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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.
  • 4.8K
  • 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.
  • 3.5K
  • 21 Sep 2020
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. 
  • 3.2K
  • 23 Dec 2022
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.
  • 2.7K
  • 19 Aug 2022
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.
  • 2.6K
  • 11 Nov 2021
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. 
  • 2.5K
  • 05 Aug 2022
Topic Review
VO2max Changes of Masters Athletes in Continuing Training
Elite masters endurance athletes are considered models of optimal healthy aging due to the maintenance of high cardiorespiratory fitness (CRF) until old age. Whereas a drop in VO2max in masters athletes has been broadly investigated, the modifying impact of training still remains a matter of debate. Longitudinal observations in masters endurance athletes demonstrated VO2max declines between −5% and −46% per decade that were closely related to changes in training volume.
  • 2.4K
  • 09 Sep 2022
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.
  • 2.3K
  • 21 Mar 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.
  • 2.3K
  • 28 Sep 2021
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.
  • 2.2K
  • 26 Aug 2020
Topic Review
Effects of Creatine Supplementation on Brain Function
Creatine, a nitrogenous organic compound derived from reactions involving the amino acids arginine, glycine, and methionine, is important for resynthesizing ATP, particularly during times of increased metabolic demand (e.g., sleep deprivation, mental health conditions, or neurological diseases). Creatine supplementation (and guanidinoacetic acid; GAA) has the ability to increase brain creatine content in humans. Furthermore, creatine has shown some promise for attenuating symptoms of concussion, mild traumatic brain injury and depression but its effect on neurodegenerative diseases appears to be lacking. 
  • 2.1K
  • 09 Jun 2022
Topic Review
Vitamin D, Oxidative-Stress and Aging
Recent advances in vitamin D research indicate that this vitamin, a secosteroid hormone, has beneficial effects on several body systems other than the musculoskeletal system. Both 25 dihydroxy vitamin D [25(OH)2D] and its active hormonal form, 1,25-dihydroxyvitamin D [1,25(OH)2D] are essential for human physiological functions, including damping down inflammation and the excessive intracellular oxidative stresses. Vitamin D is one of the key controllers of systemic inflammation, oxidative stress and mitochondrial respiratory function, and thus, the aging process in humans. In turn, molecular and cellular actions form 1,25(OH)2D slow down oxidative stress, cell and tissue damage, and the aging process. On the other hand, hypovitaminosis D impairs mitochondrial functions, and enhances oxidative stress and systemic inflammation. The interaction of 1,25(OH)2D with its intracellular receptors modulates vitamin D–dependent gene transcription and activation of vitamin D-responsive elements, which triggers multiple second messenger systems. Thus, it is not surprising that hypovitaminosis D increases the incidence and severity of several age-related common diseases, such as metabolic disorders that are linked to oxidative stress. These include obesity, insulin resistance, type 2 diabetes, hypertension, pregnancy complications, memory disorders, osteoporosis, autoimmune diseases, certain cancers, and systemic inflammatory diseases. Vitamin D adequacy leads to less oxidative stress and improves mitochondrial and endocrine functions, reducing the risks of disorders, such as autoimmunity, infections, metabolic derangements, and impairment of DNA repair; all of this aids a healthy, graceful aging process. Vitamin D is also a potent anti-oxidant that facilitates balanced mitochondrial activities, preventing oxidative stress-related protein oxidation, lipid peroxidation, and DNA damage. New understandings of vitamin D-related advances in metabolomics, transcriptomics, epigenetics, in relation to its ability to control oxidative stress in conjunction with micronutrients, vitamins, and antioxidants, following normalization of serum 25(OH)D and tissue 1,25(OH)2D concentrations, likely to promise cost-effective better clinical outcomes in humans. 
  • 1.9K
  • 29 Oct 2020
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.
  • 1.9K
  • 25 Oct 2022
Topic Review
Cadmium and Lead Exposure
This entry provides information relevant to public health policy regarding advisable exposure limits for cadmium (Cd) and lead (Pb) that have no biologic role in humans. All of their perceptible effects are toxic. These metals exist in virtually all foodstuffs. Foods which are frequently consumed in large quantities such as cereals, rice, potatoes and vegetables contribute the most to total intake of these metals. Because Cd and Pb exposure are highly prevalent, even a small increase in disease risk can result in a large number of people affected by a disease that is preventable. Public measures to minimize environmental pollution and the food-chain transfer of Cd and Pb are required to prevent Cd- and Pb- related ailments and mortality as are risk reduction measures that set a maximally permissible concentration of Cd and Pb in staple food to the lowest achievable levels.
  • 1.9K
  • 29 Oct 2020
Topic Review
Calcium Phosphate Nanocluster Complexes
Calcium phosphate nanocluster complexes comprise a core of amorphous calcium phosphate and a sequestering shell of intrinsically disordered phosphopeptides or phosphoproteins. Solutions containing the nanocluster complexes can be thermodynamically stable or metastable due to a tendency to form a precipitate enriched in calcium phosphate. Theoretical and biophysical studies with native and recombinant phosphopeptides have shown how the radius of the core and the stability of the solution depend on the concentration of the sequestering peptide, its affinity for the calcium phosphate and its concentration in relation to the concentration of the calcium phosphate. The thickness of the sequestering shell depends on the conformation of the peptide on the core surface. A sequestering peptide is a flexible sequence including one or more short linear motifs, each of which usually contains several phosphorylated and other acidic residues.  These are the main binding sites to the core so that a peptide with several binding motifs can forms loops and trains on the core surface. Calcium phosphate nanocluster complexes were first identified as substructures of casein micelles in milk and have been prepared as individual particles from peptides derived from caseins and osteopontin. Stable biofluids containing nanocluster complexes cannot cause soft tissues to become mineralized whereas stable or metastable biofluids containing nanocluster complexes can help to mineralize hard tissues.
  • 1.7K
  • 09 Nov 2020
Topic Review
New Insights into Melanocytes Beyond Conventional Recognition
Melanocytes produce melanin to protect the skin from UV-B radiation. Notwithstanding, the spectrum of their functions extends far beyond their well-known role as melanin production factories. Melanocytes have been considered as sensory and computational cells. The neurotransmitters, neuropeptides, and other hormones produced by melanocytes make them part of the skin’s well-orchestrated and complex neuroendocrine network, counteracting environmental stressors. Melanocytes can also actively mediate the epidermal immune response. Melanocytes are equipped with ectopic sensory systems similar to the eye and nose and can sense light and odor.In addition, melanocytes have also been shown to be localized in internal sites such as the inner ear, brain, and heart, locations not stimulated by sunlight.
  • 1.6K
  • 18 Jul 2022
Topic Review
Characteristics of Vitamin E
Vitamin E is a fat-soluble organic micronutrient that helps to preserve human health. Its main function is likely that of a radical scavenger protecting biological membranes from lipid peroxidation. Vegetable oils, such as wheat germ, sunflower, corn germ, soybean, and rapeseed, are the primary dietary source of vitamin E for humans. It is also found in some nuts, fruits, and vegetables, such as almonds, avocados, spinach, and kale.
  • 1.6K
  • 16 Sep 2022
Topic Review
Potato Affected by Heat and Drought Stress
Potato crop species are highly prone to different abiotic (high-temperature stress, drought, salinity, and mineral stress).
  • 1.5K
  • 01 Nov 2022
Topic Review
Food Neophobia
Food neophobia is the tendency to reject or be reluctant to try new and unfamiliar foods. Due to the period of its occurrence, which falls in the years of early childhood, it can significantly affect the child’s food choices, shape taste preferences, and significantly influence the quality of the child’s diet. 
  • 1.5K
  • 26 Apr 2022
Topic Review
B-Cell Lymphoma-Extra-Large
B-Cell Lymphoma-extra-large (BCL-xL) is involved in longevity and successful aging,which indicates a role for BCL-xL in cell survival pathway regulation. Beyond its well described role as an inhibitor of apoptosis by preventing cytochrome c release, BCL-xL has also been related, indirectly, to autophagy and senescence pathways. Although in these latter cases, BCL-xL has dual roles, either activating or inhibiting, depending on the cell type and the specific conditions. Taken together, all these findings suggest a precise mechanism of action for BCL-xL, able to regulate the crosstalk between apoptosis, autophagy, and senescence, thus promoting cell survival or cell death. All three pathways can be both beneficial or detrimental depending on the circumstances. Thus, targeting BCL-xL would in turn be a “double-edge sword” and therefore, additional studies are needed to better comprehend this dual and apparently contradictory role of BCL-XL in longevity.
  • 1.5K
  • 31 Jul 2020
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