In vivo stimulation of early peripheral axon regeneration by N-propionylmannosamine in the presence of polysialyltransferase ST8SIA2

Liquid cultures of bone marrow cells enriched for megakaryocytes were assayed for incorporation of 3H-thymidine (3H-TdR) into acid-precipitable cell digests to determine the effect of thrombopoietin on DNA synthesis. As previously described, thrombopoietin was prepared by ammonium sulfate fractionation of pooled plasma obtained from thrombocytopenic rabbits. A control fraction was prepared from normal rabbit plasma. The thrombopoietic activity of these fractions was determined in vivo with normal rabbits as assay animals and the rate of incorporation of 75Se-selenomethionine into newly formed platelets as an index of thrombopoietic activity of the infused material. Guinea pig megakaryocytes were purified using bovine serum albumin gradients. Bone marrow cultures containing 1.5-3.0x104 cells and 31%-71% megakaryocytes were incubated 18 h in modified Dulbecco’s MEM containing 10% of the concentrated plasma fractions from either thrombocytopenic or normal rabbits. In other control cultures, 0.9% NaCl was substituted for the plasma fractions. 3H-TdR incorporation was measured after cells were incubated for 3 h with 1 μCi/ml. The protein fraction containing thrombopoietin-stimulating activity caused a 25%-31% increase in 3H-TdR incorporation over that in cultures which were incubated with the similar fraction from normal plasma and a 29% increase over the activity in control cultures to which 0.9% NaCl had been added. These data suggest that thrombopoietin stimulates DNA synthesis in megakaryocytes and that this tecnique may be useful in assaying thrombopoietin in vitro.

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Potential roles of stem cell marker genes in axon regeneration

Experimental & Molecular Medicine ◽

10.1038/s12276-020-00553-z ◽

2021 ◽

Vol 53 (1) ◽

pp. 1-7

Author(s):

Jinyoung Lee ◽

Yongcheol Cho

Keyword(s):

Stem Cell ◽

Expression Profiling ◽

Axon Regeneration ◽

Stem Cell Marker ◽

Marker Genes ◽

Cell Marker ◽

Regenerative Capacity ◽

Regeneration Mechanism ◽

Central Nervous Systems

AbstractAxon regeneration is orchestrated by many genes that are differentially expressed in response to injury. Through a comparative analysis of gene expression profiling, injury-responsive genes that are potential targets for understanding the mechanisms underlying regeneration have been revealed. As the efficiency of axon regeneration in both the peripheral and central nervous systems can be manipulated, we suggest that identifying regeneration-associated genes is a promising approach for developing therapeutic applications in vivo. Here, we review the possible roles of stem cell marker- or stemness-related genes in axon regeneration to gain a better understanding of the regeneration mechanism and to identify targets that can enhance regenerative capacity.

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Contamination of erythropoietin by endotoxin: in vivo and in vitro effects on murine erythropoiesis

Blood ◽

10.1182/blood.v54.1.146.146 ◽

1979 ◽

Vol 54 (1) ◽

pp. 146-158 ◽

Cited By ~ 8

Author(s):

KS Zuckerman ◽

PJ Quesenberry ◽

J Levin ◽

R Sullivan

Keyword(s):

Significant Inhibition ◽

Erythropoietic Activity ◽

Limulus Amebocyte Lysate ◽

Endogenous Erythropoietin ◽

Significant Change ◽

In Vitro Effects ◽

Stimulation Of

Abstract Endotoxin was detected in all erythropoietin preparations tested and was removed from four lots, without loss of erythropoietic activity, by adsorption with limulus amebocyte lysate. Comparison of adsorbed (endotoxin-depleted) and nonadsorbed (endotoxin-containing) erythropoietin preparations demonstrated significant inhibition of CFU- e and BFU-e in vitro by nonadsorbed erythropoietin at concentrations higher than 0.25 U/ml and 2.0 U/ml, respectively. CFU-e and BFU-e were inhibited significantly by readdition in vitro of 10(-5)-10(-3) mug of endotoxin per unit of limulus-adsorbed erythropoietin. Administration of saline or 6 U of nonadsorbed or adsorbed erythropoietin twice a day for 4 days of CF1 mice resulted in reticulocyte counts of 2.1%, 9.9%, and 15.9%, respectively. Nonadsorbed erythropoietin resulted in a 29% decrease in erythropoiesis, a 42% decrease in CFU-e, and a 16% increase in granulopoiesis in the marrow, whereas adsorbed erythropoietin caused a 28% increase in erythropoiesis, no significant change in CFU-e and a 19% decrease in granulopoiesis in the marrow. Both preparations resulted in marked increases in splenic erythropoiesis and granulopoiesis. The effects of adsorbed erythropoietin are similar to those produced following stimulation of hematopoiesis by endogenous erythropoietin. Hemopoietic changes induced by nonadsorbed erythropoietin in vivo and in vitro are affected substantially by contamination of the erythropoietin preparations with endotoxin.

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Continuation of fast axonal transport in regenerating axons in vitro

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y79-189 ◽

1979 ◽

Vol 57 (11) ◽

pp. 1251-1255

Author(s):

M. A. Bisby ◽

C. E. Hilton

Keyword(s):

Sciatic Nerve ◽

Vagus Nerve ◽

Axonal Transport ◽

Nerve Injury ◽

Axon Regeneration ◽

Free Medium ◽

Fast Axonal Transport ◽

Sensory Axons

A previous study by McLean and co-workers reported that regenerating axons of the rabbit vagus nerve were unable to sustain axonal transport in vitro for several months after nerve injury. In contrast, we found that sensory axons of the rat sciatic nerve were able to transport 3H-labeled protein into their regenerating portions distal to the site of injury within a week after injury when placed in vitro. Transport in vitro was not significantly less than transport in axons maintained in vivo for the same period. Transport occurred in the medium that was used by the McLean group, but was significantly reduced in calcium-free medium. When axon regeneration was delared, only small amounts of activity were present in the nerve distal to the site of injury, showing that labeled protein normally present in that part of the nerve was associated with axons and was not a result of local precursor uptake by nonneural elements in the sciatic nerve. We were not able to explain the failure of McLean and co-workers to demonstrate transport in vitro in regenerating vagus nerve, but we conclude that there is no general peculiarity of growing axons that makes them unable to sustain transport in vitro.

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