of brainstem targets after SCI and an essential role for chemotropic axon guidance in target selection

Treatment of brain tumours with electroporation and bleomycin in an in vivo rat model

The purpose of the study was to examine the possibilities of prolonging the life of rats with brain tumours using electroporation only while conducting impedance scans to evaluate the rate of electroporation. During the experiments, the treated rats in the first batch had tumors grow for 14 days and were then given electroporation with 8 + 8 exponential pulses at 800 v/cm, and 15 micro-F. Three of the animals given electroporation and bleomycin and one of the animals given electroporation alone died within three days of treatment. The reason for this may be oedema and increased intracranial pressure due to the large amount of energy delivered to the brain. In the second batch of rats given electroporation with 8 + 8 exponential pulses at 800 V/cm but with the lower capacitance setting of 4.5 micro-F, none of the treated rats died within a week after treatment. Among these rats, the tumors had also grown for only 10 days, thus further decreasing the risk of critical increases of the intracranial pressure directly after treatment. Interpretation of the impedance scans made before and after is made difficult due to factors such as possible short-circuiting of electrodes due to bleeding in the operating area. Not counting the rats in the first batch that died within three days of treatment, the rats treated with electroporation had a significantly prolonged life compared to controls. These results combined with results of a prior study of treatment of brain tumors in rats with electroporation in combination with Bleomycin suggest that this form of treatment may prolong the life of patients with brain tumours

Exponential stability of the solutions of the Boltzmann equation for the Benard problem

International audienceWe complete the result in the former paper 'Stability for Rayleigh-benard convective solutions of the Boltzmann equation' by showing the exponential decay of the perturbation of the laminar solution below the critical Rayleigh number and of the convective solutions above the critical Rayleigh number, in the kinetic framework

Effect of BHT (Butylated Hydroxytoluene) on the protein value of herring meal for the young rat

The effect of BHT (butylated hydroxytoluene) on the protein quality of herring meal was studied in nitrogen balance experiments with young rats. BHT at the 0.03% level in the meal improved the protein quality of meals produced from small summer herring when it was added after the drying process but was without any effect when it was added before the drying process. BHT had only little effect on the protein quality of meals produced from winter herring. Different production methods of the meals had little effect on the protein quality. Pelleting of the meals seemed to be no advantage, there were indications that the protein quality might be adversely affected by this process

Protein value of herring meal and some other protein concentrates of marine origin for the young rat

Protein concentrates, mainly of marine origin, were tested in nitrogen balance experiments with young rats. Commercial herring meals produced by several methods showed only small differences in protein utilization values. In most cases when differences in nitrogen balance values were found they were mainly due to corresponding differences in the protein digestibility. Press cake meals were slightly better utilized than whole meals, this difference was not accounted for by a corresponding difference in digestibility. Steam drying did not produce meals of better protein value than flame drying. No effect on the protein quality of herring meals was found of the preservatives sodium nitrite or formalin used during the storage of the raw material. Extraction of a whole meal with light petrol did not improve the protein quality wheras extraction of another whole meal with ethyl alcohol, ethyl ether and acetone improved the quality. Four foreign fish meals were of about the same protein value as Norwegian herring meal, whereas one was decidedly better. A sand-eel press cake meal was better than a whole meal produced from this raw material. The whole meal was of about the same protein quality as the herring meals. A flash dried whale meat meal was of about equal protein value as herring meals, but decidedly better than a slowly dried whale meal. A squid meal, a spray dried herring solubles meal and two fish off-fall meals were of decidedly poorer protein quality than the herring meals. Rennet casein was of about the same protein value as the herring meals, whereas the reference protein source, spray dried egg albumin, was better than all the other protein sources tested. Acetone dried samples of herring fillets and whole herring were of moderately better protein value than commercial herring meals. Acetone dried male herring was of poorer protein value than a corresponding sample of female herring. Acetone dried herring roe was of good protein value whereas the corresponding sample of herring milt was of poor protein value

Protein value of cod and coalfish and some products for the young rat

The protein quality of cod muscle protein and of some products of cod and coalfish was determined in nitrogen balance experiments with young rats. In most of the experiments spray dried egg albumin was used as a standard of reference. All the fish proteins showed as expected a lower utilization than egg albumin, but the results indicated that the preparations tested had high biological values. There was no appreciable difference between raw cod fillets, acetone dried cod fillets, or acetone dried fillets which had been boiled before drying. Two pilot plant fish flours from cod fillet waste showed high biological values. There was no difference in the utilization values between freeze dried coalfish fillet pastes containing different amounts of residual bones. Stockfish flours showed utilization values of about the same magnitude as the acetone dried fillets. There was no difference in the utilization values for stockfish and paste made from stockfish soaked in NaOH or NaC03 («lutefisk»). A comparison between acetone dried cod and herring fillets and meat from porbeagle and basking shark showed the elasmobranchs to be less well utilized than the teleosts