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M Kanje

Publications and source records attributed to M Kanje.

At least 55 records · Page 3Linked to original sources
PubMed1993

An in vitro system for the study of slow axonal transport.

Here we present a model system which for the first time permits studies of slow axonal transport in vitro. Axonally transported proteins of rat vagus nerves were radiolabelled with [35S]methionine in the nodose ganglion in vitro and were incubated for up to 3 days in culture medium. Slowly transported proteins were analyzed by one- and two-dimensional polyacrylamide gel electrophoresis and identified on Western blots of two-dimensional gels with antibodies to actin and alpha-tubulin. The system will be valuable for pharmacological analysis of the mechanisms of slow transport.

Animals↗
PubMed1993

Pretreatment of rats with pulsed electromagnetic fields enhances regeneration of the sciatic nerve.

Regeneration of the sciatic nerve was studied in rats pretreated in a pulsed electromagnetic field (PEMF). The rats were exposed between a pair of Helmholtz coils at a pulse repetition rate of 2 pps at a field density of 60 or 300 microT. The PEMF treatment was then discontinued. After an interval of recovery, regeneration of the sciatic nerve was initiated by a crush lesion. Regeneration of sensory fibers was measured by the "pinch test" after an additional 3-6 days. A variety of PEMF pretreatments including 4 h/day for 1-4 days or exposure for 15 min/day during 2 days resulted in an increased regeneration distance, measured 3 days after the crush lesion. This effect could be demonstrated even after a 14-day recovery period. In contrast, pretreatment for 4 h/day for 2 days at 60 microT did not affect the regeneration distance. The results showed that PEMF pretreatment conditioned the rat sciatic nerve in a manner similar to that which occurs after a crush lesion, which indicates that PEMF affects the neuronal cell body. However, the mechanism of this effect remains obscure.

Animals↗
PubMed1993

The influence of predegeneration on regeneration through peripheral nerve grafts in the rat.

Nerve regeneration through predegenerated (PNG) or fresh (FNG) autografts in either fresh or delayed recipient nerve beds were studied in the rat sciatic nerve. Grafts 10 mm in length were excised either immediately or following a 7-day period of predegeneration. They were sutured into gaps on the contralateral side which were either freshly made or had been made 7 days previously. The early recovery (10 days at 2-day intervals) was evaluated by the sensory pinch test to measure the rate of regeneration and the delay period. The PNG group had an improvement in axonal regeneration as evidenced by a reduced delay period, a reduced number of regeneration failures, and less variability in regeneration distances compared to the FNG group. Conditioning the host site blocked some of the delay reduction in the PNG group, but had no effect on regeneration rate or delay in the FNG group. The presence of axons in the graft was confirmed by immunocytochemistry for neurofilament protein and by electron microscopy. The results suggest that proliferated cells, primarily Schwann cells, promote regeneration through the suture line and graft into the distal segment.

Animals↗
PubMed1993

Protein secretion from mouse skeletal muscle: coupling of increased exocytotic and endocytotic activities in denervated muscle.

The secretion of proteins labelled by incorporation of radioactive amino acids was studied in innervated and 10 to 13-day-denervated mouse skeletal muscle. The secretion of 3H-leucine-labelled proteins, expressed per mg muscle wet weight, increased after denervation, and the kinetics of the secretory process was also altered in denervated muscle. Separation of secreted 35S-methionine-labelled proteins by sodium dodecyl sulphate polyacrylamide gel electrophoresis followed by autoradiography revealed some denervation-induced alterations in the pattern of secreted proteins. The secretion from both innervated and denervated muscle was highly temperature sensitive and was reversibly inhibited by brefeldin A, a drug that blocks forward membrane transport from the endoplasmic reticulum/Golgi apparatus. This drug was also found to inhibit the uptake of fluorescein isothiocyanate-labelled dextran in denervated muscle but had no effect on the endocytotic activity of innervated muscle. This lends support to the hypothesis that the increased endocytotic activity in denervated muscle is coupled to a high secretory activity.

Animals↗
PubMed1993

A mathematical model for regeneration rate and initial delay following surgical repair of peripheral nerves.

A mathematical model is presented by which the regeneration rate and initial delay for peripheral nerve regeneration can be calculated from sensory pinch test data following surgical repair of peripheral nerves. The model is based on the assumption that experimental variations in regeneration distances between animals is due to the initial delay period--the time period before the regenerating fibers cross the suture line whereas the rate of regeneration is constant. This model which accounts for all observed data including 'regenerating failures' showed that nerve fibers in the rat sciatic nerve repaired with a fresh nerve graft regenerated at a rate of 1.5 mm/day after an initial delay of 3.6 days.

Animals↗
PubMed1992

The formation of a 'pseudo-nerve' in silicone chambers in the absence of regenerating axons.

The formation of a regenerate between sciatic nerve segments or stumps inserted into Y-tunnelled silicone chambers was studied under conditions where regenerating axons were prevented from entering the chamber. This was accomplished by using an isolated segment of the nerve as a proximal insert. After one week, a cellular regenerate spanned the proximal and distal inserts. The size of the regenerate increased if circulation was preserved in the distal inserts. At four weeks, a perineurium-like sheath surrounded the regenerate and longitudinally oriented Schwann cell columns could be observed throughout the regenerate. A similar 'pseudo-nerve' formed towards a piece of distally inserted tendon. Thus, the information required for the formation of a nerve-like structure is inherent to the non-neuronal cells entering the chamber. Schwann cells, in contrast to regenerating axons, do not exhibit preferential growth towards nervous tissue.

Animals↗
PubMed1992

The stimulatory effect of magnetic fields on regeneration of the rat sciatic nerve is frequency dependent.

The effects of exposure to sinusoidal magnetic fields on regeneration of the rat sciatic nerve were studied. Regeneration distances were measured after a crush lesion. The rats were exposed to a 0.1-mT magnetic field of various frequencies (50-2000 Hz) inside a pair of Helmholtz coils for various periods of time. Regeneration was measured by the pinch test or by immunocytochemical staining for neurofilaments 3, 4, or 6 days after the lesioning. Frequencies of 250, 500, and 1000 Hz significantly increased the regeneration distance. Higher (2000 Hz) and lower (50 Hz) frequencies had no effect. Maximal stimulation was obtained at 1000 Hz. At this frequency the rate of regeneration was increased by 24%. The results suggest that a broad frequency window exists within which the regeneration processes are sensitive to perturbation by magnetic fields and/or currents induced in the animal.

Animals↗
PubMed1992

Specificity of muscle reinnervation following repair of the transected sciatic nerve. A comparative study of different repair techniques in the rat.

Specificity of muscle reinnervation and the recovery of muscle contractility were studied after repair of the transected rat sciatic nerve. Six different techniques were compared: epineurial suture, perineural suture, whole nerve graft, interfascicular grafts, skeletal muscle bridge and tubulization. Muscle tetanic force and specificity of reinnervation were evaluated 12 weeks after nerve repair. Recovery of tetanic force was superior after repair with epineurial sutures. There was no statistical significance between the other methods in respect of tetanic force. The specificity of muscle reinnervation was best after tubulization, repair with interfascicular grafts and perineurial suture.

Animals↗
PubMed1992

D600, a Ca2+ antagonist, prevents stimulation of nerve regeneration by magnetic fields.

We have found that regeneration of the rat sciatic nerve is stimulated if the rats are exposed to a 50 Hz sinusoidal magnetic field. In this study we investigated the effect of a Ca2+ antagonist, methoxyverapamil (D600) on this response. D600 was administered to the regenerating segment of the nerve via implanted osmotic minipumps. Magnetic field exposure increased regeneration distances in vehicle perfused nerves. This enhancement was blocked by perfusion with D600 at a concentration which alone failed to affect outgrowth of nerve fibres, lending support to the idea that Ca2+ fluxes could be involved in mediating the biological actions of magnetic fields.

Animals↗
PubMed1992

Magnetic fields stimulate peripheral nerve regeneration in hypophysectiomized rats.

The effect of a sinusoidal 50 Hz magnetic field, 0.4 mT on regeneration of the rat sciatic nerve was studied. The sciatic nerve of intact and hypophysectomized rats was crushed and regeneration was evaluated by the pinch test and by immunocytochemical staining for neurofilaments. The animals were exposed to the magnetic field for 3-6 days, between a pair of Helmholtz coils. Hypophysectomy of the rats resulted in an impaired regeneration. However, the magnetic field exposure stimulated regeneration in both the intact and hypophysectomized animals. The results imply that the pituitary gland is not involved in magnetic field induced stimulation of nerve regeneration.

Animals↗
PubMed1992

Reinnervation of muscles in rats after repair of transsected sciatic nerves with Y-shaped and X-shaped silicone tubes. Muscle reinnervation after nerve repair.

Reinnervation of the gastrocnemius and anterior tibial muscles was assessed by measurements of tetanic force after repair of sciatic nerves with Y-shaped or X-shaped silicone tubes in rats. The transsected proximal stump of either the tibial or the peroneal fascicle was introduced into the opening of a Y-shaped silicone tube, or both fascicles were introduced into an X-shaped tube. The distal tibial and peroneal fascicles were inserted into the distal outlets of the tubes leaving a gap of 4 mm between proximal and distal stumps. In the X-shaped tubes the proximal inserts were placed opposite or adjacent to their respective distal parts. Sixteen weeks later reinnervation was evaluated by measurements of tetanic force of the gastrocnemius and anterior tibial muscles after electrical stimulation of the fascicles. There was preferential reinnervation in both types of tubes. In Y-shaped tubes about 90% of the tetanic force could be recorded from both muscles after stimulation of the peroneal and tibial fascicles, respectively. Recovery was lower in the X-shaped tubes, amounting to about 75%. Contractions evoked by misrouted fibres were similar (roughly 40%) in both models. We conclude that motor axons preferentially, but not exclusively, selected a path to reinnervate their original target muscle.

Animals↗
PubMed1992

Conditioning effect induced by chronic nerve compression. An experimental study of the sciatic and tibial nerves of rats.

To find out if chronic nerve compression could affect the peripheral nerve by acting as a "conditioning lesion", silicone tubes (internal diameter 0.8-1.6 mm) were placed round the sciatic or tibial nerves of adult rats for different time periods. After the period of compression the tubes were removed and a test crush lesion was made on the sciatic nerve in the thigh. Regeneration distances of the sensory nerve fibres were analysed by the pinch reflex test after a further three or six days. Compression of sciatic or tibial nerves induced a significant increase in outgrowth length compared with nerves subjected to mobilisation and crush lesion alone. All the tubes tested had a conditioning effect, but only tubes with a small internal diameter seemed to induce nerve fibre degeneration as assessed by immunocytochemistry. The results showed that chronic compression induced a regenerative response in the peripheral nerve. The mechanism by which this was accomplished remains obscure but it may involve both the neurons and the non-neuronal cells.

Animals↗
PubMed1991

Does insulin-like growth factor I (IGF-1) trigger the cell body reaction in the rat sciatic nerve?

Regeneration was measured after the infliction of a crush lesion on rat sciatic nerves which 4 days earlier had been subjected to a distal conditioning transection. Such nerves exhibited an increased outgrowth of nerve fibers as compared to nerves subjected to a single crush lesion. This increased outgrowth could be prevented, if the nerve was locally perfused around the site of the transection during the 4 days conditioning interval, with cycloheximide, actinomycin D and vinblastine, inhibitors of protein-, RNA-synthesis and retrograde axonal transport, respectively. The inhibitory effect of cycloheximide could be overcome by simultaneous perfusion with insulin-like growth factor I (IGF-1). The results suggest that proteins including IGF-1 which are synthesised locally around a nerve lesion and then transported retrogradely could trigger regenerative events in the neuronal cell body.

Animals↗
PubMed1991

Survival and regeneration of the adult rat vagus nerve in culture.

Here I report that the vagus nerve from the adult rat survives in culture for several days. The cultured preparation retains its ability to propagate action potentials and transport proteins within its sensory axons. Regeneration could be induced by a crush lesion and nerve fibers regenerated at a rate of 1.4 mm/day. The production of proteins, later subjected to retrograde axonal transport, and outgrowth of neurites could be prevented by inhibition of protein synthesis at the site of the crush lesion.

Action Potentials↗
PubMed1991

Stimulation of regeneration of the rat sciatic nerve by 50 Hz sinusoidal magnetic fields.

The effect of sinusoidal magnetic field stimulation on regeneration of the rat sciatic nerve was studied. Rats were exposed, after crush lesioning of the nerve, between a pair of Helmholtz coils to a 50 Hz magnetic field of 0.2 mT or 0.4 mT, respectively. Regeneration of the sciatic nerve was measured by the "pinch test," or by immunocytochemical staining for neurofilaments 1 to 6 days after the crush lesion. Intermittent stimulation (4 h/day) at 0.2 mT did not affect regeneration, while continuous stimulation with the same field enhanced regeneration distances measured at Days 1, 2, and 3. Intermittent stimulation with 0.4 mT increased regeneration distances in 3-day regenerated nerves. In the rats exposed continuously to 0.4 mT regeneration was higher in all groups (1, 2, 3, 4, and 6 days). This field enhanced the regeneration velocity by 21%. Pretreatment for 7 days with continuous stimulation either at 0.2 mT or at 0.4 mT did not affect regeneration of the sciatic nerve after a crush lesion.

Animals↗
PubMed1991

A calmodulin inhibitor with high specificity, compound 48/80, inhibits axonal transport in frog nerves without disruption of axonal microtubules.

The calmodulin inhibitor compound 48/80 has previously been shown to arrest axonal transport in vitro in the regenerating frog sciatic nerve. The inhibition was limited to the outgrowth region of nerves, which had been allowed to regenerate in vivo for 6 days after a crush lesion, before they were incubated with or without drugs in vitro overnight. The effects of compound 48/80 on the regenerating nerve were further investigated. A concentration of compound 48/80 (50 micrograms ml-1), which effectively inhibits axonal transport, did not cause observable changes of the microtubules of regenerating axons in the outgrowth region as judged by electron microscopy. Furthermore, it was shown that also a lower concentration (25 micrograms ml-1) inhibited axonal transport. As a measure of possible metabolic effects, the level of ATP was assessed in the regenerating nerve after exposure to compound 48/80. Compound 48/80 at 25 micrograms ml-1 did not change the level of ATP in the nerve. The assembly of bovine brain microtubule proteins in a cell-free system was unaffected by 25 micrograms ml-1 of compound 48/80 and slightly inhibited by 50 micrograms ml-1. At higher concentrations (greater than 100 micrograms ml-1) assembly of microtubules appeared stimulated, and microtubule spirals as well as closely aligned microtubules could be seen. These effects appeared to be unrelated to the transport effects. The present results indicate that compound 48/80 arrests axonal transport via mechanisms other than destruction of axonal microtubules or interference with the energy metabolism. It is possible that these mechanisms involve inhibition of calmodulin-regulated events essential to the transport.

Adenosine Triphosphate↗
PubMed1991

Effect of drying on regenerating rat sciatic nerve.

To study the effects of drying on regeneration, crush lesions were made on the sciatic nerve of 38 rats and the injured area was then air-dried for various periods of time (0-60 min). The regeneration distance of sensory nerve fibres was measured by the pinch reflex test three or six days later. Regeneration was significantly impaired by drying the nerve for 30 or 60 min, but shorter periods (10 min) also seemed to affect axonal outgrowth. Regeneration distances were increased in nerves that were subjected to drying and then allowed to recover for a week (conditioning interval) before the nerve was crushed. The results show that drying of a peripheral nerve is detrimental to nerve regeneration, and we suggest that nerves should not be exposed to air for more than a few minutes during operation without irrigation.

Animals↗