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Pathophysiology
Published in Ibrahim Natalwala, Ammar Natalwala, E Glucksman, MCQs in Neurology and Neurosurgery for Medical Students, 2022
Ibrahim Natalwala, Ammar Natalwala, E Glucksman
Poliovirus, which is transmitted by the faecal-oral route, causes poliomyelitis. It is most often seen in developing countries in young unimmunised children. The virus replicates in the oropharynx and small intestine before spreading through the bloodstream to the CNS. Once in the CNS, it destroys ventral horn neurones in the spinal cord, resulting in lower motor neurone signs. A prodromal syndrome of malaise, headache, fever and abdominal pain is commonly seen. Lumbar puncture results would reveal a viral cause with no change in CSF glucose. Poliomyelitis is usually diagnosed by recovery of the virus from a stool culture.8
Myofascial Trigger Points, Sensitization, and Chronic Musculoskeletal Pain
Published in Sahar Swidan, Matthew Bennett, Advanced Therapeutics in Pain Medicine, 2020
Vy Phan, Jay P. Shah, Pamela Stratton
The ensuing spinal facilitation is characterized by: Increased ventral horn outflow that stimulates anterior motor horn cells, resulting in increased muscle tone in the myotome corresponding to its segmental level of afferent barrage.Increased lateral horn outflow which results in autonomic reflexes that enhance nociceptive activity.Increased dorsal horn outflow that causes antidromic (retrograde) electrical activity along a sensory nerve.
Spinal Cord and Reflexes
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
Monoamines exercise their effects through G protein second-messenger systems (Section 6.3). Generally speaking, these effects vary progressively from predominantly excitatory in the ventral horn to predominantly inhibitory in the dorsal horn, depending on the receptors involved. The excitatory effects involve Gαq protein subunits and 5-HT2 and NEα1 receptors, whereas the inhibitory effects involve Gi/o protein and 5-HT1 and NEa2 receptors and is mostly extrasynaptic (Section 6.2.3), affecting both interneurons and astrocytes. On the sensory side, the inhibition in the dorsal horn is mostly presynaptic inhibition of high-threshold afferents and is linked to the suppression of pain pathways, as may be required during exposure to a high-stress environment or stimulus. On the motor side, the monoamines strongly suppress the flexion reflex (Section 11.3.2). In the intermediate regions of the spinal cord, there is moderate facilitation of interneurons receiving inputs from Ia, II, and Ib afferents.
PU.1 interaction with p50 promotes microglial-mediated inflammation in secondary spinal cord injury in SCI rats
Published in International Journal of Neuroscience, 2023
Mingchen Yu, Yiqing Ou, Hongmei Wang, Weidong Gu
The number of PU.1-positive cells on the spinal cord sections taken at 2 mm from the injury epicenter was counted in 500 × 500 μm frames. For each animal, the transverse sections of the dorsal horn, lateral funiculus, and ventral horn were selected. The cell counts were then used to determine the total number of PU.1-positive cells per square millimeter. The percentage of cells that stained positive for PU.1 or p-p50 was also quantified. The cells double stained with PU.1 and NeuN, GFAP, or Iba-1, as well as cells double stained with PU.1 and OX42 or p-p50, were also quantified. To identify the proportion of PU.1-expressing cells with positive expression of specific phenotypic markers, a minimum of 200 cells positive for the specific phenotypic markers in the white and gray matter of the sections were included. We then recorded the number of cells double-labeled with PU.1 and cell-specific markers. Two or three adjacent sections taken at 2 mm from the injury epicenter were used for quantitative analysis.
Craniorachischisis with Exencephaly
Published in Fetal and Pediatric Pathology, 2021
Jessenia Guerrero, Debra S. Heller, Ada Baisre de Leon
We received a female fetus weighing 53 g, measuring 10 cm from crown to heel and a foot length of 17 mm. The face was elongated, the neck was short, the chin was directly connected to the upper chest, the eyes were protruding, and the ears were poorly formed. The single-lobed brain was entirely exposed, as the dura mater, calvarial bones and scalp were absent. The brainstem and cerebellum were not clearly identified, and in their place, a pale and rudimentary hindbrain was noted, which merged with the abnormal spinal cord (Figures 1a–d). Posteriorly, the vertebral column was open along its entire length with absence of spinous processes (Figure 1d). The spinal canal, as well as the exposed spinal cord, were flattened. Both halves of the spinal cord were placed laterally as if it had been sectioned at the posterior median sulcus and flattened in an “open book” fashion (Figure 2). The surface of the exposed spinal cord was covered by ependymal linning, without significant reaction or inflammation. Neurons of the ventral horn were evident, as were the ventral and dorsal nerve roots (Figure 2 Insert). Sections through the anterior portion of the single-lobed brain showed immature neural elements with several true/ependymoblastomatous rosettes (Figure 3).
Multiple retrograde tracing methods compatible with 3DISCO clearing
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Shuai Han, Dongdong Li, Yuhui Kou, Zhongguo Fu, Xiaofeng Yin
The distribution of motor neurons in the spinal cord has significantly described through the previous works [1–5]. Together, they have established that motor neurons in the ventral horn of the spinal cord are arranged into longitudinal columns. Recently, retrograde tracers, such as the horseradish peroxidase-family, the fluorescent inorganic compounds, and cholera toxin subunit B (CTb) family, have been instrumental in delineating the connectivity between the specific skeletal muscle and the innervating motor neuron pools in various mammalian species [6–23]. These studies further characterized the organization of motor neuron columns throughout the spinal cord. However, the single-labelling tracing was employed in all these studies, which could only delineate one single motor neuron pool in one specimen at the same time. Labelled neurons could only be observed via sectioning, which always caused transformation and information missing due to the mechanical cutting or section holding. Exploring the three-dimension (3D) spatial relationship of different neuron pools in one intact specimen was difficult to achieve limited by temporal techniques of neuroanatomy tracing.