Search results for " epithelium"

Gap junctions and connexin hemichannels both contribute to the electrical properties of retinal pigment epithelium.

2022

Gap junctions are intercellular channels that permit the transfer of ions and small molecules between adjacent cells. These cellular junctions are particularly dense in the retinal pigment epithelium (RPE), and their contribution to many retinal diseases has been recognized. While gap junctions have been implicated in several aspects of RPE physiology, their role in shaping the electrical properties of these cells has not been characterized in mammals. The role of gap junctions in the electrical properties of the RPE is particularly important considering the growing appreciation of RPE as excitable cells containing various voltage-gated channels. We used a whole-cell patch clamp to measure …

2019

The olfactory epithelium is continuously exposed to exogenous chemicals, including odorants. During the past decade, the enzymes surrounding the olfactory receptors have been shown to make an important contribution to the process of olfaction. Mammalian xenobiotic metabolizing enzymes, such as cytochrome P450, esterases and glutathione transferases (GSTs), have been shown to participate in odorant clearance from the olfactory receptor environment, consequently contributing to the maintenance of sensitivity toward odorants. GSTs have previously been shown to be involved in numerous physiological processes, including detoxification, steroid hormone biosynthesis, and amino acid catabolism. The…

Effects of Citric Acid on Human Gingival Epithelium

1987

All-trans to 11-cis retinol isomerization in nuclear membrane fraction from bovine retinal pigment epithelium

1991

Abstract Isomerization of all-trans to 11-cis retinol has been studied in a membrane preparation from the nuclear fraction of bovine retinal pigment epithelium. When the nuclear membrane preparation deprived of endogenous retinoids is incubated with 4·5 μ m all-trans-retinol, the mean value calculated for the isomerase activity is 1·32 nmol 11-cis retinol formed hr−1 mg protein−1. Simultaneous formation of all-trans and 11-cis retinyl esters is also observed in the nuclear preparation. When assayed under the same experimental condition, RPE 150 000 g post-nuclear sediment shows about 70% of the isomerase activity found in the nuclear membrane fraction. Treatment of the nuclear membrane frac…

Ocular gelling microspheres: in vitro precorneal retention time and drug permeation through reconstituted corneal epithelium.

2008

Purpose: The model drug norfloxacin (NOR)was encapsulated into trehalose (TRH) and hydroxyethylcellulose(NAT) microspheres to obtain a novel gelling ophthalmic delivery system for prolonged release on corneal tissue. Methods: We assessed NOR release from microspheres, prepared by the emulsion-solvent evaporation method. A new in vitro tear turnover model, including inserts containing reconstituted human corneal epithelium (RHC), was designed to evaluate the TRH/NAT microspheres’ precorneal retention time. Bioadhesive properties of TRH/NAT microspheres were validated by using drug-loaded microspheres prepared with gelatine (GLT) commonly used as reference material in adhesion studies. Result…

Electrofunctional features of the tilted disc syndrome.

1986

The ERG, EOG and VEPs of 15 patients with tilted disc syndrome were studied. The ERG showed abnormal amplitudes in about 1/4 of the eyes and the EOG values were pathological in 3 patients. It is probable that the abnormality of the inferior-nasal portion of the retina and retinal pigment epithelium seen in the tilted disc syndrome causes the changes in the ERG and EOG. Pattern VEPs latency was delayed in most patients. This finding is probably due to the poor focusing of the light in the retina.

Glaucomatous Maculopathy: Thickness Differences on Inner and Outer Macular Layers between Ocular Hypertension and Early Primary Open-Angle Glaucoma U…

2020

The purpose of this study was to compare the thickness of all inner and outer macular layers between ocular hypertension (OHT) and early primary open-angle glaucoma (POAG) using spectral domain optical coherence tomography (SD-OCT) 8 × 8 posterior pole algorithm (8 × 8 PPA). Fifty-seven eyes of 57 OHT individuals and fifty-seven eyes of 57 early POAG patients were included. The thickness of macular retinal nerve fiber layer (mRNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform and nuclear layer, photoreceptor layer (PRL) and retinal pigment epithelium were obtained in 64 cells for each macular layer and mean thickness of superior and inf…

Cigarette smoke alters primary human bronchial epithelial cell (PBEC) differentiation atAir-Liquid Interface (ALI): role of Oct-4, CD146 and CD105

2017

The airway epithelium is a dynamic tissue that undergoes slow but constant renewal. Dysregulation of airway epithelial cell function related to cigarette smoke (CS) exposure plays an important role in the pathophysiology of COPD. Oct-4 is the crucial POU domain transcription factor responsible for maintaining cellular self-renewal and regeneration, and CD146 and CD105 are adhesion molecule involved in cellular proliferation, differentiation, epithelial-mesenchymal transition and tissue remodelling. Bronchial biopsy specimens (BBs) were obtained from 9 healthy controls (C) and 9 COPD. ALI cultures of PBEC from C were exposed to CS extract (CSE) for 7, 14, 21 days. Oct-4, CD105 and CD146 expr…

Tachykinin-, calcitonin gene-related peptide-, and protein gene product 9.5-immunoreactive nerve fibers in alveolar walls of mammals.

1991

The presence and distribution of the presumed pan-neural marker protein gene product 9.5 (PGP)- and peptide-immunoreactive (ir) nerve fibers in alveolar walls of various species was investigated by light microscopic single and double staining immunohistochemistry. PGP-, tachykinin (TK)-, and calcitonin gene-related peptide (CRGP)-ir fibers were sparsely distributed in a similar pattern in alveolar walls of all species investigated. No vasoactive intestinal peptide-, peptide histidine isoleucine-, galanin-, and opioid-ir nerve fibers could be detected. PGP-ir fibers outnumbered those staining for TKs and CGRP. There was partial coexistence of PGP and TK as well as of TK and CRGP. PGP-, TK-, …

Pilot Study on Visual Function and Fundus Autofluorescence Assessment in Diabetic Patients.

2015

Purpose. Evaluate optimized fundus autofluorescence (FAF) imaging in early stages of diabetic retinopathy (DR) and relate findings with conventional colour fundus imaging and visual function in diabetic patients and control subjects.Materials and Methods. FAF and colour images were obtained using the CR-2 Plus digital nonmydriatic retinal camera in seven diabetic patients and thirteen control subjects. Visual-Functioning Questionnaire-25 (VFQ-25) and Diabetes Self-Management Questionnaire (DSMQ) were used to assess the quality of life and diabetes self-care. Contrast sensitivity function (CSF) was evaluated with the Vistech 6500 chart.Results. FAF and optimized-FAF imaging showed more retin…