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Background: Heterogeneity can impact biomarker identification. Thus, we investigated the somatic copy number alterations (SCNAs) of individual tumor cells in the vitreous humor of a retinoblastoma patient using single-cell whole-genome profiling and explored the genomic concordance among vitreous and aqueous humor, vitreous seeds, and tumor. Methods: Aqueous humor (AH), vitreous humor (VH), and tumor biopsy were obtained from an enucleated globe with retinoblastoma and vitreous seeding. Micromanipulation was used to manually isolate 39 live single tumor cells from vitreous seeds harvested from the VH. The SCNA profiles of these individual cells were generated via whole-genome sequencing and analyzed alongside profiles from the tumor mass and cell-free DNA (cfDNA) from AH and VH. Results: Heatmap of VH single-cell SCNA profiles demonstrates heterogeneity among individual vitreous seeds with one clearly dominant subclone (23 of 37 cells). The SCNA profiles from the cells in this subclone demonstrate an average concordance of 98% with cfDNA profiles from acellular AH and VH and with the tumor profile. Conclusions: Our findings reveal some heterogeneity among single-cell SCNA profiles in individual VH seeds. Despite this heterogeneity, the dominant vitreous subclone exhibits extremely (>98%) high concordance with the SCNA profile from tumor and AH, suggesting AH cfDNA is representative of the dominant genomic subclone. This may facilitate tumoral biomarker identification via the AH. This preliminary work supports the potential of applying single-cell technology to VH seeds in retinoblastoma as a platform to study tumor subclones, which may provide insight into the genomic complexity of disease. [ABSTRACT FROM AUTHOR]

Purpose: To report the clinical features and treatment outcomes in adult Caucasians with ocular toxocariasis (OT) and investigate their prognosis depending on their serological status. Methods: Retrospective observational cohort study (2016–2021) including consecutive adults with uveitis and positive western blot (WB) in the aqueous humor or vitreous. The presence of serum antibodies was not necessary for inclusion, allowing to compare the outcomes depending on the serological status. Results: Seventeen eyes of 15 patients were included. Mean age at diagnosis was 51.9 years. Vitreous inflammation was the most frequent sign (100%). Vitreoretinal tractions (41.2%) and chorioretinal granulomas (58.8%) were less prevalent. Atypical features were: spontaneous intravitreal hemorrhage (23.5%), exudative retinal detachment (11.8%), isolated macular edema (17.6%), papillitis (29.4%) and vasculitis (47.1%). Twenty percent of patients had a positive serum serology. Baseline clinical features did not differ statistically depending on the serological status; however, the degree of inflammation was numerically higher in patients with negative serology. Overall, macular thickness, anterior and posterior segment inflammation improved significantly after treatment with oral albendazole, systemic ± local corticosteroids. Vitrectomy (47.1%) was performed in case of persistent vitritis (62.5%), retinal detachment (12.5%) and intravitreous hemorrhage (25%). Conclusion: OT has no pathognomonic sign and atypical presentations were not infrequent in this adult Caucasian cohort. Serum antibodies were rarely positive, stressing on the importance of ocular sample analysis, especially in case of atypical features. Serum antibodies may prove useful in forecasting the rapidity of inflammation clearance. Antiparasitic and anti-inflammatory treatment was safe and efficient in most cases. [ABSTRACT FROM AUTHOR]

Purpose: To develop diagnostic recommendations for diffuse large B-cell vitreoretinal lymphoma (VRL) in Chinese patients. Methods: Retrospective observational case series. Seventy-three eyes of 40 VRL patients and 8 control patients were analyzed. Eighteen patients from Beijing Tongren Hospital and 46 patients from literature were involved as validations. Results: Diagnostic methods included (1) typical clinical manifestations; (2) vitreous cytology; (3) immunohistochemical examination of vitreous or choroid/retina; (4) aqueous humor or vitreous cytokine; (5) vitreous cell gene rearrangement; (6) vitreous flow cytometry. If patients meet (1)+(2)+(3), or if they meet (1), and two of (4), (5), (6) are positive, they can be diagnosed as VRL. The sensitivity and specificity values for accurate diagnosis were 0.975 and 1.00. One hundred percent eyes from Beijing Tongren Hospital and 92.7% eyes from literature can be diagnosed. Conclusion: We developed diagnostic recommendations for diffuse large B-cell VRL through vitreous cytology combined with multiple auxiliary examinations. [ABSTRACT FROM AUTHOR]

The amount of drug in the eye depends on various factors such as genetics, layers structure, temperature distribution, and aqueous humor flow field. The heat transfer, fluid flow field, and drug delivery in the eye are numerically simulated using a three-dimensional model. The results are compared with experimental data on human and rabbit eyes. The effect of ambient temperature on the flow field in standing and supine positions was investigated. Then the transfer of drug concentration by intravitreal injection method was simulated using the obtained flow field. The results showed that the temperature distribution and the position of the eye relative to the direction of gravity have a significant role in the process of concentration transfer in the anterior segment of the eye. The results showed that in an intravitreal injection method, the drug has a significant concentration in the posterior part of the eye. In the intravitreal injection method with the injection of 1.25 mg of the drug, the maximum concentration in the vitreous humor is 1575.5 μg/ml, and the drug vanishes into the eye after 30 days. In this case, the maximum drug concentration in the aqueous humor is 30.16 μg/ml, which occurs after 1.5 days. [ABSTRACT FROM AUTHOR]

To screen for the differentially expressed genes in experimental retinal detachment rats, and to explore the expression of S100 calcium-binding protein A9 and Toll-like receptor 4 in the vitreous of rhegmatogenous retinal detachment patients. Three rats of experimental retinal detachment and three normal rats were enrolled in the study. Transcriptomics (RNAseq) sequencing technology was used to screen differentially expressed genes in the retinas of the experimental retinal detachment group and the normal group. The selected differentially expressed genes for gene ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analysis were performed. In addition, the vitreous of 15 patients with rhegmatogenous retinal detachment and six patients with the control group were collected. The expressions of S100 calcium-binding protein A9 and Toll-like receptor 4 were detected by Elisa, and the differences in expression levels were analyzed statistically. A total of 198 differentially expressed genes were screened by RNAseq sequencing, including 118 upregulated genes and 80 downregulated genes. Kyoto Encyclopedia of Genes and Genomes analysis confirmed that the most enriched pathway was the mitogen-activated protein kinase signaling pathway. Compared to the normal group, the expressions of suppressor of cytokine signaling-3, Storkhead box-2, S100 calcium-binding protein A9, Spi-1 proto-oncogene, phosphodiesterase 1B, and kinesin-light chain 1 mRNA in the retinas of the experimental retinal detachment rats were up-regulated, and the expressions of Max interacting protein 1 and the voltage-gated sodium 1 were down-regulated. Compared to the control group, the expressions of S100 calcium-binding protein A9 and Toll-like receptor 4 were upregulated by Elisa in the vitreous humor of rhegmatogenous retinal detachment patients with a statistically significant difference (p all <.05). The differentially expressed genes of experimental retinal detachment rats were suppressor of cytokine signaling-3, Storkhead box-2, S100 calcium-binding protein A9, Spi-1 proto-oncogene, phosphodiesterase 1B, kinesin-light chain 1, Max interacting protein 1, voltage-gated sodium 1, etc. The differences of S100 calcium-binding protein A9 and Toll-like receptor 4 expressions between the rhegmatogenous retinal detachment patients and the control group were statistically significant, indicating that they may play a potential role in the inflammatory process of rhegmatogenous retinal detachment. [ABSTRACT FROM AUTHOR]

Purpose: Intravitreal administration of drug molecules is one of the most common routes for treating posterior segment eye diseases. However, the properties of vitreous humour changes with the time. A number of ocular complications such as liquefaction of the vitreous humour, solidification of the vitreous humour in the central vitreous cavity and detachment of the limiting membrane due to the shrinking of vitreous humour are some of the factors that can drastically affect the efficacy of therapeutics delivered via intravitreal route. Although significant research has been conducted for studying the properties of vitreous humour and its changes during the ageing process, there have been limited work to understand the effect of these changes on therapeutic efficacy of intravitreal drug delivery systems. Therefore, in this review we discussed both the coomposition and characteristics of the vitreous humour, and their subsequent influence on intravitreal drug delivery. Methods: Articles were searched on Scopus, PubMed and Web of Science up to March 2022. Results: In this review, we discussed the biological composition and biomechanical properties of vitreous humour, methods to study the properties of vitreous humour and the changes in these properties and their relevance in ocular drug delivery field, with the aim to provide a useful insight into these aspects which can aid the process of development of novel intravitreal drug delivery systems. Conclusions: The composition and characteristics of the vitreous humour, and how these change during natural aging processes, directly influence intravitreal drug delivery. This review therefore highlights the importance of understanding the properties of the vitreous and identifies the need to achieve greater understanding of how changing properties of the vitreous affect the therapeutic efficacy of drugs administered for the treatment of posterior eye diseases. [ABSTRACT FROM AUTHOR]

The biomechanical properties of the vitreous humor and replication of these properties to develop substitutes for the vitreous humor have rapidly become topics of interest over the last two decades. In particular, the behavior of the vitreous humor as a viscoelastic tissue has been investigated to identify its role in a variety of processes related to biotransport, aging, and age-related pathologies of the vitreoretinal interface. A thorough search and review of peer-reviewed publications discussing the biomechanical properties of the vitreous humor in both human and animal specimens was conducted. Findings on the effects of biomechanics on vitreoretinal pathologies and vitreous biotransport were analyzed and discussed. The pig and rabbit vitreous have been found to be most mechanically similar to the human vitreous. Age-related liquefaction of the vitreous creates two mechanically unique phases, with an overall effect of softening the vitreous. However, the techniques used to acquire this mechanical data are limited by the in vitro testing methods used, and the vitreous humor has been hypothesized to behave differently in vivo due in part to its swelling properties. The impact of liquefaction and subsequent detachment of the vitreous humor from the posterior retinal surface is implicated in a variety of tractional pathologies of the retina and macula. Liquefaction also causes significant changes in the biotransport properties of the eye, allowing for significantly faster movement of molecules compared to the healthy vitreous. Recent developments in computational and ex vivo models of the vitreous humor have helped with understanding its behavior and developing materials capable of replacing it. A better understanding of the biomechanical properties of the vitreous humor and how these relate to its structure will potentially aid in improving clinical metrics for vitreous liquefaction, design of biomimetic vitreous substitutes, and predicting pharmacokinetics for intravitreal drug delivery. [ABSTRACT FROM AUTHOR]

To determine the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in postmortem ocular specimens of patients with severe COVID-19 disease. Postmortem conjunctival (28 samples), aqueous humor (30 samples) and vitreous humor (30 samples) specimens were obtained bilaterally from the eyes of 15 deceased COVID-19 patients within one hour of death. The presence of viral RNA was evaluated in samples using Real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Positive RT-PCR SARS-COV-2 results were found in one conjunctival and 2 vitreous humor samples. All aqueous humor samples tested negative for the presence of SARS-COV-2 RNA. Of note, three positive samples were obtained from three different patients. The overall prevalence of positive RT-PCR ocular samples was 3.4% among all samples and 20% at the patient level. SARS-CoV-2 RNA is detectable in postmortem conjunctival and vitreous humor samples of patients with severe COVID-19. [ABSTRACT FROM AUTHOR]

Using post-mortem vitreous humour (VH) electrolyte in estimating the post-mortem interval (PMI) is not well studied in the infant population. We hypothesize that VH can be useful in estimating PMI in shorter PMI. This 5-year retrospective study investigated the changes in VH electrolytes (Na+, Cl− and K+) with respect to shorter PMI. This study examined PMI <48 hours and stratified the PMI into two groups (i.e. <24 hours and 24–48 hours). The electrolyte levels were compared and linear regression analysis was performed between the two groups. Our result showed that K+ increases with PMI and is a relatively good estimator (compared to adults) for PMI especially when PMI was <24 hours. Na+ and Cl− showed some evidence that they decrease with PMI but have no use in estimating PMI. The results from this study suggested K+ is useful in estimating PMI but limited to only when the PMI is <24 hours. [ABSTRACT FROM AUTHOR]

This study aims to explore the differences in the levels of complement components and complement regulatory factors in the vitreous humor of patients with retinal detachment with choroidal detachment (RRDCD), patients with rhegmatogenous retinal detachment (RRD). A prospective case-control study design was used to recruit 20 patients with RRDCD and 20 patients with RRD in consecutive cases who underwent pars plana vitrectomy from March 2019 to January 2020. The control group comprised 15 patients with epiretinal membrane and 5 eyes from cadavers. The concentrations of complement C2, complement C4b, complement C5/C5a, complement C9, complement factor D (CFD), lectin, and complement factor I (CFI) were measured using Multiplex Luminex Assay, and the concentration of soluble decay acceleration factor (sDAF) was measured using ELISA. As compared with the RRD and control groups, complement C2, complement C4b, complement C5/C5a, complement C9, CFD, lectin, CFI, and sDAF were significantly increased in the RRDCD group. Additionally, as compared with the control group, the concentrations of complement component C2 and CFD were significantly increased in the vitreous humor of the RRD group. Components of all three complement pathways were elevated in eyes with RRDCD. Interestingly, while there was evidence of early complement activation in RRD, the final common pathway components were not elevated. In contrast, RRDCD eyes showed significant elevations of the MAC complex components, underscoring a potential pathophysiologic impact of complement activation in this condition. [ABSTRACT FROM AUTHOR]

To summarize the clinical features and probable factors associated with recurrence within 6 months in northern Chinese ocular toxocariasis (OT) patients. A retrospective cohort study (38 OT eyes) was conducted. Clinical features, aqueous inflammatory cytokines, complications, and parameters associated with recurrence after treatment were analyzed. The initial best-corrected visual acuity (BCVA) was related to the anterior inflammation grade at the onset (P =.028). The mean BCVA and anterior inflammation improved significantly (P <.05) after treatment. The OT eyes had higher aqueous humor cytokine levels (IL-6, IL-8, and IL-10) compared with the normal eyes (P <.001). More severe anterior inflammation grade or longer duration of uveitis were more likely to increase the probability of recurrence (P =.008 and P =.025), TA injection during/after vitreous surgery can reduce the probability of recurrence (P =.031). The combination therapy of vitreoretinal surgery, steroids, and albendazole therapy may reduce inflammation and recurrence of OT effectively. Abbreviations: BCVA: best-corrected visual acuity; BFGF: basic fibroblast growth factor; CFT: central foveal thickness; CI: confidence interval; ELISA: Enzyme-linked immunosorbent assay; ERM: epiretinal membrane; IOP: intraocular pressure; IQR: interquartile range; IL: interleukin; LFM: laser flare meter; MH: macular hole; OCT: optical coherence tomography; OR: odds ratio; OT: ocular toxocariasis; RD: retinal detachment; TA: triamcinolone acetonide; TCLA: Toxocara canis larva crude antigen; TGF: transforming growth factor; VCAM: vascular cell adhesion molecule; VEGF: vascular endothelial growth factor [ABSTRACT FROM AUTHOR]

Purpose: Many intraocular pressure (IOP)-lowering medications contain benzalkonium chloride (BAK), a preservative associated with unfavorable outcomes. A formulation of latanoprost 0.005% ophthalmic without BAK is approved by the FDA and indicated for reduction of IOP in patients with open-angle glaucoma or ocular hypertension. We present two preclinical studies of latanoprost 0.005% BAK-free vs latanoprost with BAK; one examining plasma and ocular tissue pharmacokinetics (PK) in New Zealand white rabbits, and one comparing in vivo IOP-lowering efficacy in healthy beagles. Methods: In the PK study, one drop of treatment (latanoprost BAK-free or latanoprost with BAK) was instilled into both eyes of rabbits in each treatment group (n = 18). At 0.25, 0.5, 1, 4, 6, and 24 hours postdose, three rabbits per study group underwent terminal blood and tissue collection. In the IOP study, in the first dosing period, both eyes of each beagle received either 1 drop latanoprost BAK-free or latanoprost with BAK, once daily for 10 days. After a 10-day washout period, a second 10-day dosing period was conducted and latanoprost BAK-free or latanoprost with BAK were dosed in the opposite eyes, respectively. IOP measurements were taken at 1, 6, and 12 hours postdose. Results: The maximum plasma concentration for latanoprost BAK-free and latanoprost with BAK occurred 0.25 hours after administration (174.1 vs 217.2 pg/mL, respectively). Area under the concentration time curve from zero to infinity was highest in aqueous humor for latanoprost BAK-free and latanoprost with BAK (133.1 vs 119.6 hr·ng/mL, respectively) and was not estimable in vitreous humor. In beagles, once-daily administration of latanoprost BAK-free or latanoprost with BAK led to a significant reduction in IOP vs baseline (P <.001); there was no difference between groups (P >.05). Conclusions: Latanoprost BAK-free showed comparable activity in reducing IOP, and comparable plasma and ocular PK parameters to latanoprost with BAK. [ABSTRACT FROM AUTHOR]

To report a case of acute retinal necrosis (ARN) due to varicella zoster virus (VZV) after COVID-19 vaccine administration. Observational case report. A 62-year-old immunocompetent African American male presented with left eye redness, decreased vision, and floaters after receiving a COVID-19 vaccine seven days prior. Slit-lamp examination revealed diffuse fine endothelial keratic precipitates. Funduscopic examination was notable for vitreous cells, occlusive retinal vasculitis, large retinal hemorrhages, and three quadrants of peripheral areas of retinal whitening. Quantitative polymerase chain reaction testing was positive for varicella zoster virus in the vitreous humor. Treatment with intravitreal and intravenous antiviral therapy resulted in symptomatic improvement. COVID-19 mRNA vaccination may cause an immunomodulatory response that leads to reactivation of dormant VZV. Early recognition and treatment can improve visual outcomes. [ABSTRACT FROM AUTHOR]

Research on the vitreous humor and development of hydrogel vitreous substitutes have gained a rapid increase in interest within the past two decades. However, the properties of the vitreous humor and vitreous substitutes have yet to be consolidated. In this paper, the mechanical properties of the vitreous humor and hydrogel vitreous substitutes were systematically reviewed. The number of publications on the vitreous humor and vitreous substitutes over the years, as well as their respective testing conditions and testing techniques were analyzed. The mechanical properties of the human vitreous were found to be most similar to the vitreous of pigs and rabbits. The storage and loss moduli of the hydrogel vitreous substitutes developed were found to be orders of magnitude higher in comparison to the native human vitreous. However, the reported modulus for human vitreous, which was most commonly tested in vitro, has been hypothesized to be different in vivo. Future studies should focus on testing the mechanical properties of the vitreous in situ or in vivo. In addition to its mechanical properties, the vitreous humor has other biotransport mechanisms and biochemical functions that establish a redox balance and maintain an oxygen gradient inside the vitreous chamber to protect intraocular tissues from oxidative damage. Biomimetic hydrogel vitreous substitutes have the potential to provide ophthalmologists with additional avenues for treating and controlling vitreoretinal diseases while preventing complications after vitrectomy. Due to the proximity and interconnectedness of the vitreous humor to other ocular tissues, particularly the lens and the retina, more interest has been placed on understanding the properties of the vitreous humor in recent years. A better understanding of the properties of the vitreous humor will aid in improving the design of biomimetic vitreous substitutes and enhancing intravitreal biotransport. [ABSTRACT FROM AUTHOR]

Tissues in the eye are particularly susceptible to oxidative damage due to light exposure. While vitamin C (ascorbic acid) has been noted as a vital antioxidant in the vitreous humor, its physiological concentration (1–2 mM) has been shown to be toxic to retinal and lens epithelial cells in in vitro cell culture. We have explored adding vitamin C to hydrogel vitreous substitutes as a potential therapeutic to prevent oxidative damage to intraocular tissues after vitrectomy. However, vitamin C degrades rapidly even when loaded at high concentrations, limiting its long-term effectiveness. Glutathione, another antioxidant found abundantly in the lens at concentrations of 2–10 mM, was proposed to be used in conjunction with vitamin C. Cell viability and reactive oxygen species activity of human retinal and lens epithelial cells treated with various combinations of vitamin C, glutathione, hydrogen peroxide, and a hydrogel vitreous substitute were determined using CellTiter-Glo luminescent cell viability assay and dichlorofluorescein assay, respectively. The vitamin C remaining in hydrogel vitreous substitute or glutathione-vitamin C solutions was determined using a microplate reader at 265 nm wavelength, compared against standard solutions with known concentrations. Glutathione protected the lens and retinal cells from the negative effect of vitamin C on cell viability and prolonged the antioxidant effect of vitamin C in vitro. While the detected reading of pure vitamin C solution decreased rapidly from 100% to 10% by 3 days, glutathione provided a significant extension to vitamin C stability, with 70% remaining after 14 days when the glutathione was used at physiological concentrations found in the lens (2–10 mM). These results indicate glutathione might be an effective addition to vitamin C in intraocular implants, including potential vitreous substitutes, and warrants additional studies on the effectiveness of the vitamin C – glutathione combination in preventing oxidative stress post-vitrectomy. [ABSTRACT FROM AUTHOR]

In forensic practice, the nonspecificity of macroscopic and microscopic findings renders the diagnosis of fatal hypothermia an ongoing challenge for forensic pathologists. Thus, the development of new methods to help improve the accurate diagnosis of fatal hypothermia is needed. In this study, attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy in combination with chemometrics was employed to characterize rabbit vitreous humour (VH) in fatal hypothermia. First, a statistical analysis of spectra from two groups revealed that nucleic acid and glucose levels were significantly higher in the VH of the fatal-hypothermia group than that of the control group. Subsequently, principal component analysis further indicated that the fatal-hypothermia group had increased glucose and nucleic acid levels than those of the control group. Ultimately, a robust genetic algorithm-guided partial least-square discriminant analysis model was constructed to predict unknown VH donors with 100% accuracy. This preliminary study demonstrates that combining VH ATR-FTIR spectroscopy and chemometrics may be an effective method in the identification of fatal hypothermia. [ABSTRACT FROM AUTHOR]

Purpose: The main purpose of this study was to increase the concentration and bioavailability of Ciprofloxacin (CPX) in the rabbit eye by liposomal formulation. Methods: CPX- loaded liposomes with and without Carbomer 934 (carbomer) were prepared by a thin-layer hydration method. Liposomal formulations after evaluation for characters such as particle size and entrapment efficiency were used in in-vivo experimental for installation into the rabbit's eyes. This experimental study consisted of 10 rabbits divided into two groups. Group 1 (liposomes without coating) and group 2 (carbomer coated liposomes) received one drop per h of liposomes consists of 0.3% CPX in the right eye and commercial CPX eye drop in the left eye until 6 h. Aqueous humor and vitreous samples were collected from all rabbits at the baseline, 1, 3 and 6 h and the drug concentration determined by high pressure liquid chromatography (HPLC). On the other hand, minimum inhibitor concentration (MIC) and minimum bactericidal concentration (MBC) of CPX-loaded in liposomes were determined. Results: liposomal formulations increased ocular bioavailability of CPX around four-folds compared with a commercial CPX eye drop. The increase in the ocular bioavailability may be effective and help to treat bacterial endophthalmitis as well as can be used in prophylaxis of post-operative endophthalmitis. Conclusion: The concentrations of CPX on the aqueous humor and vitreous after liposomes application were more than MIC of CPX against pseudomonas auroginosa and staphylococcus aurous but for commercial eye drop was less than MIC. Therefore liposomes modified the pharmacokinetics of CPX and improved pharmacodynamics property. [ABSTRACT FROM AUTHOR]

The postmortem diagnosis of fatal heatstroke (hyperthermia) is a challenging task in forensic practice. Attenuated Total Reflectance Fourier transform infrared spectroscopy combined with chemometrics was utilized to explore the biochemical difference of fatal heatstroke and to establish diagnosis models in this study. The complementary results of spectral absorbance comparison and principal component analysis demonstrated that the spectral differences between the hyperthermia and control groups mainly arose from the variations in the structure or composition of nucleic acids, proteins, amino acids, and carbohydrates in the vitreous humor. A genetic algorithm-guided partial least squares discriminant analysis model was established for the postmortem diagnosis of heatstroke, which achieved great specificity and sensitivity, both with scores of 100%. Furthermore, classification predictions of unknown vitreous humor samples collected from 11 rabbits were also performed by the model, resulting in 100% correct discrimination. This preliminary research demonstrates that Attenuated Total Reflectance Fourier transform infrared spectroscopy in combination with chemometrics has the potential to be an effective aid for the postmortem diagnosis of fatal heatstroke. [ABSTRACT FROM AUTHOR]

Cefuroxime is one of the widely used antibiotics. The objective of this study was to determine pharmacokinetics and disposition in various ocular tissues following topical (TOP), intracameral (IC) and intravitreal (IVT) administration of cefuroxime to rabbits. Following TOP, IC and IVT dosing plasma and various ocular tissues (aqueous humor (AH), vitreous humor (VH), conjunctiva, trabecular mesh (TM), lens and retina-choroid (RC)) were collected and analyzed to understand the disposition of cefuroxime. Postintravenous administration plasma samples were collected to determine the systemic pharmacokinetics. Post-TOP dosing cefuroxime concentrations were observed only in conjunctiva up to 48 h. IC administration showed cefuroxime concentrations in AH up to 8 h; in conjunctiva, TM and plasma, the concentration lasted up to 4 h and in RC and VH till 1 h. IVT administration of cefuroxime showed concentrations in all ocular tissues (up to 8 h) and lasted up to 48 h except in conjunctiva and RC. There was evidence that the mechanism(s) of cefuroxime entry into the eye by via IVT, IC and TOP routes is clearly different. The present ocular tissue data may aid clinicians for considering appropriate choice in the treatment of post-operative ocular complications due to bacterial infections including endophthalmitis. [ABSTRACT FROM AUTHOR]

In this study, acute carbon monoxide (CO) was used to cause the death of experimental animals through inhalation. The sample size of the study was made up of 18 rabbits divided into the control group (CG), disguised death (DD) and carbon monoxide death (CD) groups respectively. Vitreous humours were extracted using standard methodologies and biochemical parameters estimated using WHO approved methods and procedures. The findings showed a significant decrease (P < 0.05) in vitreous humour chloride ion, calcium ion, pH, uric acid and total calcium in the CDs. However, vitreous lactate dehydrogenase (LDH) of the experimental animals significantly increased (P < 0.05) only in the CD group, while creatine kinase (CK) and creatine significantly increased in both the DD and CD animal groups, although they were markedly higher in the CD. Therefore, decreases in concentrations of vitreous humour uric acid, chloride and calcium profile, and an increase in vitreous LDH could serve as possible indicators of CO poisoning, especially in scenarios of impracticable use of blood, as in rigor mortis, livor mortis or decomposition. [ABSTRACT FROM AUTHOR]

Introduction: γ-Hydroxybutyric acid is an endogenous substance, a therapeutic agent, and a recreational drug of abuse. This psychoactive substance acts as a depressant of the central nervous system and is commonly encountered in clinical and forensic practice, including impaired drivers, poisoned patients, and drug-related intoxication deaths. Objective: The aim of this review is to assist clinical and forensic practitioners with the interpretation of γ-hydroxybutyric acid concentrations in blood, urine, and alternative biological specimens from living and deceased persons. Methods: The information sources used to prepare this review were PubMed, Scopus, and Web-of-Science. These databases were searched using keywords γ-hydroxybutyrate (GHB), blood, urine, alternative specimens, non-conventional biological matrices, saliva, oral fluid, sweat, hair, vitreous humor (VH), brain, cerebrospinal fluid (CSF), dried blood spots (DBS), breast milk, and various combinations thereof. The resulting 4228 references were screened to exclude duplicates, which left 1980 articles for further consideration. These publications were carefully evaluated by taking into account the main aims of the review and 143 scientific papers were considered relevant. Analytical methods: The analytical methods used to determine γ-hydroxybutyric acid in blood and other biological specimens make use of gas- or liquid-chromatography coupled to mass spectrometry. These hyphenated techniques are accurate, precise, and specific for their intended purposes and the lower limit of quantitation in blood and other specimens is 0.5 mg/L or less. Human pharmacokinetics: GHB is rapidly absorbed from the gut and distributes into the total body water compartment. Only a small fraction of the dose (1-2%) is excreted unchanged in the urine. The plasma elimination half-life of γ-hydroxybutyric acid is short, being only about 0.5-0.9 h, which requires timely sampling of blood and other biological specimens for clinical and forensic analysis. Endogenous concentrations of GHB in blood: GHB is both an endogenous metabolite and a drug of abuse, which complicates interpretation of the laboratory results of analysis. Moreover, the concentrations of GHB in blood and other specimens tend to increase after sampling, especially in autopsy cases. This requires the use of practical "cut-off" concentrations to avoid reporting false positive results. These cut-offs are different for different biological specimen types. Concentrations of GHB in clinical and forensic practice: As a recreational drug GHB is predominantly used by young males (94%) with a mean age of 27.1 years. The mean (median) and range of concentrations in blood from apprehended drivers was 90 mg/L (82 mg/L) and 8-600 mg/L, respectively. The concentration distributions in blood taken from living and deceased persons overlapped, although the mean (median) and range of concentrations were higher in intoxication deaths; 640 mg/L (280 mg/L) and 30-9200 mg/L, respectively. Analysis of GHB in alternative specimens: All biological fluids and tissue containing water are suitable for the analysis of GHB. Examples of alternative specimens discussed in this review are CSF, saliva, hair strands, breast milk, DBS, VH, and brain tissue. Conclusions: Body fluids for the analysis of GHB must be obtained as quickly as possible after a poisoned patient is admitted to hospital or after a person is arrested for a drug-related crime to enhance chances of detecting the drug. The sampling of urine lengthens the window of detection by 3-4 h compared with blood samples, but with longer delays between last intake of GHB and obtaining specimens, hair strands, and/or nails might be the only option. In postmortem toxicology, the concentrations of drugs tend to be more stable in bladder urine, VH, and CSF compared with blood, because these sampling sites are protected from the spread of bacteria from the gut. Accordingly, the relationship between blood and urine concentrations of GHB furnishes useful information when drug intoxication deaths are investigated. [ABSTRACT FROM AUTHOR]

This study reports on a smartphone-based application for the determination of time since death (TSD) from vitreous humour (VH) protein via recognition and quantification using a simple biuret method for on-the-spot analysis. In basic pH, in the presence of protein, the biuret reagent forms a protein-biuret complex resulting in a colour change that is measurable using a UV-vis spectrophotometer. The limit of detection (LOD) for Bovine serum albumin (BSA) was found to be 8 μg/ml and the limit of quantification (LOQ) was found to be 10 μg/ml. The developed method was further validated and applied for TSD determination from VH samples in the range of 3-60 h. The results showed that there is a linear correlation between the VH protein concentration and TSD, as the protein concentration decreases up to 60 h, with the equation TSD = 33.72 + (-0.27) × concentration. Further, in the present study smart approach was applied for the TSD determination. The results obtained showed that the current method proves to have a great utility up to 60 h. The linear regression equation between TSD and RGB (red, green and blue) intensities of protein concentration tup to 60 h ± 4.5 h was found to be TSD = 6.27E2+1.41*RGB intensity. The proposed method provides a smart, rapid and sensitive, as well as cost effective, TSD determination via VH protein. [ABSTRACT FROM AUTHOR]

Bevacizumab is an anti-vascular endothelial growth factor drug that can be used to treat choroidal neovascularization (CNV). Bevacizumab-loaded multivesicular liposomes (Bev-MVLs) have been designed and developed to increase the intravitreal retention time of bevacizumab and reduce the number of injection times. In this study, Bev-MVLs with high encapsulation efficiency were prepared by double emulsification technique, and antibody activity was determined. The results revealed that 10% of human serum albumin (HSA) could preserve the activity of bevacizumab. In vitro release of Bev-MVLs appeared to be in a more sustained manner, the underlying mechanisms of Bev-MVLs indicated that bevacizumab was released from MVLs through diffusion and erosion. Results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that bevacizumab could retain its structural integrity after being released from MVLs in vitro. In vivo imaging was used to evaluate the retention time of antibody in rat eyes, while pharmacokinetic analysis was performed on rabbit eyes. These results indicated that Bev-MVLs exhibited sustained release effects as compared to bevacizumab solution (Bev-S). Bev-MVLs could effectively inhibit the thickness of CNV lesion as compared to Bev-S at 28 days after treatment. Furthermore, these data suggest that Bev-MVLs are biologically feasible to increase the retention time of bevacizumab in vitreous humor. This novel Bev-MVLs may therefore serve as a promising sustained release drug delivery system for the treatment of CNV. [ABSTRACT FROM AUTHOR]

Purpose: To assess cellular composition and local cytokine response in vitreous humor of tubercular uveitis. Methods: Cells were collected from vitreous cassettes and peripheral blood of 8 tubercular uveitis and 5 control subjects, undergoing vitrectomy and analyzed by flow cytometry for cellular composition, activation status, proinflammatory cytokine expression, and uptake of TLR9 ligand, CpG ODN 2216. Results: CD3 + T cells with equal proportion of CD4+ and CD8 + T cells formed major fraction of infiltrating cells. The vitreous humor showed higher expression of recent activation marker, CD69, and proinflammatory cytokines, IFN-γ and IL-17A, in CD4 + T cells as compared to peripheral blood. Lastly, intraocular CD4 + T cells showed reduced uptake of ODN 2216 than peripheral blood. Conclusions: Our results indicate that local antigenic stimuli trigger T cell infiltration and activation of CD4 + T cells that are hyporesponsive to TLR9 stimulation. These infiltrating T cells might be responsible in further aggravating ocular inflammation. [ABSTRACT FROM AUTHOR]

VEGF-A and VEGF-B are proangiogenic and key regulating factors for blood vessel growth. This study aims to compare VEGF-A and VEGF-B levels in the serum and vitreous of patients with neovascular pathology versus non-neovascular pathology. Our findings showed vitreous VEGF-A and VEGF-B levels increased in patients with neovascular disease, with higher levels of VEGF-A compared to VEGF-B (p ≤ .05). In the diabetic retinopathy (DR) group, higher vitreous VEGF-A or VEGF-B were found in proliferative diabetic retinopathy (PDR) than in non-PDR. The strong correlation between VEGF-A and VEGF-B demonstrates a simultaneous pathological increase of cytokines (p < .001), suggesting besides VEGF-A, VEGF-B is another contributor to ocular pathologies involving angiogenesis. There was no correlation between vitreous and serum VEGF-A or VEGF-B; however, a correlation between vitreous (VEGF-A or VEGF-B) and macular volume (p < .05) in DR patients was found. Targeting VEGF-A and VEGF-B in macular and retinal vascular diseases, involving neovascularization, may improve treatment outcomes. [ABSTRACT FROM AUTHOR]

The disadvantages associated with routine toxicological samples, such as blood samples, have encouraged the forensic toxicologist to use vitreous humour as an alternative matrix. However, its use is still limited. The reason for this is the lack of a systematic study in this domain. Moreover, the phenomena of drug disposition in ocular tissues are mostly unexplored. This paper presents a controlled study to investigate the distribution of diazepam in post-mortem blood, vitreous humour and ocular tissues using rabbit as an animal model. This study reveals that diazepam levels in vitreous and aqueous humour increase with their decrease in whole blood at post-mortem. A further study on the distribution of diazepam in ocular tissues reveals that the anterior and posterior segment tissues might be responsible for the increase in diazepam levels in aqueous humour and vitreous humour respectively. The present study strengthens the possibility of using vitreous humour as a complementary sample to blood in forensic toxicological investigations. [ABSTRACT FROM PUBLISHER]

Methotrexate (MTX) is an anticancer drug while metoclopramide (MCP) is an antiemetic agent. Both the drugs are commonly coprescribed to avoid the emesis caused by anticancer drug. In this study, a novel, rapid, sensitive, and cost-effective reverse-phase high-performance liquid chromatography method was developed and validated for simultaneous determination of the methotrexate and metoclopramide in biological and pharmaceutical samples using sparfloxacin as internal standard. The analytes were separated on a Kromasil 100-5C18 RP (250 × 4.6 mm, 5 µm) column, methanol, and 0.05% trifloroacetic acid (36:64 v/v) as mobile phase with a flow rate of 1 mL/min, detection wavelength of 290 nm, and column oven temperature at 40°C. Both the analytes were extracted from physiological fluids (bovine aqueous humor, vitreous humor, and human plasma) using mixture of methanol and 10% perchloric acid (50:50 v/v). The method was linear over the concentration range of 0.025–1.0 µg/mL for methotrexate and 0.030–1.0 µg/mL for metoclopramide. The % recovery from human plasma was 98.57 and 96.74% for MTX and MCP, respectively, while from aqueous humor and vitreous humor was 95.84 and 98.51% for MTX. The developed method was applied forin vitrorelease of MTX from polymeric nanoparticles and can be applied for analysis of pharmaceutical and biological samples containing both the drugs. [ABSTRACT FROM PUBLISHER]

Purpose: To compare the lowering effects of ketorolac 0.4% and nepafenac 0.1% on aqueous and vitreous humor prostaglandin E2 (PGE2) levels in rabbits.Methods: Ketorolac and nepafenac ophthalmic solutions were administered to the right eyes of 24 healthy rabbits after randomized division into two groups. The left eyes of these rabbits were considered as controls for the two groups. On the 4th day of the experiment, the samples were taken from the aqueous and vitreous humors of the rabbits bilaterally, and PGE2 levels were measured by an enzyme immune assay kit.Results: Ketorolac and nepafenac achieved a statistically significant decrease (p<0.001, for each) in PGE2 levels in the aqueous (11.75 ± 6.15 and 14.75 ± 7.60 pg/mL, respectively) and the vitreous humor (6.58 ± 4.62 and 9.83 ± 4.55 pg/mL, respectively).Conclusions: Both ketorolac and nepafenac inhibited PGE2 levels in both the aqueous and vitreous humors of rabbits. Although PGE2-lowering effects were similar in the aqueous humor, nepafenac seemed to be more potent than ketorolac in the vitreous humor. [ABSTRACT FROM AUTHOR]

Purpose: To develop a simple, specific, and rapid method to determine corticosteroid concentrations in vitreous humor. Methods: An analytical method based on high-pressure liquid chromatography-tandem mass spectrometry (HPLC-MS) with a simple extraction procedure was developed. New Zealand albino rabbits (n= 54) received a single (0.1 mL) intravitreal injection of dexamethasone (DXM, 0.1 mg), methylprednisolone (MP, 2 mg), or triamcinolone acetonide (TA, 10 mg). Eyes were enucleated and mean vitreous steroid levels were quantified at 12 h and 1, 2, 3, 7, and 14 days. Results: Corticosteroids were extracted from the vitreous with acetonitrile, and TA was extracted with ethyl acetate, yielding high protein precipitation and clean solution samples. Vitreous samples were analyzed by isocratic HPLC-MS with mobile phase comprising acetonitrile and 2 mM ammonium formate buffer in water, pH 3.5. The linear range was 50–100,000 ng/g with a lower quantification limit of 45 ng/g for DXM and MP, and 50 ng/g for TA. Vitreous levels of DXM and MP were not detectable 14 days post-administration. Vitreous levels of TA were positive and stable throughout the study in both injected and control eyes. Conclusions: The HPLC-MS analytical method is an alternative to HPLC-MS/MS methods, sensitive enough for identifying and quantifying steroids in vitreous humor at a therapeutic dosage scale. [ABSTRACT FROM PUBLISHER]

Background: The aim was to investigate the effect of uneventful phacoemulsification on vitreoretinal interface evaluated by optical coherence tomography (OCT) and ultrasound.Methods: One hundred and fifty eyes were evaluated for the presence or absence of posterior vitreous detachment by ultrasound and OCT prior to cataract surgery. Only those eyes with intact vitreoretinal adhesion were included in the study. All patients underwent cataract surgery. At one month, three months and six months, all patients were assessed with OCT and ultrasound. The data were analysed for statistical significance.Results: The study was carried out on 30 of 31 patients with no posterior vitreous detachment. The mean age of patients was 62.63 ± 7.15 years (range 49 to 75 years) and 15 were female. Posterior vitreous detachment developed in 17 patients (56.66 per cent) at one month, 21 patients (70 per cent) at three months and 22 patients (73.33 per cent) at six months following the surgery. No complications or acute symptoms were detected associated with posterior vitreous detachment.Conclusion: Vitreoretinal interface changes and vitreoretinal separations and progression of separation can be easily evaluated by OCT. The current study confirms that posterior vitreous detachment occurs commonly soon after cataract surgery. [ABSTRACT FROM AUTHOR]

Vitreomacular adhesion (VMA) describes the adhesion of the posterior hyaloid face to the inner retina in any part of the macula. This can arise after incomplete separation of the posterior vitreous cortex from the macula during vitreous liquefaction. While the VMA may resolve spontaneously, a strong and persistent adhesion can lead to a variety of anatomical changes, including vitreomacular traction (VMT) and macular hole (MH). Both conditions can present with metamorphopsia and decreased vision. In cases of symptomatic VMT and full-thickness macular hole, pars plana vitrectomy has long been the standard of care. However, due to the possible surgical complications and need for postoperative care, many have searched for non-surgical options via pharmacologic vitreolysis. Ocriplasmin (Jetrea, Thrombogenics USA, Alcon/Novartis EU) is a recombinant protease approved in October 2012 for the treatment of symptomatic vitreomacular adhesion (VMA). There have been conflicting views on the safety of Ocriplasmin with changes in the ellipsoid zone seen on OCT and changes seen on ERG indicating photoreceptor damage. This publication reviews the efficacy and safety of ocriplasmin injection for VMA based on previously published data. [ABSTRACT FROM AUTHOR]

Fungal endophthalmitis is an important cause of vision loss worldwide with a large body of literature describing the treatment of the disease. The evidence supporting the use of pars plana vitrectomy in the management of fungal endophthalmitis is largely comprised of case reports and case series and demonstrates the important role of vitrectomy surgery. Vitrectomy can improve the likelihood of establishing the diagnosis, enhance the treatment of infection by removing fungal elements in the vitreous, aid in the removal of other inoculated intraocular structures, and is an important tool in the management of vision-threatening post-infectious sequelae like retinal detachment and epiretinal membrane. [ABSTRACT FROM AUTHOR]

Aim: To set-up a simple technique for collecting spontaneous vitreal reflux (VR) in patients undergoing intravitreal injection. Both total protein concentration and vascular endothelial growth factor (VEGF)/Interleukin 13 (IL13) levels were used to validate the technique. Methods: Sixty consecutive patients with neovascular age-related macular degeneration (nAMD, vitreal reflux drop, VR) and 10 patients underwent vitrectomy for macular hole (whole vitreous removal) were enrolled for the study as controls. Thirty-three out of 60 patients were also subjected to tear sampling. VR sampling was performed after the intravitreal injection. Four sampling tools (10 Schirmer strips, 10 microsponges, 20 millipore filters; 20 micropipettes) were tested. Analysis of protein concentration/composition was performed between VR samples and vitreous samples to analyze the difference. The concentration of VEGF and IL 13 levels between cases and control samples were compared. Results: Millipore and micropipette techniques allowed the collection of higher protein concentrations in VR samples, comparison of both protein concentrations revealed no significant difference in the protein profile. However, the micropipette sampling was found easier to perform and did not require additional protein extraction from a solid support (membrane). Indeed, tear proteins and drug contaminants were not detected in micropipette samples. Increased VEGF levels were detected in naive VR group and to a less extend in VR group of nAMD patients undergoing intravitreal injection, with respect to the controls (macular holes). No significant differences in IL13 levels were quantified in nAMD sub-groups, as compared to naive and controls. Conclusions: Overall, we provide evidence for a safe method for sampling VR at the end of intravitreal injection. This procedure might represent an interesting approach either for the prognosis of disease or monitoring the efficacy of intravitreal therapy. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the alteration ofN-glycans in the vitreous fluid of patients with neovascular glaucoma (NVG) secondary to proliferative diabetic retinopathy (PDR). Methods: Vitreous samples were collected from 18 patients with PDR (including 7 with NVG and 11 without NVG), and 17 patients without diabetes. Profiles ofN-glycans were analyzed by glycoblotting-based high throughput protocol, which we recently developed. Protein levels of vascular endothelial growth factor (VEGF)-A were measured by ELISA. Results: The concentration of totalN-glycans and the concentration ofN-glycans with sialic acids were significantly higher in NVG group compared with those in non-NVG group or control group, whereas there was no significant difference in concentrations of high-mannoseN-glycans among three groups. There was a moderate correlation between the concentrations of sialylatedN-glycans and VEGF-A. Conclusions: Our data demonstrate the distinct changes ofN-glycan profile and the increase of sialylatedN-glycans in eyes with NVG secondary to PDR. [ABSTRACT FROM AUTHOR]

Vitreous humour (VH) is a quite stable and well-protected biological fluid from post-mortem degradation and contamination, making it a usable specimen in forensic pathology. We aimed to analyse the biochemical markers in VH stored for one month at –20°C and to compare them with those of serum samples of the same deceased people. To the best of our knowledge this is the first time this has been reported in the literature. Serum levels of sodium, potassium and calcium, phosphorous and VH levels of calcium, creatinine, and urea were not statistically different between fresh and stored samples. There was no significant difference in VH urea and creatinine levels whereas serum levels were significantly decreased by the 15th and 30th days. In conclusion, urea and creatinine levels in VH showed adequate stability after one month of storage at –20°C, whereas large variations were seen in the stability of inorganic components such as Na, K, Mg, Cl, and P. Our results indicate the validity of using post-mortem VH samples for urea and creatinine but not for VH stored at –20°C for a limited time frame. The differences in sample handling before being stored at –20°C may introduce bias on some components of VH. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the present study was to investigate the profile of posterior precortical vitreous pocket (PPVP) in children using spectral-domain optical coherence tomography (OCT) and to compare the profile with that of adults. Materials and methods: In this retrospective comparative study, the height at the fovea and the horizontal diameter of PPVP in healthy children and adults in the upright position were measured based on OCT (Spectralis, Heidelberg Engineering GmbH, Heidelberg, Germany) images. PPVP diameter was divided into nasal length and temporal length based on the center of the fovea. The proportion of temporal length to the entire horizontal diameter was calculated as temporal length/horizontal diameter of PPVP. The association of age with the height and the proportion of temporal length to the entire horizontal diameter were evaluated in each group. The two values were also compared between the two groups. Results: Sixty-three eyes of 63 children (mean age: 6.9 ± 1.8 years) and 44 eyes of 44 young adults (mean age: 32.1 ± 5.3 years) were included. The height of PPVP at the fovea was 355.3 ± 80.3 µm in children and 367.8 ± 75.6 µm in adults. The proportion of temporal length to the entire horizontal diameter was 0.45 ± 0.05 and 0.50 ± 0.03. The proportion was significantly greater in adults than in children (p < 0.001), whereas the height (p = 0.349) was not different between the two groups. In children, there was a positive association between the age and the proportion of temporal length to the entire horizontal diameter (p = 0.001). Conclusion: The results suggest a progressive temporal extension of PPVP during childhood. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the elimination rate of daptomycin after intravitreal injection in uveitis-induced rabbits. Materials and methods: Intravitreal injection of the single dose of 200 μg/0.05 mL daptomycin was administered to rabbits starting 24 h after induction of uveitis by an intravitreal endotoxin injection. Aqueous humor and vitreous humor samples of eight eyes per time point were collected at selected time intervals (1, 3, 6, 24, 48, 72 and 96 h), and the in vitreous half-life was calculated. Daptomycin concentrations in vitreous and aqueous humor were assayed with high-performance liquid chromatography. Results: The vitreous concentration was noted to decline slowly with time. The mean vitreous concentration was 23.25 ± 10.99 μg/mL and 11.10 ± 3.33 μg/mL at 96 h in inflamed and normal eyes, respectively. The vitreous daptomycin concentration showed an exponential decay with a half-life of 25.67 h in normal eyes and 34.6 h in inflamed eyes. The aqueous levels of daptomycin in normal eyes were low but remained significantly higher than those of inflamed eyes. Conclusions: Given that the injected dose corresponds to several times the minimum inhibitory concentrations of organisms most involved in endophthalmitis, and that therapeutic levels are present up to 96 h after injection, intravitreal daptomycin should be considered for the treatment of endophthalmitis caused by Gram-positive bacteria. [ABSTRACT FROM AUTHOR]

This study has been carried out to determine the death interval from the biochemical parameter of vitreous potassium. In 308 medicolegal cases vitreous humor was taken and analyzed for potassium with known time of death. There was a linear rise in potassium concentration with increasing death interval. Regression equation was calculated for the same. The study indicates that potassium levels in vitreous for determining death interval are useful and can afford a good method of determining the death interval along with other traditional methods. Also the previously established formulae for estimating death interval from vitreous potassium were also studied. [ABSTRACT FROM AUTHOR]

Thrombospondins are a family of large multi-domain glycoproteins described as matricelluar proteins based on their ability to interact with a broad range of receptors, matrix molecules, growth factors or proteases, and to modulate array of cellular functions including intracellular signaling, proliferation and migration. Two members of the thrombospondin family, thrombospondin 1 (TSP-1) and thrombospondin 2 (TSP-2) are studied extensively to determine their structure and function. While expressed at low levels in normal adult tissues, their increased expression is seen predominantly in response to cellular perturbations. Despite structural similarities, a notable functional difference between TSP-1 and TSP-2 includes the ability of former to activate of latent TGF-β and its competitive inhibition by the latter. Both these thrombospondins are reported to play important roles in TGF-β rich ocular environment with most reports related to TSP-1. They are expressed by many ocular cell types and detectable in the aqueous and vitreous humor. TSP-1 and TSP-2 influence many cellular interactions in the eye such as angiogenesis, cell migration, wound healing, TGF-β activation and regulation of inflammatory immune responses. Together, these processes are known to contribute to the immune privilege status of the eye. Emerging roles of TSP-1 and TSP-2 in ocular functions and pathology are reviewed here. [ABSTRACT FROM AUTHOR]

Many chemical-based methods have been examined for determination of the post-mortem interval (PMI) using body fluid. However, creatine, a non-protein nitrogen, has hardly been investigated over the last 20 years, even though the possibility of using it for PMI determination has been reported. The aim of the present study was to assess if creatine in vitreous humour and cerebrospinal fluid (CSF) correlates with PMI. Fifty-one subjects underwent vitreous humour and 56 subjects underwent CSF creatine measurement, respectively. The results showed that the creatine concentration increased linearly in the CSF and vitreous humour until about 50 and 90 hours after death, respectively. In particular, the creatine concentration in CSF (Pearson correlation = 0.79,p< 0.01) until 50 hours post-mortem was more strongly correlated with PMI than that in vitreous humour (Pearson correlation = 0.55,p< 0.01). Regarding the vitreous humour creatine concentration and PMI, our results showed a broad range at 24 hours post-mortem. [ABSTRACT FROM AUTHOR]

Purpose: This study was designed to measure vitamin D metabolites in the aqueous and vitreous humor and in tear fluid, and to determine if dietary vitamin D3 supplementation affects these levels. We also determined if the corneal epithelium can synthesize vitamin D following UV-B exposure. Methods: Rabbits were fed a control or vitamin D3 supplemented diet. Pilocarpine-stimulated tear fluid was collected and aqueous and vitreous humor were drawn from enucleated eyes. Plasma vitamin D was also measured. To test for epithelial vitamin D synthesis, a human corneal limbal epithelial cell line was irradiated with two doses of UV-B (10 and 20 mJ/cm2/day for 3 days) and vitamin D was measured in control or 7-dehydrocholesterol treated culture medium. Measurements were made using mass spectroscopy. Results: 25(OH)-vitamin D3 and 24,25(OH)2-vitamin D3 increased significantly following D3 supplementation in all samples except vitreous humor. Tear fluid and aqueous humor had small but detectable 1,25(OH)2-vitamin D3 levels. Vitamin D2 metabolites were observed in all samples. Vitamin D3 levels were below the detection limit for all samples. Minimal vitamin D3 metabolites were observed in control and UV-B-irradiated epithelial culture medium except following 7-dehydrocholesterol treatment, which resulted in a UV-B-dose dependent increase in vitamin D3, 25(OH)-vitamin D3 and 24,25(OH)2-vitamin D3. Conclusions: There are measurable concentrations of vitamin D metabolites in tear fluid and aqueous and vitreous humor, and oral vitamin D supplementation affects vitamin D metabolite concentrations in the anterior segment of the eye. In addition, the UV exposure results lead us to conclude that corneal epithelial cells are likely capable of synthesizing vitamin D3 metabolites in the presence of 7-dehydrocholesterol following UV-B exposure. [ABSTRACT FROM AUTHOR]

Purpose: To measure adrenomedullin (ADM) levels in the blood, vitreous fluid and fibrous membrane in patients with proliferative diabetic retinopathy (PDR) and study its changes in different pathological conditions. Methods: We used radioimmunoassay technique to determine immunoreactive- adrenomedullin (IR-ADM) concentrations in the plasma, vitreous samples and fibrous membrane obtained from 9 control subjects with idiopathic macular hole and 23 patients with PDR undergoing vitrectomy. Results: IR-ADM levels in the plasma, vitreous samples and fibrous membrane tissues (16.1 ± 2.91fmol/ml, 9.80 ± 2.51fmol/ml and 34.8 ± 5.22fmol/mg) were all significantly elevated in patients with PDR compared with control subjects (11.6 ± 2.38 fmol/ml, 5.8 ± 1.64 fmol/ml and 22.4 ± 1.72 fmol/mg). The levels of ADM in vitreous were also significantly higher in PDR patients with diabetic macular edema (DME) (11.2 ± 2.36 fmol/ml) than those of patients without DME (8.0 ± 1.11 fmol/ml) and controls (5.8 ± 1.64 fmol/ml). Conclusions: These findings suggest that ADM may be produced locally in the eyes and may correlate with the severity and proliferative reactions of diabetic retinopathy. [ABSTRACT FROM AUTHOR]

A 50-year-old man presented with uncontrolled erythroclastic glaucoma and recurrent vitreous hemorrhage from a previously irradiated choroidal melanoma. Despite trabeculectomy, intraocular pressure became uncontrolled due to increasing bleeding from the melanoma. The vitreous hemorrhage became voluminous and could not be stopped with multiple vitrectomies with endolaser, transpupillary thermotherapy, and transscleral laser. Endoresection of the regressed tumor and its bleeding vasculature resulted in immediate cessation of the bleeding and control of the intraocular pressure. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the interleukin (IL)-6 levels, IL-8 levels, and cellular composition of the vitreous humor in patients with proliferative diabetic retinopathy (PDR), proliferative vitreoretinopathy (PVR), and traumatic PVR.Methods: Vitreous samples from 14 patients with PDR, 10 patients with PVR, and 10 patients with traumatic PVR were analyzed. Fifteen cadaver eyes were used as controls. Cytokine levels were measured by ELISA.Results: Elevated IL-6 levels were detected in the vitreous of 12 (85.7%) of the PDR patients, eight (80%) of the PVR patients, and all (100%) of the traumatic PVR patients. None of the control IL-6 results were elevated. Vitreous IL-8 levels were elevated in 12 (85.7%) of the PDR patients, six (60%) of the PVR patients, all (100%) of the traumatic PVR patients, and one (6.7%) of the control eyes. Cytological examination of the vitreous specimens revealed a predominance of macrophages (50%) in the PDR samples and a predominance of retinal pigment epithelial (RPE) cells (60%) in the PVR samples. In contrast, neutrophils predominated (88%) in the traumatic PVR samples.Conclusion: The findings suggest that IL-6 and IL-8 may be involved in the pathogenesis of PDR, PVR, and traumatic PVR. High proportions of RPE cells and macrophages are associated with elevated IL-6 and IL-8 levels in the vitreous of PDR and PVR patients; however, the fact that these cells are not predominant in traumatic PVR suggests that different immune response mechanisms may be active in the pathogenesis of these disorders. [ABSTRACT FROM AUTHOR]

objective: To examine the results of pars plana vitrectomy for nonclearing vitreous opacities associated with ocular sarcoidosis that is resistant to corticosteroid treatment. Methods: Eight consecutive patients (II eyes) with vitreous opacities and uveitis associated with sarcoidosis were studied. All patients were resistant to or intolerant of corticosteroid therapy. All eyes underwent pars plana vitrectomy. followed by evaluation of visual acuity and recording of the grade of inflammation and complications. Results: Seven eyes had gained two or more lines of Snellen visual acuity six months postoperatively; visual acuity remained unchanged in the other four eyes. Vitreous inflammation was reduced in all cases. Severe postoperative inflammation did not recur in any eyes. Five eyes developed visually significant cataracts and underwent cataract extraction and intraocular lens insertion within 8-30 months. Based on slit-lamp biomicroscopy and fluorescein angiography, preoperative cystoid macular edema in five eyes resolved or improved within six months after vitrectomy. Postoperative complications included elevated intraocular pressure in three eyes, cataract formation in six eyes, epiretinal membrane formation in one eye. and choroidal neovascularization in one eye. None of the patients developed cystoid macular edema postoperatively. Only three patients received systemic corticosteroids after surgery. At the final visit, only one patient required systemic corticosteroid therapy. Conclusions: Pars plana vitrectomy appears to have beneficial effects on restoring vision, stabilizing vitreous inflammation, and reducing systemic corticosteroid requirements in eyes with thick vitreous opacities associated with sarcoidosis that is resistant to medical treatment. [ABSTRACT FROM AUTHOR]

Purpose. The objective of the present study was to explore acyl diester prodrugs (acetate, propionate, and butyrate) of ganciclovir (GCV) to achieve sustained therapeutic concentrations of GCV in the vitreous over a prolonged period of time following intra vitreal administration. Methods. Male New Zealand albino rabbits (2-2.5 kg) were used for these studies. Animals were kept under anesthesia throughout the course of an experiment using ketamine HC1 and xylazine. A concentric microdialysis probe was implanted into the vitreous chamber with a 21-gauge needle and a linear microdialysis probe was inserted into the anterior chamber across the cornea using a 25-gauge needle. The probes were perfused with isotonic phosphate buffer saline (pH 7.4) at a flow rale of 2μl/min. GCV prodrugs (33.2μg of diacetate. 35.9u,g dipropionate prodrugs, and 9.87μg of dibutyrate prodrug) or GCV (50, 25, and 12.5 μg) were administered intravitreally and the microdialysis samples were collected every 20 minutes over a period of 10 hours. Results. Vitreal terminal elimination half-life of GCV was found to be similar with all three doses and ranged from 325 to 401 min. Elimination rate constant (λ) and vitreal clearance of diesters increased with the ester chain length, Vitreal elimination half-lives of GCV diacetate, dipropionate. and dibutyrate esters were found to be 112 ±37, 41.9 ±13.1, and 33.5± 6.5min. respectively. Mean residence time (MRT) of regenerated GCV (356 ± 16 min, 341 ±11 min and 324 ± 19 min from GCV diacetate. dipropionate and dibutyrate, respectively) increased by 2-fold following prodrug administration as compared to direct GCV administration (185 ± 28 min).Conclusions. GCV showed linear kinetics in the dose range studied. Acyl diester prodrugs of GCV generated therapeutic concentrations of GCV in vivo. Moreover, these studies have shown that MRT of GCV could be enhanced about 2-fold through prodrug modification. [ABSTRACT FROM AUTHOR]

Purpose. Penetration of drug from the anterior chamber to the vitreous is substantial in aphakic eyes, but negligible in normal phakic eyes. The purpose of this study is to investigate the effect of the presence of peripheral iridectomy (PI) which bypasses iris-lens diaphragm on the drug penetration from the anterior chamber to (he vitreous. Methods. Twelve Japanese White rabbits underwent PI in a randomly chosen eye and the same procedures except removal of the peripheral iris in the contralateral eye. Nine weeks after the procedure, topical instillation of 20μl of 1% nipradilol into the both eyes was repeated three times at five-minute intervals, and two hours later the animals were sacrificed and the both eyes were enucleated. Concentrations of nipradilol in the aqueous and vitreous were determined using a high-performance liquid chromatography. Result. The concentrations of nipradilol were significantly greater in the eyes with PI than those in the contralateral control eyes in the aqueous (5636 ±1688 vs2835 ±663ng/g, mean ± standard error, n = 12, p = 0.0028) and in the anterior vitreous (11.9 ± 2.5 vs 5.6 ± 1.0 ng/g, p = 0.0047) while not in the posterior vitreous or in the posterior retina-choroid. The ratios of the nipradilol concentrations in the anterior or posterior vitreous to that in the aqueous were not significantly different between the both eyes. Conclusions. The presence of PI had little effect on the penetration of topically instilled nipradilol from the anterior chamber to vitreous. [ABSTRACT FROM AUTHOR]

Purpose The objective of this study was to determine the effect of the multi-drug efflux transport protein, P-glycoprotein (P-gp). on the ocular distribution of a model substrate, quinidine. Methods. Male New Zealand albino rabbits (2-2.5 kg) were employed in these studies. Animals were kept under anesthesia and a concentric microdialysis probe was implanted in the vitreous humor and a linear probe in the anterior chamber. Isotonic phosphate buffered saline was perfused through the probes, and samples were collected every 20 minutes over a period of 10 hours. Quinidine was administered both systemically (5mg/kg bodyweight) and intravitreally (5.68 μg and 0.568 μg). Inhibition experiments were performed in vivo in the presence of verapamil, which is a known P-gp inhibitor. Results. Vitreal pharmacokinetic parameters of quinidine in the presence of verapamil, i.e.. Area under the curve (AUC) (39.27±6.47minμg/ml). maximum concentration achieved (C[submax] (0.095 ± 0.011 μg/ml). vitreal elimination half-life (231.96 ± 10.77min), vitreal permeation half-life (16.57 ± 6.96 min) were significantly different from the control values (19.21 ± 3.73min.μg/ml, 0.05± 0.008 μg/ml, 165.08 ± 31.5min, 43.29 ± 12.5min respectively). A significant elevation in anterior chamber C[submax] and AUC was also observed in the presence of verapamil. Verapamil had no significant effect on vitreal kinetics of quinidine following intravitreal dose of 5.68μg, but a significant difference was observed at a lower dose of quinidine (0.568μg). A decrease in vitreal elimination half-life and AUC was observed in the presence of verapamil relative to control. Ocular kinetics of fluorescein was studied to ascertain ocular barrier integrity in the presence of verapamil. Western-blot analysis of retina-choroid sections indicates expression of P-gp on rabbit retina-choroid. Conclusion. Results suggest the involvement of a multi drug efflux transporter on the retinal pigment epithelium and neural retina affecting the intraocular kinetics of its sub-strates following systemic and intravitreal administrations. [ABSTRACT FROM AUTHOR]

PURPOSE. The expression of Fas ligand (FasL) in ocular tissues is thought to play a critical role in maintaining immune privilege in the eye. In this study, to clarify the involvement of the Fas-FasL system in inflammatory processes of the eye,we examined soluble FasL (sFasL) in ocular inflammation. METHODS. Using ELISA systems recently developed, sFasL concentrations in aqueous humor (AH) and/or vitreous fluid (VF) were measured. AH was obtained from 17 eyes of 17 uveitis patients and from 12 eyes of 12 non-uveitis (cataract) patients. VF was obtained from 22 eyes of 22 uveitis patients and 7 eyes of 7 non-uveitis (macular hole) patients. Serum levels of sFasL were also determined. RESULTS. sFasL in AH and VF was below the detection limit of the ELISA systems in all non-uveitis eyes. On the other hand, sFasL was detected in AH from uveitis patients where it measured 367.0 ± 154.7 pg/ml (mean ± SEM). sFasL was also detected in VF from uveitis patients where it measured 1132.2 ± 281.7 pg/ml. None of the sera from patients with or without uveitis contained a detectable level of sFas L. CONCLUSIONS. sFasL levels in AH and VF are elevated in the eye during ocular inflammation. Fas-FasL mediated apoptosis may play an important role in the regulation of inflammation during uveitis. [ABSTRACT FROM AUTHOR]