Sökresultat

Filtyp

Din sökning på "*" gav 536472 sökträffar

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

Mitogen activated protein (MAP) kinase activity is increased in adult mouse superior cervical ganglia during culturing

We have used adult mouse superior cervical ganglia (SCG) to study the role of mitogen activated protein (MAP) kinase activity during axonal outgrowth in vitro. An initial peak in activity within the first hours of culture was followed by a substantially higher activity after 1 to 2 days, a time when axons were actively growing. The latter peak is probably a result of both higher levels of protein

Neurones and glial cells of the mouse sciatic nerve undergo apoptosis after injury in Vivo and in Vitro

Analogous to the death of developing neurones deprived of trophic factors, nerve injury in adult life could lead to nerve cell death by apoptosis. Here the occurrence of apoptotic mouse sciatic sensory neurones after injury was investigated by nick-labelling DNA breaks. A small proportion of the neurones reliably became apoptotic after injury in vivo. The response was strongly amplified when the n

Increased cyclic AMP in in vitro regenerating frog sciatic nerves inhibits Schwann cell proliferation bur has no effect on axonal outgrowth

In the present study the role of cAMP for axonal outgrowth and Schwann cell proliferation was studying using the cultured frog sciatic nerve. An intrinsic rise in nerve injury, both in vitro and in vivo. Treatment with 0.1‐1.0μM forskolin, an activator of the cAMP‐generating enzyme adenylyl cyclase, increased the cAMP content up to 13‐fold, but was yet without effect on axonal outgrowth during an

Retrograde axonal transport of locally synthesized proteins, e.g., actin and heat shock protein 70, in regenerating adult frog sciatic sensory axons

The local synthesis and subsequent retrograde axonal transport of [35S]methionine‐labelled proteins was studied in the in vitro regenerating adult frog sciatic sensory axons. By the use of a three compartment culture system, proteins in the outgrowth region were selectively labelled. After 2 days in culture a rise in TCA‐insoluble radioactivity was detected in the dorsal root ganglia, which could

Okadaic Acid and Cultured Frog Sciatic Nerves : Potent Inhibition of Axonal Regeneration in Spite of Unaffected Schwann Cell Proliferation and Ganglionic Protein Synthesis

Abstract: Okadaic acid (OA) is a frequently used phosphatase inhibitor that by inhibiting dephosphorylation increases the net phosphorylation level in various systems. In the present study OA was used to assess the role of balanced phosphorylation‐dephosphorylation reactions for successful regeneration of peripheral nerves. To achieve this, the effects of OA on phosphorylation levels, neurite outg

Increased levels of mitogen activated protein kinase (MAP-K) detected in the injured adult mouse sciatic nerve

Adult mouse sciatic nerves (SNs) with attached dorsal root ganglia (DRG) were analysed for the presence of mitogen activated protein kinase (MAP-K) during normal and regenerative conditions. By immunohistochemistry, MAP-k was found to be present in the normal nerve at low levels in both Schwann cells and DRG nerve cell bodies, with a profoundly increased expression during regeneration. In axonal o

Long-term adverse effects after curative radiotherapy and radical prostatectomy : population-based nationwide register study

Objective: The aim of this study was to assess the risk of serious adverse effects after radiotherapy (RT) with curative intention and radical prostatectomy (RP). Materials and methods: Men who were diagnosed with prostate cancer between 1997 and 2012 and underwent curative treatment were selected from the Prostate Cancer data Base Sweden. For each included man, five prostate cancer-free controls,

Upregulation of cytosolic phospholipase A2 correlates with apoptosis in mouse superior cervical and dorsal root ganglia neurons

The involvement of cytosolic phospholipase A2 (cPLA2) in apoptosis of adult mouse superior cervical and dorsal root ganglia neurons has been investigated by the use of immunohistochemistry for cPLA2 and DNA nick-end labeling for apoptotic cells, respectively, cPLA2 immunoreactivity was strongly upregulated in neurons of both preparations during in vitro culturing. By double labeling it was unequiv

Calmodulin and In Vitro Regenerating Frog Sciatic Nerves : Release and Extracellular Effects

Although calmodulin (CaM) is commonly considered to be an intracellular protein, it has been suggested lately that it is released and exerts functions extracellularly. In the present investigation this was studied in in vitro regenerating adult frog (Rana temporaria) sciatic nerves. Using a multi‐compartment incubation chamber, the non‐neuronal cells in the outgrowth region of such nerves were rad