Cold bandage contact lens use reduces post-photorefractive keratectomy or corneal collagen-crosslinking pain perception in patients

Purpose: To compare post?operative pain perception using bandage contact lens (BCL) stored at 2–8?C (Cold BCL, CL?BCL) or room temperature (23 – 25?C, RT?BCL) after photorefractive keratectomy (PRK) or corneal collagen?crosslinking (CXL) and determine status of nociception associated factors. Methods: In this prospective interventional study, 56 patients undergoing PRK for refractive correction and 100 keratoconus (KC) undergoing CXL were recruited following approval from the institutional ethics committee with informed consent. Patients undergoing bilateral PRK received RT?BCL on one eye and CL?BCL on the other. Pain was graded by Wong–Baker scoring on the first post?operative day (PoD1). Expression of transient receptor potential channels (TRPV1, TRPA1, TRPM8), calcitonin gene?related peptide (CGRP) and IL?6 was measured in cellular content from used BCLs collected on PoD1. Equal number of KC patients received RT?BCL or CL?BCL post?CXL. Pain was graded by Wong–Baker scoring on PoD1. Results: Pain scores on PoD1 were significantly (P < 0.0001) reduced in subjects receiving CL?BCL (Mean ± SD: 2.6 ± 2.1) compared to RT?BCL (6.0 ± 2.4) post?PRK. 80.4% of subjects reported reduced pain scores with CL?BCL. 19.6% reported no change or increased pain scores with CL?BCL. TRPM8 expression was significantly (P < 0.05) increased in BCL of subjects reporting reduced pain with CL?BCL compared to those who did not. Pain scores on PoD1 were significantly (P < 0.0001) reduced in subjects receiving CL?BCL (3.2 ± 2.1) compared to RT?BCL (7.2 ± 1.8) post?CXL. Conclusion: The simple approach of using a cold BCL post?operatively substantially reduced pain perception and could overcome post?operative pain?related limited acceptance of PRK/CXL.

Fatty acid composition of Drosophila photoreceptor light-sensitive microvilli

Phototransduction, the mechanism underlying the electrical response to light in photoreceptor cells, has been thoroughly investigated in Drosophila melanogaster, an essential model in signal transduction research. These cells present a highly specialized photosensitive membrane consisting of thousands of microvilli forming a prominent structure termed a rhabdomere. These microvilli encompass the phototransduction proteins, most of which are transmembrane and exclusively rhabdomeric. Rhabdomere membrane lipids play a crucial role in the activation of the transient receptor potential ionic channels (TRP and TRPL) responsible for initiating the photoresponse. Despite its importance, rhabdomere lipid composition has not been established. We developed a novel preparation enriched in rhabdomere membranes to perform a thorough characterization of the lipidomics of Drosophila rhabdomeres. Isolated eyes (500) were homogenized and subjected to a differential centrifugation protocol that generates a fraction enriched in rhabdomere membrane. Lipids extracted from this preparation were identified and quantified by gas chromatography coupled to mass spectrometry. We found an abundance of low sterol esters (C16:0, C18:0), highly abundant and diverse triglycerides, free fatty acids, a moderate variety of mono and diacyglycerols (C:16:0, 18:0, C18:1) and abundant phospholipids (principally C18:2). This preparation opens a new avenue for investigating essential aspects of phototransduction.

Regulatory role of phosphatidylinositol 4,5-bisphosphate in transient receptor potential channel / 第二军医大学学报

Transient receptor potential(TRP) superfamily includes seven subfamilies and TRP channels are regulated by a wide variety of physical and chemical factors. Recently, several members of the TRP channel family have been reported to be regulated by phosphatidylinositol 4,5-bisphosphate(PIP2). The regulation is complex and it can be activation or inhibition, involving multiple mechanisms and factors. This review summarizes the PIP2 regulation of several TRP channels of different superfamilies and the related pathophysiological significance.