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History of Asphyxia-related Deaths
Published in Burkhard Madea, Asphyxiation, Suffocation,and Neck Pressure Deaths, 2020
The working group of Kondo (see also Chapter 15) investigated the suitability of the expression of aquaporin-3 and aquaporin-1 as vitality markers of strangulation marks (Ishida et al. 2018). Aquaporins are membrane water channels that play critical roles in controlling the water contents of cells. They are expressed in many epithelia and endothelia that can regulate osmolality throughout the body. Aquaporin-1 is expressed in vascular endothelial cells throughout the body, including the skin. Epidermal aquaporin-3 is increased in a cutaneous burn wound. A total of 24 neck compression marks by ligatures were investigated. After immunostaining, a total of ten high power fields were selected randomly. Antemortem neck compression enhanced aquaporin-3 expression in the keratinocytes. These results have been confirmed by this author's own working group (Figure 1.40). Aquaporin-3 might be useful as a marker of all kinds of antemortem skin injuries.
Mechanism of Action of Isotretinoin
Published in Ayse Serap Karadag, Berna Aksoy, Lawrence Charles Parish, Retinoids in Dermatology, 2019
ATRA, and especially isotretinoin, enhanced the expression of AQP3 in human keratinocytes and human skin (97,98). At the promoter level, the expression of AQP3 is induced by p53 (99,100). As a result, isotretinoin-induced upregulation of AQP3 explains isoretinoin’s adverse effect on epidermal barrier homeostasis. Aquaporin 1 (AQP1) is widely distributed in the human brain and is associated with water secretion into the subarachnoid space. Notably, AQP1 is an ATRA-inducible gene (101) that has been linked to retinoid-induced intracranial hypertension (102), which is a known potential adverse effect of systemic isotretinoin treatment (103). Stratum corneum ceramides play key functions in epidermal barrier homeostasis. There is recent evidence for the involvement of p53 in the regulation of ceramide metabolism (104).
Embryology, Anatomy, and Physiology of the Kidneys and Ureters
Published in Karl H. Pang, Nadir I. Osman, James W.F. Catto, Christopher R. Chapple, Basic Urological Sciences, 2021
Paul Sturch, Sanjeev Madaan, Seshadri Sriprasad
Divided into three distinct parts:Descending limbPassive reabsorption of water occurs through highly water permeable aquaporin 1 channels.Very little movement of salt with low permeability to salt and no active transport, which creates an osmotic gradient.Thin ascending limbHighly permeable to sodium chloride with very low permeability to water.No active salt transport.Sodium chloride and urea diffuse down a concentration gradient.Thick ascending limbVery low permeability to water.Sodium, potassium, and chloride passively diffuse into the cells and are actively transported out of the basolateral surface using ATP.
Anti-cataract therapies: is there a need for a new approach based on targeting of aquaporins?
Published in Expert Opinion on Therapeutic Targets, 2021
An important class of lens proteins, which are far lower in proportion that the crystallins, but which play a vital role in water transport, microcirculation and homeostasis in protein/water balance in the lens are the aquaporins [21]. Aquaporins are small membrane proteins found in a number of tissues in humans and animals. The three main aquaporins that are expressed in the human lens are aquaporin 0, 1, and 5 [21]. These aquaporins are water transporting proteins [22]. Aquaporin 0 (also known as Membrane Intrinsic Protein) is found in the fiber cells throughout the lens, constituting over half of the protein concentration of the cell membranes [22]. Aquaporin 1 is found in the epithelial cells [22] and aquaporin 5 has been detected in all parts of the lens [23] and is the second most prevalent of the aquaporins in mature lens fiber cells [23]. Aquaporin 7, an aquaglyceroporin which facilitates transport of small molecules as well as water and may be active in transport of nutrients, has also been detected in the eye lens epithelium [22]; it has a significantly lower water permeability than aquaporin 1 [24].
The Role of C-Jun N-terminal Kinase-1 in Controlling Aquaporin-1 and Choroidal Thickness during Recovery from Form-deprivation Myopia in Guinea Pigs
Published in Current Eye Research, 2021
Wei Chen, Zhiwei Li, Qimiao Wang, Yan Wang, Yue Zhang
The choroid is a dense network of blood vessels with multiple functions. Specifically, the choroid provides nourishment for the outer layers of the retina and participates in refractive adjustment. In addition, choroidal secretory cells secrete growth factors that modulate vascularization and growth of the sclera or affect the molecular signals to the sclera.4 The causes of changes in choroidal thickness(CT) include choroidal blood flow,5 lymphatics,6 nonvascular smooth muscle,7 osmotic macromolecules8 and suprachoroidal volume.3 Aquaporin-1 (AQP-1) is a water channel protein which selectively allows the passage of water through the plasma membrane of fluid-transporting cells throughout the body.9 We have found that AQP-1 was highly expressed in choroidal endothelial cells and had a positive correlation with CT and the recovery from form-deprivation myopia in guinea pigs,3 but the mechanism of optical signaling regulating AQP-1 and choroidal thickness has not been studied.
Liposomes as vehicles for topical ophthalmic drug delivery and ocular surface protection
Published in Expert Opinion on Drug Delivery, 2021
José Javier López-Cano, Miriam Ana González-Cela-Casamayor, Vanessa Andrés-Guerrero, Rocío Herrero-Vanrell, Irene Teresa Molina-Martínez
The deepest corneal layer is the endothelium, a single layer of hexagonal cells [39]. Although endothelial cells have proliferative capacity, it is too slow to replace cell loss, so the number of these cells decreases with age [54,55]. Its main function is to regulate the hydration of the stroma, allowing the transparency of the cornea to be maintained. The underlying mechanisms by which it is regulated involves the presence ionic pumps [56]. Also, the aquaporin-1 channels present in the endothelium have been suggested as responsible for regulating the transport of water through the endothelium and as a key to preventing corneal edema [44].