Glaucoma is the leading cause of irreversible blindness worldwide, with its primary risk factor arising from elevated intraocular pressure (IOP) due to an imbalance between aqueous humor production and outflow. This study aims to establish quantitative correlations among IOP, iris mechanical properties, channel microstructures, and aqueous humor dynamics through three-dimensional modeling and finite element analysis, overcoming the limitations of conventional experimental techniques in studying aqueous flow within the trabecular meshwork (TM) outflow pathway. A three-dimensional fluid-structure interaction (FSI) model incorporating the layered TM structure, Schlemm's canal (SC), iris, and other anterior segment tissues was developed based on human ocular anatomy. FSI simulations were performed to quantify the effects of IOP variations and iris Young's modulus on tissue morphology and aqueous humor dynamics parameters. The computational results demonstrated that axial iris deformation showed significant correlations with IOP and iris Young's modulus. Although elevated IOP exhibited minimal effects on hydrodynamic parameters in the anterior and posterior chambers, it markedly suppressed aqueous flow velocity in the TM region. Additionally, wall shear stress in SC and collector channels displayed high sensitivity to IOP variations. These findings reveal that the tissue mechanics-FSI mechanism modulates outflow resistance by regulating aqueous humor dynamics, offering valuable references for developing clinical therapies targeting IOP reduction in glaucoma management.
Humans ; Trabecular Meshwork/anatomy & histology* ; Finite Element Analysis ; Aqueous Humor/metabolism* ; Intraocular Pressure/physiology* ; Glaucoma/physiopathology* ; Iris/anatomy & histology* ; Computer Simulation ; Models, Biological

A HPLC method was developed for the determination of mangiferin in rat plasma and aqueous humor. 4-Nitrophenol was used as internal standard. Analysis was performed on a Cosmosil ODS C18 analytical column (4.6 mm x 250 mm, 5 microm) with mobile phase consisting of methanol-water (40: 60) with 2% glacial acetic acid at a flow rate of 1.0 mL x min(-1). The calibration curve of mangiferin in rat plasma and aqueous humor showed excellent linear behaviors over the investigated concentration of 0. 50-250.00 mg x L(-1) in plasma and 0.10-10.00 mg x L(-1) in aqueous humor, respectively, and the correlation coefficients were all above 0.995 4. The intra-day and inter-day precisions for all samples were measured to be below 12%. The limit of quantitation was 0.10 mg x L(-1) and low enough for the determination of mangiferin in all samples. The validated method has been successfully applied to preliminary pharmacokinetics study of mangiferin in rat plasma and aqueous humor.
Animals ; Aqueous Humor ; chemistry ; Chromatography, High Pressure Liquid ; Female ; Male ; Nitrophenols ; analysis ; Rats ; Rats, Wistar ; Reproducibility of Results ; Sensitivity and Specificity ; Xanthones ; blood ; pharmacokinetics

BACKGROUNDOphthalmic gel has been developed to increase the drug concentration in aqueous humor and to retard the loss of drug from the conjunctival sac. The research was to compare the drug concentration in aqueous humor of cataract patients administered 0.3% gatifloxacin ophthalmic gel with that in patients administered 0.3% gatifloxacin ophthalmic solution.

METHODSNinety-six patients with cataract (96 eyes) were randomly assigned to 8 groups. The patients in groups 1-4 received topical gatifloxacin 0.3% ophthalmic gel and those in groups 5-8 received gatifloxacin 0.3% ophthalmic solution. The dose regimen was 1 drop, 4 times a day for 3 consecutive days prior to cataract surgery. On the day of surgery, 1 drop was applied at 15, 30, 60 or 120 minutes before commencement of cataract surgery in groups 1 and 5, groups 2 and 6, groups 3 and 7, and groups 4 and 8, respectively. Aqueous humor was extracted during the cataract surgery for the analysis of gatifloxacin concentration..

RESULTSThe concentrations of gatifloxacin in aqueous humor were (0.24 +/- 0.25) microg/ml, (1.11 +/- 0.74) microg/ml, (2.32 +/- 2.01) microg/ml and (1.85 +/- 1.14) microg/ml in groups 1 to 4, and (0.16 +/- 0.25) microg/ml, (0.31 +/- 0.24) microg/ml, (0.75 +/- 0.28) microg/ml and (0.33 +/- 0.22) microg/ml in groups 5 to 8, respectively. Patients receiving gatifloxacin ophthalmic gel showed greater mean values of gatifloxacin concentration in aqueous humor than those receiving gatifloxacin solution, and such differences were significant with P < 0.05 for all comparisons except that between groups 1 and 5.

CONCLUSIONTopical gatifloxacin ophthalmic gel can attain significantly greater drug concentrations in human aqueous humor than gatifloxacin ophthalmic solution.

Aged ; Aged, 80 and over ; Anti-Infective Agents ; administration & dosage ; analysis ; pharmacokinetics ; therapeutic use ; Aqueous Humor ; metabolism ; Cataract ; drug therapy ; metabolism ; Chromatography, High Pressure Liquid ; Female ; Fluoroquinolones ; administration & dosage ; analysis ; pharmacokinetics ; therapeutic use ; Humans ; Male ; Middle Aged ; Tandem Mass Spectrometry

OBJECTIVE: To explored the relationship between the concentration of potassium ion as well as sodium ion in the aqueous humor and post-mortem interval (PMI). METHODS: The concentrations of potassium ion and sodium ion in the aqueous humor of swine within 48 h after death at 4 degrees C and 28 degrees C were detected using Z-500 atomic absorption spectrophotometer. RESULTS: The concentrations of potassium ion and sodium ion in aqueous humor of isolated swine eyeballs within 48 h after death when the environmental temperature was 4 degrees C were significantly related to PMI. The relationship between PMI and the concentration of potassium ion was PMI = -0.178[K+]2 + 49.978 (R2 = 0.995). The relationship between PMI and the rate of sodium ion and potassium ion was PMI = 120.987/[Na+/K+]-28.834 (R2 = 0.905). CONCLUSION The concentration of potassium in aqueous humor of isolated swine eyeballs may be one of the reference indicators to estimate PMI of the corpses at lower temperatures.
Animals ; Aqueous Humor/chemistry* ; Female ; Forensic Pathology/methods* ; Male ; Postmortem Changes ; Potassium/analysis* ; Regression Analysis ; Sodium/analysis* ; Spectrophotometry, Atomic/methods* ; Swine ; Temperature ; Time Factors

PURPOSE: To compare the levels of calcium and phosphorus in the aqueous humor and serum of diabetics and non-diabetics. METHODS: We divided patients into two groups: seventy-six non-diabetic cataract patients and fifty-two diabetic cataract patients. The diabetic group was divided again into three subgroups: twenty-six patients with no diabetic retinopathy, thirteen patients with non-proliferative diabetic retinopathy, and thirteen patients with proliferative diabetic retinopathy. The authors compared the levels of calcium and phosphorus in the serum and aqueous humor of cataract patients. Statistic analysis was performed to form two comparisons: 1) a comparison between non-diabetics and diabetics and 2) a comparison among non-diabetics and the three subgroups of diabetics. RESULTS: In serum, calcium levels did not statistically differ between non-diabetics and diabetics. The phosphorus level was also not significantly different. In the aqueous humor, however, while calcium levels did not differ significantly, the phosphorus levels in diabetics were considerably higher than those in non-diabetics. When non-diabetics were compared to the three diabetic subgroups, calcium levels did not differ in serum or aqueous humor, but the phosphorus levels in diabetics with proliferative diabetic retinopathy were significantly higher than those in non-diabetics, diabetics without diabetic retinopathy, and diabetics with non-proliferative diabetic retinopathy. CONCLUSIONS: The level of phosphorus in the aqueous humor and serum of diabetics was significantly increased, especially in diabetics with proliferative diabetic retinopathy. This result may be related to hydrophilic acrylic IOL opacification. Future studies regarding the pathogenic role of a high concentration of aqueous humor and serum phosphorus are required.
Aged ; Aged, 80 and over ; Aqueous Humor/*chemistry ; Biological Markers/analysis ; Calcium/*analysis ; Cataract/complications/*metabolism ; Diabetic Retinopathy/complications/*metabolism ; Female ; Humans ; Male ; Middle Aged ; Phosphorus/*analysis ; Regression Analysis ; Retrospective Studies

PURPOSE: To compare the levels of calcium and phosphorus in the aqueous humor and serum of diabetics and non-diabetics. METHODS: We divided patients into two groups: seventy-six non-diabetic cataract patients and fifty-two diabetic cataract patients. The diabetic group was divided again into three subgroups: twenty-six patients with no diabetic retinopathy, thirteen patients with non-proliferative diabetic retinopathy, and thirteen patients with proliferative diabetic retinopathy. The authors compared the levels of calcium and phosphorus in the serum and aqueous humor of cataract patients. Statistic analysis was performed to form two comparisons: 1) a comparison between non-diabetics and diabetics and 2) a comparison among non-diabetics and the three subgroups of diabetics. RESULTS: In serum, calcium levels did not statistically differ between non-diabetics and diabetics. The phosphorus level was also not significantly different. In the aqueous humor, however, while calcium levels did not differ significantly, the phosphorus levels in diabetics were considerably higher than those in non-diabetics. When non-diabetics were compared to the three diabetic subgroups, calcium levels did not differ in serum or aqueous humor, but the phosphorus levels in diabetics with proliferative diabetic retinopathy were significantly higher than those in non-diabetics, diabetics without diabetic retinopathy, and diabetics with non-proliferative diabetic retinopathy. CONCLUSIONS: The level of phosphorus in the aqueous humor and serum of diabetics was significantly increased, especially in diabetics with proliferative diabetic retinopathy. This result may be related to hydrophilic acrylic IOL opacification. Future studies regarding the pathogenic role of a high concentration of aqueous humor and serum phosphorus are required.
Aged ; Aged, 80 and over ; Aqueous Humor/*chemistry ; Biological Markers/analysis ; Calcium/*analysis ; Cataract/complications/*metabolism ; Diabetic Retinopathy/complications/*metabolism ; Female ; Humans ; Male ; Middle Aged ; Phosphorus/*analysis ; Regression Analysis ; Retrospective Studies

OBJECTIVETo detect the levels of vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) in aqueous humor of patients with active choroidal neovascularization (CNV).

METHODSAqueous humor samples were obtained from 32 patients with active CNV. The concentrations of VEGF and PEDF in aqueous humor were measured by enzyme linked immunosorbent assay (ELISA) for quantitative analysis. VEGF and PEDF in 10 samples of aqueous humor from patients with cataract were also detected by the same methods as control.

RESULTThe mean VEGF and PEDF concentrations in aqueous humor of active CNV patients were higher than those in the control group (P=0.000).

CONCLUSIONThe patients with active CNV exhibit significantly higher VEGF and PEDF levels than those in control, indicating that VEGF along with PEDF may modulate the formation of CNV.

Adult ; Aged ; Aged, 80 and over ; Aqueous Humor ; chemistry ; Choroidal Neovascularization ; metabolism ; Eye Proteins ; analysis ; Female ; Humans ; Male ; Middle Aged ; Nerve Growth Factors ; analysis ; Serpins ; analysis ; Vascular Endothelial Growth Factor A ; analysis

BACKGROUNDNuclear factor-kappa B (NF-kappaB) is elevated in regulating transcription of many cytokines and inflammatory mediators. The purpose of this study was to investigate the activation and the significance NF-kappaB in lipopolysaccharide (LPS) induced keratitis.

METHODSLPS induced keratitis model was based on Wistar rats. At 0.5, 1, 3, 6, 12, 24 or 72 hours after LPS treatment, the rat corneas were observed with a slit lamp microscope, then the rats were sacrificed and their corneas were excised for routine histological analysis. The expression of NF-kappaB was detected with immunohistochemical staining. The change of tumour necrosis factors-alpha (TNF-alpha) mRNA expression was identified by reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTSHistological findings demonstrated that LPS treated corneas showed significant changes in corneal structure. Corneal edema, pronounced inflammatory cells infiltration and inordinate collagen fibres were observed. Immunohistochemical results showed that the expression of NF-kappaB and its activation obviously increased after LPS treatment compared with the normal group and control group. Positive cells could be observed at 0.5 hour and peak expression of NF-kappaB was observed between 3 hours and 12 hours after infection, but returned to or approached normal level by 72 hours. RT-PCR showed that the level of TNF-alpha mRNA began to increase 0.5 hour after LPS treatment, peaked at 6 hours and then subsided by 72 hours. NF-kappaB had a positive correlation with the expression of TNF-alpha mRNA (r = 0.964, P < 0.01), both NF-kappaB and TNF-alpha had a strong positive correlation with the degree of inflammatory response in LPS treated corneas (r = 0.929, P < 0.01; r = 0.587, P < 0.05, respectively).

CONCLUSIONSThe activation of NF-kappaB was increased in LPS treated corneas and was elevated in LPS induced keratitis by promoting overexpression of TNF-alpha mRNA. NF-kappaB may play an important role in the pathogenesis of LPS-associated keratitis in rats.

Animals ; Aqueous Humor ; cytology ; Epithelium, Corneal ; physiology ; Immunohistochemistry ; Keratitis ; chemically induced ; pathology ; Lipopolysaccharides ; toxicity ; NF-kappa B ; analysis ; physiology ; RNA, Messenger ; analysis ; Rats ; Rats, Wistar ; Tumor Necrosis Factor-alpha ; genetics ; physiology

OBJECTIVETo develop an RP-HPLC method for assay of pilocarpine in rabbit ocular aqueous humor.

METHODSThe RP-HPLC method was performed on a column of ODS-C(18) with the mobile phase consisting of 0.5% of triethylamine (TEA) of phosphate solutions (10 mmol/L, pH 2.5) and acetonitrile (98/2,v/v). The detection wavelength was 215 nm and flow rate was 1.0 ml/min. Ninety albino rabbits were divided into 3 groups (30 in each):group 1 received 50 microl of eye drops containing 1% generic pilocarpine, group 21% mixture pilocarpine solution consisting of aqueous sample and liposome and group 31% liposome pilocarpine, respectively. The aqueous humor was withdrawn at 5, 10, 30, 40, 60, 90, 120, 180, 240 and 360 min. Pilocarpine was extracted from aqueous humor with dichloromethane.

RESULTThe linear calibration curve was obtained in the concentration range of 0.1 - 20 microg/ml. The average recovery was (68.1+/-2.7)% (n=9). Inter-day and intra-day RSD were 4.33% and 2.87%, respectively. In three formations 1% liposome pilocarpine was the best for the areas under curve and measurable amounts.

CONCLUSIONThe RP-HPLC method is simple and reliable for pilocarpine measurement in ocular aqueous. Liposome formulation can significantly increase the bioavailability of pilocarpine in ocular aqueous.

Animals ; Aqueous Humor ; chemistry ; Chemistry, Pharmaceutical ; Chromatography, High Pressure Liquid ; Pilocarpine ; administration & dosage ; analysis ; Rabbits

In this paper we reviewed the formulae and analyzed the factors which modified the relationship and estimate the time of death as precise as possible by potassium concentration in vitreous humor. The extra factors including numbers of the cases, cause of death, different eye of both, the urea or/and creatinine in vitreous humor, environmental temperature, sampling techniques, experimental and analytical method were also mentioned.
Aqueous Humor/chemistry* ; Creatinine/analysis* ; Forensic Medicine ; Humans ; Linear Models ; Postmortem Changes ; Potassium/analysis* ; Time Factors ; Urea/analysis*