Topic Review
Cataracts
A cataract is an ophthalmic disorder characterized by the opacification of the lens and occurs commonly in older people. Age-related cataract is a significant cause of blindness affecting the quality of life worldwide. An imbalance between oxidative stress and antioxidant potential of ocular tissue is considered responsible for structural modifications of crystallins, the protein constituents of the lens, which eventually leads to cataracts. Lutein and zeaxanthin are two major carotenoids which are concentrated in the human lens. Many preclinical and clinical studies provide compelling evidence for a protective role of dietary carotenoids in age-related cataracts.
  • 3.8K
  • 28 Sep 2021
Topic Review
Xanthine Oxidoreductase Activities
Xanthine oxidoreductase (XOR) is the enzyme that catalyzes the oxidation of hypoxanthine to xanthine and xanthine to uric acid. XOR is widely distributed throughout living organisms and is highly conserved in prokaryotic, plant, and animal species. XOR activity is very versatile, generating both pro-oxidant (primarily within the cell) and anti-oxidant (primarily in plasma) products.
  • 2.9K
  • 21 Sep 2020
Topic Review
Intracardiac Nervous System
The intracardiac nervous system (IcNS), sometimes referred to as the “little brain” of the heart, is involved in modulating aspects of cardiac physiology. The IcNS is composed of neuronal and non-neuronal compartments intrinsic to the heart and includes afferent, efferent, and intra- neurons, using sympathetic, parasympathetic, and non-adrenergic, non-cholinergic neural transmitters, and forming feedback loops with the central (brain and spine) and peripheral (paravertebral ganglia) nervous systems.
  • 2.2K
  • 11 Nov 2021
Topic Review
Taurine, Bile Acids, and Microbiota
Taurine is the most abundant free amino acid in the body, and is mainly derived from the diet, but can also be produced endogenously from cysteine. It plays multiple essential roles in the body, including development, energy production, osmoregulation, prevention of oxidative stress, and inflammation. Taurine is also crucial as a molecule used to conjugate bile acids (BAs). In the gastrointestinal tract, BAs deconjugation by enteric bacteria results in high levels of unconjugated BAs and free taurine. Depending on conjugation status and other bacterial modifications, BAs constitute a pool of related but highly diverse molecules, each with different properties concerning solubility and toxicity, capacity to activate or inhibit receptors of BAs, and direct and indirect impact on microbiota and the host, whereas free taurine has a largely protective impact on the host, serves as a source of energy for microbiota, regulates bacterial colonization and defends from pathogens.
  • 2.1K
  • 19 Aug 2022
Topic Review
Embodied 'Basic' Emotions in Chinese and English Language
References to the body are one feature shared across languages, particularly when describing the mental processes of emotion, reflecting the embodiment of an emotional experience. Embodied emotion concepts encompass these categorized outcomes of bidirectional brain–body interactions yet can be differentiated further into afferent or interoceptive and efferent or autonomic processes. Between languages, a comparison of emotion words indicates the dominance of afferent or interoceptive processes in how embodied emotions are conceptualized in Chinese, while efferent or autonomic processes feature more commonly in English. Correspondingly, in linguistic expressions of emotion, Chinese-speaking people are biased toward being more receptive, reflective, and adaptive, whereas native English speakers may tend to be more reactive, proactive, and interactive. 
  • 2.0K
  • 05 Aug 2022
Topic Review
Melanin regulation peptides
Certain analogs of α-melanocyte stimulating hormone (MSH) and peptides with the sequences derived from the hormone were shown to promote or suppress melanin synthesis in cells and in vivo models. Various amino acids, peptides, their analogs, and their hybrid compounds with other chemical moieties were shown to inhibit tyrosinase (TYR) catalytic activity or downregulate TYR gene expression. Certain peptides were shown to inhibit melanosome biogenesis or induce autophagy, leading to decreased pigmentation. In vivo and clinical evidence are available for some compounds, including [Nle4-D-Phe7]-α-MSH, glutathione disulfide, and glycinamide hydrochloride.
  • 1.9K
  • 28 Sep 2021
Topic Review
Hypertensive Nephropathy
Hypertension is one of the most common risk factors for developing chronic cardiovascular diseases, including hypertensive nephropathy. Within the glomerulus, hypertension causes damage and activation of mesangial cells (MCs), eliciting the production of large amounts of vasoactive and proinflammatory agents. Accordingly, the activation of AT1 receptors by the vasoactive molecule angiotensin II (AngII) contributes to the pathogenesis of renal damage, which is mediated mostly by the dysfunction of intracellular Ca2+ ([Ca2+]i) signaling. Similarly, inflammation entails complex processes, where [Ca2+]i also play crucial roles. Deregulation of this second messenger increases cell damage and promotes fibrosis, reduces renal blood flow, and impairs the glomerular filtration barrier. In vertebrates, [Ca2+]i signaling depends, in part, on the activity of two families of large-pore channels: hemichannels and pannexons. Interestingly, the opening of these channels depends on [Ca2+]i signaling. 
  • 1.9K
  • 23 Dec 2022
Topic Review
Exercise influence on calcium-phosphorous metabolism
Exercise perturbs homeostasis, alters the levels of circulating mediators and hormones, and increases the demand by skeletal muscles and other vital organs for energy substrates. Exercise also affects bone and mineral metabolism, particularly calcium and phosphate, both of which are essential for muscle contraction, neuromuscular signaling, biosynthesis of adenosine triphosphate (ATP), and other energy substrates. Parathyroid hormone (PTH) is involved in the regulation of calcium and phosphate homeostasis. Understanding the e ects of exercise on PTH secretion is fundamental for appreciating how the body adapts to exercise.
  • 1.9K
  • 26 Aug 2020
Topic Review
Corneal Sensory Nerves
The cornea is an avascular connective tissue that is crucial, not only as the primary barrier of the eye but also as a proper transparent refractive structure. Corneal transparency is necessary for vision and is the result of several factors, including its highly organized structure, the physiology of its few cellular components, the absence of blood and lymphatic vessels in healthy conditions, the tightly controlled hydration state, and the lack of myelinated nerves, among others. The cornea is supplied by both sensory and autonomic nerves, being one of the most densely innervated tissues in the body. Corneal innervation is anatomically organized into four levels ranging from the nerve trunks in the corneal stroma to the nerve terminals in the epithelium. Electrophysiological recordings of corneal sensory nerve fibers have revealed the existence of three different functional types of sensory neurons that are classified into mechanonociceptors, polymodal nociceptors and cold thermoreceptors depending on the modality of stimuli by which they are activated. The impulse discharge is conducted by these neurons to the central nervous system, where sensory input is processed to finally evoke a sensation and to regulate ocular protective functions, such as tearing and blinking.
  • 1.8K
  • 21 Mar 2022
Topic Review
Molecular and Functional Properties of Acid-Sensing Ion Channels
Acid-sensing ion channels (ASICs) are voltage-independent H+-gated cation channels largely expressed in the nervous system of rodents and humans, and involved in pain sensing and associated pathologies. At least six isoforms (ASIC1a, 1b, 2a, 2b, 3 and 4) associate into homotrimers or heterotrimers to form functional channels with highly pH-dependent gating properties.
  • 1.7K
  • 25 Oct 2022
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