Vitreous Humor Samples Research Articles

Development and validation of headspace gas chromatography with a flame ionization detector method for the determination of ethanol in the vitreous humor.

Qualitative and quantitative testing of ethanol in post-mortem samples is an important analytical procedure that provides accurate, precise, and reliable results. Given the complexity of the issue, obtaining a realistic picture of lifelong alcoholemia requires supporting blood ethanol findings with analyses of alternative samples, primarily vitreous humor (VH). The objective of this study was to develop and validate a headspace gas chromatography with flame ionization detection (HS/GC-FID) method for determining ethanol concentration in VH. Conditions for the HS/GC-FID method were established and the method was validated according to the guidelines of the European Medicines Agency. Validation parameters such as precision, accuracy, specificity, sensitivity, and linearity over a wide concentration range were evaluated through statistical analysis. The method demonstrated precision, accuracy, specificity, and sensitivity. Additionally, it proved to be linear across a wide concentration range and relatively fast, making it suitable for rapid and routine determination of ethanol concentration in VH, particularly for forensic applications. Results from validation and application of the method to VH samples indicate that ethanol concentration in VH can be reliably determined using the presented HS/GC-FID method, making it a valuable tool in forensic investigations.

Study on Hematological and Biochemical Index of Blood and Vitreous Humor in the Celestial-Eye Goldfish

In this study, we conducted an exploration of blood collection, hematological and biochemical comparative analysis of the unique vitreous humor and blood of the celestial-eye goldfish (CE) (Carassius auratus), and obtained hematological and biochemical indicators for healthy celestial goldfish blood. After exploring the optimal method for collecting blood and ocular fluid, blood and vitreous humor samples were drawn from healthy CE, and an automatic hematology analyzer was used to measure 17 physiological indicators in the blood and vitreous humor. Additionally, 20 biochemical indices were measured by an automatic biochemical analyzer. Experiments were also conductedto evaluate the effect of blood and vitreous humor collection on the subsequent survival rate of the CE. The results showed that the blood of CE exhibited values for 17 hematological indicators, including red blood cells (mean value: 2.19 × 1012/L), white blood cells (mean value: 62.21 × 109/L), hemoglobin (mean value:138.25 g/L), and no eosinophils or basophils. We also found that the levels of aspartate amino transferase (AST) and glutamyl transpeptidase (GGT) in the vitreous humor of CE were significantly higher than those in the serum (p < 0.01). No cells were detected in the vitreous humor of CE, and there was no significant difference in survival rate compared to normal goldfish after extracting blood and vitreous humor from CE (p > 0.05). This study provides fundamental data for the cultivation of healthy goldfish, the development of goldfish hematology, and further research on the development and formation of CE’s unique eye traits.

Bladder Wash: A Proof of Concept as an Alternative Specimen for Postmortem Toxicology.

In postmortem forensic investigation cases where the bladder is voided or dehydrated prior to autopsy, it is possible to wash the bladder with saline and collect the 'bladder wash' and any residual urine for toxicological analysis. While not conventional, this study aims to determine the use of bladder washes as alternative specimens in postmortem forensic toxicology. Comprehensive drug and alcohol analysis was performed on blood, urine, vitreous humor and bladder wash samples. Control studies consisted of matched bladder wash and urine samples for comparison. Authentic applicability studies were performed on bladder wash samples in cases where only blood or no urine samples were available. Bladder wash testing via the routine urine methodology were shown to have the appropriate sensitivity and specificity to serve as an alternative specimen. Specificity of the applicability studies was further improved when comparisons were corrected by evaluating individual analytes jointly with their related parent drug or metabolites. Individual and corrected sensitivity and specificity rates of above 99% were typically observed in both comparisons against urine and blood paired samples. Following drug analysis of 31 cases in which only a bladder wash was available, 57 detections from 23 different analytes were detected that otherwise would have not been obtained. This study demonstrates that standardized collection of the easily accessible bladder wash for postmortem toxicological analysis serves forensic toxicologists and pathologists with invaluable information where urine or other biological specimens are not available.

Ocular and Plasma Pharmacokinetics of Sitagliptin Eye Drops: Preclinical Data.

Background/Objectives: Early stages of diabetic retinopathy are currently considered an unmet medical need due to the lack of effective treatments beyond proper monitoring and control of glycemia and blood pressure. Sitagliptin eye drops have emerged as a new therapeutic approach against early stages of the disease, as they can prevent its main hallmarks, including both neurodegeneration and microvascular impairment. Interestingly, all of these effects occur without any glycemic systemic improvement. In the present study, we aimed to investigate the pharmacokinetics and distribution of the drug within the eye and plasma. Methods: A total of 48 male New Zealand rabbits were treated with topical administration (eye drops) of sitagliptin at two concentrations: 5 mg/mL and 10 mg/mL. Blood, iris/ciliary body, retina/choroid, aqueous humor, and vitreous humor samples were collected at specific intervals post-administration (10 and 30 min and 1, 3, 6, 15, and 24 h), processed, and analyzed using an LC-MS/MS method. The pharmacokinetics of sitagliptin were then calculated, and statistical comparisons were performed. Results: Our findings indicate that sitagliptin reaches the retina prior to the aqueous and vitreous humors, suggesting that its absorption follows the transscleral route. Additionally, systemic absorption was minimal and below pharmacologically active concentrations. Conclusions: These results support the use of an eye drop formulation for the treatment of diabetic retinopathy and other retinal diseases.

Pharmacokinetics and metabolism of ketoconazole after single ocular instillation in Sprague-Dawley rats.

Ketoconazole is limited to its conditioned oral use due to hepatic toxicity. Its ocular eye drop administration may be an option for mycotic keratitis treatment. Therefore, it is necessary to explore its pharmacokinetic and metabolic profile via topical ocular administration. Nine rats were dosed at 300 μg/rat via topical ocular administration, and sacrificed at 5, 30, and 120 min with 3 rats/timepoint. Plasma, cornea, retina, and vitreous humour samples were collected, processed, and analysed. Ketoconazole was quantified with a mean peak plasma concentration of 445 ng/mL at 5 min post-dose. In the rat ocular tissue, the mean ketoconazole concentration at 5 min post-dose was 423 μg/g in the cornea, 4.96 μg/g in the retina, and 1.19 μg/g in the vitreous humour, respectively. The mean ketoconazole concentration in each matrix decreased from 5 to 120 min. The mean ketoconazole concentration at 120 min was 38.4 ng/mL in plasma, and 8.36, 0.0944, and 0.116 μg/g in the cornea, retina, and vitreous humour, respectively. Pooled plasma, cornea, retina, and vitreous humour homogenates were used for metabolite identification. Nine metabolites were identified in rat plasma, and O-dealkylated metabolite (M3) and dehydrogenated metabolite (M11) were the top two, accounting for 5.0 and 5.8 % of the relative mass abundance. The metabolic pathways were O-dealkylation, mono-oxygenation, and dehydrogenation. Eleven metabolites were identified in the rat cornea, and two metabolites were identified in the rat retina and vitreous humour, respectively. The O-dealkylated and hydrogenated metabolite (M2) was a dominant metabolite in the cornea, retina, and vitreous humour, while M3 and M11 were the dominant metabolites in plasma. Ketoconazole was a dominant component (≥ 98.5 %) in the cornea, retina, and vitreous humour, having higher concentrations in cornea than in plasma. M2 was identified as a dominant metabolite (1.1-1.2 %) in the cornea, retina, while M3 (5.0 %) and M11 (5.8 %) were identified as dominant metabolites in the plasma.

Impact of genetic alterations on central nervous system progression of primary vitreoretinal lymphoma.

Primary vitreoretinal lymphoma (PVRL) is a rare malignant lymphoma subtype with an unfavorable prognosis due to frequent central nervous system (CNS) progression. Thus, identifying factors associated with CNS progression is essential for improving the prognosis of PVRL patients. Accordingly, we conducted a comprehensive genetic analysis using archived vitreous humor samples of 36 PVRL patients diagnosed and treated at our institution and retrospectively examined the relationship between genetic alterations and CNS progression. Whole-exome sequencing (N=2) and amplicon sequencing using a custom panel of 107 lymphomagenesis-related genes (N=34) were performed to assess mutations and copy number alterations. The median number of pathogenic genetic alterations per case was 12 (range, 0-22). Pathogenic genetic alterations of CDKN2A, MYD88, CDKN2B, PRDM1, PIM1, ETV6, CD79B, and IGLL5, as well as aberrant somatic hypermutations, were frequently detected. The frequency of ETV6 loss and PRDM1 alteration (mutation and loss) was 23% and 49%, respectively. Multivariate analysis revealed ETV6 loss (hazard ratio [HR]=3.26, 95% confidence interval [CI]: 1.08-9.85) and PRDM1 alteration (HR=2.52, 95% CI: 1.03-6.16) as candidate risk factors associated with CNS progression of PVRL. Moreover, these two genetic factors defined slow-, intermediate-, and rapid-progression groups (0, 1, and 2 factors, respectively), and the median period to CNS progression differed significantly among them (52 vs. 33 vs. 20 months, respectively). Our findings suggest that genetic factors predict the CNS progression of PVRL effectively, and the genetics-based CNS progression model might lead to stratification of treatment.

B-294 Case report: Postmortem ethanol production following traumatic injury

Abstract Background Ethanol is the most commonly encountered psychoactive substance in forensic toxicology. Accurate interpretation of ethanol concentrations from postmortem samples is fraught with potential hurdles, including decomposition, redistribution, and postmortem production of ethanol. Through the fermentation of substrates like glucose, pyruvate, lactate, and amino acids, microorganisms present in the gut and/or environment can generate ethanol in contaminated human tissues, especially following traumatic injury. The degree of fermentation varies widely depending on the time between death and autopsy, temperature, humidity, tissue glucose concentrations, and the specimen type. Vitreous humor (VH) is the preferred specimen for postmortem toxicological analysis of ethanol because it accurately reflects the antemortem ethanol concentration in serum while being resistant to microbial contamination. This case highlights the utility of VH in an extreme instance of postmortem ethanol production. Methods Postmortem toxicological analysis of liver tissue and VH (NMS Labs, Horsham, PA) was performed by headspace-gas chromatography (HS-GC) Results Case presentation: A man in his sixties with a history of type 1 diabetes mellitus and hypertension was involved in a fatal mining accident while operating heavy machinery in which the equipment fell down a cliff, causing the man to be ejected onto the ground nearby. The decedent was discovered hours after the fall with extensive traumatic injuries to the left side of his body and head. Seven days later, an autopsy was performed by the medical examiner’s office. Postmortem toxicological analysis of liver tissue by HS-GC revealed ethanol at a concentration of 690 mg/100g. The liver tissue also tested positive for amlodipine, nicotine, cotinine, and caffeine. A vitreous humor (VH) sample tested negative (<10 mg/dL) for ethanol. Conclusions The toxicological findings reported herein are inconsistent with antemortem alcohol consumption and are instead an example of severe postmortem ethanol production by microbial contamination. Several factors likely led to the stark discrepancy between the concentrations of ethanol in VH and liver tissue. First, the decedent suffered traumatic injuries, creating conditions favorable for extensive microbial contamination. Second, the time between death and autopsy was seven days, allowing ample time for fermentation to occur, even under refrigerated conditions. Third, postmortem glycogenolysis in addition to the patient’s underlying T1DM likely provided a high concentration of glucose to fuel postmortem fermentation. Ultimately, this case underscores the importance of forensic specimen selection in accurately interpreting toxicology findings following traumatic injury.

Comprehensive microRNA analyses using vitreous humor of ocular sarcoidosis.

MicroRNAs (miRNAs) are non-coding RNAs which have attracted attention as biomarkers in a variety of diseases. However, extensive unbiased analysis of miRNA in vitreous humor of sarcoidosis patients has not been reported. In the present study, we comprehensively analyzed the dysregulated miRNAs in ocular sarcoidosis to search for potential biomarkers. This study included seven patients diagnosed with ocular sarcoidosis (five definite and two presumed). Five patients with unclassified uveitis and 24 with non-inflammatory diseases served as controls. MicroRNA expression levels in vitreous humor samples were measured by microarray, and differentially expressed miRNAs between sarcoidosis and other diseases were explored. Next, pathway enrichment analysis was performed to evaluate the functions of the dysregulated miRNAs, and machine learning was used to search for candidate biomarkers. A total of 614 upregulated miRNAs and 8 downregulated miRNAs were detected in vitreous humor of patients with ocular sarcoidosis compared with patients with unclassified uveitis and non-inflammatory diseases. Some dysregulated miRNAs were involved in the TGF-β signaling pathway. Furthermore, we identified miR-764 as the best predictor for ocular sarcoidosis using Boruta selection. In this study, comprehensive miRNA analysis of vitreous humor samples identified dysregulated miRNAs in ocular sarcoidosis. This study suggests new insights into molecular pathogenetic mechanisms of sarcoidosis and may provide useful information toward developing novel diagnostic biomarkers and therapeutic targets for sarcoidosis.

Ocular pharmacokinetics of acetazolamide from intravitreal implants by high-performance liquid chromatography coupled to tandem mass spectrometry

Glaucoma, a leading cause of irreversible blindness, affects about 70 million people globally. Its treatment focuses on reducing intraocular pressure. Acetazolamide, a potent anti-glaucoma drug, is currently used only systemically due to low solubility and permeation, which cause severe side effects. Developing topical medications with acetazolamide requires robust analytical methods for its detection in biological samples. In this context, this study aimed to develop a method to quantify acetazolamide in rabbit vitreous humor samples. The method involved a simple, fast, inexpensive, and environmentally friendly protein precipitation step for sample preparation, needing just 50 μL of sample and 200 μL of organic solvent, with adequate recovery. This was combined with high-performance liquid chromatography coupled to tandem mass spectrometry, enabling highly sensitive (LOQ of 5 ng/mL) quantification within only 5 min. The method proved to be selective, precise, and accurate, with well-fitted analytical curves, with no carryover, and no matrix effect impacting reliability. The method was successfully applied to analyze vitreous humor samples from rabbits in pharmacokinetic studies, monitoring drug release from intravitreal implants. Results showed a controlled release profile, with a maximum drug concentration (Cmax) of 426.01 ± 64.57 ng/mL, time to reach Cmax (Tmax) of 28 days, and area under the curve (AUC0–42 and AUC0-∞) of 7722.66 ± 1125.96 ng days/mL and 8998.11 ± 1311.92 ng days/mL, respectively. The device demonstrated significantly slower elimination, ensuring therapeutic levels for an extended period when compared to intravitreal injection.

P18-15 Determination of tramadol and its metabolite O-desmethyltramadol in blood and vitreous humor samples

P18-15 Determination of tramadol and its metabolite O-desmethyltramadol in blood and vitreous humor samples

Proteomic Analysis of Aqueous Humor in Central Retinal Artery Occlusion: Unveiling Novel Insights Into Disease Pathophysiology.

Central retinal artery occlusion (CRAO) is an ocular emergency that results from acute blockage of the blood supply to the retina and leads to a sudden vision loss. Other forms of ischemic retinopathies include diabetic retinopathy (DR), which involves chronic retinal ischemia and remains the leading cause of blindness in working-age adults. This study is the first to conduct a proteomic analysis of aqueous humor (AH) from patients with CRAO with a comparative analysis using vitreous humor (VH) samples from patients with DR. AH samples were collected from 10 patients with CRAO undergoing paracentesis and 10 controls undergoing cataract surgery. VH samples were collected from 10 patients with DR and 10 non-diabetic controls undergoing pars plana vitrectomy (PPV). Samples were analyzed using mass spectrometry. Compared with controls, AH levels of 36 differentially expressed proteins (DEPs) were identified in patients with CRAO. Qiagen Ingenuity Pathway Analysis (IPA) revealed 11 proteins linked to ophthalmic diseases. Notably, enolase 2, a glycolysis enzyme isoform primarily expressed in neurons, was upregulated, suggesting neuronal injury and enzyme release. Additionally, clusterin, a protective glycoprotein, was downregulated. ELISA was conducted to confirm proteomics data. VH samples from patients with DR exhibited changes in a distinct set of proteins, including ones previously reported in the literature. The study provides novel insights into CRAO pathophysiology with multiple hits identified. Proteomic results differed between DR and CRAO studies, likely due to the different pathophysiology and disease duration. This is the first proteomic analysis of CRAO AH, with the potential to identify future therapeutic targets.

Unmasking of molecular players: proteomic profiling of vitreous humor in pathologic myopia

BackgroundThis study aimed to identify the differentially expressed proteins in the vitreous humor (VH) of eyes with and without pathologic myopia (PM), providing insights into the molecular pathogenesis.MethodsA cross-sectional, observational study was conducted. VH samples were collected from patients undergoing vitrectomy for idiopathic epiretinal membrane (ERM), macular hole (MH), or myopic retinoschisis (MRS). Label-free quantitative proteomic analysis identified differential protein expression, with validation using ELISA.ResultsThe proteomic profiling revealed significantly higher expressions of tubulin alpha 1a (TUBA1A) and eukaryotic translation elongation factor 1 alpha 1 (EEF1A1) in PM groups (MH-PM, MRS-PM) compared to controls (MH, ERM). Conversely, xylosyltransferase 1 (XYLT1), versican core protein (VCAN), and testican-2 (SPOCK2) expressions were lower in PM. ELISA validation confirmed these findings.ConclusionsOur study provides novel insights into the molecular mechanisms of PM. The differentially expressed proteins EEF1A1, TUBA1A, XYLT1, VCAN, and SPOCK2 may play crucial roles in chorioretinal cell apoptosis, scleral extracellular matrix (ECM) synthesis, and scleral remodeling in PM. These proteins represent potential new targets for therapeutic intervention in PM, highlighting the importance of further investigations to elucidate their functions and underlying mechanisms in disease pathogenesis.

Nanoscale potassium sensing based on valinomycin-anchored fluorescent gold nanoclusters.

Gold nanoclusters are a smart platform for sensing potassium ions (K+). They have been synthesized using bovine serum albumin (BSA) and valinomycin (Val) to protect and cap the nanoclusters. The nanoclusters (Val-AuNCs) produced have a red emission at 616nm under excitation with 470nm. In the presence of K+, the valinomycin polar groups switch to the molecule's interior by complexing with K+, forming a bracelet structure, and being surrounded by the hydrophobic exterior conformation. This structure allows a proposed fluorometric method for detecting K+ by switching between the Val-AuNCs' hydrophilicity and hydrophobicity, which induces the aggregation of gold nanoclusters. As a result, significant quenching is seen in fluorescence after adding K+. The quenching in fluorescence in the presence of K+ is attributed to the aggregation mechanism. This sensing technique provides a highly precise and selective sensing method for K+ in the range 0.78 to 8µM with LOD equal to 233nM. The selectivity of Val-AuNCs toward K+ ions was investigated compared to other ions. Furthermore, the Val-AuNCs have novel possibilities as favorable sensor candidates for various imaging applications. Our detection technique was validated by determining K+ ions in postmortem vitreous humor samples, which yielded promising results.

Presence of CoV-2 antibody in vitreous humor after Cov-2 infection

PurposeCoronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a life-threatening disease with largely unknown intraocular pathogenesis. Herein, we determined the presence of SARS-CoV-2-specific ribonucleic acid (RNA) and virus-associated antibodies in the vitreous humor of people who have recently recovered from SARS-CoV-2 infection. DesignThis cross-sectional study included 33 patients (33 eyes) who have recently recovered from SARS-CoV-2 infection. Vitreous humor and blood serum samples were tested for the SARS-CoV-2 RNA and virus-associated antibodies. ResultsAmong 33 participants, blood serum and vitreous humor were all tested negative for SARS-CoV-2 RNA. SARS-CoV-2-specific IgM was detected in 87.88 % (29/33) patients in blood serum and 6.10 % (2/33) in vitreous humor; SARS-CoV-2-specific IgG was detected in 96.97 % (32/33) patient in blood serum and 81.82 % (27/33) in vitreous humor. Statistical significance was found for IgM expression between blood serum and vitreous humor (P < 0.01), while IgG was not (P = 0.11). The days after recovery were statistically longer both in IgM-positive blood serum samples group and IgG-positive vitreous humor samples group compared with negative samples of each group (P < 0.01). Additionally, no statistical difference could be detected in antibody expression in vitreous humor between different groups divided on the condition of the risk of blood-retina-barrier (BRB) failure (P = 0.49 for IgM; P = 0.37 for IgG). ConclusionAfter recovering from COVID-19, no SARS-CoV-2 RNA was detected in vitreous humor, but anti-CoV-2 IgM was detected in 6.1 % and IgG in approximately 80 % of vitreous humor samples of participants. We also found that the positivety rate of SARS-CoV-2-specific antibodies in the blood serum and vitreous humor were both correlated with the days after recovery since the infection.

Vitreous humor in the forensic toxicology of quetiapine and its metabolites.

Τhe aim of the present study was to investigate the use of vitreous humor as an alternative biological material in forensic toxicology for the determination of quetiapine, 7-hydroxy-quetiapine, and nor-quetiapine. The distribution of these substances in vitreous humor was studied by determining and correlating their concentrations in vitreous humor with the respective concentrations in blood. During this study, a method for the determination of these substances was developed, validated and applied to postmortem samples obtained from 16 relative forensic cases. The sample preparation procedure included the isolation of the analytes from vitreous humor and blood samples using solid-phase extraction, with Bond Elut LRC C18 columns followed by derivatization with BSTFA with 1% TMCS prior to GC/MS analysis. The developed method is characterized by a dynamic range of 10.0-1000.0ng/mL (R2 ≥ 0.991) for the three substances, with a limit of detection and quantification of 3.0 and 10.0ng/mL, respectively. Accuracy and precision were below 8.09% and 8.99%, respectively, for both biological materials, while absolute recovery for the three substances was greater than 81%. According to the results, quetiapine, 7-hydroxy-quetiapine, and nor-quetiapine are easily distributed in vitreous humor. The results of the study indicate the usefulness of vitreous humor in toxicological analysis for the determination of these substances, especially when the traditional biological materials are not available. The levels of quetiapine and its metabolites in vitreous humor as well as the vitreous humor to blood concentration ratios can provide important information for a more thorough toxicological investigation of forensic cases.

A Case of Medical Malpractice; Misdiagnosis of Methamphetamine-related Cardiac Complications

Background: Professional neglect is a civil responsibility for any specialist or individual with a specific skill, including therapists, and is not limited to any particular profession. Case Presentation: A man 41-year-old drug abuser was diagnosed with a heart problem due to methamphetamine abuse. Despite his drug history, he was once admitted to the emergency room for chest pain, where acetaminophen and diazepam were prescribed. For the second time, he went to another medical center due to continued chest pain, and due to the suspicion of contracting COVID-19, a CT scan of the chest was performed, yielding negative results, and then he was discharged. The patient was found deceased in his bed the following day. An autopsy revealed a thinned heart wall, subendocardial hemorrhages, and severe atherosclerosis. Methamphetamine, amphetamine, and acetaminophen were detected in urine samples, and ethanol was detected in blood and vitreous humor samples. Conclusion: The case highlights the importance of medical negligence in treating patients with drug abuse.

Methanol intoxication in the central region of Saudi Arabia: Five case studies

Outbreaks of methanol poisoning have been described in the medical literature worldwide. However, the few outbreaks that have occurred in Saudi Arabia remain undocumented. This is especially noteworthy in light of the fact that Saudi Arabia is among the countries that explicitly prohibit the usage of alcoholic beverages and recreational drugs. Herein, we describe five cases of methanol poisoning in Saudi Arabia. The first three comprise patients admitted to the emergency room (ER) with signs of methanol toxicity, such as heart palpitations, vomiting, and blurred vision; otherwise, those patients were considered medically free. The remaining two cases were examined postmortem. A headspace gas chromatography-flame ionization detector was used to test blood, vitreous humor, and urine samples for methanol. Specific lethal concentrations of methanol were defined based on published case studies as 23–740 mg/dL in blood and 12–396 mg/dL in vitreous humor. In postmortem cases of our present study, samples exhibited lethal concentrations: 118 and 257 mg/dL in blood, 116.3 and 283 mg/dL in vitreous humor. In ER cases, methanol concentrations in urine samples were lower, at 7.5, 9.1, and 20.9 mg/dL; however, toxic symptoms were still observed. These case studies indicate that it is necessary to raise community awareness about the risk of methanol poisoning in order to minimize future poisoning epidemics.

Revealing new insights: Two-center evidence of microplastics in human vitreous humor and their implications for ocular health

Microplastics (MPs), an emerging environmental contaminant, have raised growing health apprehension due to their detection in various human biospecimens. Despite extensive research into their prevalence in the environment and the human body, the ramifications of their existence within the enclosed confines of the human eye remain largely unexplored. Herein, we assembled a cohort of 49 patients with four ocular diseases (macular hole, macular epiretinal membrane, retinopathy and rhegmatogenous retinal detachment) from two medical centers. After processing the samples with an optimized method, we utilized Laser Direct Infrared (LD-IR) spectroscopy and Pyrolysis Gas Chromatography/Mass Spectrometry (Py-GC/MS) to analyze 49 vitreous samples, evaluating the characteristics of MPs within the internal environment of the human eye. Our results showed that LD-IR scanned a total of 8543 particles in the composite sample from 49 individual vitreous humor samples, identifying 1745 as plastic particles, predominantly below 50 μm. Concurrently, Py-GC/MS analysis of the 49 individual samples corroborated these findings, with nylon 66 exhibiting the highest content, followed by polyvinyl chloride, and detection of polystyrene. Notably, correlations were observed between MP levels and key ocular health parameters, particularly intraocular pressure and the presence of aqueous humor opacities. Intriguingly, individuals afflicted with retinopathy demonstrated heightened ocular health risks associated with MPs. In summary, this research provides significant insights into infiltration of MP pollutants within the human eye, shedding light on their potential implications for ocular health and advocating for further exploration of this emerging health risk.

CircRNA expression profiles and regulatory networks in the vitreous humor of people with high myopia

Myopia is a global health and economic issue. Circular RNAs (circRNAs) have been shown to play an important role in the pathogenesis of many ocular diseases. We first evaluated the circRNA profiles and possible roles in vitreous humor samples of individuals with high myopia by a competitive endogenous RNA (ceRNA) array. Vitreous humor samples were collected from 15 high myopic (5 for ceRNA array, and 10 for qPCR) and 15 control eyes (5 for ceRNA array, and 10 for qPCR) with idiopathic epiretinal membrane (ERM) and macular hole (MH). 486 circRNAs (339 upregulated and 147 downregulated) and 264 mRNAs (202 upregulated and 62 downregulated) were differentially expressed between the high myopia and control groups. The expression of hsa_circ_0033079 (hsa-circDicer1), hsa_circ_0029989 (hsa-circNbea), hsa_circ_0019072 (hsa-circPank1) and hsa_circ_0089716 (hsa-circEhmt1) were validated by qPCR. Pearson analysis and multivariate regression analysis showed positive and significant correlations for axial length with hsa-circNbea and hsa-circPank1. KEGG analysis showed that the target genes of circRNAs were enriched in the mTOR, insulin, cAMP, and VEGF signaling pathways. GO analysis indicated that circRNAs mainly targeted transcription, cytoplasm, and protein binding. CircRNA-associated ceRNA network analysis and PPI network analysis identified several critical genes for myopia. The expression of circNbea, circPank1, miR-145-5p, miR-204-5p, Nras, Itpr1 were validated by qPCR in the sclera of form-deprivation myopia (FDM) mice model. CircPank1/miR-145-5p/NRAS and circNbea/miR-204-5p/ITPR1 were identified and may be important in the progression of myopia. Our findings suggest that circRNAs may contribute to the pathogenesis of myopia and may serve as potential biomarkers.

Estimation of Time Since Death by Potassium ion Level in the Vitreous Fluids: A Postmoterm Study in a Tertiary Care Center, South India

Background: It is of great value to find time since death in the medicolegal investigations like serious crimes.Vitreous humor was more often used for the biochemical analysis as it is less contaminated or not affected by the putrefactive changes than other fluids of the body. It was stated by many researchers that potassium levels in the vitreous humour is more accurate in predicting time since death.Aim: The aim of the study is to assess the time since death using potassium level in the vitreous humorMethodology: This study includes 54 cases of victims brought to the tertiary care hospital based on inclusion and exclusion criteria. Cases with known time of death and with clear vitreous humor samples were included. Baseline characteristics like name, age, gender, exact time since death was collected. Vitreoushumor was collected through appropriate standardized technique. Sampling time was also noted. The collected data was entered in MS excel and analysis done in SPSS 23 software. P value &lt;0.05 is considered to be significant.Results: Majority of the study participants belongs to 57-67 years of age group (28%) followed by 27-37 years of age (22%).Male predominance was observed in our study 41(76%). There is a linear correlation found between the vitreous potassium concentration and the postmortem interval (R2=0.907). The rate of the vitreous potassium increase was 0.36 meq/hr (Coefficient of regression =2.76 meq/l/hr)Conclusion: There is a linear relationship found between vitreous potassium concentration and time since death.Thus potassium in the vitreous can be used for assessing the time since death.