scholarly journals Whole Vitreous Humor Dissection for Vitreodynamic Analysis

10.3791/52759 ◽  
2015 ◽  
Author(s):  
Karthik Murali ◽  
Amir H. Kashani ◽  
Mark S. Humayun
Keyword(s):  
Vitreous Humor

Leptin in serum and vitreous humor, and retinal ob mRNA, in human diabetes

2013 ◽  
pp. 1-1
Author(s):  
A Syed Imran ◽  
A Diane Wilkinson ◽  
Y Alex Tan ◽  
D John Dickinson ◽  
M Dan O'Brien ◽  
...  
Keyword(s):  
Vitreous Humor ◽  
Human Diabetes

scholarly journals Bio-Distribution and Pharmacokinetics of Topically Administered γ-Cyclodextrin Based Eye Drops in Rabbits

2021 ◽  
Vol 14 (5) ◽  
pp. 480
Author(s):  
Martin Kallab ◽  
Kornelia Schuetzenberger ◽  
Nikolaus Hommer ◽  
Bhavapriya Jasmin Schäfer ◽  
Doreen Schmidl ◽  
...  
Keyword(s):  
Single Dose ◽  
Drug Concentration ◽  
Vitreous Humor ◽  
Controlled Study ◽  
Eye Drops ◽  
Corneal Tissue ◽  
Single Administration ◽  
Local Tolerability ◽  
Dose Administration ◽  
Retinal Tissue

The purpose of this study was to evaluate the ocular pharmacokinetics, bio-distribution and local tolerability of γ-cyclodextrin (γCD) based irbesartan 1.5% eye drops and candesartan 0.15% eye drops after single and multiple topical administration in rabbit eyes. In this randomized, controlled study, a total number of 59 New Zealand White albino rabbits were consecutively assigned to two study groups. Group 1 (n = 31) received irbesartan 1.5% and group 2 (n = 28) candesartan 0.15% eye drops. In both groups, single dose and multiple administration pharmacokinetic studies were performed. Rabbits were euthanized at five predefined time points after single-dose administration, whereas multiple-dose animals were dosed for 5 days twice-daily and then euthanized 1 h after the last dose administration. Drug concentration was measured by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the retinal tissue, vitreous humor, aqueous humor, corneal tissue and in venous blood samples. Pharmacokinetic parameters including maximal drug concentration (Cmax), time of maximal drug concentration (Tmax), half-life and AUC were calculated. To assess local tolerability, six additional rabbits received 1.5% irbesartan eye drops twice daily in one eye for 28 days. Tolerability was assessed using a modified Draize test and corneal sensibility by Cochet Bonnet esthesiometry. Both γCD based eye drops were rapidly absorbed and distributed in the anterior and posterior ocular tissues. Within 0.5 h after single administration, the Cmax of irbesartan and candesartan in retinal tissue was 251 ± 142 ng/g and 63 ± 39 ng/g, respectively. In the vitreous humor, a Cmax of 14 ± 16 ng/g for irbesartan was reached 0.5 h after instillation while Cmax was below 2 ng/g for candesartan. For multiple dosing, the observed Cmean in retinal tissue was 338 ± 124 ng/g for irbesartan and 36 ± 10 ng/g for candesartan, whereas mean vitreous humor concentrations were 13 ± 5 ng/g and <2 ng/g, respectively. The highest plasma concentrations of both irbesartan (Cmax 5.64 ± 4.08 ng/mL) and candesartan (Cmax 4.32 ± 1.04 ng/mL) were reached 0.5 h (Tmax) after single administration. Local tolerability was favorable with no remarkable differences between the treated and the control eyes. These results indicate that irbesartan and candesartan in γCD based nanoparticle eye drops can be delivered to the retinal tissue of the rabbit’s eye in pharmacologically relevant concentrations. Moreover, safety and tolerability profiles appear to be favorable in the rabbit animal model.

scholarly journals Application of Innovative TGA/Chemometric Approach for Forensic Purposes: The Estimation of the Time since Death in Contaminated Specimens

Diagnostics ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 121
Author(s):  
Roberta Risoluti ◽  
Giuseppina Gullifa ◽  
Vittorio Fineschi ◽  
Paola Frati ◽  
Stefano Materazzi
Keyword(s):  
Multidisciplinary Approach ◽  
Vitreous Humor ◽  
Classification Model ◽  
Forensic Sciences ◽  
Time Since Death ◽  
Time Of Death ◽  
Novel Approach ◽  
Chemometric Approach ◽  
Postmortem Examinations

Chronothanatology has always been a challenge in forensic sciences. Therefore, the importance of a multidisciplinary approach for the characterization of matrices (organs, tissues, or fluids) that respond linearly to the postmortem interval (PMI) is emerging increasingly. The vitreous humor is particularly suitable for studies aimed at assessing time-related modifications because it is topographically isolated and well-protected. In this work, a novel approach based on thermogravimetry and chemometrics was used to estimate the time since death in the vitreous humor and to collect a databank of samples derived from postmortem examinations after medico–legal evaluation. In this study, contaminated and uncontaminated specimens with tissue fragments were included in order to develop a classification model to predict time of death based on partial least squares discriminant analysis (PLS-DA) that was as robust as possible. Results demonstrate the possibility to correctly predict the PMI even in contaminated samples, with an accuracy not lower than 70%. In addition, the correlation coefficient of the measured versus predicted outcomes was found to be 0.9978, confirming the ability of the model to extend its feasibility even to such situations involving contaminated vitreous humor.

scholarly journals Spectroscopy as a useful tool for the identification of changes with time in post-mortem vitreous humor for forensic toxicology purposes

2021 ◽  
Author(s):  
Anna Wójtowicz ◽  
Agata Mitura ◽  
Renata Wietecha-Posłuszny ◽  
Rafał Kurczab ◽  
Marcin Zawadzki
Keyword(s):  
Ir Spectra ◽  
Forensic Toxicology ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Vitreous Humor ◽  
Attenuated Total Reflection ◽  
Glass Slides ◽  
Added Benefit ◽  
Ft Ir ◽  
Non Destructive

AbstractVitreous humor (VH) is an alternative biological matrix with a great advantage of longer availability for analysis due to the lack of many enzymes. The use of VH in forensic toxicology may have an added benefit, however, this application requires rapid, simple, non-destructive, and relatively portable analytical analysis methods. These requirements may be met by Fourier transform infrared spectroscopy technique (FT-IR) equipped with attenuated total reflection accessory (ATR). FT-IR spectra of vitreous humor samples, deposited on glass slides, were collected and subsequent chemometric data analysis by means of Hierarchical Cluster Analysis and Principal Component Analysis was conducted. Differences between animal and human VH samples and human VH samples stored for diverse periods of time were detected. A kinetic study of changes in the VH composition up to 2 weeks showed the distinction of FT-IR spectra collected on the 1st and 14th day of storage. In addition, data obtained for the most recent human vitreous humor samples—collected 3 and 2 years before the study, presented successful discrimination of all time points studied. The method introduced was unable to detect mephedrone addition to VH in the concentration of 10 µg/cm3. Graphic abstract

scholarly journals Enhanced Transport and Permeation of a Polymeric Nanocarrier across the Retina by Mixing with ATP upon Intravitreal Injection

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 463
Author(s):  
Kiyoon Kwon ◽  
Youngmin Hwang ◽  
Junyoung Jung ◽  
Giyoong Tae
Keyword(s):  
Great Increase ◽  
Pigment Epithelium ◽  
Outer Part ◽  
Vitreous Humor ◽  
Retinal Diseases ◽  
P2y Receptor ◽  
Main Site ◽  
Tight Junction Disruption ◽  
Polymeric Nanocarrier ◽  
Retina Pigment Epithelium

The outer part of the retina pigment epithelium (RPE) in the retina is the main site of neovascularization associated with retinal diseases. However, various obstacles interrupt the delivery of medicines across the RPE, mainly due to the well-developed tight junctions in the RPE. Currently, there is no practical formulation to overcome this issue. In this study, we demonstrated that simple mixing with adenosine tetraphosphate (ATP) has the potential to greatly enhance the transport and permeation of a polymeric nanocarrier across the retina via intravitreal administration. Chitosan-functionalized, pluronic-based nanocarrier (NC), which can deliver various biomolecules efficiently, was used as a polymeric nanocarrier. Mixing with ATP facilitated the diffusion of the nanocarrier in the vitreous humor by reducing the electrostatic interaction between NC and negatively charged glycosaminoglycans (GAGs) in the vitreous humor. Mixing with ATP also allowed the penetration of NC across the whole retina, and it resulted in a great increase (approximately nine times) in the transport of NC across the retina, as well as spreading it throughout the whole retina upon intravitreal administration in a mouse model. This enhanced permeation across the retina was specific to ATP but not to GTP, suggesting the possibility of P2Y receptor-mediated tight junction disruption by ATP.

Interpretation of drug concentrations in an alternative matrix: the case of meprobamate in vitreous humor

2011 ◽  
Vol 125 (3) ◽  
pp. 463-468 ◽  
Author(s):  
Fabien Bévalot ◽  
Marie-Paule Gustin ◽  
Nathalie Cartiser ◽  
Catherine Le Meur ◽  
Daniel Malicier ◽  
...  
Keyword(s):  
Vitreous Humor ◽  
Drug Concentrations

Chromatographic determination of drugs of abuse in vitreous humor using solid-phase extraction

2012 ◽  
Vol 33 (8) ◽  
pp. 740-745 ◽  
Author(s):  
Purificación Fernández ◽  
Santiago Seoane ◽  
Cristina Vázquez ◽  
María Jesús Tabernero ◽  
Antonia M. Carro ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Drugs Of Abuse ◽  
Solid Phase ◽  
Chromatographic Determination ◽  
Vitreous Humor ◽  
Phase Extraction

scholarly journals Thanatochemistry: Study of vitreous humor potassium

2014 ◽  
Vol 50 (4) ◽  
pp. 365-368 ◽  
Author(s):  
Nilesh Keshav Tumram ◽  
Vipul Namdeorao Ambade ◽  
Anand Paikuji Dongre
Keyword(s):  
Vitreous Humor
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