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Comparative Anatomy, Physiology, and Biochemistry of Mammalian Skin
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
One of the best methods available for distinguishing Langerhans’ cells from other epidermal cells is TEM. These cells have been classified as nonkeratinocytes because they lack the characteristic features, namely tonofilaments and desmosomes. They possess slender processes which penetrate the intercellular spaces among the prickle cells. These processes contain all the organelles which are normally found in the perikaryon.149 Their nucleus (Figure 9) is indented and the cytoplasm contains Golgi complexes, smooth and rough endoplasmic reticulum, and lysosomes. The characteristic feature which distinguishes Langerhans’ cells from other cells is the presence of a rod- or racket-shaped structure in the cytoplasm (Figures 10 and 11)38,89,142,143,150,151 his structure, first described by Birbeck, is commonly known as the Birbeck or Langerhans’ cell granule.152 This specific granule (Figure 11) is shaped like a racket, having a “handle” portion and an expanded end. The “handle” consists of an outer limiting membrane with a central lamella which appears as a row of particles exhibiting a 50 to 70 Å periodicity. The expanded end of the limiting membrane is usually clear, and on occasion may have a cross-striated pattern within.38,89,142,152
Vagal Receptor Transport
Published in Sue Ritter, Robert C. Ritter, Charles D. Barnes, Neuroanatomy and Physiology of Abdominal Vagal Afferents, 2020
The movement of materials involved in synaptic transmission from the perikaryon to the nerve terminal occurs by fast axonal transport. While the mechanisms underlying this transport are not completely understood, it has been demonstrated that microtubules play an essential role. Antimitotic alkyloids, or colchicine which are known to disrupt microtubules, interfere with fast transport. In contrast, the mechanism for slow axonal transport differs. It is unidirectional, dependent upon the cell body and appears to occur by bulk flow.
Radiation Damage of the Nervous System
Published in Kedar N. Prasad, Handbook of RADIOBIOLOGY, 2020
The neuron is subdivided according to anatomical and functional criteria. The perikaryon includes and surrounds the nucleus, and contains most of the cytoplasmic organelles. The dendrites and axons arise from the perikaryon. At its end, the axon splits into branches, each forming a presynaptic terminal. The various parts of a neuron show differential radiation response.
Possible anti-inflammatory, antioxidant, and neuroprotective effects of apigenin in the setting of mild traumatic brain injury: an investigation*
Published in Immunopharmacology and Immunotoxicology, 2023
Pınar Kuru Bektaşoğlu, Dilan Demir, Türkan Koyuncuoğlu, Meral Yüksel, İrem Peker Eyüboğlu, Ayça Karagöz Köroğlu, Dilek Akakın, Alper Yıldırım, Erhan Çelikoğlu, Bora Gürer
The brain samples were fixed in the 4% paraformaldehyde in phosphate buffer (pH 7.4) for 24 h at 4 °C. Tissues were then embedded in paraffin and 5-μm-thick coronal sections were created using a rotary microtome. The sections were stained with hematoxylin and eosin stains. Finally, sections were examined under a photomicroscope (Olympus BX51, Japan). The severity of neuronal damage in the cortex was scored semiquantitatively as follows: 0 = no damage, 1 = mild damage, 2 = moderate damage, and 3 = severe damage [5,30,31]. Pyknotic nuclei and intense staining of the shrunken neuronal perikarya were considered in scoring the degree of neuronal degeneration. The histopathological scorings were performed by investigators blinded to treatment groups to reduce the potential for bias.
Distribution of Aquaporin-4 channels in hippocampus and prefrontal cortex in mk-801-treated balb/c mice
Published in Ultrastructural Pathology, 2022
Omer Burak Ericek, Kübra Akillioglu, Dilek Saker, Ibrahim Cevik, Meltem Donmez Kutlu, Samet Kara, Dervis Mansuri Yilmaz
The electron microscopic examination of the tissue samples of the hippocampus control group revealed that the neuron perikaryon had a spherical and centrally located vesicular nucleus and a nucleus in the middle of this nucleus. The cytoplasm around the nucleus contained mitochondria with well-developed granular endoplasmic reticulum (GER), transverse and longitudinal type cristae. In addition, the cytoplasm had also widespread neurotubules, and neurofilaments. Neuroglial cells also had an ovoid or spherical nucleus and a thin cytoplasm around the nucleus. Mitochondria, GER, and microtubules were detected in the cytoplasm. The myelinated axon cytoplasm and myelin sheath, lamellar structure, and concentric arrangement seemed normal (Figure 9(a-c)).
A primary cilium in oligodendrocytes: a fine structure signal of repairs in thalamic Osmotic Demyelination Syndrome (ODS)
Published in Ultrastructural Pathology, 2021
Jacques Gilloteaux, Joanna Bouchat, Valery Bielarz, Jean-Pierre Brion, Charles Nicaise
The oligodendrocyte cells typically revealed a pear- to round-shaped and revealed a more electron dense contrasted cytoplasm than any other cell seen with ultrastructure in the CNS (Fig 5A-C). The euchromatic, spherical nucleus is often seen in an eccentric position in a pear-shaped perikaryon where innumerable free or attached polyribosomes to short cisterns of endoplasm are speckled among other organelles such as short, ellipsoid mitochondria, a Golgi apparatus and its processing saccules distributed around the nucleus envelope in the remaining narrow perikaryon with sections of microtubules. Moreover, according to some lucky section views, either an entire centrosome, or one of both centrioles, involved in the transfer of outward products by microtubules, dispatched for the maintenance of the many myelin sheaths wrapping the axonal extensions in the adjacent neuropil Fig 5(A-C). An example of oligodendrocyte satellite showed with typical formed junctions with astrocytes and neuron cell bodies as in Figure 5A-B while interfibrillar oligodendrocyte associated with its adjacent maintained axons and can form junctional complexes with adjacent astrocyte (Fig 5C).