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Forensic Science International May 2020The chemical and biochemical analysis of bodily fluids after death is an important thanatochemical approach to assess the cause and time since death. Vitreous humor (VH)... (Review)
Review
The chemical and biochemical analysis of bodily fluids after death is an important thanatochemical approach to assess the cause and time since death. Vitreous humor (VH) has been used as a biofluid for forensic purposes since the 1960s. Due to its established relevance in toxicology, a literature review highlighting the use of VH with an emphasis on endogenous compounds has not yet been undertaken. VH is a chemically complex aqueous solution of carbohydrates, proteins, electrolytes and other small molecules present in living organisms; this biofluid is useful tool for its isolated environment, preserved from bacterial contamination, decomposition, autolysis, and metabolic reactions. The post-mortem analysis of VH provides an important tool for the estimation of the post-mortem interval (PMI), which can be helpful in determining the cause of death. Consequently, the present review evaluates the recent chemical and biochemical advances with particular importance on the endogenous compounds present at the time of death and their modification over time, which are valuable for the PMI prediction and to identify the cause of death.
Topics: Autopsy; Forensic Pathology; Humans; Illicit Drugs; Postmortem Changes; Vitreous Body
PubMed: 32169668
DOI: 10.1016/j.forsciint.2020.110235 -
Translational Vision Science &... Jul 2022To develop a machine-learning image processing model for three-dimensional (3D) reconstruction of vitreous anatomy visualized with swept-source optical coherence...
PURPOSE
To develop a machine-learning image processing model for three-dimensional (3D) reconstruction of vitreous anatomy visualized with swept-source optical coherence tomography (SS-OCT).
METHODS
Healthy subjects were imaged with SS-OCT. Scans of sufficient quality were transferred into the Fiji is just ImageJ image processing toolkit, and proportions of the resulting stacks were adjusted to form cubic voxels. Image-averaging and Trainable Weka Segmentation using Sobel and variance edge detection and directional membrane projections filters were used to enhance and interpret the signals from vitreous gel, liquid spaces within the vitreous, and interfaces between the former. Two classes were defined: "Septa" and "Other." Pixels were selected and added to each class to train the classifier. Results were generated as a probability map. Thresholding was performed to remove pixels that were classified with low confidence. Volume rendering was performed with TomViz.
RESULTS
Forty-seven eyes of 34 healthy subjects were imaged with SS-OCT. Thirty-four cube scans from 25 subjects were of sufficient quality for volume rendering. Clinically relevant vitreous features including the premacular bursa, area of Martegiani, and prevascular vitreous fissures and cisterns, as well as varying degrees of vitreous degeneration were visualized in 3D.
CONCLUSIONS
A machine-learning model for 3D vitreous reconstruction of SS-OCT cube scans was developed. The resultant high-resolution 3D movies illustrated vitreous anatomy in a manner like triamcinolone-assisted vitrectomy or postmortem dye injection.
TRANSLATIONAL RELEVANCE
This machine learning model now allows for comprehensive examination of the vitreous structure beyond the vitreoretinal interface in 3D with potential applications for common disease states such as the vitreomacular traction and Macular Hole spectrum of diseases or proliferative diabetic retinopathy.
Topics: Humans; Imaging, Three-Dimensional; Machine Learning; Tomography, Optical Coherence; Vitrectomy; Vitreous Body
PubMed: 35802368
DOI: 10.1167/tvst.11.7.3 -
European Journal of Pharmaceutics and... Oct 2018Numerous literature reports describe the liquefaction of the vitreous body with increasing age. It must be expected that this process also influences drug distribution...
Numerous literature reports describe the liquefaction of the vitreous body with increasing age. It must be expected that this process also influences drug distribution and elimination following intravitreal application of active pharmaceutical ingredients (APIs). To better understand the impact and extent of the liquefaction a magnetic resonance imaging (MRI) study was performed examining human donor eyes post mortem. For comparison, eyes of juvenile pigs were also examined representing a fully gelled vitreous. 7.1Tesla ultra-high field MRI and T2 mapping of the vitreous body were used in this study since it must be expected that age-induced degradation processes and structural changes of the vitreous gel to a liquid state will result in changes of the T2 relaxation time of water proton spins. The vitreous bodies were imaged in 12 axial slices and within each image the T2 relaxation times of water proton spins were determined. It was found that T2 relaxation time increased with increasing age of the donor. Whilst the mean T2 relaxation time (±standard deviation) of water proton spins within the central vitreous body of a juvenile porcine eye was 210.1 ± 31.1 ms, the mean T2 relaxation time within the central vitreous body of the 88-year-old and therefore oldest human donor was 528.0 ± 79.3 ms. Within the vitreous body of a single donor, the T2 relaxation time increased from the anterior to the posterior segment, for example in the vitreous body of the oldest human donor from 388.0 ± 31.1 ms on average in the anterior to 631.7 ± 42.8 ms in the posterior segment, indicating an increase in intravitreal liquefaction respectively inhomogeneity from anterior to posterior regions. Additionally, physicochemical parameters were determined yielding averages of 7.54 ± 0.34 for pH, 1.33629 ± 0.00044 for refractive index, 368.99 ± 26.87 mosmol/kg for osmolality, 97.56 ± 0.43% for drying mass loss and 0.73 ± 0.18 mg/mL for total protein content. The aging process and the liquefaction of the vitreous body are expected to affect the pharmacokinetic profile of intravitreally injected APIs, which is of high relevance to drug release from intravitreal drug delivery systems and the therapeutic concept in the treatment of posterior segment diseases. Our data indicate that such processes are not reflected in animal models. Since there is still a need for valid pharmacokinetic data, invitro test systems for the characterization of intraocular drug delivery systems have to be improved according to the current state of knowledge about the vitreous structure and intravitreal transport phenomena.
Topics: Adult; Aged; Aged, 80 and over; Aging; Animals; Eye Proteins; Female; Humans; Intravitreal Injections; Magnetic Resonance Imaging; Male; Middle Aged; Postmortem Changes; Swine; Vitreous Body
PubMed: 30055255
DOI: 10.1016/j.ejpb.2018.07.021 -
Der Ophthalmologe : Zeitschrift Der... Jan 2015Clinicopathological studies of the vitreoretinal interface (VRI) improve our understanding of the pathogenesis of vitreal maculopathy, facilitate differential diagnoses... (Review)
Review
BACKGROUND
Clinicopathological studies of the vitreoretinal interface (VRI) improve our understanding of the pathogenesis of vitreal maculopathy, facilitate differential diagnoses and help to develop new treatment strategies.
OBJECTIVE
The aim of the study was to provide a comprehensive overview on clinicopathological correlations of the VRI.
METHODS
A semi-structured literature search was performed in the Medline and Embase databases for relevant original studies on clinicopathological correlations of vitreal maculopathy, in addition to the latest books and review articles.
RESULTS
Age-related vitreous changes with persistent vitreomacular adhesions on the retinal surface promote cellular migration and proliferation onto the vitreal side of the internal limiting membrane (ILM), thereby cementing the vitreomacular adhesions and strengthening the traction forces on retinal layers. Cellular or fibrocellular proliferation at the vitreomacular interface can be seen in all vitreal maculopathies. Furthermore, vitreoschisis in the context of anomalous posterior vitreous detachment causes the presence of vitreous cortex collagen fibrils on the vitreal side of the ILM which is associated with epiretinal membrane formation. Glial cells, hyalocytes and myofibroblasts represent the major cell types in the epiretinal cell proliferation. Glial cells and hyalocytes are capable of transdifferentiation into myofibroblasts which possess strong contractive properties and are well known for the production of extracellular matrix components.
CONCLUSION
Removing vitreomacular adhesions and vitreous cortex collagen fibrils from the retinal surface is most important for successful treatment. In cases with epiretinal cell proliferation, however, removal of the ILM during macular surgery is mandatory to avoid reproliferation and recurrence. Improving the detection of epiretinal cell proliferation and cell distribution in patient eyes by optical coherence tomography or by introduction of new technologies should be addressed in the future.
Topics: Diagnosis, Differential; Epiretinal Membrane; Humans; Retinal Perforations; Treatment Outcome; Vitreous Body
PubMed: 25588538
DOI: 10.1007/s00347-014-3049-5 -
PloS One 2017To evaluate porcine vitreous flow and water flow rates in a new prototype hypersonic vitrectomy system compared to currently available pneumatic guillotine vitrectors...
PURPOSE
To evaluate porcine vitreous flow and water flow rates in a new prototype hypersonic vitrectomy system compared to currently available pneumatic guillotine vitrectors (GVs) systems.
METHODS
Two vitrectors were tested, a prototype, ultrasound-powered, hypersonic vitrector (HV) and a GV. Porcine vitreous was obtained within 12 to 24 h of sacrifice and kept at 4°C. A vial of vitreous or water was placed on a precision balance and its weight measured before and after the use of each vitrector. Test parameters included changes in aspiration levels, vitrector gauge, cut rates for GVs, % ultrasound (US) power for HVs, and port size for HVs. Data was analysed using linear regression and t-tests.
RESULTS
There was no difference in the total average mean water flow between the 25-gauge GV and the 25-gauge HV (t-test: P = 0.363); however, 25-gauge GV was superior (t-test: P < 0.001) in vitreous flow. The 23-gauge GV was only more efficient in water and vitreous removal than 23-gauge HV needle-1 (Port 0.0055) (t-test: P < 0.001). For HV, wall thickness and gauge had no effect on flow rates. Water and vitreous flows showed a direct correlation with increasing aspiration levels and % US power (p<0.05).
CONCLUSIONS
The HV produced consistent water and vitreous flow rates across the range of US power and aspiration levels tested. Hypersonic vitrectomy may be a promising new alternative to the currently available guillotine-based technologies.
Topics: Animals; Body Weight; Equipment Design; Microsurgery; Swine; Ultrasonics; Video Recording; Vitrectomy; Vitreous Body; Water
PubMed: 28586375
DOI: 10.1371/journal.pone.0178462 -
The British Journal of Ophthalmology Nov 2017To determine the potential and usefulness of ultrasound biomicroscopy (UBM) as a diagnostic procedure on a larger cohort of paediatric patients with ocular toxocariasis.
PURPOSE
To determine the potential and usefulness of ultrasound biomicroscopy (UBM) as a diagnostic procedure on a larger cohort of paediatric patients with ocular toxocariasis.
METHODS
UBM was performed on 41 eyes of 41 patients with ocular toxocariasis in order to determine configuration of peripheral retina, pars plana and vitreous. Location and range of peripheral pathology using ophthalmoscopy with scleral indentation, UBM and intraoperative confirmation were recorded and compared.
RESULTS
Pathological structures such as vitreous condensations or membranes of various configuration and extent were identified by UBM. UBM revealed peripheral granuloma and pseudocystic changes in the peripheral vitreous in 15 of 41 eyes. Compared with indirect ophthalmoscope, statistical analysis showed significant differences in the number of clock-hours of peripheral pathology detected by UBM (p=0.015), while statistical differences were not found between UBM and intraoperative peripheral examinations using scleral indentation (p=0.432).
CONCLUSIONS
UBM seems to be a valuable and reliable diagnostic technique for the evaluation of patients with ocular toxocariasis. Longitudinal studies will have to determine the relevance of UBM findings for the individual clinical course and their influence on therapeutic decisions.
Topics: Adolescent; Animals; Child; Child, Preschool; Eye Infections, Parasitic; Female; Follow-Up Studies; Humans; Male; Microscopy, Acoustic; Reproducibility of Results; Retrospective Studies; Time Factors; Toxocara; Toxocariasis; Vitreous Body
PubMed: 28302681
DOI: 10.1136/bjophthalmol-2016-309850 -
Electrophoresis Sep 2014Proteomic analysis of human vitreous humor (VH) may elucidate the pathogenesis of retinal ocular diseases and may provide information for the development of potential... (Review)
Review
Proteomic analysis of human vitreous humor (VH) may elucidate the pathogenesis of retinal ocular diseases and may provide information for the development of potential therapeutic targets due to its pivotal location near lens and retina. The discovery of whole VH proteome involves a complex analysis of thousands of proteins simultaneously. Therefore, in proteomic studies the protein fractionation is important for reducing sample complexity, facilitating the access to the low-abundant proteins, and recognizing them as biotargets for clinical research. Although several separation methods have been used, gel-based proteomics are the most popular and versatile ones applied for global protein separation. However, chromatographic methods and its combination with other separation techniques are now beginning to be used as promising set-ups for VH protein identification. This review attempts to offer an overview of the techniques currently used with VH, exploring its methodological demands, exposing its advantages, and helping the reader to plan future experiences. Moreover, this review shows the relevance of VH proteomic analysis as a tool for the study of the mechanisms underlying some ocular diseases and for the development of new therapeutic approaches.
Topics: Chromatography, High Pressure Liquid; Electrophoresis, Gel, Two-Dimensional; Eye Proteins; Humans; Proteomics; Vitreous Body
PubMed: 24825767
DOI: 10.1002/elps.201400049 -
International Ophthalmology May 2024To evaluate the levels of anxiety and depression in patients with symptomatic vitreous floaters and to determine the possible correlations of psychological implications...
PURPOSE
To evaluate the levels of anxiety and depression in patients with symptomatic vitreous floaters and to determine the possible correlations of psychological implications with the symptoms duration and possible improvement, the degree of posterior vitreous detachment, and the discomfort severity.
METHODS
Ninety patients complaining for floaters and fifty-seven age- and gender-matched healthy-control subjects were recruited. Every participant underwent a complete ophthalmological examination, including funduscopy and optical coherence tomography scans, while clinical and demographic data were also gathered. The Patient Health Questionnaire-9 (PHQ-9), the Zung Depression Inventory-Self-Rating Depression Scale (Zung SDS), and the Hospital Anxiety and Depression Scale (HADS) were completed by everyone.
RESULTS
Between the studied groups, no significant differences were detected regarding the clinical and demographic data (p > 0.05). The patients with floaters had significantly higher scores of PHQ-9, Zung SDS, HADS Anxiety, and HADS Depression (p < 0.001). After adjustment for several confounders, PHQ-9 (p = 0.041), Zung SDS (p = 0.003), and HADS Anxiety (p = 0.036) values remained significantly impaired. Among the patients, PHQ-9 and Zung SDS scores were significantly elevated in the patients with floaters duration less than 4 weeks (p < 0.05). Finally, anxiety and depression were significantly correlated with the symptoms duration and intensity, with the floater-associated discomfort, and with the stage of posterior vitreous detachment.
CONCLUSION
Vitreous floaters have a negative impact on patients' psychological status, by the terms of enhanced depressive and anxiety levels. To the best of our knowledge, our study is the first in the literature to elaborate the aforementioned association, by assessing three different questionnaires simultaneously.
Topics: Humans; Male; Female; Middle Aged; Vitreous Body; Depression; Adult; Anxiety; Eye Diseases; Tomography, Optical Coherence; Surveys and Questionnaires; Aged; Case-Control Studies; Vitreous Detachment; Vision Disorders
PubMed: 38713290
DOI: 10.1007/s10792-024-03006-y -
Retina (Philadelphia, Pa.) Feb 2021To compare the flow dynamics of beveled-tip to that of flat-tip vitreous cutters.
PURPOSE
To compare the flow dynamics of beveled-tip to that of flat-tip vitreous cutters.
METHOD
The aspiration rates of balanced salt solution and swine vitreous were measured for 25-gauge and 27-gauge beveled-tip and flat-tip vitreous cutters. Fluorescent polymer microspheres were mixed with balanced salt solution to make the flow visible. The flow dynamics at maximal cutting rates and reflux of balanced salt solution were measured with video images of a high-speed camera.
RESULTS
The aspiration rates of balanced salt solution of the 25-gauge and 27-gauge beveled-tip cutters were significantly higher than that of the flat-tip cutters at 7,500 cut/min (P = 0.0001, P = 0.038, respectively). The aspiration rate of swine vitreous by the 25-gauge beveled-tip cutter was significantly higher than that of the flat-tip cutters (P = 0.006). The mean aspiration flow in front of the cutter was significantly faster for both beveled-tip than flat-tip cutters (P = 0.003, P = 0.023). The angle of the mean aspiration flow of both beveled-tip cutters was turned to the proximal side (P = 0.004, P = 0.003). The mean reflux flow of both beveled-tip cutters was significantly faster than that of the flat-tip cutters (P = 0.006, P = 0.006).
CONCLUSION
The beveled-tip cutters have a greater velocity of aspirating frontal and proximal flow resulting in higher aspiration rates and greater reflux flow velocity.
Topics: Animals; Disease Models, Animal; Microsurgery; Saline Solution; Swine; Video Recording; Vitrectomy; Vitreous Body
PubMed: 32271276
DOI: 10.1097/IAE.0000000000002811 -
Ophthalmology Feb 2016
Topics: Animals; Anterior Chamber; Diptera; Eye Infections, Parasitic; Fluorescein Angiography; Glucocorticoids; Humans; Male; Middle Aged; Myiasis; Retinal Diseases; Vitreous Body
PubMed: 26802704
DOI: 10.1016/j.ophtha.2015.10.064