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Regeneration in vitro of the adult frog sciatic sensory axons

The adult frog sciatic nerve offers several advantages as an in vitro model to study nerve regeneration. The nerve with the attached dorsal root ganglia can easily be isolated and incubated in a culture medium for several days. If the nerve is subjected to a crush immediately after dissection there is a delay of 3.4 days after which the sensory axons start to regenerate into the distal nerve stump

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

Insulin stimulates ganglionic protein synthesis and reduces thymidine incorporation in support cells of the in vitro regenerating adult frog sciatic sensory neurons

Insulin was tested for effects on crush injured, in vitro regenerating, adult frog sciatic sensory axons. A wide range of insulin concentrations (0.01-10 μg × ml-1) was found to stimulate incorporation of radioactive leucine into ganglionic protein by 50-80%. without affecting the regeneration distance. Simultaneously insulin inhibited the proliferation of the support cells at the crush region by

Primary triage nurses do not divert patients away from the emergency department at times of high in-hospital bed occupancy - a retrospective cohort study

Background: Emergency department (ED) overcrowding is frequently described in terms of input- throughput and output. In order to reduce ED input, a concept called primary triage has been introduced in several Swedish EDs. In short, primary triage means that a nurse separately evaluates patients who present in the Emergency Department (ED) and either refers them to primary care or discharges them h

A Fast Axonally Transported Protein of the Frog Sciatic Sensory Axons Undergoes Similar Qualitative Changes During Regeneration In Vitro and In Vivo

The adult frog sciatic sensory neurons have been shown to regenerate in vitro. If a crush injury is made at the beginning of culture, regeneration starts after 3.4 days and proceeds at a rate of ∼0.8 mm/day for several days. Two‐dimensional gel electrophoresis was used to study the patterns of radiolabeled, fast axonally transported proteins during the first 7 days of regeneration. Interest was fo

Effects of protein kinase inhibitors on regeneration in vitro of adult frog sciatic sensory axons

The effects of protein kinase inhibitors on regeneration in vitro of adult frog sciatic sensory axons were tested. Regeneration of crush‐injured nerves for 8 days in serum‐free medium was inhibited by staurosporine (100 nM) and H‐7 (100 μM), which are both known to inhibit protein kinase C. With the use of a compartmented culture system it could be shown that H‐7 exerted both local (outgrowth regi

Growth cones of regenerating adult sciatic sensory axons release axonally transported proteins

Labelled, rapidly transported axonal proteins were shown to be released frog adult frog sciatic sensory neurons, regenerating in vitro after a crush injury. The spatial distribution of the transported, released proteins could accurately be resolved by culturing the nerve on nitrocellulose paper, which trapped the released proteins. The release was located to the crush and to the entire outgrowth r

Adenosine inhibition of the regeneration in vitro of adult frog sciatic sensory axons

The sensory axons of the adult frog sciatic nerve have earlier been shown to regenerate in vitro. If a local test crush is made at the initiation of culturing, regeneration starts after 3.4 days and proceeds at a rate of about 0.8-0.9 mm/day for several days. In the present experiments regeneration was inhibited by adenosine in a reversible and dose-dependent fashion. Similarly, both an adenosine

Time‐dependent effects of insulin on Schwann cell proliferation in the in vitro regenerating adult frog sciatic nerve

The present study showed that insulin (0.01 μg/ml, ≈︂ 2 nM) inhibited [3H]‐thymidine incorporation in support cells, most likely Schwann cells, of the cultured frog sciatic nerve. A 25–35% inhibition took place in regenerating nerve preparations as well as in preparations devoid of neuronal protein synthesis, i.e., in isolated 5 mm nerve segments and in gangliectomized nerves, suggesting that the

Effects of phenothiazines and dibenzazepines on axonal transport and microtubule assembly in vitro

Various phenothiazines (thioridazine, trifluoperazine and chlorpromazine) and dibenzazepines (lofepramine, amitriptyline and desipramine) were studied for effects on fast axonal transport (AXT) in vitro in frog sciatic nerves. AXT, measured as the accumulation of (3H) leucine‐labelled proteins in front of a ligature, was inhibited by more then 50% by all the drugs tested at 0.2 mM concentrations.

Insulin and IGF-II, but not IGF-I, stimulate the in vitro regeneration of adult frog sciatic sensory axons

We used the in vitro regenerating frog sciatic nerve to look for effects of insulin and insulin-like growth factors I and II (IGF-I, IGF-II) on regeneration of sensory axons and on injury induced support cell proliferation in the outgrowth region. In nerves cultured for 11 days, a physiological dose (10 ng/ml, ≈ nM) of insulin or IGF-II increased ganglionic protein synthesis (by 20% and 50%, respe

Use of explant cultures of peripheral nerves of adult vertebrates to study axonal regeneration in vitro

Explanted preparations of peripheral nerves with attached dorsal root ganglia of adult mammals and amphibia survive for several days in serum-free medium and can be used to study axonal regeneration in vitro. This review outlines the methods which we routinely use and how they may be applied to study different aspects of axonal regeneration. When the peripheral nerves are crushed in vitro, axons r

High Podocalyxin levels promote cell viability partially through up-regulation of Annexin A2

Podocalyxin (PODXL) is a highly glycosylated and sialylated transmembrane protein that is up-regulated in various types of tumors and whose expression levels positively correlate with tumor grade. We previously found Podxl to be highly expressed in murine tumorigenic neural stem/progenitor cells (NSPs). Here we investigated the effects of elevated Podxl levels in these cells. NSPs overexpressing P

Leukemia inhibitory factor null mice : Unhampered in vitro outgrowth of sensory axons but reduced stimulatory potential by nerve segments

Leukemia inhibitory factor (LIF) is locally up-regulated after peripheral nerve injury and may be involved in the subsequent regeneration. Here, adult mice with or without LIF gene deletions were used to study the role of LIF in regeneration. The results show that axonal regeneration in vitro from dorsal root ganglia (DRGs) was unaffected by LIF deletion. However, segments from wild type mice prom

Involvement of axonal phospholipase A2 activity in the outgrowth of adult mouse sensory axons in vitro

The effect on axonal outgrowth of inhibition of phospholipase A2 activity was studied in a recently developed in vitro model, where dorsal root ganglia with attached spinal roots and nerve stumps from young adult mice were cultured in an extracellular matrix material (Matrigel). The phospholipase A2 inhibitors 4-bromophenacyl bromide and oleyloxyethyl phosphorylcholine dose-dependently reduced axo

The immune modulator Linomide prevents neuronal death in injured peripheral nerves of the mouse

Neuronal death after injury or disease could result from imbalanced cytokine expression. Linomide (LS-2616, quinoline-3-carboxamide), a synthetic immunomodulator with effects on cytokine production, suppresses autoimmune diseases of the nervous system. Here adult mice were pre-treated with 200 mg/kg/day of Linomide for 9 days, after which the sciatic nerves were crushed. After another 10 days of L

Regenerating peripheral nerves release a diffusable protein kinase

Using [γ32P]ATP and 1-dimensional electrophoresis this report shows that a protein kinase is released in the culture medium from adult frog sciatic nerves during regeneration in vitro. The kinase, which phosphorylated serine and to some extent threonine residues, was released from non-neuronal cells. It showed an increased activity during the 3rd to 6th day after injury, coinciding with the injury

Protein kinase C inhibition has only a transient growth arresting effect on in vitro regenerating mouse sensory neurons

Adult mice sensory ganglia were cultured in an extracellular matrix gel. Analyses of extending axons were made 48 h (long-term) or immediately (short-term) after addition of protein kinase inhibitors. Long- and short-term growth was insensitive to protein kinase A/G inhibition by HA-1004. Long-term protein kinase C inhibition by chelerythrine affected only certain, long axons. In the short-term vi

Axonal outgrowth from adult mouse nodose ganglia In vitro is stimulated by neurotrophin-4 in a Trk receptor and mitogen-activated protein kinase-dependent way

The actions of neurotrophic factors on sensory neurons of the adult nodose ganglion were studied in vitro. The ganglia were explanted in an extracellular matrix-based gel that permitted observation of the growing axons. Neurotrophin-4 (NT-4) was a very efficient stimulator of outgrowth of axons from the nodose ganglion and had almost doubled the outgrowth length when this was analyzed after 2 days