Publications by authors named "Taina Westerlund"

2 Publications

  • Page 1 of 1

The perineurium modifies the effects of phenol and glycerol in rat sciatic nerve.

Acta Neuropathol 2004 Oct 5;108(4):319-31. Epub 2004 Aug 5.

Department of Pathology, Turku University Central Hospital, Kiinamyllynkatu 4-8, 20520 Turku, Finland.

Endoneurial cell response and type of nerve fibre damage were studied after perineural injections of 7% phenol-aqua and pure glycerol. Our previous studies have shown that phenol and glycerol induce different types of nerve fibre degeneration after intraneural injections: phenol dissolves axons and Schwann cells inside the basal lamina tubes but glycerol breaks them down into cellular flakes. The current study investigated whether the difference in type of endoneurial damage also appears after perineural application and how the perineurium affects the effect of these neurolytic agents. Rat sciatic nerves were treated with perineural injections of 7% phenol-aqua or pure glycerol and were followed up to 6 months. The results support the previous findings that perineural phenol injection induces damage that covers almost the whole endoneurium, but glycerol injection results in minor subperineurial damage. An ultrastructural study showed that the endoneurial effects are much milder after perineural injection than after intraneural injections. Phenol-induced nerve fibre dissolving was only rarely seen and the nerve fibre damage appeared similar to that after regular Wallerian degeneration in both groups. Axonal regeneration began within 2 weeks of the injections. Endoneurial macrophages were numerous in the damaged area in many individual nerves even at 3-6 months in both groups, which may indicate impaired phagocytotic activity. Regenerating axonal sprouts were seen first at 1 week post injection and Schwann cells proliferated within 2 weeks in both groups. However, the number of axonal sprouts was higher (P=0.002) and the size of the sprouts appeared larger after glycerol injection at 4 weeks post injection. The present study shows that the effects of extraneurally applied neurolytic agents phenol and glycerol are modified by the perineurium. Phenol readily penetrates the perineurium, but glycerol causes only subperineurial damage. The type of damage is rather similar to regular Wallerian degeneration in both groups and the endoneurial effects differ from those seen after intraneural injections.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00401-004-0896-1DOI Listing
October 2004

The effect of combined neurolytic blocking agent 5% phenol-glycerol in rat sciatic nerve.

Acta Neuropathol 2003 Sep 10;106(3):261-70. Epub 2003 Jul 10.

Department of Anaesthesiology, Loimaa District Hospital, 32200 Loimaa, Finland.

Combined 5% phenol-glycerol has been used to treat cancer pain or spasticity and as sympathetic blocks. The major clinical problems have been the unpredictable effects on pain and on the duration of the blocks. Previously we have shown that intraneurally injected phenol induces haemorrhagic necrosis as well as dissolving of the nerve fibres. Glycerol, on the other hand, induces dispersion of nerve fibre debris into the endoneurium. We have now studied the effects of a combination of these two chemically different agents. The endoneurial and epineurial responses of rat peripheral nerve were followed after intraneural and perineural injections. Samples for electron microscopic and immunohistochemical studies were taken at 1-26 weeks after the injection. The intraneural phenol-glycerol injection resulted in gross endoneurial damage with partly or totally dissolved nerve fibres. Totally dissolved nerve fibres showed empty, collapsed basal lamina tubes and partly dissolved nerve fibres showed breaching of remaining degenerative debris into the endoneurial space. Axonal regeneration was delayed and was observed first after 2 weeks and it took 4 months before most of the nerve fibres were myelinated. The perineural injections resulted in partial subperineurial damage of the endoneurium morphologically similar to the results caused by the intraneural injection. An initial high accumulation of epineurial macrophages was noted at 1 and 2 weeks. An invasion of macrophages into the endoneurium occurred within 1 week after the intraneural and perineural injections and the number of endoneurial macrophages remained high for up to 6 months. The present study shows that glycerol added to phenol diminishes the necrotizing effect of phenol after an intraneural injection. Combined phenol-glycerol-induced nerve injury is reversible and the axons regenerate but residual morphological changes can be observed even after 6 months.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00401-003-0730-1DOI Listing
September 2003