Emulsification of Silicone Oils: Altering Factors and Possible Complications-A Narrative Review

Background: Endotamponade of the vitreous body with silicone oil is a common procedure, being the basis of many vitreoretinal surgeries. However, emulsification may happen, which is a clinically relevant adverse event of silicone oil use. Methods: This review provides a thorough analysis of the emulsification process. It focuses on describing factors affecting this event as well as its possible subsequent complications. Results: The viscosity of silicone oil, the duration of emulsification, the status of the lens and many other factors have an influence on the onset and intensity of emulsification. This phenomenon carries several risks for operated eyes such as increased intraocular pressure, keratopathy or structural changes to the retina. Conclusions: The use of modern imaging techniques, especially optical coherence tomography, enables faster detection of the emulsification process. This allows for an adequate clinical response and more accurate follow-up of the patient.

Subclinical retinopathy in systemic lupus erythematosus patients - optical coherence tomography study

Introduction

The aim was to detect subclinical structural retinal abnormalities in optical coherence tomography (OCT) in ophthalmologically asymptomatic systemic lupus erythematosus (SLE) patients without signs of lupus retinopathy or drug toxicity in fundus examination and in OCT and to assess the relationship between OCT parameters and disease activity, therapy type and burden on other organs to demonstrate the utility of OCT in early retinal impairment in SLE patients.

Material and methods

Cross-sectional study. Thirty-three SLE patients (57 eyes) and 31 healthy individuals (56 eyes) were enrolled in the study. We excluded patients with evidence of lupus retinopathy or hydroxychloroquine (HCQ) toxicity on OCT or fundus examination to reveal any subclinical changes. All patients underwent full ophthalmologic examination in the slit lamp including best corrected visual acuity, tonometry, and OCT. The Kolmogorov-Smirnov distribution test was used to assess the normal distribution in quantitative values. The differences between the individual measured parameters in the groups were analyzed using the Mann-Whitney U test. Spearman's rank correlation test was used to assess the correlation between the measured parameters and quantitative clinical data.

Results

There was no difference in the OCT findings between SLE and healthy control groups. Among the study group a negative correlation was found between disease duration and age and retinal nerve fiber layer thickness in the inferior quadrant (p = 0.0063, p = 0.0036). No correlations were observed between examined retinal parameters and duration of hydroxychloroquine therapy, hydroxychloroquine as well as chloroquine cumulative dose and disease activity indices.

Conclusions

Optical coherence tomography is a widespread ophthalmic modality used for SLE retinopathy and HCQ toxicity screening. Our study did not demonstrate its clinical potency in diagnosis of subclinical retinal involvement. An optical coherence tomography device seems to be less sensitive in subclinical retinal impairment detection than optical coherence tomography angiography.

Evaluation of Subclinical Retinal Disease in Patients Affected by Systemic Lupus Erythematosus with No Evidence of Ocular Involvement-An Optical Coherence Tomography Angiography Original Study

Lupus retinopathy is the second most common eye involvement in systemic lupus erythematosus (SLE), associated with significant visual deterioration and well-known negative prognostic factor for survival. Ocular manifestation in SLE, relating the retina, ranges from asymptomatic vascular involvement to vision devastating vascular occlusions. Subclinical microvascular changes are undetectable in slit lamp examination, hence are underdiagnosed. Optical coherence tomography angiography (OCTA) is a novel, easy to interpret and non-invasive technique that allows retinal vessels visualization. OCTA simplifies clinical approach and measures the severity of decreased perfusion. The aim of the study was to demonstrate the retinal vascularization in a subclinical stage of ocular involvement in a cohort of SLE patients. Thirty-three patients (57 eyes) diagnosed with SLE were enrolled into the study group and 31 healthy individuals (56 eyes) into the control group. Vessel density reduction in parafovea, inferior and nasal quadrants of superficial retinal capillary plexus in a cohort of SLE patients was found. Among study group kidney involvement was associated with further microvasculature reduction. Knowing that retinal involvement may precede other organs impairment, early detection of retinal impairment and use of OCTA as a screening modality, may decrease overall disease morbidity.

Fusarium Keratitis-Review of Current Treatment Possibilities

In many parts of the world, fungi are the predominant cause of infectious keratitis; among which, Fusarium is the most commonly isolated pathogen. The clinical management of this ophthalmic emergency is challenging. Due to the retardation of the first symptoms from an injury and the inability to differentiate fungal from bacterial infections based on clinical symptoms and difficult microbial diagnostics, proper treatment, in many cases, is postponed. Moreover, therapeutical options of Fusarium keratitis remain limited. This paper summarizes the available treatment modalities of Fusarium keratitis, including antifungals and their routes of administration, antiseptics, and surgical interventions.

Lysyl-tRNA synthetase produces diadenosine tetraphosphate to curb STING-dependent inflammation

Inflammation is an essential part of immunity against pathogens and tumors but can promote disease if not tightly regulated. Self and non-self-nucleic acids can trigger inflammation, through recognition by the cyclic GMP-AMP (cGAMP) synthetase (cGAS) and subsequent activation of the stimulator of interferon genes (STING) protein. Here, we show that RNA:DNA hybrids can be detected by cGAS and that the Lysyl-tRNA synthetase (LysRS) inhibits STING activation through two complementary mechanisms. First, LysRS interacts with RNA:DNA hybrids, delaying recognition by cGAS and impeding cGAMP production. Second, RNA:DNA hybrids stimulate LysRS-dependent production of diadenosine tetraphosphate (Ap4A) that in turn attenuates STING-dependent signaling. We propose a model whereby these mechanisms cooperate to buffer STING activation. Consequently, modulation of the LysRS-Ap4A axis in vitro or in vivo interferes with inflammatory responses. Thus, altogether, we establish LysRS and Ap4A as pharmacological targets to control STING signaling and treat inflammatory diseases.

Erythrocyte glycophorins as receptors for Plasmodium merozoites

Glycophorins are heavily glycosylated sialoglycoproteins of human and animal erythrocytes. In humans, there are four glycophorins: A, B, C and D. Glycophorins play an important role in the invasion of red blood cells (RBCs) by malaria parasites, which involves several ligands binding to RBC receptors. Four Plasmodium falciparum merozoite EBL ligands have been identified: erythrocyte-binding antigen-175 (EBA-175), erythrocyte-binding antigen-181 (EBA-181), erythrocyte-binding ligand-1 (EBL-1) and erythrocyte-binding antigen-140 (EBA-140). It is generally accepted that glycophorin A (GPA) is the receptor for P. falciparum EBA-175 ligand. It has been shown that α(2,3) sialic acid residues of GPA O-glycans form conformation-dependent clusters on GPA polypeptide chain which facilitate binding. P. falciparum can also invade erythrocytes using glycophorin B (GPB), which is structurally similar to GPA. It has been shown that P. falciparum EBL-1 ligand binds to GPB. Interestingly, a hybrid GPB-GPA molecule called Dantu is associated with a reduced risk of severe malaria and ameliorates malaria-related morbidity. Glycophorin C (GPC) is a receptor for P. falciparum EBA-140 ligand. Likewise, successful binding of EBA-140 depends on sialic acid residues of N- and O-linked oligosaccharides of GPC, which form a cluster or a conformational structure depending on the presence of peptide fragment encompassing amino acids (aa) 36–63. Evaluation of the homologous P. reichenowi EBA-140 unexpectedly revealed that the chimpanzee homolog of human glycophorin D (GPD) is probably the receptor for this ligand. In this review, we concentrate on the role of glycophorins as erythrocyte receptors for Plasmodium parasites. The presented data support the long-lasting idea of high evolutionary pressure exerted by Plasmodium on the human glycophorins, which emerge as important receptors for these parasites.

The patient's view on rare disease trial design - a qualitative study

Background

Clinical trials in rare diseases are more challenging than trials in frequent diseases. Small numbers of eligible trial participants, often complicated by heterogeneity among rare disease patients, hamper the design and conduct of a ‘classical’ Randomized Controlled Trial. Therefore, novel designs are developed by statisticians. However, it is important to be aware of possible design aspects that may jeopardize the feasibility of trial conduct. If the burden of participation is considered out of proportion by patients or parents, recruitment may fail or participants may drop out before trial completion. In order to maximize the chance of success of trials in small populations, it is important to know which aspects of trial design are considered important by patients.

Results

We have interviewed all ten members of the Patient Think Tank (PTT) of the ASTERIX project, a European research consortium on methodology for clinical trials in small populations. The PTT members are rare disease patient representatives who have completed extensive training in clinical trial methodology. We have analyzed the interviews qualitatively according to Grounded Theory using a thematic analysis, and we structured the topics in four chronologically ordered themes: 1. Involvement in trial design; 2. Opinions on trial design; 3. Trial participation; 4. Phase after the trial. Our main findings are that the PTT-members recommend that patients are involved in trial design from an early stage on, and have influence on the outcomes and measurement instruments that are chosen in the trial, the length of the study, the choice of participants, and the information that is sent to potential participants. Also, according to the PTT-members, patient groups should consider setting up disease registries, placebo groups should be minimized, and more education on clinical trials is advised.

Conclusions

Rare disease patient representatives who have been educated about clinical trial methodology think it is important to involve patient representatives in research at an early stage. They can be of advice in trial design in such a way that the ratio of potential benefit and burden of trial participation as well as the chosen outcome measures and in- and exclusion criteria are optimized.

Electronic supplementary material

The online version of this article (10.1186/s13023-019-1002-z) contains supplementary material, which is available to authorized users.

[Gene therapy of haemophilia - has the cure come within reach?]

Haemophilia is a bleeding disorder (usually congenital) caused by the deficiency of coagulation factor VIII (haemophilia A) or IX (haemophilia B). The genes encoding factors VIII and IX are located on the X chromosome, so the symptoms of congenital haemophilia A and B occur predominantly in males. Recurring episodes of spontaneous bleeding into joints are the main symptom of haemophilia, which lead to haemophilic artropathy. Historically, patients with haemophilia were treated with whole blood transfusions and then with blood plasma. The first big breakthrough in treatment efficacy was the advent of cryoprecipitate, followed by lyophilized coagulation factor concentrates, derived from plasma. The latter dramatically improved patients' quality of life and allowed for prophylactic self-infusions at home (home treatment). Since the 1990s, the standard treatment has also included recombinant coagulation factor concentrates derived from cell cultures. Today, the main challenges are the need for frequent venipunctures (factor concentrates must be administered intravenously) to maintain successful prophylaxis and emergence of neutralizing antibodies in response to exogenous coagulation factors. Several novel recombinant factors with extended half-life were approved in recent years. Clinical trials of other new technologies are ongoing. These are non-replacement therapies with different mechanisms of action (e.g. emicizumab, a bispecific antibody that mimics the procoagulant activity of factor VIII; fitusiran, siRNA downregulating antithrombin III) and gene therapies using AAV vectors.

A comparison of intraocular pressure values obtained using a Goldmann applanation tonometer and a handheld version of applanation resonance tonometer: A preliminary report

BACKGROUND

Despite the development of various methods of intraocular pressure (IOP) measurement, Goldmann applanation tonometry (GAT) is still the most popular. The measurement using GAT depends on the biomechanical properties of the cornea, such as the thickness, the radius of curvature, as well as the amount of the fluorescein used.

OBJECTIVES

The aim of the study was to compare IOP values measured by GAT with those measured by applanation resonance tonometry (ART).

MATERIAL AND METHODS

A total of 47 patients (94 eyes), including 28 patients with primary open-angle glaucoma (POAG) and 19 subjects from the control group, were examined at the Glaucoma Outpatient Clinic of the Department and Clinic of Ophthalmology at Wroclaw Medical University (Poland). The measurements of IOP were performed using GAT and a handheld version of ART. Also, the central corneal thickness (CCT) of all patients was measured.

RESULTS

The study showed that the IOP values measured by both tonometers were comparable, but ARTacquired values were higher than GAT-obtained values both in the glaucomatous group and in the control group. CCT had little impact on mean IOP difference between GATand ART-obtained values.

CONCLUSIONS

Applanation resonance tonometry is a precise method of IOP measurement and is less affected by biomechanical properties of the cornea than GAT. Our results show that ART is a new, promising, comfortable for both patients and doctors method of IOP measurement, which, in the future, can replace GAT.

Self-Regulating Iris Based on Light-Actuated Liquid Crystal Elastomer

The iris, found in many animal species, is a biological tissue that can change the aperture (pupil) size to regulate light transmission into the eye in response to varying illumination conditions. The self-regulation of the eye lies behind its autofocusing ability and large dynamic range, rendering it the ultimate "imaging device" and a continuous source of inspiration in science. In optical imaging devices, adjustable apertures play a vital role as they control the light exposure, the depth of field, and optical aberrations of the systems. Tunable irises demonstrated to date require external control through mechanical actuation, and are not capable of autonomous action in response to changing light intensity without control circuitry. A self-regulating artificial iris would offer new opportunities for device automation and stabilization. Here, this paper reports the first iris-like, liquid crystal elastomer device that can perform automatic shape-adjustment by reacting to the incident light power density. Similar to natural iris, the device closes under increasing light intensity, and upon reaching the minimum pupil size, reduces the light transmission by a factor of seven. The light-responsive materials design, together with photoalignment-based control over the molecular orientation, provides a new approach to automatic, self-regulating optical systems based on soft smart materials.

The effects and safety of intravitreal triamcinolone injections in the treatment of diabetic macular edema

BACKGROUND

Diabetic macular edema (DME) is responsible for three-quarters of vision-loss cases in diabetic eye disease. In most cases, early treatment by laser photocoagulation can only stabilize vision. Glucocorticoids have been used as a local pharmacological treatment in DME when the inflammation seems to have a pathological background.

OBJECTIVES

The aim of the study was to establish the effectiveness and safety of intravitreal triamcinolone injections in the treatment of DME.

MATERIAL AND METHODS

Twenty mg intravitreal injections of triamcinole acetonide (IVTA) were applied to 110 DME patients after ineffective laserphotocoagulation or as an initial treatment. Best corrected visual acuity (BCVA) for distant and near vision, central retinal thickness and intraocular pressure (IOP) were analyzed before and after the treatment at intervals of 1 week, 1 month, 3 months and 6 months. The measurements were continued in cases of repeated IVTA.

RESULTS

Statistically significant improvements were observed in BCVA in near and distant vision, as well as a decrease in central retinal thickness after all time-intervals following IVTA. BCVA in distant vision was not significantly improved after repeated IVTA. IOP increases were observed 1 week, 1 and 3 months after IVTA, but not at 6 months after IVTA. No sight-threatening side effects of IVTA were observed.

CONCLUSIONS

IVTA is useful in stabilizing DME progression, although its therapeutic effect may be timelimited.

Can mutations in the gene encoding transcription factor EKLF (Erythroid Krüppel-Like Factor) protect us against infectious and parasitic diseases?

Transcription factor EKLF (Erythroid Krüppel-Like Factor) belongs to the group of Krüppellike factors, which regulate proliferation, differentiation, development and apoptosis of mammalian cells. EKLF factor is present in erythroid cells, where it participates in regulation of hematopoiesis, expression of genes encoding transmembrane proteins (including blood group antigens), and heme biosynthesis enzymes. It is also a key factor in downregulation of γ-globins and activation of β-globin gene expression. The EKLF factor consists of two domains: proline-rich transactivation domain and DNA-binding domain containing three zinc finger motifs, which recognize DNA. EKLF can act as a transcription activator (for example in the case of β-globin gene) or repressor, which depends on the type of posttranslational modification (phosphorylation, SUMOylation, ubiquitination and acetylation). Mutations in the gene encoding EKLF may cause hemoglobinopathies, such as hereditary persistence of fetal hemoglobin and β-thalassemia intermedia, and congenital dyserythropoietic anemia type IV, which is a hematopoietic disorder. These changes may impede invasion of red blood cells by malaria merozoites and cause faster removal of invaded erythrocytes. In addition, mutations in KLF1 may decrease the number of erythrocyte surface antigens that belong to blood group systems such as MN, P1PK, Lutheran, Duffy, Diego and OK. Such antigens can be receptors for protozoans (such as Plasmodium falciparum or Plasmodium vivax), bacteria (like uropathogenic strains of Escherichia coli, Neisseria meningitidis), and toxins (Shiga toxins), which may cause several dangerous diseases including malaria, pyelonephritis, hemorrhagic colitis, hemolytic uremic syndrome (HUS) and meningitis. Here, we propose a hypothesis on possible liaisons between mutations in the gene encoding EKLF and resistance to pathogens.

[From malaria parasite point of view--Plasmodium falciparum evolution]

Malaria is caused by infection with protozoan parasites belonging to the genus Plasmodium, which have arguably exerted the greatest selection pressure on humans in the history of our species. Besides humans, different Plasmodium parasites infect a wide range of animal hosts, from marine invertebrates to primates. On the other hand, individual Plasmodium species show high host specificity. The extraordinary evolution of Plasmodium probably began when a free-living red algae turned parasitic, and culminated with its ability to thrive inside a human red blood cell. Studies on the African apes generated new data on the evolution of malaria parasites in general and the deadliest human-specific species, Plasmodium falciparum, in particular. Initially, it was hypothesized that P. falciparum descended from the chimpanzee malaria parasite P. reichenowi, after the human and the chimp lineage diverged about 6 million years ago. However, a recently identified new species infecting gorillas, unexpectedly showed similarity to P. falciparum and was therefore named P. praefalciparum. That finding spurred an alternative hypothesis, which proposes that P. falciparum descended from its gorilla rather than chimp counterpart. In addition, the gorilla-to-human host shift may have occurred more recently (about 10 thousand years ago) than the theoretical P. falciparum-P. reichenowi split. One of the key aims of the studies on Plasmodium evolution is to elucidate the mechanisms that allow the incessant host shifting and retaining the host specificity, especially in the case of human-specific species. Thorough understanding of these phenomena will be necessary to design effective malaria treatment and prevention strategies.

Bacterially expressed truncated F2 domain of Plasmodium falciparum EBA-140 antigen can bind to human erythrocytes

The recently identified erythrocyte binding antigen-140 (EBA-140) is a member of the Plasmodium falciparum DBL family of erythrocyte binding proteins, which are considered as prospective candidates for malaria vaccine development. The EBA-140 ligand is a paralogue of the well-characterized P. falciparum EBA-175 antigen. They share homology of domain structure, including Region II, which consists of two homologous F1 and F2 domains and is responsible for ligand-erythrocyte interaction during invasion. It was shown that the F2 domain of EBA-175 antigen seems to be more important for erythrocyte binding. In order to study activity and immunogenicity of EBA-140 antigen F2 domain, it is necessary to obtain recombinant protein of high purity and in a sufficient amount, which used to pose a challenge due to the high content of disulphide bridges. Here, we present a new method for expression and purification of Plasmodium falciparum EBA-140 antigen F2 domain in E. coli Rosetta-gami strain in fusion with the maltose binding protein (MBP). The truncated F2 domain formed by spontaneous proteolytic degradation of the fusion protein was purified by affinity chromatography on Ni-NTA resin followed by size exclusion chromatography. Molecular mass of this protein was confirmed by mass spectrometry. Its N-terminal amino acid sequencing revealed a proteolytic cleavage site within the F2 domain. The proper folding of the recombinant, truncated F2 domain of EBA-140 antigen was confirmed by circular dichroism analysis. The truncated F2 domain can specifically bind to human erythrocytes but its binding is not as efficient as that of full Region II. This confirms that both the F1 and F2 domains of EBA-140 antigen are required for effective erythrocyte binding.

Bacterially expressed truncated F2 domain of Plasmodium falciparum EBA-140 antigen can bind to human erythrocytes

The recently identified erythrocyte binding antigen-140 (EBA-140) is a member of the Plasmodium falciparum DBL family of erythrocyte binding proteins, which are considered as prospective candidates for malaria vaccine development. The EBA-140 ligand is a paralogue of the well-characterized P. falciparum EBA-175 antigen. They share homology of domain structure, including Region II, which consists of two homologous F1 and F2 domains and is responsible for ligand-erythrocyte interaction during invasion. It was shown that the F2 domain of EBA-175 antigen seems to be more important for erythrocyte binding. In order to study activity and immunogenicity of EBA-140 antigen F2 domain, it is necessary to obtain recombinant protein of high purity and in a sufficient amount, which used to pose a challenge due to the high content of disulphide bridges. Here, we present a new method for expression and purification of Plasmodium falciparum EBA-140 antigen F2 domain in E. coli Rosetta-gami strain in fusion with the maltose binding protein (MBP). The truncated F2 domain formed by spontaneous proteolytic degradation of the fusion protein was purified by affinity chromatography on Ni-NTA resin followed by size exclusion chromatography. Molecular mass of this protein was confirmed by mass spectrometry. Its N-terminal amino acid sequencing revealed a proteolytic cleavage site within the F2 domain. The proper folding of the recombinant, truncated F2 domain of EBA-140 antigen was confirmed by circular dichroism analysis. The truncated F2 domain can specifically bind to human erythrocytes but its binding is not as efficient as that of full Region II. This confirms that both the F1 and F2 domains of EBA-140 antigen are required for effective erythrocyte binding.

Microprocessor Control of the Spraying of Graded Coatings

A systematic study was made of the characteristics of a microprocessor controlled powder feeder in view of its utilization for the deposition of graded coating. The unit tested had the capability of feeding three different powders at rates which could be continuously varied up to about 40 g/min. MgOZrO2. was deposited on a stainless steel substrate using a series of thin (Ni/Cr)-Zirconia coats as intermediate layers. The results showed that such a technique could provide a valuable means of achieving a precise and effective control on the composition of the intermediate layers which can have important effects on the final quality of the deposit.

Patomechanisms in proliferative vitreoretinopathy

Proliferative vitreoretinopathy (PVR) remains the most common cause of recurrent retinal detachment following retinal detachment surgery. The development of PVR is a complex process involving humoral and cellular factors. Surgical treatment of PVR, which consists of removal of the fibrous membranes and restoration of physiological anatomic ocular conditions is often unsuccessful. Therefore the surgery should by backed up by local medication to inhibit new formation of proliferative lesions. Unfortunately, there is no satisfactory antiproliferative treatment available so far. Proliferative vitreoretinopathy remains a therapeutic challenge.

[Alterations of Lewis histo-blood group antigen expression in cancer cells]

Carcinogenesis in various tissues is accompanied by alterations in protein and lipid glycosylation, such as changes in the expressions of Lewis histo-blood group antigens. Neoplastic transformation is often followed by changes in expression of one or more of these oligosaccharides in a pattern that is typical for the tissue. These alterations correlate with changes in the expressions of specific glycosyltransferases. Overexpression of Lewis antigens in some types of cancer might be a significant prognostic factor. Upregulation of Lewis(y), Lewis(b), and other alpha1,2-fucosylated oligosaccharides is linked to an increased tendency to metastasis and resistance to treatment. For example, invasive breast cancer of poor prognosis reveals high expression levels of Lewis(y) and Lewis(b). Lewis(x) is also overexpressed in breast cancer cells. Overexpression of Lewis(a) also occurs in precancerous states of stomach tissue. Upregulation of sialyl Lewis(a) correlates with the metastatic potential of colon and pancreatic malignancies and inversely with survival rate of patients. A similar relation was observed between sialyl Lewis(x) overexpression and malignancies of the lungs, prostate, urinary bladder, stomach, breast, kidney, and liver. Some of the Lewis antigens are ligands of specific receptors and adhesion molecules. For example, Lewis(x) is recognized by scavenger receptor C-type lectin (SRCL), which belongs to the group of innate immunity receptors. Sialyl Lewis(a) and sialyl Lewis(x) specifically interact with E- and P-selectins, which are key molecules in leukocyte rolling process. Ongoing research shows an increasing number of potential therapeutic applications related to the upregulation of Lewis antigens.

Antiproliferative properties of mycophenolic acid on human retinal pigment epithelial cells in vitro

PURPOSE

Mycophenolate mofetil (MMF) is an immunosuppressive agent used in the prophylaxis of graft rejection in transplantology. Its antyproliferative effects on lymphocyte, monocytes, vascular smooth muscle cells and fibroblasts are well known, but to our knowledge there are no reports on its action on the retinal epithelial (RPE) cells in vitro.

MATERIAL AND METHODS

In all experiments we used mycophenolic acid (MPC), which is the biologically active form of MME Its activity was assessed on the cultures of immortalized non-transformed cells line from a human donor (ARPE19). Cells were seeded and incubated in vitro with deferent concentrations of MPC: 0.0025 pg/ml, 0.025 pg/ml, 0.25 pg/ml, 2.5 pg/ml, 25 pg/ml and 250 microg/ml. After 24 and 72 hours of incubation, proliferative activity was assessed by 5'-bromo-2'-deoxyuridine (BrdU) incorporation into cellular DNA and the amount of cell proliferation was determined using the 3-(4.5-dimethylthiazol-2yl)-2.5-diphenyltetrazolium bromide (MTT) assay. Additionally, to determine cytotoxicity of MPC, ARPE19 cells were grown to confluence and subsequently cultured in a serum-deficient medium and then, after 24 hours of incubation with different concentrations of MPC, the MTT test was performed.

RESULTS

The BrdU assay showed the decrease of DNA synthesis activity for increasing concentrations of MPC starting with 0.025 microg/ml to 250 microg/ml. The number of RPE cells assessed with MTF test decreased after the exposition to the drug concentrations of 25 microg/ml and 250 microg/ml after 24 and 72 hours of incubation, and additionally for the concncentrations of 0.25 microg/ml and 2.5 microg/ml after 72 hours of incubation.

CONCLUSIONS

MMF influences the proliferation of immortalized ARPE19 cells without evident cytotoxic effect.

Antiproliferative effects of preservative-free triamcinolone acetonide on cultured human retinal pigment epithelial cells

BACKGROUND

The control of retinal pigment epithelial cell proliferation is an essential factor in the clinical management of proliferative vitreoretinopathy (PVR). Factors inhibiting PVR without toxic potential are of special interest in ophthalmology. The aim of the study was to investigate the antiproliferative and cytotoxic effects of a preservative-free triamcinolone acetonide (PFTA) suspension on a human retinal pigment epithelial (ARPE19) cell line in vitro.

MATERIAL/METHODS

ARPE19 cells (immortal non-transformed cells from a human donor) were seeded and incubated in vitro with increasing concentrations of PFTA (0.01-1 mg/ml). After 1, 3, and 7 days, cellular proliferative activity was assessed by 5'-bromo-2'-deoxyuridine (BrdU) incorporation into cellular DNA and cell proliferation was determined using the 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay. To determine cytotoxicity, ARPE19 cells were grown to confluence and subsequently cultured in serum-deficient medium to ensure a static milieu and the MTT test was performed after 24 hours of incubation with PFTA. Cell recovery after transient PFTA exposure was also compared with continuous exposure after 7 days.

RESULTS

PFTA inhibits ARPE19 cell proliferation in a dose-dependent manner. Significant inhibition of cell proliferation was observed on the first day of the study at 1, 0.1, and 0.01 mg/ml PFTA and significant reductions in ARPE19 cells were noted for 1 and 0.1 mg/ml PFTA. Proliferation was resumed in all ARPE19 cultures and was dependent on the initial PFTA concentration. PFTA did not cause a cytotoxic effect.

CONCLUSIONS

PFTA influences the proliferation of vital ARPE19 cells in a reversible manner without cytotoxic effect.

Histopathological analysis in experimental macular surgery with trypan blue

AIM

To analyse the effect of trypan blue on the retina in an experimental setting of macular surgery.

METHODS

Porcine eyes were used within 3 hours after death. The eyes were hemisected and the vitreous removed. Trypan blue (0.15%) was applied over the trephined posterior pole, whereas the rest of the eye cup was filled with a balanced salt solution (BSS). The dye and the BSS were removed after 1 minute and the complete eye cup irrigated and filled with fresh BSS. Both the treated and untreated retinas were illuminated with a standard surgical light pipe and source at maximum power for 10 minutes. Both the trypan blue exposed retina and the non-treated surrounding retina were processed for histology.

RESULTS

Exposure of the retina to trypan blue for 1 minute, followed by illumination caused no histologically detectable damage compared to the controls. No microarchitectural disorganisation, cellular disruption, or affection of the vitreoretinal interface was detected.

CONCLUSIONS

These findings indicate that a 1 minute exposure of trypan blue followed by illumination does not cause an acute morphologically detectable toxic effect on the porcine retina.

[Prevalance of open angle glaucoma and ocular hypertension as a risk factor for primary open angle glaucoma in Wroclaw population. Wroclaw Epidemiology Study]

OBJECTIVE

The purpose of the study is to assess the prevalence of various types of open angle glaucoma (OAG) and ocular hypertension (OH) as a risk factor for AOG. The second aim of the study was to determine the detection level of glaucoma in the population of Wroclaw inhabitants aged 40-79.

MATERIAL AND METHODS

The population based cross-sectional sample of 4853 Wroclaw inhabitants aged 40-79 years underwent two stage examination. First stage of the study included medical history interview and five screening tests: tonometry, peripheric anterior chamber depth assessment by Van Herick technique, ocular nerve head (ONH) assessment by stereoscopic ophthalmoscopy, Heidelberg Retina Tomograph (HRT) and Nerve Fiber Analyzer (GDx) investigation. Second stage included complete ophthalmological examination with gonioscopy, static perimetry and 24 hours monitoring of intraocular pressure (IOP), and pachymetry in OH group.

RESULTS

The prevalence of glaucoma in Wroclaw population aged 40-79 years was 1.6%. Open angle glaucoma (OAG) that includes primary open angle glaucoma (POAG), normal pressure glaucoma (NPG) and capsular glaucoma (PEX-glaucoma) was found in 1.53% of the population. Glaucoma detection level was low: 71% of all cases of glaucoma were diagnosed for the first time. The percentage of OH detected in Wrodaw population was 1.9%. Following the criteria of Ocular Hypertension Treatment Study (OHTS) we found that the pachymetric value of central corneal thickness (CCT) in OH group was less than 555 microm (thin cornea) in 12.5%, from 555 microm to 588 microm (normal thickness of central cornea) in 26.14% and more than 588 microm (thick cornea) in 61.36% of the subjects.

CONCLUSIONS

The Wroclaw Epidemiological Study revealed OAG as 91% of overall glaucoma cases. The relatively high percentage of glaucoma cases was diagnosed for the first time. This number is higher than reported by other authors of population studies in white communities. In the OH group the 26.14% of the eyes with normal CCT has increased risk, and the 12.5% eyes with thin cornea has highly increased risk of POAG, according to OHTS results.

[The role of electrooculographic examinations in the glaucoma diagnosis]

PURPOSE

To evaluate the significance of the electrooculography in the diagnosis of glaucoma.

MATERIAL AND METHODS

We studied 31 patients with primary open-angle glaucoma (aged 22-69 years), 29 patients with normal-tension glaucoma (aged 19-77 years) and 22 healthy controls (aged 38-65 years). We performed routine ophthalmological examinations and electrooculography in all patients.

RESULTS

Arden's coefficient results concerning electrooculography were the highest in control group and the lowest in primary open-angle glaucoma group, but the differences were not statistically significant.

CONCLUSION

Electrooculographic examinations do not seem to be effective for detecting glaucoma.

Pattern of respiration in patients recovering from barbiturate overdose

Ventilation has been recorded in seven patients who were unconscious following self-poisoning. Measurements were obtained on admission to the hospital and repeated daily until the patients regained consciousness. On admission, recordings were characterized by a low minute ventilation as a result of a low tidal volume in spite of a high frequency of respiration. During the period of recovery tidal volume and minute ventilation increased, whereas frequency decreased. The modifications observed during recovery were the reverse of those noted during the induction of anaesthesia wih barbiturates in man. However, these modifications differ from those observed during induction of anaesthesia in cats. Consequently, as far as respiratory control is concerned, models elaborated in animals cannot be extrapolated to deeply anaesthetized human subjects.