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At least 307 records · Page 17Linked to original sources

PubMed2005

Nonhuman primate models for diabetic ocular neovascularization using AAV2-mediated overexpression of vascular endothelial growth factor.

Neovascularization leads to blindness in numerous ocular diseases, including diabetic retinopathy, age-related macular degeneration, retinopathy of prematurity, and sickle cell disease. More effective and stable treatments for ocular neovascularization are needed, yet there are major limitations in the present animal models. To develop primate models of diabetic retinopathy and choroidal neovascularization, rhesus monkeys were injected subretinally or intravitreally with an adeno-associated virus (AAV)-2 vector carrying the cDNA encoding human vascular endothelial growth factor (VEGF). Overexpression of VEGF was measured by intraocular fluid sampling over time. Neovascularization was evaluated by ophthalmoscopy through angiography, optical coherence tomography, and ultimately histopathology. Overexpression of VEGF through AAV2 results in rapid development of features of diabetic retinopathy or macular edema, depending on the targeted cell type/mode of production of VEGF and diffusion of VEGF. Nonhuman primate models will be useful in testing long-term safety and efficacy of novel therapeutic agents for blinding neovascular diseases.

Adenoviridae↗

PubMed1986

Time course for prostaglandin synthesis by rabbit lens during endotoxin-induced ocular inflammation.

Three hours to 14 days following the intravitreal injection of 10 ng of E. coli endotoxin into the vitreal chamber of one eye of the New Zealand white rabbit, ocular inflammation was evaluated by clinical and biochemical criteria and prostaglandins were measured in the intraocular fluids and in the incubation medium of the intact lens. Increased synthesis of PGE2 was detected for lenses from inflamed eyes beginning at 18 h post-endotoxin injection. Lenticular PGE2 synthesis remained above control levels for the duration of the time course. Lenses also exhibited increased PGF2 alpha synthesis, which began at 18 h and returned to control levels by day 7. At the times of peak production, aqueous humor PGE2 concentration correlated with lenticular PGE2 synthesis and with aqueous humor leukocyte number. No correlations were found for lenticular PGE2 vs. cell number, or vitreous humor PGE2 vs. aqueous humor PGE2. These results suggest that during ocular inflammation, aqueous humor PGE2 may be derived, at least in part, from the lens and leukocytes.

Animals↗

PubMed2000

[Typing of herpes simplex virus in patients with uveitis].

AIM: To examine the type of herpes simplex virus (HSV) in cases with uveitis. MATERIALS AND METHODS: Intraocular fluid specimens obtained from 3 cases with herpetic iridocyclitis and 6 cases with acute retinal necrosis (ARN) were examined by polymerase chain reaction (PCR). HSV typing was performed by the restriction patterns of the PCR products. Serum samples obtained from these cases and 33 cases with uveitis were examined by neutralization test (NT) for the availability of the typing of HSV. RESULTS: The restriction patterns of the PCR products amplified from 3 specimens of iridocyclitis revealed HSV type 1 DNA. HSV type 2 DNA was identified in 5 of 6 cases of ARN and HSV type 1 DNA was found in only one case. The results of serum NT titers correlated with the typing of the amplicons. CONCLUSIONS: In the cases studied, HSV type 1 was the dominant etiological agent in herpetic iridocyclitis, while HSV type 2 played a similar role in HSV-associated ARN. The examination of the serum NT may be helpful for the identification of the etiological types of HSV in patients with uveitis.

Adult↗

PubMed2000

Expression of human beta-defensins in intraocular tissues.

PURPOSE: Defensins are naturally occurring antimicrobial peptides. Recently the authors published evidence of defensin production by the human ocular surface. A study was undertaken to look for intraocular defensins that may account for unexplained antimicrobial activity of intraocular fluids. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) was performed on human postmortem ciliary body samples for beta defensins-1 (HBD-1) and beta defensin-2 (HBD-2), and alpha defensins 5 and 6. Induction of defensins by cytokines was analyzed in cultured human ciliary body epithelial (CBE) and retinal pigment epithelial (RPE) cells. Polyclonal antibodies were used to immunoblot aqueous and vitreous to detect HBD-1 and HBD-2 and to estimate their concentration. RESULTS: RT-PCR revealed constitutive HBD-1 message in ciliary body. HBD-2 and alpha defensin 5 and 6 messages were absent. HBD-2 message was induced by cytokine stimulation of both CBE and RPE cells. Immunoblots of vitreous and aqueous stained positively for HBD-1 but not HBD-2. The estimated aqueous concentration of HBD-1 was less than 16 ng/ml. CONCLUSIONS: This study demonstrates that HBD-1 is constitutively present in the aqueous and vitreous, probably at sub-bacteriocidal concentrations. HBD-2 was absent from aqueous, but cytokine stimulation studies suggest that it may be generated in response to inflammatory cytokines during infections. HBD-2 has a wider antibacterial spectrum, is 10-fold more potent, and may play a more significant role in antimicrobial defense than HBD-1. The use of defensins therapeutically may be indicated; however, caution is required because defensins also promote cell proliferation and fibrin formation, which are 2 key elements in ocular scarring processes such as proliferative vitreoretinopathy.

Aqueous Humor↗

PubMedDate not supplied

Self-sealing sclerotomies for sutureless pars plana vitrectomy.

OBJECTIVE: To determine the efficacy of self-sealing pars plana sclerotomies for vitrectomy and to identify complications associated with this new technique. METHOD: There were 150 self-sealing sclerotomies performed in 50 patients undergoing pars plana vitrectomy between October 1996 and March 1998. RESULTS: Of the 150 sclerotomies, 115 (76.6%) did not require suturing while 35 (23.3%) were closed with one radial 7.0 vicryl suture. The scleral tunnel incisions ensured minimal loss of intraocular fluids during instrument exchange and scleral plugs were not required to avoid ocular hypotony during scleral indentation. Distortion of scleral flap incisions requiring a suture were commonly seen in procedures using multiple instrumentations and extensive explants. CONCLUSIONS: Sutureless sclerotomies are simple to perform, save operative time, and reduce the risk of peroperative hypotony following removal of instruments or the infusion cannula. The technique reduces postoperative inflammation, suture-related problems including astigmatism, and allows more rapid rehabilitation.

Adult↗

PubMedDate not supplied

[Nitrogen oxide in the pathogenesis of glaucoma and cataract].

The content of nitrite (final metabolite of nitroradical) was measured in aqueous humor of patients with glaucoma and cataract. The level of NO formation is increased at the initial stage of glaucoma and decreases with the disease progress. A direct correlation between the level of nitrite in aqueous humor and coefficient of easiness of its discharge was detected. Cataract is associated with a high level of nitrite in intraocular fluid. The results are discussed from the viewpoint of ocular hydro--and hemodynamic regulation and NO involvement in the free radical oxidation reactions, playing an important role in the pathogenesis of both diseases.

Adult↗

PubMed2003

The diagnostic significance of enzyme linked immuno-sorbent assay for herpes simplex, varicella zoster and cytomegalovirus retinitis.

PURPOSE: To evaluate the diagnostic usefulness of enzyme linked immuno-sorbent assay (ELISA) in single serum samples to associate herpes simplex virus (HSV), varicella zoster virus (VZV) or cytomegalovirus (CMV) with viral retinitis as against polymerase chain reaction (PCR) on intraocular specimens. It was also designed to study the seroprevalence in normal healthy individuals, and the genomic prevalence of HSV, VZV and CMV in patients without an active viral inflammatory process. METHODS: PCR for the detection of HSV, VZV and CMV genomes was done on 33 and 90 intraocular fluids from viral retinal patients and non-viral controls respectively. ELISA was done on 30 and 100 serum samples from viral retinitis patients and normal healthy controls respectively. RESULTS: PCR did not detect HSV, VZV and CMV genomes except one, in which VZV-DNA was detected. ELISA showed prevalence rates of 28%, 83% and 90% for antibodies against HSV, VZV and CMV respectively in the normal population. In the 30 viral retinitis patients, PCR detected HSV-DNA in 2 (6.7%), VZV-DNA in 7 (23.3%) and CMV-DNA in 6 (20.0%) patients, while ELISA detected antibodies against HSV, VZV and CMV in 13 (43.3%), 24 (80.0%) and 23 (76.7%) patients respectively. ELISA was of value in indirect diagnosis only in 6 (20.0%) as compared to 15 (50.0%) of 30 patients by PCR, this difference was statistically significant (McNemar test, P value = 0.005). CONCLUSION: Serology by ELISA is no longer a useful diagnostic tool to associate HSV, VZV and CMV viruses with viral retinitis.

Adolescent↗

PubMed2004

[The frosted retinal vascular branch syndrome].

In January 2002, thirty-eight years old healthy man with unusual clinical signs of vasculitis was examined in the Center for Diagnosis and Treatment of Uveitis in our Department of Ophthalmology. The patient had a flu-like disease one month before the signs of the eye disease started. In the beginning of the disease, the visual acuity (VA) was 6/12 (20/40 or 0.5) for distance and Jaeger 8 for near and 6/6 (20/20 or 1.0) and Jaeger 1 respectively. The clinical appearance was similar to this of frosted branch angiitis. The thorough medical examination did not discover link between vasculitis and any systemic disease. Serologic examination discovered positivity of IgG immunoglobulin antibody against cytomegalovirus (CMV) only. The intraocular fluid sampling to confirm CMV antibody presence was denied by the patient. After starting the treatment with gancyclovirus and corticosteroids, the considerable improvement of clinical signs of the frosted branch angiitis was noticed. VA improved after five days of treatment. During one-year follow-up, neither recurrence of vasculitis nor the decline of VA of both eyes was marked. In Czech ophthalmologic literature, we did not find any article referring to frosted branch angiitis, so we took the liberty of offering the Czech term "syndrom omrzlých vĕtví retinálních cév".

Adult↗

PubMedDate not supplied

[Trabeculodialysis].

Trabeculodialysis, a new antiglaucoma surgical technique, developed at the Chair for Ophthalmic Diseases of the Yaroslavl Medical Institute, is described. Trabeculodialysis is aimed at recovery of intraocular fluid discharge via Schlemm's channel and then through orifices into intra- and episcleral vessels; this technique is indicated for patients with open-angle glaucoma in trabecular form of retention. Since 1990 this operation was performed in 50 glaucoma patients. The results will be presented in another paper.

Glaucoma, Open-Angle↗

PubMed1990

Factors contributing to the emulsification of intraocular silicone and fluorosilicone oils.

Silicone oil (SiO) and fluorosilicone oil (FSiO) are used as vitreous substitutes during retinal detachment surgery. Emulsification of these oils causes complications in oil-injected eyes. One factor contributing to emulsification is interfacial tension (gamma i) of the oils. In general, the lower the gamma i, the more easily the oils are emulsified. We measured the gamma i of SiO and FSiO by the ring method at 37 degrees C; corrected the measured values by the Harkins-Jordan table or the Zuidema-Waters equation; and found that the gamma i between the oils and liquefied bovine vitreous was low compared with the gamma i between the oils and water (eg, gamma i of 1000 centistokes [cs]SiO against liquefied vitreous and water was 16.0 and 42.8 dyne/cm, and that of 1000 cs FSiO was 14.7 and 38.7 dyne/cm, respectively). When SiO or FSiO and liquefied vitreous were shaken in a partially filled vial, both oils were emulsified regardless of viscosity and purity. However, when the vial was filled completely (a situation in which the hydrodynamic condition of the oils may be similar to that in the eye), SiO of 1000 and 12,500 cs and FSiO of 10,000 cs did not emulsify, although FSiO of 1000 cs did emulsify. SiO was less emulsified than FSiO of the same viscosity, possibly because the smaller density difference between SiO and intraocular fluids makes agitation difficult compared with FSiO. High viscosity of the oils restricted mechanical emulsification, which was not prevented by eliminating low-molecular-weight components of the oils. Residual catalysts may relate to spontaneous emulsification, which was observed occasionally with high-viscosity SiO in water.

Animals↗

PubMed1991

[Existence of atrial natriuretic peptide in choroid, retina and ciliary body in rabbits].

The presence of atrial natriuretic factor (ANF) in choroid, retina and ciliary body of rabbit eyes has been studied. The peptide was extracted by reverse phase chromatography using Sep-Pak C18 cartridges. Immunoreactive ANF (Ir-ANF) was measured by a specific RIA. In the choroid, retina and ciliary body the ir-ANF concentrations were 444 +/- 94, 67 +/- 12 and 223 +/- 75 pg/g tissue weight (n = 16), respectively. The biological activity of the acid extract ANF was evaluated by a 125I-ANF binding assay to a retinal particulate preparation. Results demonstrate the existence of biological active ANF in choroid, retina and ciliary body of rabbit eyes. The presence of ANF and its specific receptors in the ocular tissues suggests that this hormone might play a physiological role in the intraocular fluid homeostasis.

Animals↗

PubMedDate not supplied

[A new enriched balanced irrigation solution for intraocular surgery (experimental study)].

Experimental trials of a new intraocular irrigation solution, one of the enriched balanced salines, were carried out. A comprehensive morphologic study has revealed the protector characteristics of lactosol plus (lactosol + taurin) used in the management of irrigation injury to the posterior epithelium of the cornea in the course of experimental intrachamber perfusion. The protective properties of lactosol + taurin, a new enriched balanced saline, are explained by the similarity of its chemical composition to that of the intraocular fluid and by the presence of a stable polyfunctional bioprotector, taurin amino acid.

Animals↗

PubMedDate not supplied

[Mechanisms of organic drug electrophoresis].

Riboflavin, riboflavin mononucleotide, and fluorescein penetration from the ocular bath without electric current (control), from the anode, from the cathode, and without current after preliminary galvanization was studied in rabbit eyes. Penetration of organic drugs into intraocular fluid in electrophoresis was found to be increased not only from the adequate pole of the active electrode, but from the contrary pole as well. Galvanic current sharply abated the barrier function of the cornea. Therapeutic electrophoresis of the eyeball permits the use of many-component solutions with drug ions of different charge.

Animals↗

PubMedDate not supplied

[Fluorescein movement in a transparent lens].

Fluorescein movements in the lens laminae of isolated porcine eyes were examined by biomicroscopy. The stain disseminated in two directions: from the lens nucleus to capsules and fluorescein release into the intraocular fluid and from the outer laminae of the equatorial zone to the nucleus. Lecozyme, a proteolytic agent, accelerated fluorescein movement in both directions. The method suggested by the authors permits an objective assessment of fluorescein movement in the lens, which appears to reflect the processes of extracellular fluid ultrafiltration in the lens. The data evidence the possibility of effecting the extracellular intralenticular fluid microcirculation by proteolytic enzymes. The suggested technique may be useful in studies of cataract pathogenesis and of anticataract action of various drugs.

Animals↗

PubMed1990

Endophthalmitis due to Sporothrix schenckii after penetrating ocular injury.

A 13-year-old boy developed endophthalmitis from traumatic inoculation of vegetable material penetrating his right eye. Sporothrix schenckii was morphologically identified from the intraocular fluids. However, repeated attempts to culture the organism proved negative. Seventeen sporotrical endophthalmitis cases have so far been reported, and before this report, only one of them was secondary to trauma. This is the sole eye to our knowledge not only to have escaped enucleation after sporotrical endophthalmitis but to have achieved useful (20/50) vision.

Adolescent↗

PubMed1989

[Electron microscopic research on the manifestations of transport-metabolic interactions in intraocular nerve tissue grafts].

Electron microscopic study of intraocular grafts of the septal and hippocampal nervous tissue revealed intensive transport and metabolic interactions between various types of the cells. High level of transport exists between the recipient's blood and intraocular fluid, on the one hand, and the graft, on the other one; the abundance of pinocytotic vesicles in the endothelium, pericytes and the glial end-feet of the capillaries, and the presence of microvilli and cilia on the graft limiting glia. Signs of active communications between interstitial glial cells, as well as between gliocytes and neurons, such as pinocytosis and gap junctions were observed. Similar interactions exist between various parts of nerve cells. Besides, there is an evidence of microphagocytic interactions, particularly between pre- and postsynaptic elements, as shown by the presence of so-called spinules. An unusual fact was observed of internalization of cytoplasmic fragments of the degenerating neuron by contacting synaptic boutons. It is suggested that the high level of transport and metabolic processes may reflect adaptive and compensatory processes in the nervous tissue developing under strict limitations of the neural and neurotrophic influences.

Animals↗

PubMed1989

[Experimental studies of the precision of lamellar corneal sections].

Using an automatic rotating microkeratome for lamellar corneal grafting, 200 porcine corneal specimens were subjected to lamellar dissection. The aim of the study was to define the factors influencing the optimal thickness of the corneal lamella. The factors investigated were: the rotation speed of the trephine blade; the speed of blade advancement; the influence of lubrication fluids; intraocular pressure; geometry of the rotating blade. Ultrasound pachymetry was performed on non-fixed tissue in 13 defined positions. The optimal conditions for lamellar dissection with the rotating microkeratome were found to be a speed of 0.5 mm/s blade advancement, an intraocular pressure of 40 mmHg, lubrication of the cut area with a 0.05% Healon/BSS +/- solution. Under these conditions the thickness of the lenticule showed an inhomogenity of 2.5% total thickness, which was located in the direction of blade advancement and blade rotation speed.

Animals↗

PubMed1989

Hypotheses on the role of prostaglandins in the pathogenesis of epinephrine maculopathy and aphakic cystoid macular edema.

This article presents hypotheses regarding pathogenesis of epinephrine maculopathy. According to these hypotheses, two points are the most essential in the development of epinephrine-induced CME: one is the stimulation of PG synthesis by some tissues, presumably, the anterior uvea by the applied epinephrine, the other is the dysfunction, in some aphakic eyes, of the active transport system (Bito's pump) which is responsible for the removal of PGs from intraocular fluids. To test these hypotheses, the authors and their group conducted several experimental studies. The results of these studies, which have been reviewed in this article, strongly suggest that epinephrine maculopathy is induced by a mechanism involving PGs or possibly, other related eicosanoids and not simply by epinephrine per se, as has previously been suggested. This in turn suggest the existence of some common factors in the pathogenesis of epinephrine maculopathy and aphakic or pseudophakic CME.

Animals↗