Muscle and Nerve Histology
Maher Kurdi in Neuromuscular Pathology Made Easy, 2021
This chapter discusses the basic principles of muscle histology, which will help in understanding the pathogenetic mechanism of most neuromuscular diseases. While cells in other multicellular organisms have limited functional abilities, the muscle cells and their intracellular components in human subjects are specialized in physiological contraction, relaxation and locomotion. The sarcoplasm contains multiple organelles including mitochondria, sarcoplasmic reticulum, Golgi apparatus, microtubules, glycogens, ribosomes, lipid droplets, and myofibrils. Mitochondria are double-membrane structures located in the sarcoplasm adjacent to the I-band. Axons arise from the cell body at axon hillocks where the thin dendritic process extends. Each axon is surrounded by a plasma membrane called axolemma and contains nuclei and axoplasm; the latter has no ribosomes or rough endoplasmic reticulum. Schwann cells are nucleated spindle cells that envelope axons and serve as electrical conductors. The contain Golgi apparatus, few mitochondria, and scattered inclusions called Reich granules.
Cathepsin E
Martin Fusek, Václav Větvička in Aspartic Proteinases, 2019
Cathepsin E is produced by superficial epithelial cells, whereas pepsinogen and progastricsin are produced by glandular epithelial cells. In addition, human and rat gastric cells and rat neutrophils gave a strong labeling for cathepsin E in the cistemae of the rough endoplasmic reticulum (ER) and the perinuclear envelope as well as labeling in the cytosol. Procathepsin E has unique structural characteristics compared to other aspartic proteinases. By electron immunochemistry, cathepsin E was localized to endosomal vesicles and ER of both intestinal and tonsillar M cells. The immunological protection or mucosal protection of the gut was also hypothesized as a physiologic function of cathepsin E. The gene of human cathepsin E was shown to contain nine exons with boundary regions which are very conserved in the family of aspartic proteinases. Cathepsin E is one of the least characterized human aspartic proteinases.
Familial Inherited TSH Deficiency
Geraldo Medeiros-Neto in Inherited Disorders of the Thyroid System, 2019
Thyrotropin is a member of a family of pituitary and placental heterodimeric glycoproteins containing a common alpha and unique beta subunit. The genes encoding the common α and Thyroid-stimulating hormone (TSH)-ß subunits are present as single copies and in humans are located on chromosomes 6 and 1, respectively. The human TSH-ß subunit gene consists of a 5’ untranslated exon and two coding exons. The three exons are separated by two introns of 3.9 and 0.41 kilobase pairs, respectively. The human TSH-ß subunit gene differs from that of rat and mouse TSH-ß in several respects. Thyrotropin-releasing hormone is the major positive regulator of TSH-ß subunit gene expression and acts through a guanyl nucleotide binding protein to activate phospholipase C. A model of TSH biosynthesis was proposed by F. E. Wondisford et al. The thyrotrophs secrete intact TSH and excess free α subunits. Thus, excess α subunits are present in the rough endoplasmic reticulum (RER).
Systematic alteration of apoptosis: a review with ultrastructural observations on leukemia cells in vivo
Published in Ultrastructural Pathology, 2018
Yong-Xin Ru, Shi-Xuan Zhao, Shu-Xu Dong, Hao-yue Liang, Ying Wang
The ultrastructural characteristics of apoptosis have been described microscopically for four decades. Alterations of nuclei, apoptotic bodies, cytoplasm, and some organelles have been illustrated and investigated during apoptosis. The successive changes of cellular components corresponding with differentiation of apoptotic cells are illustrated in the present review, based on ultrastructural observation of leukemia cells of patients in our routine clinic work by transmission electron microscopy. Most electron micrographs demonstrated that membranous components of nuclear envelop, rough endoplasmic reticulum and Golgi apparatus, and mitochondria were degenerated step by step during apoptosis. The successive images suggested that the endoplasmic reticulum and Golgi apparatus were transferred to cell surface from cytoplasm and participated in formation of apoptotic bodies in apoptosis, although relevant clinical data and more experimental evidence were needed for restraining of leukemia cases from diagnostic work randomly in recent decades.
Effect of Cadmium on Cellular Ultrastructure in Mouse Ovary
Published in Ultrastructural Pathology, 2015
Ying Wang, Xuejuan Wang, Yanwu Wang, Rong Fan, Chao Qiu, Shan Zhong, Lei Wei, Daji Luo
This study aimed at analyzing the cytotoxicity and pathological effects of cadmium on the ovary. Our studies revealed that cadmium was deposited in the mouse ovary after 8 d cadmium injection in vivo. Also, the increase in the rate of body weight was slowed, while the gonadosomatic index was reduced in the CdCl2 group, compared with the control group. Meanwhile, cadmium affected the maturation of follicles, the degradation of corpus luteum, the arrangement of follicles and corpus luteum, and increased the number of atresia follicles. Besides, under the electron microscope, chromatin margination, karopyknosis, swelling of mature cisternae of Golgi apparatus, mitochondrial cristae disappearance, and swelling of the rough endoplasmic reticulum can be observed in the CdCl2 group mice. Collectively, our findings elucidated the morphological mechanism that the exposure of cadmium changed the ultrastructure of cells in ovary tissues.
Morphologic Characteristics of Blastic Plasmacytoid Dendritic Cell Neoplasm: A Case Report
Published in Ultrastructural Pathology, 2014
Yongxin Ru, Peihong Zhang, Shuxu Dong, Huijun Wang, Shixuan Zhao, Yingchang Mi, Brian Eyden
Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare aggressive lymphoma derived from plasmacytoid dendritic cells or precursor dendritic cells. Despite some 240 reported cases, its morphology and especially ultrastructure has not been satisfactorily studied. A case is reported of a 13 year old boy, who, despite chemotherapy, died within a 12-month period. The electron microscopy findings – microvillous processes, nuclei with slight irregularities, a moderate amount of heterochromatin, and rough endoplasmic reticulum in the form of long, narrow profiles, often in parallel arrangements – taken together, serve to distinguish BPDCN from other neoplastic cells, such as monocytes, plasma cells and the cells of chronic lymphocyte leukemia.
Related Knowledge Centers
- Polyribosomes
- Ribosomes
- Rna
- Smooth Endoplasmic Reticulum
- Red Blood Cell
- Endoplasmic Reticulum
- Er