Hematopoietic growth factor EPO has neuro-protective and neuro-trophic effects--review / 中国实验血液学杂志

Erythropoietin (EPO) is an acidic glycoprotein that was first detected as a hematopoietic factor and its synthesis is triggered in response to cellular hypoxia-sensing. EPO binds to type I cytokine receptors, which associate with the non-receptor tyrosine kinase Jak2, and thereby activate Stat 5a/5b, Ras/MAPK, and PI3-K/Akt signaling pathways. The recent discovery shows that there is a specific EPO/EPO-receptor system in the central nervous system (CNS), independently of the haematopoietic system. Hypoxia and anemia can up-regulate EPO/EPOR expressions in the CNS. Further studies demonstrate that EPO has substantial neuro-protective effects and acts as a neurotrophic factor on central cholinergic neurons, influencing their differentiation and regeneration. EPO also exerts neuro-protective activities in different models of brain damage in vivo and in vitro, such as hypoxia, cerebral ischaemia and sub-arachnoid haemorrhage. EPO may also be involved in synaptic plasticity via the inhibition or stimulation of various neurotransmitters. Therefore, human recombinant EPO that activate its receptors in the central nervous system might be utilized in the future clinical practice involving neuroprotection and brain repair.

Adult stem cells and possible mechanisms of its differentiation--editorial / 中国实验血液学杂志

Adult stem cells are the multi-potential cells, which exist in fetal and adult tissues. It can reproduce itself (undergo self-renewal) or give rise to more specialized (differentiated) cells. Under certain inducing conditions, adult stem cells can acquire the ability to differentiate into different tissue cells. Multipotent adult progenitor cells (MAPC), an alternative name of adult stem cell given by Catherine Verfaillie, existing in bone marrow, can differentiate into cells with characteristics of mesodermal, neuroectodermal, and endodermal lineages in vitro at the single-cell level. MAPC can also contribute to most cell types when injected into the blastocyst. Adult stem cell differentiation implies that different cell lineages are derived from a single initial cell; all differentiated cell types are functional in vitro and in vivo; and engraftment is robust and persistent in the physiological and pathological situations. The possible mechanisms may underlie the differentiation: various tissue-specific stem cells are present in different organs; adult stem cells would be reprogrammed when removed from their usual microenvironment and introduced into a different niche that imparts signals to activate a novel genetic program needed for the new cell fate. And true multi-potential stem cells persist in postnatal life. In the future, multi-potent adult stem cells might then be used for therapies of degenerative or genetic disorders of multiple different organs.

Effects of hyperthermia on brainstem auditory evoked potentials and middle latency response in rats / 中国应用生理学杂志

<p><b>AIM</b>To study the effects of hyperthermia on brainstem auditory evoked potentials (BAEP) and middle latency response (MLR) in rats.</p><p><b>METHODS</b>BAEP and MLR were recorded at the skull surface of rats. The body temperature of anesthetized rats increased gradually with a physical method and was detected by a digital thermometer inserted into the rectum. The peak latency (PL), interpeak latency (IPL), wave amplitude and the critical body temperature at which BAEP and MLR completely lost had been observed.</p><p><b>RESULTS</b>All PL and I - II, I - III and I -IV IPL of BAEP shortened more and more as the body temperature increased step by step from 37 degrees C to 41.5 degrees C. But all PL and I - II and I -IV IPL did not shortened further and prolonged a little contrary as the body temperature at 42 degrees C and over 42 degrees C. All PL and P1-P3 and P2-P3 IPL of MLR also shortened as the body temperature increased from 37 degrees C to 43 degrees C. The wave amplitudes of BAEP and MLR decreased as the body temperature increased, especially as the body temperature over 42 degrees C. BAEP and MLR lost completely and synchronously at the body temperature (43.1 +/- 0.5) degrees C, which was not reversed as the body temperature returning to normal by cooling.</p><p><b>CONCLUSION</b>There were obvious effects of hyperthermia on both BAEP and MLR in rats, and irreversible impairments appeared at a critical body temperature.</p>