Search

Oxindole-based natural indoles analogues retain the rigidity and size of the original indole ring system whilst introducing more 3-dimensionality and potential increased water solubility. We report the first preparation of a diverse series of new melatonin analogues 4, 6, 11, 12 based on 3-hydroxy-2-oxindoles (11) and hydroxy-free 2-oxindoles (4, 6, 12) and evaluated their ability to reduce intraocular pressure as well as their neuroprotective and antioxidant properties. Reductive amination was used to obtain new 5-(benzylamino)-substituted (indolin-3-yl)acetonitriles 11 and (indolin-3-yl)acetic acids 12 with high yields. Compounds 4 a, c, 6 a and 11 a, d, h, j-l demonstrated IOP reduction effect in range 15-27 % similar to the effect of reference compounds melatonin and timolol (12 % and 18 % reduction, respectively). 5-(Benzylamino)-substituted 3-hydroxy-2-oxindoles 11, unlike compounds 4, 6, inhibited lipid peroxidation in range 2.075-13.012 μM. Inhibition of NQO2 associated with antioxidant properties of melatonin was also evaluated for synthesized compounds and it was found that compound 11 h showed the best NQO2 inhibitory activity with an IC 50 =39 μM (vs. melatonin IC 50 =64 μM). All synthesized compounds 4, 6, 11, 12 at a concentration of 30 μM do not possess the mitochondrial toxicity. Moreover, no disruption of tubulin polymerization was observed even in the presence of 100 μM of the compounds. Thus, 3-hydroxy-2-oxindole derivatives 11 can be used for drug design of first-in-class antiglaucoma drugs with antioxidant and neuroprotective properties., (© 2025 Wiley-VCH GmbH.)

We conducted a study on the impact of intraperitoneal injections of melatonin and its three bioisosteres (compounds 1-3) on the development of oxygen-induced retinopathy in newborn rats during a 21-day experiment. It was demonstrated that melatonin and its analogues 1-3 effectively reduce the total protein concentration in the vitreous body of rat pups, decrease concentration of VEGF-A, and lower the level of oxidative stress (as indicated by normalization of antioxidant activity in the vitreous body). Melatonin and its analogues 1-3 equally normalize the level of VEGF-A. Analogues 1 and 2 even exceed melatonin in their ability to reduce protein influx into the vitreous body. However, analogue 2 had no effect on antioxidant activity, while analogues 1 and 3 caused a significant increase in this parameter, with analogue 3 even slightly exceeding melatonin. Thus, it can be concluded that analogues 1-3 are comparable to melatonin and can be utilized as potential therapeutic agents for the treatment of retinopathy of prematurity., (© 2024 John Wiley & Sons Ltd.)

Compounds with a 2-oxindole scaffold play an important role in organic synthesis and especially in the synthesis of bioactive organic compounds, therefore, the development of new methods for modifying this scaffold is a very interesting and urgent task. In the framework of this study, we have created a rational approach to the synthesis of 5-amino-substituted derivatives of 2-oxindole. The approach is characterized by good total yield and a small number of steps. One-stage modification of obtained 5-amino-2-oxindoles leads to compounds with promising antiglaucomic activity. The most active compound 7a reduce intraocular pressure by 24% in normotensive rabbits (18% for reference drug timolol)., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

In a rat model of experimental retinopathy of prematurity (ROP), the safety of enalaprilat and its effect on the level of angiotensin-converting enzyme (ACE) and angiotensin-II (AT-II) in the vitreous body and retina were investigated. The study was performed on 136 newborn Wistar rat pups divided into 2 groups: group A - experimental (animals with ROP, n=64) and group B - control (n=72). Each group was further divided into 2 subgroups: A0 and B0 (n=32 and n=36, respectively) - animals that did not receive injections of enalaprilat, and A1 and B1 (n=32 and n=36, respectively) - animals treated with daily intraperitoneal (i.p.) injections of enalaprilat (0.6 mg/kg of body weight). This treatment started on day 2 and lasted either to day 7 or to day 14 in accordance with the therapeutic scheme. Animals were taken out of the experiment on day 7 and day 14. In samples of the vitreous body and retina, the content of ACE and AT-II was determined by enzyme immunoassay. On day 7 in subgroups A1 and B1 the levels of ACE and AT-II in the vitreous did not differ, while on day 14 were lower than in subgroups A0 and B0, respectively. Changes in the parameters studied in the retina were somewhat different from those found in the vitreous body. On the seventh day, the level of ACE in the retina of animals of subgroup B1 did not differ significantly from subgroup B0, and in subgroup A1 it was increased compared to subgroup A0. On day 14, its significant decrease was noted in subgroups A1 and B1 as compared with subgroups A0 and B0. At the same time, the level of AT-II in the retina of rat pups of subgroup B1 was lower than in subgroup B0, both on day 7 and day 14. On day 7, the concentration of AT-II, as well as the concentration of ACE, increased in subgroup A1 as compared to subgroup A0. On day 14, this parameter in subgroup A1 was significantly lower as compared to subgroup A0, but significantly higher than in subgroup B1. It should be noted that i.p. injections of enalaprilat, increased a death rate of animals of both groups. The use of enalaprilat, starting from the preclinical period of the ROP development, led to a decrease in the activity of the renin-angiotensin system (RAS) in ROP animals at the onset of retinopathy in the experimental model used. This opens up prospects for considering enalaprilat as a means of preventing the development of this pathology; however, the recognized high toxicity of the drug requires further studies and correction of the timing of its administration and dosage in order to achieve a balance of efficacy and safety of use in order to prevent the development of ROP in children.

Glaucoma is a widespread neurodegenerative disease for which increased intraocular pressure (IOP) is a primary modifiable risk factor. Recently, we have observed that compounds with oxindole scaffolds are involved in the regulation of intraocular pressure and therefore have potential antiglaucomic activity. In this article, we present an efficient method for obtaining novel 2-oxindole derivatives via microwave-assisted (MW) decarboxylative condensation of substituted isatins with malonic and cyanoacetic acids. Various 3-hydroxy-2-oxindoles were synthesized using MW activation for 5-10 min with high yields (up to 98%). The influence of novel compounds applied in instillations on IOP was studied in vivo on normotensive rabbits. The lead compound was found to reduce the IOP by 5.6 Torr (ΔIOP for the widely used antiglaucomatousic drug timolol 3.5 Torr and for melatonin 2.7 Torr).

Alpha-2-macroglobulin ( α 2 -MG) is a multifunctional protein involved in neurodegeneration, inflammation and neovascularization, which are key processes in the pathogenesis of age-related macular degeneration (AMD) and proliferative diabetic retinopathy (PDR). AMD and PDR are two of the main causes of vision loss and blindness, are difficult to treat, and are generally diagnosed at the stage of irreversible changes., Purpose: This study estimates the activity of α 2 -MG in the blood serum and tears of patients with AMD and PDR in order to reveal the relation of its levels with the intensity of the pathological process in the retina., Material and Methods: The study included 17 patients (34 eyes) with AMD, 15 patients (30 eyes) with PDR, and 15 healthy adults (30 eyes) of the similar age. The activity of α 2 -MG in serum and tears was measured enzymatically using the specific substrate N-benzoyl-DL-arginine-p-nitroanilide (BAPNA)., Results: The activity of α 2 -MG in tears of patients with AMD was on the average 3.5 times higher than in healthy controls, and in patients with PDR - 1.5 times higher. Patients with AMD at the submacular fibrosis stage showed decreased α 2 -MG activity in tears. The activity of α 2 -MG in serum of patients with AMD and PDR was on the average 25% higher than in healthy persons. No correlation was revealed between serum and tear levels of α 2 -MG activity., Conclusion: This study revealed for the first time that in AMD and PDR the activity of α 2 -MG in tears is increased, and that in AMD the increase is higher than in PDR. An increase of α 2 -MG activity in serum confirms the presence of systemic inflammation. Absence of correlation between the serum and tear activity of α 2 -MG confirms its local origin. The high level of α 2 -MG activity in tears reflects the presence of an active destructive process in the retina, justifying its further investigation as a predictor of AMD and PDR course, as well as an indicator of therapy effectiveness.

Familial exudative vitreoretinopathy (FEVR) is a rare hereditary disease characterized by pathological retinal vascularization with a progressive and variable course. The mechanisms of disease progression remain unclear. One substance that plays an important role in the pathogenesis of retinal vascular diseases is endothelin (ET). It was found that tissue hypoxia enhances the expression of the gene encoding ET-1, and ET-1 can be locally produced in the eye., Purpose: The study evaluates the possible role of endothelin-1 in the pathogenesis of FEVR., Material and Methods: The study included 85 patients with FEVR aged from 1 months to 17 years who were examined in Helmholtz National Medical Research Center of Eye Diseases. The concentration of ET-1 was evaluated in 19 patients with FEVR in the blood serum ( n =17), lacrimal fluid ( n =18) and 16 patients from the control group., Results: The median of ET-1 in the lacrimal fluid in patients with FEVR was 13.74 pg/mL, respectively, which exceeded the same indicator of the control group 4.66 pg/mL by 2.5 times ( p <0.001). The median of ET-1 in the blood serum exceeded the control group by 2.4 times (21.61 pg/mL and 9.21 pg/mL, respectively, p <0.001)., Conclusions: An increase in the concentration of ET-1 in the lacrimal fluid and blood serum of patients with FEVR in comparison with the control group indicates its involvement in the pathogenesis of the disease.

Retinal diseases accompanied with the dysfunction or death of the retinal pigment epithelial (RPE) cells are widespread, hard to treat, and appear to be a leading case of visual loss and blindness among the persons older than 55 years. Transplantation of RPE cells derived from the induced pluripotent stem cells (IPSC-RPE) is a promising method of therapy for these diseases. To ensure the transplant survival instant follow-up is required. It can be based on biochemical analyses of tear fluid that can be easily non-invasively collected. For the post-transplantation process monitoring we have choosen such polyfunctional bioregulators as α2-macroglobulin (α2-MG) and endothelin-1 (ET-1). RPE atrophy in New Zealand Albino rabbits was modeled via the subretinal injection of bevacizumab. IPSC-RPE in suspension or as a monolayer on the scaffold were transplanted subretinally 1 month after the injection. α2-MG activity and ET-1 concentration in tears were estimated during the first month and after 2, 3 and 7 months after transplantation. On the 7-14 days after transplantation α2-MG activity increased in tears of the both operated and controlateral eye probably as a reaction on the corticosteroid therapy. In 50% rabbits there was one more increase after 2-3 months that could be due to the immune inflammation. Concentration of ET-1 in tears decreased dramatically on the 7-14 days and 7 months after transplantation, and it could have an influence upon the retinal vassal tone. The data obtained show that estimation of bioregulators in tears can help monitoring local metabolic processes after RPE transplantation that is necessary for the opportune, reasonable and focused medicamental correction of post-transplantation process.

Formulations on the base of an inhibitor of angiotensin-converting enzyme, enalaprilat, were prepared by the inclusion of the drug into calcium phosphate (CaP)-particles in situ, followed by the covering of the particles with 5 kDa chitosan or 72 kDa glycol chitosan and cross-linking with sodium tripolyphosphate. Physicochemical characterization of the resulted hybrid particles was conducted using dynamic light scattering, as well as scanning and transmission electron microscopy. Enalaprilat-containing particles had a mean hydrodynamic diameter 180 nm and 260 nm and ζ-potential +7 mV and +16 mV for 5 kDa and 72 kDa chitosans, respectively. In vivo studies showed that enalaprilat within particles stayed longer in the tear fluid after single instillation and caused a significantly pronounced and prolonged decrease of intraocular pressure in rabbits, especially in the case of CaP-particles, covered by glycol chitosan. Thus, such formulations demonstrate potential as prospective therapeutic agents for the treatment of eye diseases., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Diabetic macular edema (DME) is a microvascular complication of diabetic retinopathy. One of the key roles in the pathogenesis of DME may belong to the components of rennin-angiotensin and kallikrein-kinin systems: bradykinin (Bk) and angiotensin-converting enzyme (ACE)., Purpose: To determine the Bk and ACE concentration and ACE activity in serum of patients with proliferative diabetic retinopathy (PDR) and to estimate the significance of these parameters for the early diagnostic and prognosis of DMO., Materials and Methods: Serum was collected from the 2 groups of patients with II type diabetes. Group I (n=9) had DME, group II (n=27) had PDR without DME. Control group (n=14) consisted of adult volonteers without diabetes and ophthalmic diseases. Concentration of Bk and ACE was measured using ELISA kits, ACE activity was determined enzymatically with specific fluorogenic substrate., Results: Concentration of Bk in serum of patients without DME did not differ from one in controls (12,00 (9,70; 12,40) pg/ml) while all patients with DME had Bk level of 14,69 (13,68; 16,78) pg/ml that was significantly higher (p&lt;0,01). In patients without DME ACE concentration (88,60 (77,30; 97,45) ng/ml) and ACE activity (6,8 (5,1;7,1) nmol/min·ml) were higher than normal (p&lt;0,01) while in the case of DME concentration of ACE increased (77,36 (70,24; 86,29 ng/ml, p&lt;0,01) and activity remained normal. The Bk/ACE concentrations ratio decreased in patients without DME and increased in those having DME., Conclusion: Patients with DME have increased Bk concentration along with nearly normal ACE concentration that indicate predominance of Bk synthesis over its degradation that may lead to the DME development. The Bk/ACE ratio decrease in patients with uncomplicated PDR and increase significantly in ones with DME. It means that determination of Bk in serum of patients with PDR may be used for the prediction of DME development. The Bk/ACE concentrations ratio may be even more informative.

Inflammatory eye diseases remain the most common clinical problem in ophthalmology. The secondary processes associated with inflammation, such as overproduction of reactive oxygen species (ROS) and exhaustion of the endogenous antioxidant system, frequently lead to tissue degeneration, vision blurring, and even blindness. Antioxidant enzymes, such as copper-zinc superoxide dismutase (SOD1), could serve as potent scavengers of ROS. However, their delivery into the eye compartments represents a major challenge due to the limited ocular penetration. This work presents a new therapeutic modality specifically formulated for the eye on the basis of multilayer polyion complex nanoparticles of SOD1 (Nano-SOD1), which is characterized by appropriate storage stability and pronounced therapeutic effect without side reactions such as eye irritation; acute, chronic, and reproductive toxicity; allergenicity; immunogenicity; mutagenicity even at high doses. The ability of Nano-SOD1 to reduce inflammatory processes in the eye was examined in vivo in rabbits with a model immunogenic uveitis-the inflammation of the inner vascular tract of the eye. It was shown during preclinical studies that topical instillations of Nano-SOD1 were much more effective compared to the free enzyme in decreasing uveitis manifestations. In particular, we noted statistically significant differences in such inflammatory signs in the eye as corneal and conjunctival edema, iris hyperemia, and fibrin clots. Moreover, Nano-SOD1 penetrates into interior eye structures more effectively than SOD itself and retains enzyme activity in the eye for a much longer period of time, decreasing inflammation and restoring antioxidant activity in the eye. Thus, the presented Nano-SOD1 can be considered as a potentially useful therapeutic agent for the treatment of ocular inflammatory disorders.

Intraperitoneal injections of exogenous melatonin during the development of the retinal vascular system in experimental rats has been shown in a number of experimental studies on the model of EROP to prevent the appearance of histological signs of the development of experimental retinopathy of prematurity (EROP), stabilize the blood-retinal barrier and have a pronounced antioxidant effect, but pathogenetic basis for these phenomena hasn't been studied., Purpose: To study the influence mechanism of melatonin and its analogues on the development of EROP at the preclinical stage of the pathological process to substantiate new approaches to prevention of ROP., Material and Methods: The study included 42 Wistar rat pups (84 eyes) divided into 6 groups: control group, experimental group (rat pups with EROP), experimental groups who underwent injections of melatonin and its analogues K-148, AL-3, K-096. The pups were euthanized on day 7 (4-5 pups from each group at each study period), binocular enucleation was performed, and the content of hypoxia-induced factor1α (HIF-1α) and VEGF-A was determined in retinal samples., Results: The intraperitoneal injections of melatonin and its analogs led to a significant decrease in the level of HIF-1α and VEGF-A in the retina of the rat pups of the experimental group until the beginning of pathological vasoproliferation., Conclusion: Melatonin and its analogues are able to prevent the development of EROP by reducing the level of angiogenic factors in the retina of rat pups at the stage of existing avascular zones, which allows for them to be considered as a new promising approach to preventing the development of ROP.

The endothelin system (ES) plays a complex role in the pathogenesis of various eye diseases as a local regulator of vascular tone as well as many other physiological processes. Components of ES - endothelins and their receptors - can be found nearly in all cellular structures of the eye, their concentration increases in the presence of many eye diseases. In glaucoma, ES is involved in the mechanisms of eye hypertension by influencing the secretion and outflow of aqueous humor. The increase of endothelin level leads to the decrease of perfusion pressure, hypoxia, astrocyte proliferation, increase of density and rigidity of lamina cribrosa, apoptosis of neural cells, and has a profibrogenic effect. In retinal pathology, increase of endothelins disturbs autoregulation of retinal blood vessels changing the neurovascular interactions, breaks intercellular contacts in the retina, promotes neoangiogenesis. In diabetic retinopathy, ES contributes to the development of microangiopathy and proliferative vitreoretinopathy. The review discusses the possibility of correcting ES activity in the eye with medications by influencing its synthesis, cleavage and receptor binding.

Background: Diabetic retinopathy (DR) is one of the more serious complications of diabetes and the main cause of blindness among working-age individuals. In recent years, information has emerged on the possible role of the renin-angiotensin system (RAS) in the pathogenesis of DR, and DR's possible connection with the system of pro-angiogenic factors., Aim: To study the impact of anti-angiogenic therapy on systemic and local concentrations of angiotensin-converting enzyme (ACE), a key component of RAS, for patients with diabetic macular edema (DME)., Material and Methods: The concentration of ACE in the lacrimal fluid and blood serum in 10 patients (20 eyes) with DME was determined before and after intravitreal injection (IVI) of ranibizumab. The comparison group consisted of 7 patients (14 eyes) with age-related macular degeneration (AMD). The control group consisted of 10 healthy individuals (20 eyes). All groups were comparable in age and sex. The concentration of ACE was determined by enzyme immunoassay. The main group was examined four times: before IVI of ranibizumab, and then one week, two weeks and one month after IVI of ranibizumab. The comparison group was examined before, and then one week after, IVI of ranibizumab., Results: In patients with DME, there was an initial 1.8-fold increase in the concentration of ACE in the lacrimal fluid of both eyes. A week after IVI of ranibizumab, the concentration of ACE in the lacrimal fluid began to decrease, reaching the control level after two weeks, and remaining there one month after IVI of ranibizumab. Initially, the concentration of ACE in the blood serum in patients with DME was 2.2 times lower than the control level. After IVI of ranibizumab there was an increase in the concentration of ACE in the blood serum, but by the end of the observation, the indicators continued to remain well below the control level. In patients with AMD, the initial concentration of ACE in the lacrimal fluids was not elevated; the concentration of ACE in the lacrimal fluids decreased 1.4 times one week after IVI of ranibizumab. The concentration of ACE in the blood serum of the patients with AMD was initially 25% lower than the control level, and essentially did not change after IVI of ranibizumab. СONCLUSIONS: Changes in the concentration of ACE in patients with DME may be a new prognostic criterion for the development of DME for patients with diabetes. These changes in the concentration of ACE, in the context of antiangiogenic therapy, indicate an interaction between the renin-angiotensin and angiogenic systems. Similar changes that were observed after IVI of ranibizumab in patients with AMD confirm the mutual influence of these two systems. The data presented in this study open up prospects for finding new pathways of pathogenic therapy for diabetic macular edema and diabetes.

The study represents the new findings at the crossroads of chemistry and medicine, particularly between medicinal and organic chemistry and ophthalmology. In this work we describe how the chemical reactivity of indolinone scaffold may be used to create small molecule ligands with strong biological response comparable with and larger than that of endogenous hormone. The synthesis of oxindole-based melatonin and 5-methoxycarbonylamino-N-acetyltryptamine (5-MCA-NAT) analogues was proposed and their ability to influence intraocular pressure (IOP) was studied in vivo. Time-dependent study revealed the prolonged effect (more than 6h) of the lead-compound. This effect in combination with high IOP reducing effect (41±6%) in low concentrations of the active compound (0.1wt%) and with high water solubility represents a great potential of low-cost oxindole derivatives as potent antiglaucoma agents., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Melatonin is a pineal hormone that has a capacity to lower intraocular pressure; it exhibits neuroprotective and antioxidant properties that make it possible to use melatonin in the therapy of glaucoma. Analogs of melatonin having affinity to melatonin receptors are promising candidates for application as antiglaucomatous drugs. Chemical modification of the melatonin structure can in-crease efficiency, bioavailability and selectivity of these analogs. We have designed and synthe-sized a number of new 2-oxindole derivatives - ligands of melatonin MT3 subtype receptors that displayed ability to lower intraocular pressure in normotensive rabbits and high antioxidant activity against hydroxyl radical and superoxide anion-radical. The antioxidant activity of new ligands was several times higher than one of melatonin that makes them prospective therapeutic tools for the diseases that include oxidative stress. The maximal hypotensive effect of analogs was comparable to that of melatonin itself but prolonged. Combination of these properties gives an opportunity of using the presented melatonin analogs in complex therapy of glaucoma.

Acute immunogenic uveitis was modeled in rabbits via the subcutaneous and intravitreal injections of normal horse serum. We studied the effect of instillations of 0.1% melatonin solution on the clinical course of uveitis and biochemical parameters of tear fluid and aqueous humor: antioxi-dant activity, protein concentration and α(2)-macroglobulin level. Melatonin instillations decreased clinical manifestations of uveitis. We found that the antioxidant activity in tears of the rabbits treated with melatonin was substantially higher and the α(2)-macroglobulin level lower than in untreated animals. Antioxidant activity in aqueous humor taken on day 10 of uveitis was also twice higher while protein and α(2)-macroglobulin levels were 1.5-2 times lower than in untreated animals. These data indicate that instillations of melatonin increase the local antioxidant activity and decrease the acuity of inflammation and permeability of hematoophthalmic barrier in uveitis.

Aim: To evaluate the effect of exogenous melatonin on the blood-retinal barrier and oxidative status of the vitreous in rats with oxygen-induced retinopathy (OIR) and analyze its prospects in the treatment and prevention of retinopathy of prematurity (ROP)., Material and Methods: The study was performed on 48 Wistar rat pups (96 eyes) divided into 4 groups 12 animals each: OIR group, melatonin group and two control groups. In order to induce retinopathy, rat pups and does were placed in an incubator for 14 days after birth. Oxygen concentration in the incubator changed from 60 to 15% every 12 hours. The controls for this experiment were rats that grew under normoxic conditions (21%). The two other groups of rats were injected with 30 ml intraperitoneal melatonin (Sigma-Aldrich) in sterile 0.05 M phosphate buffer (pH 7.4) at a dose of 10 mg/kg for 14 days starting on day 1. The pups were killed on days 7 (n=16), 14 (n=16), and 18 (n=16). Binocular enucleation was performed in all cases. The total protein level and antioxidative activity (AOA) were then measured in vitreous samples., Results: Oxygen-induced retinopathy had two phases and was accompanied by a sharp increase in the vitreal AOA and total protein. After intraperitoneal melatonin injections made during the period of early OIR-associated vascular changes, the said parameters were decreased down to near-control values at any times during the follow-up period., Conclusion: Exogenous melatonin, due to its strong antiangiogenic and antioxidant activity, helps stabilize the blood-retinal barrier in OIR.

Aim: to evaluate and compare the effect of topical superoxide dismutase (SOD), which is an antioxidant enzyme, dexamethasone, and a combination of these on the course of experimental uveitis in rabbits as well as biochemical parameters of aqueous and vitreous humor., Material and Methods: Acute uveitis was induced in 16 rabbits by a double injection (subcutaneous and intravitreal) of normal horse serum. Of them 12 animals, divided into 3 groups of 4 each, received topical SOD, dexamethasone, or both daily for 7 days. The remaining 4 rabbits (8 eyes) were treated with placebo and, thus, constituted the control group. On day 8 the following parameters were measured in aqueous humor: protein concentration, antioxidant activity, SOD activity, α2-macroglobulin level, and leukocyte number. Total protein and albumin levels in vitreous humor were also determined., Results: The effects of SOD and dexamethasone instillations were considered similar in many parameters. However, SOD was associated with a greater increase in antioxidant activity and a greater decrease in aqueous humor leukocytes, while dexamethasone was more effective in decreasing aqueous humor α2-macroglobulin and vitreous humor protein and albumin. The substances had a synergistic effect on iridal edema as well as aqueous humor leukocyte number and α2-macroglobulin level. CONCLUSION. Adding SOD to the complex therapy of uveitis results in lower inflammation intensity and enhanced dexamethasone effect.

A Novel cold-active chitin deacetylase from Shewanella psychrophila WP2 (SpsCDA) was overexpressed in Escherichia coli BL21 and employed for deacetylation of chitin to chitosan. The produced chitosan was characterized, and its antifungal activity was investigated against Fusarium oxysporum. The purified recombinant SpsCDA appeared as a single band on SDS-PAGE at approximately 60 kDa, and its specific activity was 92 U/mg. The optimum temperature and pH of SpsCDA were 15 °C and 8.0, respectively, and the enzyme activity was significantly enhanced in the presence of NaCl. The bioconversion of chitin to chitosan by SpsCDA was accomplished in 72 h, and the chitosan yield was 69.2%. The solubility of chitosan was estimated to be 73.4%, and the degree of deacetylation was 78.1%. The estimated molecular weight of the produced chitosan was 224.7 ± 8.4 kDa with a crystallinity index (CrI) value of 18.75. Moreover, FTIR and XRD spectra revealed the characteristic peaks for enzymatically produced chitosan compared with standard chitosan, indicating their structural similarity. The produced chitosan inhibited spore germination of F. oxysporum with a minimum inhibitory concentration (MIC) of 1.56 mg/mL. The potential antifungal effect of chitosan is attributed to the inhibition of spore germination accompanied by ultrastructural damage of membranes and leakage of cellular components, as evidenced by transmission electron microscopy (TEM), and accumulation of reactive oxygen species (ROS) that was confirmed by fluorescence microscopy. This study shed light on the cold-active chitin deacetylase from S. psychrophila and provides a candidate enzyme for the green preparation of chitosan. [ABSTRACT FROM AUTHOR]

Deepithelialization of the cornea (diameter 7 mm) was performed in rabbits and the rate of defect epithelialization was evaluated. Conjunctival ischemia was modeled by application of graduated alkaline burn. Antioxidant activity and content of nitrates and nitrites was measured in the tear fluid before and after burn by chemiluminescence and Griess methods, respectively. Emoxypin and mexidol promoted healing of corneal epithelial defect at the stage of epitheliocyte migration to the defect area and at the stage of their proliferation, respectively. After treatment with both agents, the area of conjunctival ischemia decreased more rapidly, but the efficiency of mexidol was higher. Antioxidant activity and content of products of NO metabolism in tear fluid decreased after burn. Mexidol, but not emoxypin, increased these parameters. Thus, mexidol and emoxypin have different effects on corneal epithelialization and conjunctival ischemia and effects of mexidol are more pronounced.

Use of antioxidants to mitigate oxidative stress during ocular inflammatory diseases has shown therapeutic potential. This work examines a nanoscale therapeutic modality for the eye on the base of antioxidant enzyme, superoxide dismutase 1 (SOD1), termed "nanozyme." The nanozyme is produced by electrostatic coupling of the SOD1 with a cationic block copolymer, poly(L-lysine)-poly(ethyleneglycol), followed by covalent cross-linking of the complexes with 3,3'-dithiobis(sulfosuccinimidylpropionate) sodium salt. The ability of SOD1 nanozyme as well as the native SOD1 to reduce inflammatory processes in the eye was examined in vivo in rabbits with immunogenic uveitis. Results suggested that topical instillations of both enzyme forms demonstrated anti-inflammatory activity; however, the nanozyme was much more effective compared to the free enzyme in decreasing uveitis manifestations. In particular, we noted statistically significant differences in such inflammatory signs in the eye as the intensities of corneal and iris edema, hyperemia of conjunctiva, lens opacity, fibrin clots, and the protein content in aqueous humor. Clinical findings were confirmed by histological data. Thus, SOD1-containing nanozyme is potentially useful therapeutic agent for the treatment of ocular inflammatory disorders.

Objective: to study the influence of experimental uveitis on those biochemical parameters of aqueous humor that reflect inflammation acuity as well as local antioxidant and local antiproteolytic activity; to study the effect of topical superoxide dismutase (SOD) on the clinical course of uveitis and ocular metabolism., Material and Methods: Acute uveitis was induced in rabbits by a double injection (subcutaneous and intravitreal) of normal horse serum. The following parameters of aqueous humor were measured: protein concentration, antioxidant activity, SOD activity, alpha2-macroglobulin level, total nitrates and nitrites, and leukocyte number. Clinical assessment and histopathological study were performed., Results: It was found that uveitis is associated with a statistically significant increase in protein concentration, leukocyte number, SOD activity, and alpha2-macroglobulin level in aqueous humor as well as a decrease in anti-hydroxyl radical activity. SOD instillations contributed to the reduction of the listed parameters and improvement of the antioxidant activity. Clinical presentations of uveitis also became less pronounced., Conclusion: SOD instillations for oxidative stress correction help reduce clinical presentations of uveitis, which is confirmed by biochemical examination.

A considerable tear endothelin-1 increase (2-3 times) has been found in patients with primary open-angle glaucoma and proliferative diabetic retinopathy. Patients with proliferative retinopathy also showed an increase of plasminogen level in tear fluid and a tendency of a similar increase in blood serum. No correlation between endothelin-1 and plasminogen levels in these pathologies was established. Tear endothelin-1 and plasminogen measurement could be used as an informative and non-invasive method to help prognosis making, condition severity evaluation and control the effectiveness of treatment of ocular local microcirculatory disturbances.

Increased plasminogen level in tear fluid was found within 28 days and increased plasmin activity in 1-3 and 21 days after alkali burn of cornea, this is the time of cornel ulcers development. Increased plasminogen level and plasmin activity in cornea, conjunctiva and intraocular fluid was found in three days after trauma. Subconjunctival injections of angiostatin K1-4,5 (a product of plasminogen metabolism) during 3 weeks resulted in significant suppression of corneal neovascularization within 14 days and of active branching of the vessels in the following. The use of angiostatin reduced depth and area of corneal ulcers. Obtained data shows the promising potential of development of medications based on angiostatin K1-4,5 for suppression of corneal neovascularization and for treatment of diseases associated with corneal ulceration.

Methodology for production of calcium-phosphate nanoparticles is developed and its efficacy as a drug carrier system is estimated by example of timolol. Conditions for production of particles with optimal size and resistance are determined, methodology of loading of particles with timolol is developed. Physical parameters of particles (form, size, relief), kinetics of saturation with drug and its release are studied. Packaging of timolol into calcium phosphate nanoparticles was showed to enhance and prolong its hypotensive effect in experiment on healthy rabbits.

The authors have evaluated the local renin-angiotensin system on a model of experimental postburn conjunctival ischemia from the tear activity of angiotensin-converting enzyme (ACE) and studied whether impaired microcirculation might be restored by locally applying the ACE inhibitor captopril. It has been found that in conjunctival ischemia, there is a considerable increase in the activity of ACE, the key enzyme of the renin-angiotensin system, the activity of which largely determines the microcirculation in eye tissues. Instillations of the ACE inhibitor to rabbits within 2 weeks after alkaline burn of the eye result in a reduction in ACE activity and an earlier recovery of microcirculation in the area of conjunctival ischemia. Instillations of the ACE inhibitor captopril in ocular burn facilitate the maintenance of the tear antioxidant potential at the high level, which also suggests that the ACE inhibitor has a positive effect on the course of reparative processes after ocular burn injury. The findings suggest that it is promising to locally use ACE inhibitors for the treatment of ischemic processes in the eye.

A rabbit model of deep alkaline-induced corneal burn was used to study the involvement of the local renin-angiotensin system of the eye in the development of an inflammatory process and wound healing. Corneal burn injury was shown to cause a significant increase in the activity of angiotensin-converting enzyme (ACE) in the tear and internal ocular tissue structures, promoting their microcirculatory disorders and inflammation development. The local use of ACE inhibitors as instillations substantially reduces an inflammatory reaction and the incidence of deep and extensive corneal ulcers. The study performed provides experimental rationale for the local use of ACE inhibitors for the treatment of inflammatory processes in the eye.

The pattern of functional impairments and the antioxidative and antiproteolytic status of tear were studied, by experimentally simulating retinal ischemia in rabbits and during treatment with Selecarten. Simulated retinal ischemia resulted in the development of persistent (up to 3 weeks) retinal electrogenetic disorder. Selecarten instillations produced a moderate neuroprotective effect, by positively affecting retinal function early after ischemia stimulation and accelerated the recovery of retinal electrogenesis late after laser coagulation of retinal vessels. The altered metabolic processes were characterized by an increase in the tear antiproteolytic potential. The antioxidative activity and the activity of a2-macroglobulin proteolysis inhibitor increased in the tears of Selecarten-treated rabbits.

The nitric oxide (NO) donors Na nitroprusside and L-arginine were tested for their effects on the course of experimental immunogenic uveitis, antiproteolytic and antioxidative activities in the rabbit tear and blood. With the use of the NO donors, the course of uveitis was shown to be more severe and prolonged. In uveitis, there was a change in the activity of the antiproteinases--alpha1-antitrypsin and alpha2-macroglobulin and the antioxidative enzymes superoxide dismutase in both tear and blood. The magnitude of changes in the biochemical parameters under study suggested that the course of uveitis was more severe in the rabbits given the NO donors. Thus, the inclusion of the NO donors in the active phase enhances an inflammatory reaction in immunogenic uveitis.

The present paper deals with the study of the efficiency of oral use of the antioxidative drug Immugen (a complex of alpha-tocopherol, oubichinone, selenium aspartate, methionine, and soyabean phospholipids) on a rabbit model of severe alkaline-induced corneal burn. The investigations have indicated that addition of Immugen to the rabbit feed exerts a significant positive effect on the parameters of the local antioxidative system of the eye and causes an increase in the activity of superoxide dismutase and catalase, and, on day 14, in antioxidative activity. The early experimental periods were marked by a slight rise in the frequency of deep corneal ulcerations. Moreover, the long-term clinical effect of use of Immugen appears as a significant increase in the area of the transparency-preserving affected cornea. The findings suggest that the antioxidants can show their optimal effect in the complex therapy for burn processes, including the use of proteinase inhibitors.

The hypothesis on the biostimulating effect of exogenous nitric oxide (NO) was made use of to develop a new method to stimulate the healing of wounds through treating them by a NO saturated gas flow. The above gas flow is generated by air-plasma unit "Plazon". The experimental and clinical studies confirmed that the NO-therapy is a highly effective treatment method for different lesions of the skin and soft tissues. We tried to use the above method in ophthalmology. A comprehensive experimental study was carried out to assess the impact of the NO-containing gas flow on the eyeball structures. An optimal mode was designed, which does not exert any influence on the intraocular pressure, Ph of the lachrymal fluid, antioxidative activity and on the proteinase-inhibitor balance in tears; no morphological changes occurred in the ocular tissue structures. The mentioned morphological and biochemical studies confirmed that the application of the NO-containing gas flow speeds up the healing, process of both an experimental cornea erosion and penetrating corneal wounds. Optimal modes of NO-therapy were defined for both types of lesions.

Proteinase-inhibitor balance in the lacrimal fluid in eye burns was studied in rabbits with modified and intact immune status. Stimulation of the immune system was induced by complete Freund's adjuvant. Clinical picture of the disease was studied in parallel. Immunization accelerated the local adaptive and defense reaction of the proteolytic enzymes and their inhibitors, which was paralleled by a more benign course of burn disease of the eyes, in comparison with that in non-immunized animals.

Nitric oxide is one of the main factors of intra- and intercellular regulation in the organism. Its vasodilating, antiaggregant, antithrombogenic, antibacterial, anticarcinogenic, and immunogenic effects are well known. It stimulates the reparative processes in soft tissue injuries. We failed to find reports about the role of NO in the wound process in the eyes. The source of NO in our experiments was medical air-plasma device Plason. Exposure of the eye to NO-containing gaseous flow did not cause changes in the lacrimal pH; NO penetrated through the cornea and sclera, exerted no appreciable cytotoxic effect on the surface epithelium of the eye, did not change the intraocular pressure, and caused no morphological changes in ocular tissues. On the other hand, NO-containing gaseous flow had an appreciable lasting effect on the diameter of the conjunctival vessels, this effect being dose-dependent. The doses of NO-containing gaseous flow which can be used in the treatment of eye wounds were determined.

Chemical burns of the eye of different location (cornea, corneal fragment with adjacent conjunctiva, and limbus) were studied in experiments. Clinical picture and changes in the lacrimal proteinase inhibitor balance were analyzed. Burn disease is less severe and the number of complications is less if a fragment of the cornea with adjacent conjunctiva and a fragment of the limbus are injured than in case of a corneal burn of the same depth and area. Burn of the total limbus area is a severe injury involving essential shifts in the proteinase inhibitor balance, leading to deep organic changes in the cornea and inner structures of the eye, eventuating in its subatrophy.

The content of potassium ions in the lacrimal fluid was evaluated before and in various periods after laser specialized keratomileusis (LASIK) in order to determine the scope and terms of therapeutic measures. Seventeen patients with myopia were examined before and after LASIK. Lacrimal production before the operation was evaluated by Schirmer's and Norn's tests. The concentration of K+ ions in the lacrimal fluid was measured on a Reflotron IV biochemical analyzer. Before operation the concentrations of potassium ions were 1.5 times higher than normally in the patients complaining of discomfort. Lacrimal concentration of K+ ions and results of Norn's and Schirmer's tests were in high correlation. After LASIK potassium ion concentrations were increased in all patients and returned to the initial level almost completely within 1 week postoperation. Treatment with artificial tear preparations containing no potassium ions during the early postoperative period is physiological.

Nanobiocatalysts (NBCs), which merge enzymes with nanomaterials, provide a potent method for improving enzyme durability, efficiency, and recyclability. This review highlights the use of eco-friendly synthesis methods to create sustainable nanomaterials for enzyme transport. We investigate different methods of immobilization, such as adsorption, ionic and covalent bonding, entrapment, and cross-linking, examining their pros and cons. The decreased environmental impact of green-synthesized nanomaterials from plants, bacteria, and fungi is emphasized. The review exhibits the various uses of NBCs in food industry, biofuel production, and bioremediation, showing how they can enhance effectiveness and eco-friendliness. Furthermore, we explore the potential impact of NBCs in biomedicine. In general, green nanobiocatalysts are a notable progression in enzyme technology, leading to environmentally-friendly and effective biocatalytic methods that have important impacts on industrial and biomedical fields. [ABSTRACT FROM AUTHOR]

An efficient reaction between triphenylphosphine or triphenyl phosphite and 2-oxoindoline-3-ylidene derivatives in the presence of acetylenic esters leads to functionalized 2-oxoindoline-3-ylidene containing phosphorus ylieds or phosphonate esters. All compounds obtained in these reactions are stable and have good yields. [ABSTRACT FROM AUTHOR]

A method was developed for the synthesis of selectively labeled [15N]indole, allowing to obtain the target product with high chemical and isotopic purity. One-dimensional and two-dimensional 1H, 13C, and 15N NMR spectra were examined. The chemical shifts of 1H, 13C, and 15N nuclei were determined, as well as the spin-spin coupling constants of 15N nucleus and the isotopic chemical shifts of 13C nuclei for [15N]indole in CD3CN solution, caused by the replacement of 14N nucleus with a 15N nucleus. It was demonstrated that isotopic shifts of this type can provide important structural information. The NMR data set obtained in the current work can serve as an important reference point for establishing the structures of new aromatic heterocycles. [ABSTRACT FROM AUTHOR]