Distribution and Development of Peripheral Glial Cells in the Human Fetal Cochlea

The adult human cochlea contains various types of peripheral glial cells that envelop or myelinate the three different domains of the spiral ganglion neurons: the central processes in the cochlear nerve, the cell bodies in the spiral ganglia, and the peripheral processes in the osseous spiral lamina. Little is known about the distribution, lineage separation and maturation of these peripheral glial cells in the human fetal cochlea. In the current study, we observed peripheral glial cells expressing SOX10, SOX9 and S100B as early as 9 weeks of gestation (W9) in all three neuronal domains. We propose that these cells are the common precursor to both mature Schwann cells and satellite glial cells. Additionally, the peripheral glial cells located along the peripheral processes expressed NGFR, indicating a phenotype distinct from the peripheral glial cells located along the central processes. From W12, the spiral ganglion was gradually populated by satellite glial cells in a spatiotemporal gradient. In the cochlear nerve, radial sorting was accomplished by W22 and myelination started prior to myelination of the peripheral processes. The developmental dynamics of the peripheral glial cells in the human fetal cochlea is in support of a neural crest origin. Our study provides the first overview of the distribution and maturation of peripheral glial cells in the human fetal cochlea from W9 to W22.     

Signalling entrains the peripheral circadian clock

In mammals, 24-h rhythms of behaviour and physiology are regulated by the circadian clock. The circadian clock is controlled by a central clock in the brain's suprachiasmatic nucleus (SCN) that synchronizes peripheral clocks in peripheral tissues. Clock genes in the SCN are primarily entrained by light. Increasing evidence has shown that peripheral clocks are also regulated by light and hormones independent of the SCN. How the peripheral clocks deal with internal signals is dependent on the relevance of a specific cue to a specific tissue. In different tissues, most genes that are under circadian control are not overlapping, revealing the tissue-specific control of peripheral clocks. We will discuss how different signals control the peripheral clocks in different peripheral tissues, such as the liver, gastrointestinal tract, and pancreas, and discuss the organ-to-organ communication between the peripheral clocks at the molecular level.     

Peripheral Visual Performance Enhancement by Neurofeedback Training

Peripheral visual performance is an important ability for everyone, and a positive inter-individual correlation is found between the peripheral visual performance and the alpha amplitude during the performance test. This study investigated the effect of alpha neurofeedback training on the peripheral visual performance. A neurofeedback group of 13 subjects finished 20 sessions of alpha enhancement feedback within 20 days. The peripheral visual performance was assessed by a new dynamic peripheral visual test on the first and last training day. The results revealed that the neurofeedback group showed significant enhancement of the peripheral visual performance as well as the relative alpha amplitude during the peripheral visual test. It was not the case in the non-neurofeedback control group, which performed the tests within the same time frame as the neurofeedback group but without any training sessions. These findings suggest that alpha neurofeedback training was effective in improving peripheral visual performance. To the best of our knowledge, this is the first study to show evidence for performance improvement in peripheral vision via alpha neurofeedback training.     

Transplantation of hematopoietic stem cells from the peripheral blood

Hematopoietic stem cells can be collected from the peripheral blood. These hematopoietic stem cells (HSC), or better progenitor cells, are mostly expressed as the percentage of cells than react with CD34 antibodies or that form colonies in semi-solid medium (CFU-GM). Under steady-state conditions the number of HSC is much lower in peripheral blood than in bone marrow. Mobilization with chemotherapy and/or growth factors may lead to a concentration of HSC in the peripheral blood that equals or exceeds the concentration in bone marrow. Transplantation of HSC from the peripheral blood results in faster hematologic recovery than HSC from bone marrow. This decreases the risk of infection and the need for blood-product support. For autologous stem-cell transplantation (SCT), the use of peripheral blood cells has completely replaced the use of bone marrow. For allogeneic SCT, on the other hand, the situation is more complex. Since peripheral blood contains more T-lymphocytes than bone marow, the use of HSC from the peripheral blood increases the risk of graft-versus-host disease after allogeneic SCT. For patients with goodrisk leukemia, bone marrow is still preferred, but for patients with high-risk disease, peripheral blood SCT has become the therapy of choice.     

脂肪干细胞在周围神经损伤修复中的作用

周围神经损伤的修复是临床外科中的一个难题。尽管周围神经系统在损伤后具有内在的自我修复能力,但一般很难达到完全功能恢复,特别是近端的损伤或者大段的神经缺损。近年来,基于干细胞的细胞治疗为周围神经再生带来了曙光。大量研究表明干细胞可促进周围神经损伤的再生,然而其作用机制还不明确。为此,本文将对脂肪干细胞在周围神经损伤修复中作用包括向雪旺细胞分化、神经营养、血管形成、神经元保护、靶器官保护和免疫调节等作用进行归纳,并进一步探讨其潜在的作用机制。     

Glucocorticoid hormones inhibit food-induced phase-shifting of peripheral circadian oscillators.

The circadian timing system in mammals is composed of a master pacemaker in the suprachiasmatic nucleus (SCN) of the hypothalamus and slave clocks in most peripheral cell types. The phase of peripheral clocks can be completely uncoupled from the SCN pacemaker by restricted feeding. Thus, feeding time, while not affecting the phase of the SCN pacemaker, is a dominant Zeitgeber for peripheral circadian oscillators. Here we show that the phase resetting in peripheral clocks of nocturnal mice is slow when feeding time is changed from night to day and rapid when switched back from day to night. Unexpectedly, the inertia in daytime feeding-induced phase resetting of circadian gene expression in liver and kidney is not an intrinsic property of peripheral oscillators, but is caused by glucocorticoid signaling. Thus, glucocorticoid hormones inhibit the uncoupling of peripheral and central circadian oscillators by altered feeding time.     

Cell number and cellular composition in vermiform larvae of dicyemid mesozoans

Cell numbers and cellular composition were examined in vermiform larvae of 44 species of dicyemid mesozoans phylum Dicyemida belonging to six genera: Conocyema , Dicyema , Dicyemennea , Dicyemodeca , Microcyema and Pseudicyema . In addition, the literature on vermiform larvae of another 59 species was reviewed. Vermiform larvae typically have a constant number of peripheral cells that are species specific. Interspecific variations in the total number of peripheral cells range from 10 to 39. The most frequent number is either 22 or 23. Differences in the total number of peripheral cells are mostly due to differences in the number of trunk peripheral cells, such as parapolar cells, diapolar cells and uropolar cells. The body length of vermiform larvae is positively correlated with the number of trunk peripheral cells. Interspecific variations in the total number of trunk peripheral cells range from 2 to 31. The most frequent number is 14. In species with 14 trunk peripheral cells, individual variations of cell numbers were minimal. In species with more trunk peripheral cells, some individual variations appeared. Increase and decrease of trunk cell number might cause diversity of dicyemids, which is possibly related to speciation in these simple multicellular animals.     

A Comparative Study of Genetic Diversity of Peripheral and Central Populations of Chukar Partridge From Northwestern China

Although it has long been presumed that peripheral populations tend to exhibit low genetic diversity because of isolation and genetic drift, results of empirical investigation remain ambiguous. Some chukar partridge (Alectoris chukar) populations have expanded their ranges, resulting in several peripheral populations, due to recent deforestation by human beings in the Longdong Loess Plateau of northwestern China. On the basis of mitochondrial DNA control-region data, we compare the genetic diversity of two peripheral populations, Honghui and Wangxia, and six central populations. The Wangxia population possessed high levels of genetic diversity. The Honghui population, however, exhibited low genetic variation. The degree of isolation was the primary factor affecting the genetic diversity of the two peripheral populations. A peripheral population that was not isolated exhibited higher genetic diversity than did an isolated peripheral population.     

Peripheral glia direct axon guidance across the CNS/PNS transition zone.

CNS glia have integral roles in directing axon migration of both vertebrates and insects. In contrast, very little is known about the roles of PNS glia in axonal pathfinding. In vertebrates and Drosophila, anatomical evidence shows that peripheral glia prefigure the transition zones through which axons migrate into and out of the CNS. Therefore, peripheral glia could guide axons at the transition zone. We used the Drosophila model system to test this hypothesis by ablating peripheral glia early in embryonic neurodevelopment via targeted overexpression of cell death genes grim and ced-3. The effects of peripheral glial loss on sensory and motor neuron development were analyzed. Motor axons initially exit the CNS in abnormal patterns in the absence of peripheral glia. However, they must use other cues within the periphery to find their correct target muscles since early pathfinding errors are largely overcome. When peripheral glia are lost, sensory axons show disrupted migration as they travel centrally. This is not a result of motor neuron defects, as determined by motor/sensory double-labeling experiments. We conclude that peripheral glia prefigure the CNS/PNS transition zone and guide axons as they traverse this region.     

A motion illusion reveals mechanisms of perceptual stabilization

Visual illusions are valuable tools for the scientific examination of the mechanisms underlying perception. In the peripheral drift illusion special drift patterns appear to move although they are static. During fixation small involuntary eye movements generate retinal image slips which need to be suppressed for stable perception. Here we show that the peripheral drift illusion reveals the mechanisms of perceptual stabilization associated with these micromovements. In a series of experiments we found that illusory motion was only observed in the peripheral visual field. The strength of illusory motion varied with the degree of micromovements. However, drift patterns presented in the central (but not the peripheral) visual field modulated the strength of illusory peripheral motion. Moreover, although central drift patterns were not perceived as moving, they elicited illusory motion of neutral peripheral patterns. Central drift patterns modulated illusory peripheral motion even when micromovements remained constant. Interestingly, perceptual stabilization was only affected by static drift patterns, but not by real motion signals. Our findings suggest that perceptual instabilities caused by fixational eye movements are corrected by a mechanism that relies on visual rather than extraretinal (proprioceptive or motor) signals, and that drift patterns systematically bias this compensatory mechanism. These mechanisms may be revealed by utilizing static visual patterns that give rise to the peripheral drift illusion, but remain undetected with other patterns. Accordingly, the peripheral drift illusion is of unique value for examining processes of perceptual stabilization.     

Behavior of peripheral rods and their role in the life cycle of Myxococcus xanthus.

Myxococcus xanthus is a gram-negative bacterium with a complex life cycle including a developmental phase in which cells aggregate and sporulate in response to starvation. In previous papers, we have described a heretofore unsuspected layer of complexity in the development of M. xanthus: vegetatively growing cells differentiate into two cell types during development. In addition to the differentiation of spores within fruiting bodies, a second cell type, peripheral rods, arises outside fruiting bodies. The pattern of expression of proteins in peripheral rods is different from that of either vegetatively growing cells or spores, and peripheral rods express a number of recognized developmental markers. In this report, we examine four aspects of the biology of peripheral rods: (i) the influence of nutrients on the proportion of peripheral rods in a population of developing cells, (ii) the capacity of peripheral rods to recapitulate development, (iii) the development of peripheral rods on conditioned medium, and (iv) the ability of peripheral rods to resume growth on low amounts of exogenously added nutrients. The results of these studies suggest that peripheral rods play a significant role in the life cycle of M. xanthus by allowing the exploitation of low amounts or transient influxes of nutrients without the investment of energy in spore germination. The differentiation of vegetatively growing cells into two cell types that differ significantly in biology, shape, and localization within the population has been incorporated into a model of the life cycle of M. xanthus.     

Imbalance of peripheral B lymphocytes and NK cells in rheumatoid arthritis

The study was focused on several cellular immune disorders correlated with the imbalance between peripheral blood B lymphocytes and NK cells in severe rheumatoid arthritis. By flow cytometry we calculated the proportions of T, T helper, T cytotoxic/suppressor, B lymphocytes and natural killer cells in peripheral blood. The mitogen-induced proliferation of peripheral lymphocytes was measured by tritium-labeld uridine incorporation. Experimental data highlight a connection between annomal values of the B to natural killer cells ratio and disorders of the peripheral mononuclear cells concentration. We also showed that the polyclonal proliferation capacity of peripheral lymphocytes in rheumatoid arthritis is solely related to the B to natural killer cells ratio or to the natural killer cells proportion. The study reveals a potential role of the imbalance between proportions of peripheral B lymphocytes and natural killer cells in the immune pathogenesis of rheumatoid arthritis, thus pointing out an interrelation between the adaptive and innate immune systems.     

Global revascularization: the role of the cardiologist

There are compelling reasons for cardiologists to undertake a more global approach to patients with peripheral vascular diseases: atherosclerosis is a 'systemic' disease frequently causing both coronary and peripheral vascular problems in the same patient; coronary artery disease is the most common cause of morbidity and mortality in patients with peripheral vascular disease; and peripheral vascular disease negatively impacts the management of angina pectoris and congestive heart failure. There are four major areas of special interest to the cardiologist: (1) iliac arteries (vascular access), (2) renal arteries (hypertension and volume overload), (3) subclavian arteries (coronary steal with a left internal mammary artery [LIMA] graft), and (4) carotid arteries (stroke). Technical skills necessary to perform coronary angioplasty are transferable to the peripheral vasculature. However, an understanding of the natural history of peripheral disease, patient and lesion selection criteria, and knowledge of other treatment alternatives are essential to performing these procedures safely and effectively. Appropriate preparation and training, and a team approach, including an experienced vascular surgeon, are both desirable and necessary before interventional cardiologists who are inexperienced in the treatment of peripheral vascular disease attempt percutaneous peripheral angioplasty. There are inherent advantages for patients when the cardiologist performing the procedure is also a clinician. Judgments regarding the indications, timing, and risk/benefit ratio of procedures are enhanced by a long-term relationship between physician and patient. Finally, in view of the increased incidence of coronary artery disease in patients with atherosclerotic peripheral vascular disease, the participation of a cardiologist in their care seems appropriate.     

X线片和多层螺旋CT诊断及鉴别周围型肺癌的对比研究

目的:对比X线平片和多层螺旋CT诊断及鉴别周围型肺癌的效果。方法:选取了100例周围型肺癌患者,所有患者入院后先行X线片检查,后进行多层螺旋CT检查。通过观察并记录X线片与多层螺旋CT对周围型肺癌的影像学特征、临床TNM分期的诊断效果,评价X线平片和多层螺旋CT对周围型肺癌的诊断效果。结果:多层螺旋CT对周围型肺癌的肿块、分叶征、支气管气象征、空洞、胸膜凹陷、血管集束征,胸腔积液的检出率均高于X线片(P0.05)。根据外科病理TNM分期结果,多层螺旋CT对周围型肺癌的临床TNM分期诊断符合率为92.0%,X线对周围型肺癌的临床TNM分期诊断符合率为61.0%,多层螺旋CT对周围型肺癌的临床TNM分期诊断符合率明显高于X线(P0.05)。结论:多层螺旋CT对于周围型肺癌各类型影像学征象具有较好的检出率,对周围型肺癌临床TNM分期诊断准确性接近病理诊断结果。     

Endogenous chicken nerve growth factor from sheath cells is transported in regenerating nerve

We report the presence of endogenous nerve growth factor (NGF) in chicken peripheral nerve. The molecule has been detected with antibodies to mouse salivary gland NGF, using immunohistochemical and immunoelectrophoretic techniques. Previous studies have shown that these antibodies inhibit the survival activity of extracts of chicken peripheral nerve. The NGF accumulated distal, but not proximal, to a ligature placed on a peripheral sympathetic nerve demonstrating that it was retrogradely transported. This transport was detected in intact nerve fibers as well as in nerves from which the peripheral target had been ablated 6 hr or 7 days previously. The results indicate that avian NGF is present in adult chicken peripheral nerves and that this molecule shares antigenic determinants with the mouse molecule. The results further demonstrate that regenerating neurons retrogradely transport NGF supplied by cells within the peripheral nerve (presumably Schwann). The possibility that these cells also provide NGF to intact neurons is discussed.     

Identity, origin, and migration of peripheral glial cells in the Drosophila embryo

Glial cells are crucial for the proper development and function of the nervous system. In the Drosophila embryo, the glial cells of the peripheral nervous system are generated both by central neuroblasts and sensory organ precursors. Most peripheral glial cells need to migrate along axonal projections of motor and sensory neurons to reach their final positions in the periphery. Here we studied the spatial and temporal pattern, the identity, the migration, and the origin of all peripheral glial cells in the truncal segments of wildtype embryos. The establishment of individual identities among these cells is reflected by the expression of a combinatorial code of molecular markers. This allows the identification of individual cells in various genetic backgrounds. Furthermore, mutant analysis of two of these marker genes, spalt major and castor, reveal their implication in peripheral glial development. Using confocal 4D microscopy to monitor and follow peripheral glia migration in living embryos, we show that the positioning of most of these cells is predetermined with minor variations, and that the order in which cells migrate into the periphery is almost fixed. By studying their lineages, we uncovered the origin of each of the peripheral glial cells and linked them to identified central and peripheral neural stem cells.     

Entrainment of peripheral clock genes by cortisol

Circadian rhythmicity in mammals is primarily driven by the suprachiasmatic nucleus (SCN), often called the central pacemaker, which converts the photic information of light and dark cycles into neuronal and hormonal signals in the periphery of the body. Cells of peripheral tissues respond to these centrally mediated cues by adjusting their molecular function to optimize organism performance. Numerous systemic cues orchestrate peripheral rhythmicity, such as feeding, body temperature, the autonomic nervous system, and hormones. We propose a semimechanistic model for the entrainment of peripheral clock genes by cortisol as a representative entrainer of peripheral cells. This model demonstrates the importance of entrainer's characteristics in terms of the synchronization and entrainment of peripheral clock genes, and predicts the loss of intercellular synchrony when cortisol moves out of its homeostatic amplitude and frequency range, as has been observed clinically in chronic stress and cancer. The model also predicts a dynamic regime of entrainment, when cortisol has a slightly decreased amplitude rhythm, where individual clock genes remain relatively synchronized among themselves but are phase shifted in relation to the entrainer. The model illustrates how the loss of communication between the SCN and peripheral tissues could result in desynchronization of peripheral clocks.     

慢性阻塞性肺疾病患者外周血CD4~＋CD25~＋CD127~（（Low/-））调节性T细胞的检测及临床意义

目的：研究CD4＋CD25＋CD127（Low/-）调节性T细胞在慢性阻塞性肺疾病（COPD）急性发作期外周血中的比例改变及其临床意义。方法：以25例COPD急性发作期患者外周血为研究组,20名正常人外周血作为对照组,采用三色直接荧光素标记法和多参数流式细胞仪检测外周血CD4＋CD25＋CD127（Low/-）调节性T细胞的比例,同时检测外周血C-反应蛋白（CRP）、血沉（ESR）、免疫球蛋白（Ig）等水平。结果：COPD急性发作期患者外周血CD4＋CD25＋CD127（Low/-）调节性T细胞占外周血CD4＋T淋巴细胞的比例明显低于健康对照组（P〈0.01）。而COPD急性发作期患者外周血CRP、ESR、Ig等水平明显高于健康对照组（P〈0.05）。COPD患者外周血调节T细胞下降与CRP和IgG升高成负相关。结论：COPD患者外周血CD4＋CD25＋CD127（Low/-）调节性T细胞在CD4＋T淋巴细胞的比例明显减少,调节性T细胞等免疫调节因素可能在COPD的发病机制发挥重要作用。     

Effects of oral, intraperitoneal and intrajugular rehydrations on water retention, rumen volume, kidney function and thirst satiation in goats.

1. In order to test the hypothesis that peripheral receptors are involved in the control of fluid re-distribution following acute dehydration and rapid rehydration, peripheral rehydrations (oral or intraperitoneal) were compared with central (intrajugular) rehydration. 2. The experiments were carried out with four goats dehydrated to about 20% of their initial mass. 3. Following peripheral rehydration, a higher proportion of water was retained in comparison with central rehydration, and this was related to a more effective kidney retention mechanism, i.e. lower GFR and higher tubular reabsorption. 4. Higher proportions of water were retained in the rumen in the peripheral rehydrations in comparison with the central one apparently due to increased saliva secretion. 5. Thirst saturation was more effective with the peripheral rehydration in comparison with the central one and was related to the amount retained in the rumen and to peripheral blood expansion (or dilution).     

Influence of achene heteromorphism on life-cycle traits in the annual weed gallant soldier (Galinsoga parviflora Cav.)

Galinsoga parviflora (gallant soldier), Asteraceae, produces two morphologically distinct achenes in a single capitulum: peripheral and central. The morphological, phenological and generative reproduction traits of the progeny derived from peripheral and central achenes that were cultivated in greenhouse conditions were analyzed. Differences between the progeny of various morph types were manifested at different stages of life. The plants of both morph types developed at a similar rate and they entered key phenological phases at the same time except for the flowering stage. The average height of the studied plants was similar on the same days of the experiment. The study showed that plants from peripheral achenes realize the generative reproduction in other pattern than plants from central achenes. The plants from central achenes produce more capitula per plant at the beginning of the fruiting stage, whereas plants from peripheral seeds achieve the highest number of capitula per plant at later stages. Finally, on day 130 of the experiment, the number of capitula per plant of both morphs equalized. At the early fruiting stage, the number of achenes per capitulum of plants from the two morphs did not differ significantly. The number of achenes within one capitulum decreases with plant age in both populations, but the rate of that decline is greater in the progeny of peripheral seeds. The number of peripheral achenes per capitulum in plants from both achene types decreases at a comparable rate. In contrast, the number of central achenes is reduced at a faster rate in plants germinated from peripheral achenes. After day 83, the individuals from peripheral diaspores intensified their reproductive effort; they produced more capitula but with fewer number of achenes than in individuals from central diaspores. On day 130, the number of dispores per plant of the two morphs equalized. The changes of fecundity of peripheral and central progeny with the age of the plant (at different stages of the life cycle of a single plant) contribute to an intensive seed rain throughout the fruiting period. By producing a large number of less fertile capitula with a stable number of peripheral achenes, plants derived from peripheral achenes are able to supply a higher share of peripheral achenes than if they would produce fewer but more fertile capitula. This strategy increases the pool of peripheral achenes.