Human Aqueous Humor Research Articles

Human Aqueous Humor Phosphatase Activity in Cataract and Glaucoma

To investigate the presence and activity of protein phosphatase-2A (PPase2A), protein phosphatase-2C (PPase2C), and protein tyrosine phosphatases (PTPs) in the human aqueous humor (AH) of patients with primary open-angle glaucoma (POAG) and cataract and to study the correlation between these phosphatases and the redox state of the AH. Eighty-six cataract patients and 29 POAG patients who were scheduled for cataract surgery with or without glaucoma surgery were enrolled in the study. PPase2A, PPase2C, and PTPs levels in AH were measured by enzyme-linked immunosorbent assays, Western blot analyses, and spectral The redox state was measured by spectral and fluorescent methods. Phosphatase activity-positive results were significantly higher in AH samples from the POAG group (PP2A χ(2)(1) = 11.754, P < 0.01; PP2C χ(2)(1) = 8.754, P < 0.01; PTP χ(2)(1) = 11.073, P < 0.01). Western blot analysis revealed higher PP2C levels in the AH of glaucoma patients compared with PP2C levels in the AH of cataract patients (P = 0.012). Both oxidized/reduced glutathione ratios and superoxide dismutase levels in the AH were significantly higher in the glaucoma group than in the cataract group. Finally significant correlations were found between PP2A and PP2C, PP2A and PTP, and total antioxidant activity and PTP levels. There is a statistically significant difference between phosphatase levels in the AH of POAG patients and cataract patients. The phosphatase content of the AH represents tissue pathology, but their presence in the AH may be attributed to cell debris or to active signaling to other molecular events.

Topical application of 0.005% latanoprost increases episcleral venous pressure in normal dogs

Episcleral venous pressure (EVP) has an important role in intraocular pressure (IOP) homeostasis and accounts for more than 70% of the IOP in the normal dog. A frequently used species in glaucoma research is the normotensive dog especially when evaluating the efficacy of prostaglandin analogues and prostamides; however, aqueous humor dynamic studies in normal dogs are lacking, and the effect of 0.005% latanoprost on canine EVP is not known. We sought to determine the effects to the EVP of topically applied 0.005% latanoprost in the normotensive beagle dog. Female beagle dogs (n = 14) were used and each had a normal ophthalmic examination on study entry. EVP was determined using a standard episcleral venomanometer. Animals were dosed in one eye with 0.005% latanoprost, and the effects on EVP were compared with the averaged baseline EVP's determined in the predosing phase and the fellow nondosed eye. The Mixed Model Repeated Measures method was used to analyze the EVP data. During the dosing phase of the study with topical 0.005% latanoprost, the mean EVPs of dosed eyes were significantly higher than that of nondosed eyes (P < 0.0001). The increase in EVP in the dog with exposure to topical 0.005% latanoprost has not been observed in other species that have been studied, such as in the mouse and in humans, where the drug had no significant effect on the EVP. This response may be unique to dogs and suggests that dogs may not fully mimic human aqueous humor dynamics with topical 0.005% latanoprost. Although frequently performed in human studies, EVP should not be regarded to be a constant value in aqueous humor dynamic studies in the normal beagle dog.

Ammonium sulfate precipitation assay as a method for albumin depletion of human aqueous humor in proteomic analysis

Ammonium sulfate precipitation assay as a method for albumin depletion of human aqueous humor in proteomic analysis

Human aqueous humor concentrations of besifloxacin, moxifloxacin, and gatifloxacin after topical ocular application

To determine the concentrations of besifloxacin, moxifloxacin, and gatifloxacin in human aqueous humor after topical instillation of commercially available besifloxacin ophthalmic suspension 0.6%, moxifloxacin ophthalmic solution 0.5%, and gatifloxacin ophthalmic solution 0.3%, and to assess these concentrations relative to the minimum inhibitory concentration for 90% of strains (MIC(90)) for each drug against bacterial pathogens identified in recent cases of postoperative endophthalmitis. Six clinical sites, United States. Randomized open-label controlled clinical trial. The aqueous humor drug concentrations were compared 60 minutes ± 5 minutes after instillation of 1 topical drop to patients aged 18 years or older having uncomplicated cataract surgery. Concentrations of besifloxacin, moxifloxacin, and gatifloxacin were determined using a validated liquid chromatography with tandem mass spectrometry method. A total of 105 patients were randomized, and aqueous humor samples were analyzed for103 patients. Mean aqueous humor concentrations were 0.13 μg/mL ± 0.58 (SD), 0.67 ± 0.50 μg/mL, and 0.13 ± 0.08 μg/mL for besifloxacin, moxifloxacin, and gatifloxacin, respectively. Both besifloxacin and moxifloxacin achieved aqueous humor concentrations equal to or slightly higher than their respective MIC(90) for methicillin-resistant and methicillin-susceptible Staphylococcus aureus and Staphylococcus epidermidis; none of the fluoroquinolones achieved concentrations above their MIC(90) for ciprofloxacin-resistant strains of S aureus and S epidermidis. Based on the aqueous humor drug concentrations measured in this study, it is unlikely that any of the fluoroquinolones tested would be therapeutically effective in the aqueous humor against the most frequently identified drug-resistant staphylococcal isolates from recent cases of postoperative endophthalmitis. No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes.

3D visualization of aqueous humor outflow structures in-situ in humans

Aqueous humor (AH) exiting the eye via the trabecular meshwork and Schlemm’s canal (SC) passes through the deep and intrascleral venous plexus (ISVP) or directly through aqueous veins. The purpose of this study was to visualize the human AH outflow system 360° in three dimensions (3D) during active AH outflow in a virtual casting. The conventional AH outflow pathways of 7 donor eyes were imaged with a modified Bioptigen spectral-domain optical coherence tomography system (Bioptigen Inc, USA; SuperLum LTD, Ireland) at a perfusion pressure of 20 mmHg ( N = 3), and 10 mmHg ( N = 4). In all eyes, 36 scans (3 equally distributed in each clock hour), each covering a 2 × 3 × 2 mm volume (512 frames, each 512 × 1024 pixels), were obtained. All image data were black/white inverted, and the background subtracted (ImageJ 1.40 g, http://rsb.info.nih.gov/ij/). Contrast was adjusted to isolate the ISVP. SC, collector channels, the deep and ISVP, and episcleral veins were observed throughout the limbus. Aqueous veins could be observed extending into the episcleral veins. Individual scan ISVP castings were rendered and assembled in 3D space in Amira 4.1 (Visage Imaging Inc. USA). A 360-degree casting of the ISVP was obtained in all perfused eyes. The ISVP tended to be dense and overlapping in the superior and inferior quadrants, and thinner in the lateral quadrants. The human AH outflow pathway can be imaged using SD-OCT. The more superficial structures of the AH outflow pathway present with sufficient contrast as to be optically isolated and cast in-situ 360° in cadaver eye perfusion models. This approach may be useful as a model in future studies of human AH outflow.

Concentration of copper and iron in human aqueous humour obtained from glaucomatous and non-glaucomatous eyes

Concentration of copper and iron in human aqueous humour obtained from glaucomatous and non-glaucomatous eyes

Comparação do efeito nas culturas de humor aquoso de gatifloxacina 0,3% aplicado três dias antes de facoemulsificação e e antes do pré-operatório

OBJETIVO: Determinar o efeito de gatifloxacina 0,3% topica, nas culturas de humor aquoso humano, instilada quatro vezes ao dia por tres dias antes de facoemulsificacao comparada a uma gota gatifloxacina 0,3% topica instilada imediatamente antes da cirurgia. METODOS: Trinta e sete pacientes com catarata sem outras afeccoes oculares foram distribuidos aleatoriamente nos Grupos A e B antes da facoemulsificacao. Os pacientes do Grupo A receberam uma gota de gatifloxacina 0,3% imediatamente antes da cirurgia e o Grupo B recebeu gatifloxacina 0,3% quatro vezes ao dia tres dias antes do procedimento. Apos a facoemulsificacao, o humor aquoso foi aspirado e semeado em meios de agar-sangue, agar-chocolate, Saboraud e TSB. Foi realizado esfregaco para bacterioscopia. RESULTADOS: O Grupo B apresentou 40% das lâminas bacterioscopicas com cocos gram +. O Grupo B apresentou 17,6% de cocos gram + na bacterioscopia, estes resultados nao foram estatisticamente significativos (p=0,098). Cinco casos (25%) do Grupo A apresentaram culturas positivas para Staphylococos epidermidis, resultado significativamente maior do que o Grupo B, que nao apresentou nenhuma cultura positiva para bacterias ou fungos. CONCLUSAO: Neste estudo, a gatifloxacina 0,3% instilada tres dias antes da facoemulsificacao diminuiu significativamente o numero de culturas do humor aquoso positivas quando comparada a instilacao imediata de uma gota.

Investigation of pituitary adenylate cyclase activating polypeptide in human gynecological and other biological fluids by using MALDI TOF mass spectrometry

Pituitary adenylate cyclase activating polypeptide (PACAP) is a multifunctional and pleiotropic neuropeptide. PACAP has diverse effects in the endocrine system, among others, it plays important roles in oogenesis, implantation and development of the nervous system. However, it is not known whether PACAP is present in the fluids of the human reproductive organs. The aim of the present study was to determine, by means of mass spectrometry and radioimmunoassay, whether PACAP is present in human amniotic fluid, ovarian follicular fluid and cervico-vaginal fluid. Samples were obtained from healthy adult volunteers. Our MALDI TOF and MALDI TOF/TOF spectrometry results show that PACAP38 is present in all of the follicular fluid samples, and PACAP-like immunoreactivity was also measured by radioimmunoassay. However, we did not find the characteristic peak representing the unmodified 38 amino acid form of the peptide in normal cervico-vaginal smear and amniotic fluid samples. Furthermore, we analyzed other body fluids for comparison, such as human nasal fluid, saliva and aqueous humor. PACAP was not found in these latter samples. In summary, the present study provides evidence for the presence of PACAP in human follicular fluid, suggesting a role in oocyte function, but determination of the exact physiological significance awaits further investigation.

Endogenous Cortisol and TGF-β in Human Aqueous Humor Contribute to Ocular Immune Privilege by Regulating Dendritic Cell Function

Aqueous humor (AqH) has been shown to have significant immunosuppressive effects on APCs in animal models. We wanted to establish whether, in humans, AqH can regulate dendritic cell (DC) function and to identify the dominant mechanism involved. Human AqH inhibited the capacity of human peripheral blood monocyte-derived DC to induce naive CD4(+) T cell proliferation and cytokine production in vitro, associated with a reduction in DC expression of the costimulatory molecule CD86. This was seen both for DC cultured under noninflammatory conditions (immature DC) and for DC stimulated by proinflammatory cytokines (mature DC). DC expression of MHC classes I/II and CD83 was reduced (mature DC only). Myeloid DC from peripheral blood were similarly sensitive to the effects of human AqH, but only under inflammatory conditions. The addition of α-melanocyte stimulating hormone and vasoactive intestinal peptide did not cause significant inhibition at physiological levels. However, the addition of exogenous cortisol at physiological levels recapitulated the AqH-induced reduction in CD86 and inhibition of DC-induced T cell proliferation, and blockade of cortisol in AqH partially reversed its suppressive effects. TGF-β2 had an additional effect with cortisol, and although simultaneous blockade of cortisol and TGF-β2 in AqH reduced its effectiveness, there was still a cortisol- and TGF-β-independent component. In humans, AqH regulates DC maturation and function by the combined actions of cortisol and TGF-β2, a pathway that is likely to contribute to the maintenance of immune privilege in the eye.

Glaucoma patients present increased levels of diadenosine tetraphosphate, Ap 4A, in the aqueous humour

Previous studies have shown the presence of diadenosine tetraphosphate (Ap 4A) and pentaphosphate (Ap 5A) in the aqueous humour (AH) of different species. When topically applied to the rabbit cornea, Ap 4A decreased IOP while Ap 5A increased it. Here we study the presence of dinucleoside polyphosphates in the AH from human patients with or without glaucoma. AH was obtained at the time of cataract surgery from patients with ( n = 16) or without ( n = 10) primary open-angle glaucoma. AH (0.1–0.2 ml) was collected at the beginning of surgery through a corneal paracentesis and immediately cooled in liquid nitrogen, kept frozen and protected from light. AH aliquots were analyzed by HPLC for the presence of Ap 4A and Ap 5A. Both, Ap 4A and Ap 5A were detected in the AH of both experimental groups. No significant differences were found for Ap 5A. In contrast, Ap 4A levels were increased by ∼15-fold in the AH from glaucomatous eyes ranging from 19.5 ± 9.2 nM in normal individuals to 286.03 ± 30.9 nM in glaucomatous patients. In conclusion, both Ap 4A and Ap 5A were detected for the first time in human AH. Interestingly, glaucomatous eyes presented elevated concentrations of Ap 4A compared to controls. The role of Ap 4A needs to be elucidated but it may help to protect the autonomic innervation in the ciliary body/trabecular meshwork. Also, because of its higher levels in glaucoma patients it may be considered as a possible glaucoma biomarker.

Myocilin Levels in Primary Open-angle Glaucoma and Pseudoexfoliation Glaucoma Human Aqueous Humor

To determine the concentration of myocilin in primary open-angle glaucoma (POAG) and pseudoexfoliation glaucoma (PEXG) aqueous humor. Aqueous humor was collected during surgery from patients with POAG, PEXG, and elective cataract removal (control). Volume-equivalent aqueous samples were separated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gradient gels. Quantification of myocilin levels was performed using Western blots probed with 2 independent N-terminal polyclonal anti-myocilin antibodies (AB1 and AB2) followed by densitometry. Myocilin levels in aqueous humor were quantified by plotting the densitometry readings of the aqueous samples against a recombinant myocilin standard curve. Total protein concentration was determined by Bradford protein assay. Transforming growth factor β 2 levels were assessed by enzyme-linked immunosorbent assay. Myocilin levels are significantly elevated in human POAG aqueous humor when compared with control aqueous humor (AB1: 0.66±0.53 ng/μL vs. 0.23±0.20 ng/μL, P<0.001; AB2: 0.98±0.59 ng/μL vs. 0.65±0.5 ng/μL, P<0.03; mean±SD). Myocilin makes up a larger percent of the total protein in POAG aqueous humor compared with control aqueous (AB1: 0.26±0.20% vs. 0.10±0.20%, P<0.001; AB2: 0.43±0.32% vs. 0.28±0.18%, P<0.05). In contrast to POAG, myocilin levels were not elevated in PEXG aqueous humor when compared with control aqueous humor. No correlation between myocilin and transforming growth factor β 2 levels was observed. Myocilin is elevated in POAG, but not in PEXG aqueous humor.

Proteomic analysis of human cataract aqueous humour: Comparison of one-dimensional gel LCMS with two-dimensional LCMS of unlabelled and iTRAQ®-labelled specimens

In this study, we report a comparative and quantitative analysis by mass spectrometry of the protein content of aqueous humour from cataract (control) patients. In addition to protein profiling, the approach is layered with quantitative proteomics using the iTRAQ® methodology. Aqueous humour from ten clinically-matched patients was collected and depleted of albumin and immunoglobulin G. Pairs of patient material were pooled and divided into three aliquots for subsequent analysis by alternative proteomic approaches. Excluding keratin, trypsin, residual albumin and immunoglobulins, a total of 198 protein groups were identified across the entire study. Relative protein quantitation with iTRAQ® revealed that 88% of the proteins had a maximal ±2-fold differential regulation between 3 of the 4 labelled samples, indicating minimal variation. The identified proteins were categorised by gene ontology and one third of the proteins were annotated as extracellular. The major molecular functions of the proteins in aqueous humour are binding (protein, metal ion, heparin, and DNA) and inhibition of proteolytic activity. Complementary to molecular function, the predominant biological processes for the proteins in aqueous humour are assigned to inflammatory and immune responses, and transport.

Aqueous humor rapidly stimulates myocilin secretion from human trabecular meshwork cells

Myocilin, a protein associated with the development of glaucoma, is expressed in most eye tissues with highest expression observed in trabecular meshwork cells. In culture, primary human trabecular meshwork cells incubated in 10% fetal bovine serum have reduced myocilin expression compared to in vivo, but incubation in human aqueous humor, their normal in vivo nutrient source, restores myocilin expression to near in vivo levels. To investigate the mechanism by which human aqueous humor stimulates myocilin accumulation in conditioned media from normal human trabecular meshwork cells, three independent trabecular meshwork cell lines were cultured in Dulbecco’s Modified Eagle’s Medium (DMEM) containing various supplements: fetal bovine serum (10%), human serum (0.2%), porcine aqueous humor (50%), bovine serum albumin (0.1%), dexamethasone (10 −7 M), human aqueous humor (50%) or heat-inactivated human aqueous humor (50%). Conditioned media from cultured primary trabecular meshwork cells following incubation in human aqueous humor showed significant accumulation of myocilin in a time- (15 min) and dose-dependent manner (half maximal effective concentration ∼ 30%) while intracellular myocilin levels decreased. Minimal myocilin accumulation was observed in conditioned media isolated from trabecular meshwork cells cultured in DMEM containing fetal bovine or human serum, bovine serum albumin, porcine aqueous humor, dexamethasone or DMEM alone. Heat inactivation of human aqueous humor nearly eliminated human aqueous humor-stimulated myocilin secretion. Inhibitors of new protein synthesis, gene transcription, the endoplasmic reticulum/Golgi system and endocytic/exocytic secretory pathways failed to inhibit human aqueous humor-stimulated myocilin secretion. Using immunolabeling and transmission electron microscopy, myocilin was found associated with 70–90 nm vesicle-like structures within the cytoplasm of human aqueous humor treated trabecular meshwork cells. These studies suggest that myocilin secretion from trabecular meshwork cells occurs in a Golgi-independent manner following human aqueous humor treatment. Heat-labile factors in human aqueous humor are responsible for the time- and dose-dependent release of myocilin from vesicle-like structures within the cytoplasm of trabecular meshwork cells.

Pharmacokinetics of Azithromycin and Moxifloxacin in Human Conjunctiva and Aqueous Humor During and After the Approved Dosing Regimens

To evaluate the ocular pharmacokinetics of azithromycin and moxifloxacin in human conjunctiva and aqueous humor in subjects undergoing cataract surgery. Multicenter, open-label, randomized study. Subjects scheduled for routine cataract surgery and with normal-appearing conjunctiva were eligible. One conjunctival biopsy sample and 1 aqueous humor sample were obtained from subjects randomly assigned to 1 of 10 prespecified time points (1 to 312 hours) after treatment initiation of azithromycin ophthalmic solution 1% or moxifloxacin ophthalmic solution 0.5%. Samples were assayed using liquid chromatography tandem mass spectrometry. Azithromycin 1% provided high concentrations (peak level, 559.7 μg/g) in human conjunctiva that were sustained at levels 1 to 2 orders of magnitude higher than those of moxifloxacin 0.5% throughout the 7-day dosing period and for at least 7 days thereafter. Azithromycin also showed an extended half-life (65.7 hours) in conjunctiva relative to that of moxifloxacin (28.6 hours). Accordingly, the concentration of azithromycin was maintained well above the minimum inhibitory concentration required for inhibition of growth of 90% of tested bacterial isolates for at least 7 days, whereas moxifloxacin conjunctival levels fell to levels at or less than the minimum inhibitory concentration required for inhibition of growth of 90% of tested bacterial isolates approximately 24 hours after the last dose. Peak aqueous humor concentration of moxifloxacin was higher (0.77 μg/mL) than that of azithromycin (0.053 μg/mL). No clinically relevant safety findings were observed. Azithromycin 1% demonstrated high, therapeutic levels in the conjunctiva that were maintained up to 7 days after completion of a 1-week dosing regimen. Aqueous humor levels, however, were subtherapeutic with this dosing regimen. In comparison, moxifloxacin achieved lower conjunctival tissue levels, but higher aqueous humor levels.

Surface Tension of Aqueous Humor

To measure and compare the surface tension of aqueous humor in patients with and without glaucoma. The surface tension of aqueous humor was measured using a commercially available instrument and software that were validated by using a known fluid (deionized water and methanol). Analysis of aqueous and vitreous samples obtained from 20 rabbit eyes showed that the system could be used successfully for small amounts of ocular fluid. The effect of glaucoma drugs on the surface tension of aqueous humor was then studied in a rabbit model. Comparison of aqueous humor from 66 patients with glaucoma and 53 patients with cataracts but no glaucoma was carried out. The surface tension of rabbit aqueous humor was 65.9 ± 1.2; vitreous, 60.6 ± 2.6; and balanced salt solution, 70.7 ± 0.9. Timolol and latanoprost did not alter the surface tension of the aqueous humor in the rabbit model. The average surface tension of human aqueous humor was 63.33 ± 4.0 (glaucomatous eyes) and 66.19 ± 2.64 (nonglaucomatous eyes with cataracts) (P=0.0001). A technique of measuring the surface tension from small quantities of aqueous humor is validated. Surface tension of the aqueous humor in glaucoma patients was less than that of cataract patients.

Rapid and Sensitive Liquid Chromatography/Mass Spectrometry Assay for Caspofungin in Human Aqueous Humor

A rapid, precise, and sensitive liquid chromatography/mass spectrometry (LC/MS) method to quantify the caspofungin concentration in human aqueous humor was developed and validated. Sample preparation involved simple dilution of aqueous humor samples with acetonitrile. Azithromycin was the internal standard. Good linearity over 10 to 5,000 ng/ml was observed. The lower limit of quantification was 10 ng/ml. The intra- and interday accuracies (percent bias) were within 11%, while the intra- and interday precisions were within 6%.

Proteome Analysis of Human Aqueous Humor

Human aqueous humor (hAH) provides nutrition and immunity within the anterior chamber of the eye. Characterization of the protein composition of hAH will identify molecules involved in maintaining a homeostatic environment for anterior segment tissues. The present study was conducted to analyze the proteome of hAH. hAH samples obtained during elective cataract surgery were divided into three matched groups and immunodepleted of albumin, IgG, IgA, haploglobin, antitrypsin, and transferrin. Reduced and denatured proteins (20 μg) from each group were separated by gel electrophoresis. Thirty-three gel slices were excised from each of three gel lanes (n = 99), digested with trypsin, and subjected to nanoflow liquid chromatography electrospray ionization tandem mass spectrometry (nano-LC-ESI-MS/MS). The protein component of hAH was also analyzed by antibody-based protein arrays, and selected proteins were quantified. A total of 676 proteins were identified in hAH. Of the 355 proteins identified by nano-LC-ESI-MS/MS, 206 were found in all three groups. Most of the proteins identified by nano-LC-ESI-MS/MS had catalytic, enzymatic, and structural properties. Using antibody-based protein arrays, 328 cytokines, chemokines, and receptors were identified. Most of the quantified proteins had concentrations that ranged between 0.1 and 2.5 ng/mL. Ten proteins were identified by both nano-LC-ESI-MS/MS and antibody protein arrays. Proteomic analysis of hAH identified 676 nonredundant proteins. More than 80% of these proteins are novel identifications. The elucidation of the aqueous proteome will establish a foundation for protein function analysis and identification of differentially expressed markers associated with diseases of the anterior segment.

Human aqueous humor levels of levofloxacin 0.5%, gatifloxacin 0.3% and levofloxacin 0.3% ophthalmic solution after topical dosing

To compare the aqueous humor concentration of levofloxacin 0.5%, gatifloxacin 0.3% and levofloxacin 0.3% ophthalmic solution after topical dosing in human eyes. A randomized, double-blind and parallel study was conducted. Senile cataract patients (150 eyes in 150 cases) receiving phacoemulsification in eye center affiliated second hospital of Zhejiang university were randomized into three groups: levofloxacin 0.5%, 50 eyes;gatifloxacin 0.3%, 50 eyes and levofloxacin 0.3%, 50 eyes. Each group was randomized into five sub-groups, with 10 eyes in each sub-group. Each group received either levofloxacin 0.5% or topical gatifloxacin 0.3% or levofloxacin 0.3% preoperatively. One drop of antibiotic was administered every 15 minutes for 4 doses. More than 100 microl aqueous samples were obtained from different sub-groups during surgery, 15.0, 30.0, 60.0, 120.0 and 180.0 min after the last drop, respectively. Then 100 microl aqueous samples were put into test tube by sample injector accurately. Concentration of the antimicrobial agents was determined by the HPLC (high pressure liquid chromatography). Variance analysis was performed to detect differences among the antibiotic treatment groups. The differences between two groups were assumed by t-test. Humor concentration of levofloxacin 0.5% (1.61 +/- 0.48), (2.41 +/- 0.80), (2.93 +/- 0.50), (2.56 +/- 0.63), (1.87 +/- 0.88) mg/L was significantly higher than that of gatifloxacin 0.3% (0.70 +/- 0.18), (1.29 +/- 0.54), (1.59 +/- 0.67), (1.41 +/- 0.50), (1.13 +/- 0.28) mg/L and levofloxacin 0.3% (0.55 +/- 0.39), (1.15 +/- 0.42), (1.38 +/- 0.49), (1.02 +/- 0.33), (0.55 +/- 0.31) mg/L at the same period after the last drop (F = 23.64, 12.82, 21.13, 25.00, 12.22;P < 0.05). Topically applied levofloxacin 0.5% had the higher aqueous humor drug level than gatifloxacin 0.3% and levofloxacin 0.3%.

Penetration of topical and subconjunctival corticosteroids into human aqueous humour and its therapeutic significance

Topical and subconjunctival corticosteroids are some of the most effective and compelling treatment options in ocular inflammatory diseases. A systematic review of literature indexed by Ovid MEDLINE & EMBASE was...

Determination of uric acid concentrations in human tear fluid, aqueous humour and serum

The aim of this investigation was to assess and compare levels of uric acid in human tear fluid, aqueous humour and serum in cataract patients in order to obtain information about uric acid-dependent antioxidative status. Reflex tear fluid, aqueous humour and serum were obtained from 103 cataract patients (52 women, 51 men). Uric acid was determined by a reversed phase chromatographic method with electrochemical detection. The Randox test was used to measure the contribution of uric acid to the total antioxidative status (TAS) of these body fluids. Mean concentrations of uric acid were 20 +/- 8 microg/ml in tear fluid, 18 +/- 6 microg/ml in aqueous humour and 58 +/- 15 microg/ml in serum. Significantly less uric acid was found in tear fluid (p < 0.01) and aqueous humour (p < 0.01) in female cataract patients compared with male cataract patients. There was a significant positive correlation between uric acid content in tear fluid, aqueous humour and serum, respectively (p < 0.01). The contribution of uric acid to TAS (Randox test) amounted to 38% in tear fluid, 10% in aqueous humour and 37% in serum. Uric acid was found in comparable amounts in tear fluid and aqueous humour, but these were two- to threefold lower than in serum. Female cataract patients had lower uric acid values in tear fluid and aqueous humour compared with male cataract patients. Uric acid is an important antioxidant, as proven by its contribution to TAS as determined by the Randox test. The precise role of uric acid in the antioxidative reactions in tear fluid and aqueous humour is still under debate.