Albumin Acts as a Lubricant on the Surface of Hydrogel and Silicone Hydrogel Contact Lenses

Feeling comfortable is the greatest concern for contact lens wearers, and it has been suggested that in vivo comfort could be corresponded to the in vitro friction coefficient of contact lenses. How tear albumin could affect the friction coefficient of silicone hydrogel and hydrogel contact lenses was analyzed by sliding a lens against a quartz glass in normal and extremely high concentration of albumin solution. Albumin deposition testing and surface roughness analysis were also conducted. The results showed that the friction coefficient of tested contact lenses did not correspond to both the albumin deposition amount and surface roughness, but we proposed a model of how albumin might act as a lubricant on the surface of some hydrogel and silicone hydrogel contact lenses. In conclusion, albumin provided lubrication for silicone hydrogel contact lenses regardless of albumin concentrations, while albumin only acted as a lubricant for hydrogel contact under normal concentration.

Download Full-text

The Bio-Tribological Effect of Poly-Gamma-Glutamic Acid in the Lysozyme-Ionic Contact Lens System

Polymers ◽

10.3390/polym12010156 ◽

2020 ◽

Vol 12 (1) ◽

pp. 156

Author(s):

Chen-Ying Su ◽

Lung-Kun Yeh ◽

Chi-Chun Lai ◽

Mihaela Dubuisson ◽

Yi-Fei Tsao ◽

...

Keyword(s):

Friction Coefficient ◽

Glutamic Acid ◽

Contact Lens ◽

Contact Lenses ◽

Lens System ◽

Friction Testing ◽

Lubricating Property ◽

Velocity Variations

Feeling comfortable is an important issue for contact lens wearers as contact lenses are worn for an extensive period of time. It has been shown that the in vitro friction coefficient of contact lenses is correlated to the degree of in vivo comfort, thus many studies focus on establishing friction testing methods for investigating the friction coefficient of contact lenses or contact lens care solution. We have previously demonstrated the lubricating property of poly-gamma-glutamic acid (γ-PGA)-containing care solution, and it could reduce the high friction coefficient caused by lysozyme. However, the mechanism of how γ-PGA-containing care solution reduces the lysozyme-induced friction coefficient of contact lenses is unclear. We investigated the bio-tribological effect of γ-PGA on ionic contact lenses in the presence of lysozyme by testing load and velocity variations. The ability to remove lysozyme deposition by γ-PGA and viscosity analysis of γ-PGA-containing care solutions were also investigated to understand the potential mechanism. Our results showed that the friction coefficient of γ-PGA-containing care solution with lysozyme was the lowest in both load and velocity variations, and γ-PGA functions distinctly in the lysozyme-ionic contact lens system. We proposed a model of how γ-PGA could reduce the friction coefficient in these two conditions.

Download Full-text

In Vitro and In Vivo Evaluation of Novel Ciprofloxacin-Releasing Silicone Hydrogel Contact Lenses

Investigative Opthalmology & Visual Science ◽

10.1167/iovs.14-14855 ◽

2014 ◽

Vol 55 (8) ◽

pp. 4896 ◽

Cited By ~ 25

Author(s):

Alex Hui ◽

Mark Willcox ◽

Lyndon Jones

Keyword(s):

Contact Lenses ◽

In Vivo Evaluation ◽

Silicone Hydrogel

Download Full-text

In vitro and in vivo delivery of the secretagogue diadenosine tetraphosphate from conventional and silicone hydrogel soft contact lenses

Journal of Optometry ◽

10.1016/j.optom.2013.07.004 ◽

2013 ◽

Vol 6 (4) ◽

pp. 205-211 ◽

Cited By ~ 7

Author(s):

Carmen Olalla Dominguez-Godinez ◽

Alba Martin-Gil ◽

Gonzalo Carracedo ◽

Ana Guzman-Aranguez ◽

José Manuel González-Méijome ◽

...

Keyword(s):

Contact Lenses ◽

Soft Contact ◽

Diadenosine Tetraphosphate ◽

Silicone Hydrogel ◽

Soft Contact Lenses ◽

In Vivo Delivery

Download Full-text

Current Knowledge on Functionality and Potential Therapeutic Uses of Donkey Milk

Animals ◽

10.3390/ani11051382 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1382

Author(s):

Mina Martini ◽

Iolanda Altomonte ◽

Domenico Tricò ◽

Riccardo Lapenta ◽

Federica Salari

Keyword(s):

Animal Models ◽

Randomized Clinical Trials ◽

Current Knowledge ◽

Saturated Fatty Acids ◽

Cow Milk ◽

Donkey Milk ◽

Alpha Linolenic Acid ◽

High Concentration

The increase of knowledge on the composition of donkey milk has revealed marked similarities to human milk, which led to a growing number of investigations focused on testing the potential effects of donkey milk in vitro and in vivo. This paper examines the scientific evidence regarding the beneficial effects of donkey milk on human health. Most clinical studies report a tolerability of donkey milk in 82.6–98.5% of infants with cow milk protein allergies. The average protein content of donkey milk is about 18 g/L. Caseins, which are main allergenic components of milk, are less represented compared to cow milk (56% of the total protein in donkey vs. 80% in cow milk). Donkey milk is well accepted by children due to its high concentration of lactose (about 60 g/L). Immunomodulatory properties have been reported in one study in humans and in several animal models. Donkey milk also seems to modulate the intestinal microbiota, enhance antioxidant defense mechanisms and detoxifying enzymes activities, reduce hyperglycemia and normalize dyslipidemia. Donkey milk has lower calorie and fat content compared with other milks used in human nutrition (fat ranges from 0.20% to 1.7%) and a more favourable fatty acid profile, being low in saturated fatty acids (3.02 g/L) and high in alpha-linolenic acid (about 7.25 g/100 g of fat). Until now, the beneficial properties of donkey milk have been mostly related to whey proteins, among which β-lactoglobulin is the most represented (6.06 g/L), followed by α-lactalbumin (about 2 g/L) and lysozyme (1.07 g/L). So far, the health functionality of donkey milk has been tested almost exclusively on animal models. Furthermore, in vitro studies have described inhibitory action against bacteria, viruses, and fungi. From the literature review emerges the need for new randomized clinical trials on humans to provide stronger evidence of the potential beneficial health effects of donkey milk, which could lead to new applications as an adjuvant in the treatment of cardiometabolic diseases, malnutrition, and aging.

Download Full-text

Controlled bimatoprost release from graphene oxide laden contact lenses: In vitro and in vivo studies

Colloids and Surfaces B Biointerfaces ◽

10.1016/j.colsurfb.2021.112096 ◽

2021 ◽

Vol 208 ◽

pp. 112096 ◽

Cited By ~ 1

Author(s):

Furqan A. Maulvi ◽

Parth D. Soni ◽

Pooja J. Patel ◽

Ankita R. Desai ◽

Ditixa T. Desai ◽

...

Keyword(s):

Graphene Oxide ◽

Contact Lenses ◽

In Vivo Studies

Download Full-text

The centriolar complex isolated from starfish spermatozoa

Journal of Cell Science ◽

10.1242/jcs.49.1.33 ◽

1981 ◽

Vol 49 (1) ◽

pp. 33-49 ◽

Cited By ~ 1

Author(s):

R. Kuriyama ◽

H. Kanatani

Keyword(s):

Gradient Centrifugation ◽

Sucrose Density Gradient ◽

Microtubule Assembly ◽

High Concentration ◽

Microtubule Organization ◽

Sucrose Density Gradient Centrifugation ◽

The Difference ◽

Distal Centriole

Centrioles from spermatozoa of the starfish, Asterina pectinifera, were isolated and partially purified by solubilization of chromatin followed by sucrose density-gradient centrifugation. The ultrastructure of the isolated centriolar complex was investigated in whole mount preparations by electron microscopy. The complex unit was composed of a pair of centrioles and a pericentriolar structure, which associated with the distal end of the distal centriole by 9 spoke-like satellites extending radially to a marginal ring. Each satellite bifurcated at a dense node forming 2 fan-like shapes with a periodic striated pattern. The tubular structure of the centrioles easily disintegrated, leaving the pericentriolar structure or axonemal microtubules intact. The distal centriole in a spermatozoon served as an initiating site for flagellar microtubule assembly; that is, a number of “9 + 2′ axonemal tubules were observed adhering just beneath the distal end of the basal body. In experiments in vitro, polymerization of microtubule proteins purified from porcine brain was initiated by the structure at the ends of both proximal and distal centrioles, but not from the satellites or the marginal ring. Also, few if any microtubules were formed from the sides of each centriole, even in the presence of a high concentration of exogenous tubulin. On the other hand, centrioles of spermatozoa, when they were in mature ooplasm, could initiate the formation of sperm asters by microtubules. Therefore, centrioles in spermatozoa seem to be able to initiate microtubules in a 2 ways. A possible explanation of the difference between the 2 types of microtubule organization in vivo, i.e. in the sperm cell itself and in the ooplasm, it discussed.

Download Full-text

Novel Self-Micro Emulsifying Drug Delivery System for safe intra muscular delivery with improved pharmacodynamics and pharmacokinetics

Current Drug Delivery ◽

10.2174/1567201818666210518170139 ◽

2021 ◽

Vol 18 ◽

Author(s):

Subheet Kumar Jain ◽

Neha Panchal ◽

Amrinder Singh ◽

Shubham Thakur ◽

Navid Reza Shahtaghi ◽

...

Keyword(s):

Drug Delivery ◽

Drug Delivery System ◽

Delivery System ◽

Inflammatory Diseases ◽

Diclofenac Sodium ◽

Physical Stability ◽

In Vivo Studies ◽

High Concentration

Background: Diclofenac sodium (DS) injection is widely used in the management of acute or chronic pain and inflammatory diseases. It incorporates 20 % w/v Transcutol-P as a solubilizer to make the stable injectable formulation. However, the use of Transcutol-P in high concentration leads to adverse effects such as severe nephrotoxicity, etc. Some advancements resulted in the formulation of an aqueous based injectable but that too used benzyl alcohol reported to be toxic for human use. Objective: To develop an injectable self-micro emulsifying drug delivery system (SMEDDS) as a novel carrier of DS for prompt release with better safety and efficacy. Methods: A solubility study was performed with different surfactants and co-surfactants. The conventional stirring method was employed for the formulation of SMEDDS. Detailed in vitro characterization was done for different quality control parameters. In vivo studies were performed using Wistar rats for pharmacokinetic evaluation, toxicological analysis, and analgesic activity. Results: The optimized formulation exhibited good physical stability, ideal globule size (156±0.4 nm), quick release, better therapeutics, and safety, increase in LD50 (221.9 mg/kg) to that of the commercial counterpart (109.9 mg/kg). Further, pre-treatment with optimized formulation reduced the carrageenan-induced rat paw oedema by 88±1.2 % after 4 h, compared to 77±1.6 % inhibition with commercial DS formulation. Moreover, optimized formulation significantly (p<0.05) inhibited the pain sensation in the acetic-acid induced writhing test in mice compared to its commercial equivalent with a better pharmacokinetic profile. Conclusion: The above findings confirmed that liquid SMEDDS could be a successful carrier for the safe and effective delivery of DS

Download Full-text

Autocatalytic activities of intron 5 of the cob gene of yeast mitochondria

Molecular and Cellular Biology ◽

10.1128/mcb.8.6.2562-2571.1988 ◽

1988 ◽

Vol 8 (6) ◽

pp. 2562-2571

Author(s):

S Partono ◽

A S Lewin

Keyword(s):

Group I Introns ◽

Yeast Mitochondria ◽

High Concentration ◽

Functional Protein ◽

Full Spectrum ◽

Group I ◽

Intron Boundary ◽

Monovalent Ion

The terminal intron of the mitochondrial cob gene of Saccharomyces cerevisiae can undergo autocatalytic splicing in vitro. Efficient splicing of this intron required a high concentration of monovalent ion (1 M). We found that at a high salt concentration this intron was very active and performed many of the reactions described for other group I introns. The rate of the splicing reaction was dependent on the choice of the monovalent ion; the reaction intermediate, the intron-3' exon molecule, accumulated in NH4Cl but not in KCl. In addition, the intron was more reactive in KCl, accumulating in two different circular forms: one cyclized at the 5' intron boundary and the other at 236 nucleotides from the 5' end. These circular forms were able to undergo the opening and recyclization reactions previously described for the Tetrahymena rRNA intron. Cleavage of the 5' exon-intron boundary by the addition of GTP did not require the 3' terminus of the intron and the downstream exon. An anomalous guanosine addition at the 3' exon and at the middle of the intron was also detected. Hence, this intron, which requires a functional protein to splice in vivo, demonstrated a full spectrum of characteristic reactions in the absence of proteins.

Download Full-text