-
Forensic Science International Feb 2019The estimation of the time elapsed since death is of paramount importance in the field of forensic sciences and criminal investigation, owing, among other factors, to...
The estimation of the time elapsed since death is of paramount importance in the field of forensic sciences and criminal investigation, owing, among other factors, to the possible legal repercussions. Over the past few years various formulae have been developed to calculate this interval using a combination of different statistical methods and the concentrations of substances found in the vitreous humor. Corrective factors, such as ambient temperature, cause of death or age, which can modify the concentration of these substances and therefore the estimation of the postmortem interval, have been incorporated into models. In this paper five simple and reliable models to estimate PMI based the on the analysis of potassium, hypoxanthine and urea in the vitreous humor are presented. Corrective factors, such as body weight, rectal temperature and ambient temperature, which can influence the estimation of this interval have been incorporated into the formulae. Finally, the R and the mean squared error have been calculated for each model in order to select the best of the five. A free software program which calculates the PMI from the model and parameters used is available from the authors. It provides quick and reliable results as well as the error committed and R for each case.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Body Temperature; Body Weight; Humans; Hypoxanthine; Middle Aged; Models, Statistical; Postmortem Changes; Potassium; Urea; Vitreous Body; Young Adult
PubMed: 30611119
DOI: 10.1016/j.forsciint.2018.12.007 -
Scientific Reports Oct 2023We conducted a study to assess the pressure difference between the aqueous and vitreous humors in rabbit eyes using a direct intraocular pressure (IOP) measurement...
We conducted a study to assess the pressure difference between the aqueous and vitreous humors in rabbit eyes using a direct intraocular pressure (IOP) measurement method. A micro-optic-fiber pressure sensor was utilized for this purpose. Preliminary experiments with enucleated porcine eyes confirmed the sensor's accuracy in measuring both aqueous and vitreous humor pressure. The main study involved six healthy albino rabbits, where the sensor measured the pressure in the anterior chamber (aIOP) and posterior vitreous-cavity (pIOP). These measurements were compared to aIOP values obtained through rebound tonometry. Additionally, pre- and postoperative pressure comparisons were made after performing a vitrectomy. Results revealed a significant disparity between aqueous and vitreous humor pressures. Prior to vitrectomy, pIOP was 22.8 mmHg, over twice as high as aIOP (11.0 mmHg), but decreased to a similar level following the procedure. Comparison between the sensor measurements and rebound tonometry showed agreement in aIOP values. In conclusion, our study demonstrates that vitreous humor pressure is consistently higher than aqueous humor pressure, reaching the upper limit of normal IOP. Furthermore, vitrectomy effectively reduces pIOP, aligning it with aIOP. These findings contribute valuable insights into intraocular pressure dynamics and have implications for clinical interventions targeting ocular pressure regulation.
Topics: Animals; Swine; Rabbits; Vitreous Body; Intraocular Pressure; Vitrectomy; Tonometry, Ocular; Aqueous Humor
PubMed: 37880357
DOI: 10.1038/s41598-023-45616-z -
Journal of the Royal Society of Medicine Dec 1978
Topics: Eye Diseases; Humans; Microsurgery; Ophthalmology; Surgical Instruments; Vitreous Body
PubMed: 739498
DOI: 10.1177/014107687807101202 -
Molecular Vision Jul 2005Endothelin one (ET-1) is a vasomodulator peptide that plays a role on ocular blood flow, glial proliferation, and collagen matrix contraction by retinal pigmented...
PURPOSE
Endothelin one (ET-1) is a vasomodulator peptide that plays a role on ocular blood flow, glial proliferation, and collagen matrix contraction by retinal pigmented epithelial (RPE) cells. Both glial and RPE cells have been involved in the formation of epiretinal membranes (ERMs). This investigation was conducted to determine whether ET-1 may be associated with ERMs, either idiopathic (IERMs) or from proliferative vitreoretinopathy (PVR).
METHODS
Plasma and vitreous samples were collected from patients classified by the presence of PVR membranes, retinal detachment (RD), and other ocular conditions, such as IERMs, that made the patients candidates for vitrectomy. Immunoreactive endothelin one (IR-ET-1) was tested in plasma and vitreous by radioimmunoassay. Immunoreactive-ET-1 was localized in IERMs and PVR membranes immunohistochemically. Expression of endothelin receptors A (ETA) and B (ETB) was confirmed by reverse transcription-polymerase chain reaction.
RESULTS
IR-ET-1 levels in plasma and vitreous were higher in patients with PVR and in patients with RD than in those of the control group. Eyes with IERMs also showed higher IR-ET-1 levels than the control group cases. IR-ET-1 levels in eyes with PVR were higher than those in eyes with IERMs. IR-ET-1 levels in eyes with RD were also higher than those of eyes with IERMs. Immunoreactive ET-1 was localized in the cellular and stromal components of both IERMs and PVR membranes. Furthermore, ETA and ETB receptors were expressed in both IERMs and PVR membranes.
CONCLUSIONS
IR-ET-1 in human vitreous is elevated in PVR, RD, and IERMs. ET-1 and its receptors ETA and ETB are present in epiretinal tissue of both idiopathic and PVR membranes. These data suggest an involvement of ET-1 in retinal disease.
Topics: Adult; Aged; Aged, 80 and over; Endothelin-1; Epiretinal Membrane; Female; Glial Fibrillary Acidic Protein; Humans; Keratins; Male; Middle Aged; RNA, Messenger; Radioimmunoassay; Receptor, Endothelin A; Receptor, Endothelin B; Retinal Detachment; Reverse Transcriptase Polymerase Chain Reaction; Vitreoretinopathy, Proliferative; Vitreous Body
PubMed: 16030497
DOI: No ID Found -
Molecular Vision 2011To evaluate levels of malondialdehyde and the total antioxidant capacity (TAC) in the blood, aqueous humor, and vitreous bodies of diabetic and nondiabetic patients. We... (Comparative Study)
Comparative Study
PURPOSE
To evaluate levels of malondialdehyde and the total antioxidant capacity (TAC) in the blood, aqueous humor, and vitreous bodies of diabetic and nondiabetic patients. We also measured the blood energy charge potential (ECP).
METHODS
We examined 19 patients with type 2 diabetes mellitus and diabetic retinopathy. Ten were scheduled for cataract surgery and pars plana vitrectomy because of proliferative diabetic retinopathy (PDR). The other nine, with mild nonproliferative PDR (NPDR), and fourteen nondiabetic, age-matched subjects enrolled as a control group were scheduled for cataract surgery and vitrectomy because of epiretinal membranes. Blood, aqueous humor and vitreous body samples were collected at the time of surgery. Malondialdehyde concentrations and blood ECP were measured with high-performance liquid chromatography. The TAC of the samples was estimated with the oxygen radical absorbance capacity method.
RESULTS
The level of blood and vitreous malondialdehyde in the PDR group was significantly higher compared to controls and to NPDR patients. PDR patients also had lower levels of TAC at the vitreous body and aqueous humor level, but not at the blood level, compared to controls and with NPDR patients. In all diabetic patients, the blood ECP values were significantly lower, compared to control subjects.
CONCLUSIONS
Our data support the hypothesis that oxidative stress and the decrease of antioxidant defenses are associated with the progression of diabetic retinopathy to its proliferative form. Antioxidant supply may have the effect of correcting oxidative stress and inhibiting disease progression.
Topics: Aged; Antioxidants; Aqueous Humor; Blood Chemical Analysis; Chromatography, High Pressure Liquid; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Disease Progression; Female; Humans; Lipid Peroxidation; Male; Malondialdehyde; Oxidative Stress; Vitreous Body
PubMed: 21633716
DOI: No ID Found -
BMC Veterinary Research Oct 2014Sonographic ophthalmic examinations have become increasingly important in veterinary medicine. If the velocity of ultrasound in ocular tissues is known, the A-mode...
BACKGROUND
Sonographic ophthalmic examinations have become increasingly important in veterinary medicine. If the velocity of ultrasound in ocular tissues is known, the A-mode ultrasound method may be used to determine the axial intraocular distances, such as anterior chamber depth, lens thickness, axial length of the vitreous and axial globe length, which are required for intraocular lens (IOL) power calculations. To the authors' knowledge, the velocity of ultrasound in the ocular tissues of the horse was not previously determined. In the present study, 33 lenses, 29 samples of aqueous and 31 of vitreous from 35 healthy equine eyes have been examined. The corresponding ultrasound velocities are reported in dependence of age, temperature, gender and elapsed time after enucleation.
RESULTS
The velocity of ultrasound at 36°C in equine aqueous, lens and vitreous are 1529 ±10 m/s, 1654± 29 m/s and 1527 ±16 m/s respectively, and the corresponding conversion factors are 0.998± 0.007, 1.008 ±0.018 and 0.997 ±0.010. A linear increase of the speed of ultrasound with increasing temperature has been determined for aqueous and vitreous. No temperature dependence was found for the speed of ultrasound in the lens. The ultrasound velocity did not significantly differ (95%) on the basis of gender, age or time after enucleation during the first 72 hours after death.
CONCLUSIONS
Compared to human eyes, the ultrasound velocity in equine lental tissue deviates by one percent. Therefore, axial length measurements obtained with ultrasound velocities for the human eye must be corrected using conversion factors. For the aqueous and vitreous, deviations are below one percent and can be neglected in clinical settings.
Topics: Animals; Aqueous Humor; Female; Horses; Lens, Crystalline; Male; Ultrasonography; Vitreous Body
PubMed: 25312851
DOI: 10.1186/s12917-014-0250-3 -
PloS One 2017The aim of the present study was to assess the expression of miRNAs in the Vitreous Humor (VH) of patients with Macular Hole (MH) and Epiretinal Membrane (ERM) compared... (Comparative Study)
Comparative Study
PURPOSE
The aim of the present study was to assess the expression of miRNAs in the Vitreous Humor (VH) of patients with Macular Hole (MH) and Epiretinal Membrane (ERM) compared to a control group.
METHODS
In this prospective, comparative study, 2-ml of VH was extracted from the core of the vitreous chamber in consecutive patients who underwent standard vitrectomy for ERM and MH. RNA was extracted and TaqMan® Low Density Arrays (TLDAs) were used to profile the transcriptome of 754 miRNAs. Results were validated by single TaqMan® assays. Finally, we created a biological network of differentially expressed miRNA targets and their nearest neighbors.
RESULTS
Overall 10 eyes with MH, 16 eyes with idiopathic ERM and 6 controls were enrolled in the study. Profiling data identified 5 miRNAs differentially expressed in patients affected by MH and ERM with respect to controls. Four were downregulated (miR-19b, miR-24, miR-155, miR-451) and 1 was downregulated (miR-29a); TaqMan® assays of the VH of patients affected by MH and ERM, with respect to controls, showed that the most differentially expressed were miR-19b (FC -9.13, p:<0.00004), mir-24 (FC -7.52, p:<0.004) and miR-142-3p (FC -5.32, p:<0.011). Our network data showed that deregulation of differentially expressed miRNAs induces an alteration of several pathways associated with genes involved in both MH and ERM.
CONCLUSION
The present study suggests that disregulation of miR-19b, miR-24 and miR-142-3p, might be related to the alterations that characterize patients affected by MH and ERM.
Topics: Down-Regulation; Epiretinal Membrane; Female; Humans; Male; MicroRNAs; Middle Aged; Prospective Studies; Retinal Perforations; Transcriptome; Vitrectomy; Vitreous Body
PubMed: 28328945
DOI: 10.1371/journal.pone.0174297 -
Journal of Ocular Pharmacology and... 2018Even though the very thought of an injection into the eye may be frightening, an estimated 6 million intravitreal (IVT) injections were made in the USA during 2016. With... (Review)
Review
Even though the very thought of an injection into the eye may be frightening, an estimated 6 million intravitreal (IVT) injections were made in the USA during 2016. With the introduction of new therapeutic agents, this number is expected to increase. In addition, drug products that are injectable in ocular compartments other than the vitreous humor are expected to enter the back of the eye market in the not so distant future. Besides the IVT route, some of the most actively investigated routes of invasive administration to the eye include periocular, subretinal, and suprachoroidal (SC) routes. While clinical efficacy is the driving force behind new injectable drug product development for the eye, safety is also being improved with time. In the case of IVT injections, the procedural guidelines have evolved over the years to improve patient comfort and reduce injection-related injury and infection. Similar advances are anticipated for other routes of administration of injectable products to the eye. In addition to procedural improvements, the design of needles, particularly those with smaller diameters, length, and controlled bevel angles are expected to improve overall safety and acceptance of injected ophthalmic drug products. A key development in this area is the introduction of microneedles of a length less than a millimeter that can target the SC space. In the future, needles with smaller diameters and lengths, potentially approaching nanodimensions, are expected to revolutionize ophthalmic disease management.
Topics: Administration, Ophthalmic; Animals; Drug Delivery Systems; Humans; Injections, Intraocular; Intravitreal Injections; Needles; Ophthalmic Solutions; Vitreous Body
PubMed: 29206556
DOI: 10.1089/jop.2017.0121 -
Cells Feb 2023Lens epithelial explants are comprised of lens epithelial cells cultured in vitro on their native basement membrane, the lens capsule. Biologists have used lens...
Lens Epithelial Explants Treated with Vitreous Humor Undergo Alterations in Chromatin Landscape with Concurrent Activation of Genes Associated with Fiber Cell Differentiation and Innate Immune Response.
Lens epithelial explants are comprised of lens epithelial cells cultured in vitro on their native basement membrane, the lens capsule. Biologists have used lens epithelial explants to study many different cellular processes including lens fiber cell differentiation. In these studies, fiber differentiation is typically measured by cellular elongation and the expression of a few proteins characteristically expressed by lens fiber cells in situ. Chromatin and RNA was collected from lens epithelial explants cultured in either un-supplemented media or media containing 50% bovine vitreous humor for one or five days. Chromatin for ATAC-sequencing and RNA for RNA-sequencing was prepared from explants to assess regions of accessible chromatin and to quantitatively measure gene expression, respectively. Vitreous humor increased chromatin accessibility in promoter regions of genes associated with fiber differentiation and, surprisingly, an immune response, and this was associated with increased transcript levels for these genes. In contrast, vitreous had little effect on the accessibility of the genes highly expressed in the lens epithelium despite dramatic reductions in their mRNA transcripts. An unbiased analysis of differentially accessible regions revealed an enrichment of cis-regulatory motifs for RUNX, SOX and TEAD transcription factors that may drive differential gene expression in response to vitreous.
Topics: Animals; Cattle; Chromatin; Vitreous Body; Cell Differentiation; RNA; Immunity, Innate
PubMed: 36766843
DOI: 10.3390/cells12030501 -
Acta Ophthalmologica Aug 2008Vitreomacular traction resulting from lacking, incomplete or anomalous posterior vitreous detachment is suspected to play a crucial role in the pathogenesis of different... (Review)
Review
Vitreomacular traction resulting from lacking, incomplete or anomalous posterior vitreous detachment is suspected to play a crucial role in the pathogenesis of different forms of age-related macular degeneration (AMD) along with the known mechanisms. It is probable that the fundamental pathomechanisms of AMD formation have already begun by the time tractional forces lead to a change for the worse. Vitreomacular traction alone is perhaps not able to induce AMD. It would seem sensible to consider vitreous changes when diagnosing and treating AMD patients because of the high coincidence of vitreomacular traction and choroidal neovascularization (CNV) and the often successful treatment of other diseases of the vitreoretinal interface by vitrectomy. The concept of the pathogenesis of AMD should therefore be extended to include the influence of the vitreous, especially where therapeutic concepts such as pharmacological vitreolysis and vitreous separation have been established as causative treatment of late forms of AMD.
Topics: Adhesiveness; Exudates and Transudates; Humans; Macular Degeneration; Retina; Tissue Adhesions; Vitreous Body
PubMed: 18537930
DOI: 10.1111/j.1755-3768.2008.01210.x