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Orderly Arrangement (orderly + arrangement)
Selected AbstractsEmbryonic inner ear cells use migratory mechanisms to establish cell patterns in vitroJOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2006Lynne M. Bianchi Abstract The hair cells of the sensory epithelium in the inner ear are among the most precisely organized cells in vertebrates. The mechanisms that lead to this orderly arrangement are only beginning to be understood. It has been suggested that hair cells use migratory mechanisms to help achieve their final position in the organ of Corti. The small size and complex organization of the intact inner ear have made it difficult to monitor changes in hair cell location over time in vivo. In the present study, an established in vitro assay of dissociated, embryonic inner ear cells was used to monitor how hair cells reorganize over time. The hair cell specific marker myosin-VI demonstrated that hair cell precursors from both cochlear and vestibular regions reorganized into specific patterns between 3,24 hr in vitro. In contrast to the unlabeled cells, the myosin-VI-positive cells extended processes while establishing the hair cell patterning within an aggregate. These studies support the hypothesis that hair cell precursors actively migrate to help achieve final patterning within the inner ear sensory epithelium. © 2005 Wiley-Liss, Inc. [source] Diagnostic clues and more from photographsNEUROPATHOLOGY, Issue 1 2007Asao Hirano During over 50 years of the first author's career in neuropathology at Montefiore Medical Center in New York, we have come across certain interesting neuropathological findings. In this communication, some photographs showing macroscopic, microscopic and electron microscopic significant findings are selected to illustrate usefulness not only for the diagnosis but also for understanding of the nervous system. The six topics presented in this paper are: (i) unattached presynaptic terminals in cerebellar neuroblastoma; (ii) neurofibrillary tangle formation in the nucleus basalis of Meynert ipsilateral to a massive cerebral infarct; (iii) orderly arrangement of tumor cells in leptomeningeal carcinomatosis; (iv) interface between craniopharyngioma and brain tissue; (v) neurofibrillary tangles and Lewy bodies in a single neuron; and (vi) Cu/Zn superoxide dismutase positive Lewy body-like hyaline inclusions in anterior horn cells in familial motor neuron diseases. Analyses of these findings are presented for an educational purpose. [source] An evidence-based approach to human dermatomesCLINICAL ANATOMY, Issue 5 2008M.W.L. Lee Abstract The dermatome is a fundamental concept in human anatomy and of major importance in clinical practice. There are significant variations in current dermatome maps in standard anatomy texts. The aim of this study was to undertake a systematic literature review of the available evidence for the distribution of human dermatomes. Particular emphasis was placed on the technique of ascertainment, the location and extent of each dermatome, the number of subjects studied, and methodologic limitations. Our findings demonstrate that current dermatome maps are inaccurate and based on flawed studies. After selecting the best available evidence, a novel evidence-based dermatome map was constructed. This represents the most consistent tactile dermatomal areas for each spinal dorsal nerve root found in most individuals. In addition to highlighting the orderly arrangement, areas of consistency and clinical usefulness of dermatomes, their overlap and variability deserve greater emphasis. This review demonstrates the validity of an evidence-based approach to an anatomical concept. Clin. Anat. 21:363,373, 2008. © 2008 Wiley-Liss, Inc. [source] JET-SUSPENDED, CALCITE-BALLASTED CYANOBACTERIAL WATERWARTS IN A DESERT SPRING1JOURNAL OF PHYCOLOGY, Issue 3 2002Ferran Garcia-Pichel We describe a population of colonial cyanobacteria (waterwarts) that develops as the dominant primary producer in a bottom-fed, O2 -poor, warm spring in the Cuatro Ciénegas karstic region of the Mexican Chihuahuan Desert. The centimeter-sized waterwarts were suspended within a central, conically shaped, 6-m deep well by upwelling waters. Waterwarts were built by an Aphanothece -like unicellular cyanobacterium and supported a community of epiphytic filamentous cyanobacteria and diatoms but were free of heterotrophic bacteria inside. Sequence analysis of 16S rRNA genes revealed that this cyanobacterium is only distantly related to several strains of other unicellular cyanobacteria (Merismopedia, Cyanothece, Microcystis). Waterwarts contained orderly arrangements of mineral crystallites, made up of microcrystalline low-magnesium calcite with high levels of strontium and sulfur. Waterwarts were 95.9% (v/v) glycan, 2.8% cells, and 1.3% mineral grains and had a buoyant density of 1.034 kg·L,1. An analysis of the hydrological properties of the spring well and the waterwarts demonstrated that both large colony size and the presence of controlled amounts of mineral ballast are required to prevent the population from being washed out of the well. The unique hydrological characteristics of the spring have likely selected for both traits. The mechanisms by which controlled nucleation of extracellular calcite is achieved remain to be explored. [source] | ||||||||||