Tear lipid layer structure and stability following expression of the meibomian glands

1995 ◽  
Vol 15 (6) ◽  
pp. 569-574 ◽  
Author(s):  
J Craig
1994 ◽  
Vol 71 (Supplement) ◽  
pp. 142
Author(s):  
Jennifer P. Craig ◽  
Kenneth J. Blades ◽  
Sudhir Patel

2018 ◽  
Vol 19 (12) ◽  
pp. 3819 ◽  
Author(s):  
Sudarat Tharad ◽  
Öykü Üzülmez ◽  
Boonhiang Promdonkoy ◽  
José Toca-Herrera

Cytolytic protein (Cyt) is a member of insecticidal proteins produced by Bacillus thuringiensis. Cyt protein has activity against insect cells and mammalian cells, which differ in lipid and cholesterol composition. This study presents the lipid binding behavior of Cyt2Aa2 protein on model membranes containing different levels of cholesterol content by combining Quartz Crystal Microbalance with Dissipation (QCM-D) and Atomic Force Microscopy (AFM). QCM-D results revealed that cholesterol enhances the binding rate of Cyt2Aa2 protein onto lipid bilayers. In addition, the thicker lipid bilayer was observed for the highest cholesterol content. These results were confirmed by AFM. The analysis of protein surface coverage as a function of time showed a slower process for 5:0 and 5:0.2 (POPC:Chol) ratios than for 5:1 and 5:2 (POPC:Chol) ratios. Significantly, the Cyt2Aa2-lipid binding behavior and the protein–lipid layer were different for the 5:3 (POPC:Chol) ratio. Furthermore, AFM images revealed a transformation of Cyt2Aa2/lipid layer structure from strip pattern to ring shape structures (which showed a strong repulsion with AFM tip). In summary, cholesterol increases the binding rate and alters the lipid binding behavior of Cyt2Aa2 protein, although it is not required for Cyt2Aa2 protein binding onto lipid bilayers.


2011 ◽  
Vol 89 (s248) ◽  
pp. 0-0
Author(s):  
PE KING‐SMITH ◽  
RJ BRAUN ◽  
JJ NICHOLS ◽  
KK NICHOLS

2021 ◽  
pp. 153537022110520
Author(s):  
Gengxi Lu ◽  
Sumanth Gollapudi ◽  
Runze Li ◽  
Margaret L Pfeiffer ◽  
Preeya Mehta ◽  
...  

Current treatments for meibomian gland dysfunction have several limitations, creating a necessity for other advanced treatment options. The purpose of this study is to determine the effectiveness of focused ultrasound stimulation for the treatment of dry eye disease caused by meibomian gland dysfunction. An in vivo study of nine Dutch Belted rabbits was conducted with focused ultrasound stimulation of the meibomian glands. A customized line-focused ultrasonic transducer was designed for treatment. Fluorescein imaging, Schirmer’s test, and Lipiview II ocular interferometer were used to quantify outcomes from three aspects: safety, tear production, and lipid layer thickness. Both tear secretion and lipid layer thickness improved following ultrasound treatment. Five to 10 min after the ultrasound treatment, the mean values of lipid layer thickness increased from 55.33 ± 11.15 nm to 95.67 ± 22.77 nm ( p < 0.05), while the mean values measured with the Schirmer’s test increased from 2.0 ± 2.3 to 7.2 ± 4.3 ( p < 0.05). Positive effects lasted more than three weeks. Adverse events such as redness, swelling, and mild burn, occurred in two rabbits in preliminary experiments when the eyelids sustained a temperature higher than 42°C. No serious adverse events were found. The results suggest that ultrasound stimulation of meibomian glands can improve both tear production and lipid secretion. Ultimately, ultrasound stimulation has the potential to be an option for the treatment of evaporative dry eye disease caused by meibomian gland dysfunction.


PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245329
Author(s):  
Min Seung Kang ◽  
Jonghoon Shin ◽  
Jeong Min Kwon ◽  
Jin Huh ◽  
Ji Eun Lee

Purpose To quantitatively evaluate the effects of 0.05% cyclosporine A (CsA) on lipid layer thickness (LLT) and meibomian glands after cataract surgery using the LipiView® ocular surface interferometer. Methods This study was a prospective randomized double-masked clinical trial conducted by Pusan National University Yangsan Hospital between April 04, 2019, and November 31, 2019. Sixty-two participants were recruited, and 12 of them were not enrolled because they had undergone previous treatments for ocular surface diseases. The participants were adult patients with cataract, exhibiting normal lid position; they did not present any other ocular disease and did not meet the exclusion criteria of the clinical trial. Fifty subjects were enrolled in the study. The randomized subjects received treatment with 0.05% CsA (group A) or 0.5% carboxymethyl cellulose (CMC) (group B) over the 3 months following the cataract surgery. Subjective and objective assessments were performed at preoperative and postoperative visits. Ocular Surface Disease Index (OSDI), tear breakup time (TBUT), and Schirmer’s I test were performed by the same surgeon, and LLT and meiboscore were determined using the LipiView® interferometer. Results Fifty subjects subjects enrolled consisted of men (50%) and women (50%), with a mean (SD) age of 65.94 (10.35) years. Four subjects in group A and five in group B were excluded from the analysis as they were lost to follow-up within 1 month after cataract surgery. Thus, the study comprised 41 eyes of 41 subjects; 21 subjects were treated with CsA and 20 subjects with CMC. Comparing the clinical measurements between groups A and B taken at the last visit, while controlling the effects of the preoperative values, TBUT and LLT showed significant differences (p = 0.035 and p = 0.047, respectively, by ANCOVA). The TBUT between the subjects using CsA and those using CMC after cataract surgery showed a significant difference during follow up (p = 0.003 by repeated measures ANOVA). In the multivariate analysis, preoperative LLT and the use of CsA were found to be independent parameters for postoperative LLT (R2 = 0.303; p = 0.008 and p = 0.045, respectively), whereas the follow-up duration exhibited a positive correlation with the difference between the preoperative and postoperative values of LLT in the group treated with CsA (R2 = 0.738 and p < 0.001). Conclusion Treatment with 0.05% CsA following cataract surgery is effective in improving TBUT and LLT in comparison with 0.5% CMC. A higher preoperative value of LLT and the postoperative use of CsA could be significant determinants of a higher postoperative LLT value. Trial registration ISRCTN registry with ISRCTN 10173448.


2015 ◽  
Vol 74 (1) ◽  
Author(s):  
Deanne L. Nicholas ◽  
Wayne D.H. Gillan

The meibomian glands of the upper and lower eyelids play a valuable role in secreting the lipidlayer of the tear film. Disturbances in meibomian gland function may result in altered secretion andvariations in tear composition which may lead to meibomian gland dysfunction and evaporativedry eye, leading to ocular discomfort. To diagnose and monitor the structural and functionalchanges occurring within the glands of the eyelids, various imaging techniques are available.Some of the methods used to evaluate the tears and therefore the meibum within the tears includeevaporimetry, interferometry, tear osmolarity and meibometry. With these techniques, changesin the lipid layer of the tear film can be quantified and alterations in meibomian gland functionassessed. Meibography is an additional method that can be used; it has the unique feature ofallowing the assessment of meibomian gland morphology during ocular surface disease processes.The aim of this review is to create an improved understanding of the meibomian glands and theways that they may be investigated in order to expand on the treatment methods available.


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