Experimental study of VEGF immune expression dynamics in the retina using photoinduced BRVO model

Aim. To describe the dynamics of vascular endothelial growth factor (VEGF) immune expression in the retina using the model of photoinduced branch retinal vein occlusion (BRVO) and to establish the terms of neovascularization appearance.Materials and methods. BRVO was modelled on 21 chinchilla rabbits (21 eyes) weighing 1.5‑2 kg (fellow eyes served as controls). Photosensitizer «Fotoditazin» (2.5 mg / kg) was injected intravenously. 15 min later, transpupillary laser irradiation of branch retinal vein near the optic nerve head was performed. Irradiation energy density was 200 J / cm2. Histological analysis and immunohistochemistry of the retina was performed following 30 min, at days 1, 2, 3, 7, 14 and 30.Results. Maximum VEGF accumulation in photoinduced BRVO model was observed on day 2. From day 3, direct neovascularization was confirmed. VEGF levels were stably high throughout the follow-up to the day 30 inclusive.Conclusion. VEGF immune expression in the retina using the model of BRVO induced by photodynamic exposure was explored for the first time. These data can serve as the basis for future studies in order to define optimal anti-VEGF agent, its dosage and terms to manage this condition

Intraflagellar transport dynein is autoinhibited by trapping of its mechanical and track-binding elements

Cilia are multi-functional organelles that are constructed using intraflagellar transport (IFT) of cargo to and from their tip. It is widely held that the retrograde IFT motor, dynein-2, must be controlled in order to reach the ciliary tip and then unleashed to power the return journey. However, the mechanism is unknown. Here, we systematically define the mechanochemistry of human dynein-2 motors as monomers, dimers, and multi-motor assemblies with kinesin-II. Combining these data with insights from single-particle electron microscopy, we discover that dynein-2 dimers are intrinsically autoinhibited. Inhibition is mediated by trapping dynein-2’s mechanical “linker” and “stalk” domains within a novel motor-motor interface. We find that linker-mediated inhibition enables efficient transport of dynein-2 by kinesin-II in vitro. These results suggest a conserved mechanism for autoregulation among dimeric dyneins, which is exploited as a switch for dynein-2’s recycling activity during IFT

Uveal effusion syndrome (clinical case)

The purpose — to evaluate the effectiveness of the posterior sclerectomy with the corneal trepan in a uveal effusion syndrome.Patients and methods. Patient 1. The man, 61 years, complained about a blindness of the right eye and the progressing decrease in vision of the left eye. According to data of examinations the diagnosis was: uveal effusion syndrome, detachment of the choroid, exudative retinal detachment, the complicated cataract of both eyes. Patient 2. The man, 62 years, with complaints to low vision of the right eye and a blindness of the left-hand eye. Diagnosis: uveal effusion syndrome, detachment of the choroid, exudative retinal detachment, the initial complicated cataract of the right eye. Subatrophy operated retinal detachment, complicated cataract, silicone into the vitreal cavity of the left eye. Both patients underwent trepanation posterior sclera. Results. The patient 1noted significant improvement of vision in both eyes at the last examination. Мisual acuity with correction was OD — 0,2, OS — 0.3. Intraocular pressure was normal, improvement of electrical sensitivity and lability was diagnosed. On ultrasound examination of the retina belonged, moderate swelling of the choroid remained. Patient 2. Visual acuity was 0,1 + 3,0 D at the time of the last inspection. According to the ultrasonic B-scan of the right eye retinal detachment decreased to 3,8 mm, moderate swelling of the choroid remained. The OСT has showed detachment of the neuroepithelium in the macula to 60 μm. In ultrasonic biomicroscopy circular, ciliochoroidal detachment to 0,15 mm was diagnised.Conclusion. Described clinical cases confirmed the almost complete recovery of patients with the uveal effusion syndrome. Sclerectomy with the use of corneal trepan is a technically simple procedure and helps to define the path of the outflow suprachoroidal fluid subtenon space

The morphometric study of retinal vessels in the early stages retinopathy of prematurity

Purpose: To define diagnostic morphometric parameters for temporal and nasal arcades in fundus central zone, 2nd order vessels and peripheral vessels beyond avascular retina for each type of ROP active stages.Methods: 155 premature children (310 eyes) with I, II, III stages of ROP. The patients were divided according to types of ROP active stages (type 1 — with low risk of ROP progressing, type 2 — with high risk of ROP progressing). Morphometric analysis of digital «RetCam 120» and «RetCam 3» fundus photos was made by means of original soft «ROP-MORPHOMETRY».Results: Renal vessels diameter, and tortuosity index increasing at type 2 (unfavorable) as compared with type 1 (favorable) (p<0.05) was determined at all active ROP stages both in central fundus zone and at periphery. A tendency to retinal vessels diameters decreasing as distance from central zone increasing was shown in the direction of temporal and nasal arcades at all active ROP stages.Conclusion: The given retinal vessels quantitative morphometric parameters might be the precise criteria for high and low risk of ROP progressing determination within each ROP stage

the first experience of combined positioning of electrodes in electrochemical destruction of intraocular tumor in experi- ment

In experiment on fresh enucleated eyes with large tumors it was shown that a new method of electrochemical lysis with original combined positioning of electrodes for intraocular tumors treatment provides a minimal traumatic impact and total destruction of tumor tissue at electrodes encirclement. Superficial electrode allows to aim the electrochemical destruction at hole tumor basis. the combination of the both superficial and intratumoral electrodes gives an opportunity to minimize a scleral injury in tumor basis scleral projection. Further examination on alteration of both intratumoral electrode injection depth and quantity of electricity in combinationwith bioimpedancemetry might it possible for regulation of morphological changes in tumor structure

Electrochemical lysis at the stage of endoresection for large posterior intraocular tumors

Purpose: to design the new combined technique of endoresection with intraoperative intraocular electrochemical lysis at the tumor destruction stage for large posterior intraocular tumors.Methods: 3 patients (3 eyes) with large choroidal melanomas t3N0M0 (tumor thickness — 8-10 mm, base diameter — 13-15 mm, juxtapapillary localization). Mean age was 55.4 years old. Endoresection with intraoperational intraocular electrochemical lysis of the tumor was performed. Electrochemical lysis was performed with use of the technical unit ECU 300 (Soering, Germany) and the original method of combined intratumoral positioning of two platinum electrodes: anode and cathode.Results: the tumor was removal completely in all 3 cases. the anatomical retinal reattachment was reached in all patients. Sclera was safe in all 3 cases. Visual acuity was not changed (NLP). At the place of the removal tumor a surgical choroidal coloboma without pigmentation all over scleral bed and periphery was shown in all cases in distant postoperative period (from 1.5 to 3 years). No local recurrences or metastasis were revealed in all patients.Conclusion: Further investigations in clinical group are necessarily to determinate the real possibilities of the combined method and the indications for endoresection with intraoperative intraocular electrochemical lysis for large intraocular tumors

The modern view on the concept of treatment of active stages of retinopathy of prematurity

Purpose: To show the basic regulations of the complex retinopathy of prematurity (ROP) treatment with use of retinal pattern scanning laser coagulation and early vitrectomy.Methods: Pascal pattern scanning lasercoagulation is performed for stage 2 ROP type 2, stage 3 ROP type 2 and subclinical stageand early clinical stage of aggressive posterior ROP (S. N. Fyodorov Federal State Institution «IRTC «Eye Microsurgery» Kaluga Branchclassification). Early 3‑ports 25G vitrectomy is performed if ROP progressing 2‑4 weeks after the laser treatment.Results: In 2003‑2011 823 different interventions for infants with active ROP was performed: 737 retinal lasercoagulations, 3‑ports vitrectomy — 72, 3‑ports lensvitrectomy — 14. Treatment efficacy was 98.6 % for stage 2 and stage 3 ROP (regress of the disease occurred in 557 of 565 eyes), and 74.4 % for aggressive posterior ROP (regress of the disease occurred in 128 of 172 eyes). The total efficacy of the complex treatment was 92.9 % (regress of the disease occurred in 685 of 737 eyes).Conclusion: The basic regulations of the complex ROP treatment are early, within first 6 weeks of chronologic age, photocoagulationto delay progression of the retinal detachment and to stabilize vascularity, and early vitrectomy if ROP progressing after the lasertreatment

AGGRESSIVE POSTERIOR RETINOPATHY OF PREMATURITY CLASSIFICATION

Based on dynamic monitoring of 163 premature infants (326 eyes) with aggressive posterior retinopathy of prematurity (ROP), digital retinoscopy and computer morphometry the disease clinical and morphometric features were revealed and systematized, and their consecutive replacement was fixed. As a result the separate classification of aggressive posterior disease was worked up. In aggressive posterior ROP course the next consecutive stages were marked out: subclinical, early clinical appearances stage, manifestation stage, advanced, far-advanced and terminal stages. The peculiarity of early clinical appearances stage and manifestation stage is the presence of such course types: favorable and unfavorable

TREATMENT OF ACTIVE STAGES OF RETINOPATHY OF PREMATURE BABIES WITH THE USE OF MODERN TECHNOLOGIES

Purpose. To show the basic regulations of the complex retinopathy of prematurity (ROP) treatment with use of retinal pattern scanning laser coagulation and early vitrectomy. Material and methods. Pascal pattern scanning retina laser coagulation of (RLC) was performed in children for stage 2 ROP type 2, stage 3 ROP type 2 and subclinical stage and early clinical stage of aggressive posterior ROP according to the classification developed at the Kaluga Branch of the S. Fyodorov Eye Microsurgery State Institution. Early 3-ports 25G vitrectomy was carried out in case of ROP progressing 2-4 weeks after the laser treatment. Results. Between 2003 and 2011 total 823 different surgical interventions for infants with active ROP was performed: 737 retinal laser coagulations, 3-port lens preserving vitrectomy – 72, 3-ports lensvitrectomy – 14. Treatment efficacy was in classical ROP course 98.6% for stage 2 and stage 3 ROP (regress of the disease occurred in 557 of 565 eyes), and 74.4% for aggressive posterior ROP (regress of the disease occurred in 128 of 172 eyes). The total efficacy of the complex treatment was 92.9% (regress of the disease occurred in 685 of 737 eyes). Conclusion. The basic regulations of the complex ROP treatment are an early, within first 6 weeks of chronologic age, photocoagulation to delay progression of the retinal detachment and to stabilize vascularity, and an early vitrectomy in case of ROP progressing after the laser treatment

Aggressive posterior retinopathy of prematurity classification, based on clinical and morphometric disease features

Based on dynamic monitoring of 133 premature infants (266 eyes) with aggressive posterior retinopathy of prematurity (ROP), digital retinoscopy and computer morphometry the disease clinical and morphometric features were revealed and systematized, and their consecutive replacement was fixed. As a result the separate classification of aggressive posterior disease was worked up. In ag- gressive posterior ROP course the next consecutive stages were marked out: subclinical, early clinical appearances stage, manifesta- tion stage, developed, advanced and terminal stages. the peculiarity of early clinical appearances stage and manifestation stage is thepresence of types: favourable and unfavourable