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It states that the cerebral cortex develops during embryogenesis as an array of interacting cortical columns, or 'radial units', each of which originates from a transient stem cell layer called the ventricular zone, which contains neural stem cells known as radial glial cells.
The ventricular and subventricular zones exist inferior to the intermediate zone and communicate with other zones through cell signalling. These zones additionally create neurons destined to migrate to other areas in the cortex. [1] [6] The marginal zone, along with the cortical zone, make up the 6 layers that form the cortex. This zone is the ...
The marginal zone is the region at the interface between the non-lymphoid red pulp and the lymphoid white-pulp of the spleen. (Some sources consider it to be the part of red pulp which borders on the white pulp, while other sources consider it to be neither red pulp nor white pulp.) A marginal zone also exists in lymph nodes. [1] [2]
In 1891 Santiago Ramón y Cajal described slender horizontal bipolar cells he had found in an histological preparation of the developing marginal zone of lagomorphs. [28] These cells were then considered by Gustaf Retzius as homologous to the ones he had found in the marginal zone of human fetuses around mid-gestation in 1893 and 1894. He ...
In humans the splenic marginal zone B cells have evidence of somatic hypermutation in their immunoglobulin genes, indicating that they have been generated through a germinal centre reaction to become memory cells. While naive MZ B cells produce low-affinity IgM antibodies, memory MZ B cells express high-affinity Ig molecules.
Conditions at the centre of the range differ from those at the periphery, therefore adapted alleles at the centre may not benefit marginal populations experiencing different conditions. [11] The asymmetrical gene flow hypothesis posits that there is more gene flow from central to peripheral populations. Empirical data supporting this theory is ...
The null hypothesis of marginal homogeneity states that the two marginal probabilities for each outcome are the same, i.e. p a + p b = p a + p c and p c + p d = p b + p d. Thus the null and alternative hypotheses are [1]: =:
Extranodal marginal zone lymphomas (EMZLs) are a form of MZL [9] in which malignant marginal zone B-cells initially infiltrate MALT tissues of the stomach (50-70% of all EMZL) or, less frequently, the esophagus, small intestine, large intestine, rectum, conjunctiva of the eye, nasal passages, pharynx, lung bronchi, vulva, vagina, skin, breast, thymus gland, meninges (i.e. membranes) that ...