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Degenerative Diseases of the Nervous System
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
James A. Mastrianni, Elizabeth A. Harris
Additional pathologic findings may include the following: Lewy body–related neurites: found by means of ubiquitin staining in the hippocampus (CA2–3 region), amygdala, nucleus basalis of Meynert, dorsal vagal nucleus, and other brainstem nuclei. They are a neurofilament abnormality in which the proteins are present as a diffuse aggregate that does not contain crystallin.Plaques (all morphologic types). Senile neuritic plaques, often in similar numbers to those found in AD, and Aβ deposition are common.Neocortical NFTs are few or absent.Regional neuronal loss occurs, particularly in brainstem (substantia nigra and locus ceruleus) and nucleus basalis of Meynert.Microvacuolation (spongiform change) and synapse loss.Neurochemical abnormalities and neurotransmitter deficits.
Comparative Anatomy and Physiology of the Mammalian Eye
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
The lens proteins are divided into water-soluble and insoluble.168 Immunologically, these proteins are organ, but not species specific.70,169 The water soluble proteins are mostly crystallins (α, β, and γ) and comprise 85% of the lens protein in young animals, decreasing with age (Table 8).70,168 The γ crystallin constitutes 1.5% of the lens proteins in the adult, but can constitute as much as 60% in weanling animals.168 In addition in the avian species, there is an additional crystallin, δ.168 The precise role of the crystallins is not known, but they are likely to be a major contributor to the cytoarchitecture. The insoluble proteins are associated with the membranes of the lens fibers, are found primarily in the nucleus, and increase with age and in a cataractous lens.
The Molecular Genetics OF DNA Methylation in Colorectal Cancer
Published in Leonard H. Augenlicht, Cell and Molecular Biology of Colon Cancer, 2019
For all the tumors studied, benign and malignant, substantial hypomethylation of several of the genes was seen. These genes fell into three categories. Six were usually hypomethylated to a significant degree (γ-crystallin, growth hormone, β-chorionic gonadotropin, γ-globin, c-Ha-ras, and c-myc); four were occasionally hypomethylated to a lesser degree (insulin, proopiomelanocortin, γ-chorionic gonadotropin, and platelet-derived growth factor); and in two no change was seen (α-fetoprotein and parathyroid hormone). Of the first class, γ-crystallin was the most extensively hypomethylated of all the genes we examined. This gene is normally expressed and undermethylated only in the embryonic lens, and the degree of hypomethylation we have observed is even greater than that seen in normal developing lens tissue.28
Crocin as a vision supplement
Published in Clinical and Experimental Optometry, 2023
Mojtaba Heydari, Mousa zare, Mohammad Reza Badie, Ronald Ross Watson, Mohammad Reza Talebnejad, Mehrdad Afarid
Cataract is the leading cause of blindness worldwide.47 Surgical management is the only current option for the treatment of cataracts. In this respect, medical treatments have been investigated for the prevention and treatment of cataracts.48 Bahmani et al.49 evaluated the preventive effect of intraperitoneal crocin on the α-crystallin glycation-induced cataract in an animal model. α-crystallin is a protein that helps to maintain the transparency of the eye lens. The compromised function of α-crystallin by glycation can result in cataract formation in ageing and diabetes. Cross-linking of crystalline lens proteins is known as causative factor for cataract formation. Increased hydrophobicity and decreased solubility of these proteins is another factor associated with lens opacity and cataract. Bahmani et al.49 observed that crocin inhibited advanced glycation end product, protein cross-linking, and hydrophobicity in the experimental model of streptozotocin-induced diabetes.
A Review of Lens Biomechanical Contributions to Presbyopia
Published in Current Eye Research, 2023
The outstanding clarity of a healthy ocular lens arises both from crystallin protein concentration and crystallin protein organization within the fiber cells and aggregate lens tissue. Alpha, beta, and gamma crystallin proteins are three of the most common lens crystallin proteins and can be found in the eyes of all vertebrate species. These species are non-homogenously distributed throughout the lens and each have additional subfractions. The alpha and beta crystallins mostly consist of oligomers while the gamma proteins are mostly monomeric. Many species have additional crystallin proteins that serve unique needs in vision or have additional biological function in the lens.20,97,103,108 Specific crystallin proteins are concentrated in different areas of the lens and significant change to protein expression can be measured between the nuclear and cortical fiber cells when sampling along the radial axis of a lens. Crystallin proteins in the lens are known to break down and can form truncation products after exposure to thermal stress or as a function of age. Additionally, some proteins are only found in cortical fiber cells, suggesting that these proteins may completely degrade with age.33
Endoplasmic reticulum stress as an underlying factor in leading causes of blindness and potential therapeutic effects of 4-phenylbutyric acid: from bench to bedside
Published in Expert Review of Ophthalmology, 2022
Sahar Askari, Fatemeh Azizi, Pegah Javadpour, Nasser Karimi, Rasoul Ghasemi
Crystallin is one of the lens’ structural proteins fundamental for lens transparency. Its mutations lead to structural and functional changes in the lens structure and the development of cataracts. In one in vitro investigation, 4-PBA with chaperoning properties reduced apoptosis, possibly by reversing the defective phenotype of the protein [120]. In addition, 4-PBA is able to keep HLECs from morphological changes by suppressing ER stress and regulating EMT after cataract surgery [30]. Another study that administered 4-PBA orally to galactose-fed rats (as a model of diabetic cataract) demonstrated that treatment with 4-PBA suppressed LECs death by decreasing ER stress markers, which partially delayed cataract formation [128]. In another study, it was established that 4-PBA is able to improve cataracts in diabetic rats. In details, by 4-PBA treatment, alteration of protein profile in the lenses of diabetic model rats was retarded as most of the control rat eyes. In line with these clinical findings, examination of lens histopathology also confirmed the potential utility of 4-PBA in diabetic animals cataract [129].