Regime shift in microalgal dynamics: Impact of water level changes on planktonic and benthic algal biomass.

Whole-lake microalgal biomass surveys were carried out in Lake Balaton to investigate the seasonal, spatial, and temporal changes of benthic algae, as well as to identify the drivers of the phytobenthos. Phytobenthos was controlled mainly by light: the highest benthic algal biomass was in the shallow littoral region characterized by large grain size (sand) with good light availability but lower nutrient content in the sediment. During the investigated period, phytoplankton biomass showed a significant decrease in almost the entire lake. At the same time, the biomass of benthic algae increased significantly in the eastern areas, increasing the contribution of total lake microalgae biomass (from 20 % to 27 %). Benthic algal biomass increase can be explained by the better light supply, owing to the artificially maintained high water level which greatly mitigates water mixing. The decrease in planktonic algal biomass could be attributed to increased zooplankton grazing, which is otherwise negatively affected by mixing. As a result of the high water level, the trophic structure of the lake has been rearranged in recent decades with a shift from the planktonic life form to the benthic one while the nutrient supply has largely remained unchanged.

Acetabular Revision with McMinn Cup: Development and Application of a Patient-Specific Targeting Device.

BACKGROUND: Surgeries of severe periacetabular bone defects (Paprosky ≥ 2B) are a major challenge in current practice. Although solutions are available for this serious clinical problem, they all have their disadvantages as well as their advantages. An alternative method of reconstructing such extensive defects was the use of a cup with a stem to solve these revision situations. As the instrumentation offered is typically designed for scenarios where a significant bone defect is not present, our unique technique has been developed for implantation in cases where reference points are missing. Our hypothesis was that a targeting device designed based on the CT scan of a patient's pelvis could facilitate the safe insertion of the guiding wire. METHODS: Briefly, our surgical solution consists of a two-step operation. If periacetabular bone loss was found to be more significant during revision surgery, all implants were removed, and two titanium marker screws in the anterior iliac crest were percutaneously inserted. Next, by applying the metal artifact removal (MAR) algorithm, a CT scan of the pelvis was performed. Based on that, the dimensions and positioning of the cup to be inserted were determined, and a patient-specific 3D printed targeting device made of biocompatible material was created to safely insert the guidewire, which is essential to the implantation process. RESULTS: In this study, medical, engineering, and technical tasks related to the design, the surgical technique, and experiences from 17 surgical cases between February 2018 and July 2021 are reported. There were no surgical complications in any cases. The implant had to be removed due to septic reasons (independently from the technique) in a single case, consistent with the septic statistics for this type of surgery. There was not any perforation of the linea terminalis of the pelvis due to the guiding method. The wound healing of patients was uneventful, and the implant was fixed securely. Following rehabilitation, the joints were able to bear weight again. After one to four years of follow-up, the patient satisfaction level was high, and the gait function of the patients improved a lot in all cases. CONCLUSIONS: Our results show that CT-based virtual surgical planning and, based on it, the use of a patient-specific 3D printed aiming device is a reliable method for major hip surgeries with significant bone loss. This technique has also made it possible to perform these operations with minimal X-ray exposure.

Custom-made 3D printing-based cranioplasty using a silicone mould and PMMA.

All types of cranioplasty techniques restore the morphology of the skull and affect patient aesthetics. Safe and easy techniques are required to enhance patients' recovery and the rehabilitation process. We propose a new method of cranioplasty. The 3-dimensional (3D) reconstruction of a thin-layer computed tomography (CT) scan of the skull was used to reflect the intact side onto the defect and subtract the overlapping points from one another. In this way, a 3D model of the planned implant can be built in the required shape and size. The precise fit of the implant can be checked by printing the defective part of the skull in case it can be modified. A sterilisable silicone mould based on the finalized model was created afterwards. Polymethyl methacrylate implants were prepared directly in an aseptic environment in the operating room during surgery. Between 2005 and 2020, we performed 54 cranioplasties on 52 patients whose craniotomies were performed previously for indications of traumatic brain injury, stroke or tumour surgeries. No technical problems were noted during the operations. In 2 cases, septic complications that occurred were not connected to the technique itself, and the implants were removed and later replaced. Our proposed technique based on 3D-printed individual silicone moulds is a reliable, safe, easily reproducible and low-cost method to repair different skull defects.

Comparative Analysis of Bone Ingrowth in 3D-Printed Titanium Lattice Structures with Different Patterns.

In this study, metal 3D printing technology was used to create lattice-shaped test specimens of orthopedic implants to determine the effect of different lattice shapes on bone ingrowth. Six different lattice shapes were used: gyroid, cube, cylinder, tetrahedron, double pyramid, and Voronoi. The lattice-structured implants were produced from Ti6Al4V alloy using direct metal laser sintering 3D printing technology with an EOS M290 printer. The implants were implanted into the femoral condyles of sheep, and the animals were euthanized 8 and 12 weeks after surgery. To determine the degree of bone ingrowth for different lattice-shaped implants, mechanical, histological, and image processing tests on ground samples and optical microscopic images were performed. In the mechanical test, the force required to compress the different lattice-shaped implants and the force required for a solid implant were compared, and significant differences were found in several instances. Statistically evaluating the results of our image processing algorithm, it was found that the digitally segmented areas clearly consisted of ingrown bone tissue; this finding is also supported by the results of classical histological processing. Our main goal was realized, so the bone ingrowth efficiencies of the six lattice shapes were ranked. It was found that the gyroid, double pyramid, and cube-shaped lattice implants had the highest degree of bone tissue growth per unit time. This ranking of the three lattice shapes remained the same at both 8 and 12 weeks after euthanasia. In accordance with the study, as a side project, a new image processing algorithm was developed that proved suitable for determining the degree of bone ingrowth in lattice implants from optical microscopic images. Along with the cube lattice shape, whose high bone ingrowth values have been previously reported in many studies, it was found that the gyroid and double pyramid lattice shapes produced similarly good results.

Retinal biomarkers for Alzheimer's disease and vascular cognitive impairment and dementia (VCID): implication for early diagnosis and prognosis.

Cognitive impairment and dementia are major medical, social, and economic public health issues worldwide with significant implications for life quality in older adults. The leading causes are Alzheimer's disease (AD) and vascular cognitive impairment/dementia (VCID). In both conditions, pathological alterations of the cerebral microcirculation play a critical pathogenic role. Currently, the main pathological biomarkers of AD-ß-amyloid peptide and hyperphosphorylated tau proteins-are detected either through cerebrospinal fluid (CSF) or PET examination. Nevertheless, given that they are invasive and expensive procedures, their availability is limited. Being part of the central nervous system, the retina offers a unique and easy method to study both neurodegenerative disorders and cerebral small vessel diseases in vivo. Over the past few decades, a number of novel approaches in retinal imaging have been developed that may allow physicians and researchers to gain insights into the genesis and progression of cerebromicrovascular pathologies. Optical coherence tomography (OCT), OCT angiography, fundus photography, and dynamic vessel analyzer (DVA) are new imaging methods providing quantitative assessment of retinal structural and vascular indicators-such as thickness of the inner retinal layers, retinal vessel density, foveal avascular zone area, tortuosity and fractal dimension of retinal vessels, and microvascular dysfunction-for cognitive impairment and dementia. Should further studies need to be conducted, these retinal alterations may prove to be useful biomarkers for screening and monitoring dementia progression in clinical routine. In this review, we seek to highlight recent findings and current knowledge regarding the application of retinal biomarkers in dementia assessment.

The Impact of Deterministic Signal Loss on OCT Angiography Measurements.

Purpose: In this study, we aimed at investigating the impact of deterministic signal loss on image quality and, thus, on optical coherence tomography angiography (OCTA) measurements performed by the RTVue-XR Avanti System. Methods: Absorptive filters with different optical densities (ODs) were used to simulate signal loss in a controlled way in 30 eyes from 15 healthy subjects. Scan Quality (SQ), provided by the AngioVue software, was applied as a measure of image quality. Results: Assessing the effect of decreased light transmittance on SQ values as well as that of attenuated image quality on OCTA parameters revealed a strong systematic dependence between these quantities. Attenuated image quality was associated with significantly decreased macular and peripapillary vessel density (VD) values, and we calculated a correction factor of 2.27% to 3.97% for a one-unit change in SQ for the different VD parameters. Conclusions: Our findings suggest that the influence of systematic changes in image quality on OCTA parameters needs to be considered during patient follow-up in order to make valid assessment of progression. Translational Relevance: For accurate evaluation of longitudinal changes in OCTA parameters, equal scan quality or using a correction factor is suggested.

Choroidal thickness changes in patients with diabetes / A chorioidea vastagságának változása diabeteses betegekben.

INTRODUCTION: Swept-source optical coherence tomography is a useful non-invasive device that is used to understand better the role of choroid in the pathogenesis of diabetic retinopathy. AIM: To measure choroidal thickness in diabetic eyes and to correlate it with established systemic risk factors, the severity and the therapy of diabetic retinopathy. METHOD: Prospective cross-sectional study using swept-source optical coherence tomography has been performed. Choroidal and macular thickness maps of 117 eyes of 60 diabetic patients were compared to data from 45 eyes of 24 healthy controls. In all diabetic patients, the systemic risk factors (duration and type of diabetes, blood hemoglobin A1C level, hypertension), the type (no, non-proliferative or proliferative) and the therapy of diabetic retinopathy were recorded, and their relation to choroidal thickness was evaluated using multiple regression models. RESULTS: A significantly thinner choroid was measured in diabetic patients compared to controls (p<0.05). Analysing the whole cohort, aging (p<0.001) and the presence of hypertension (p<0.05) showed significant correlation with choroidal thinning. In diabetic patients, the duration of diabetes significantly correlated with choroidal thinning (p<0.05). In multivariable analysis, the duration of diabetes remained a significant predictor of choroidal thickness (ß -0.18; p = 0.02). A significantly thinner choroid was measured in patients with proliferative retinopathy and in patients after panretinal photocoagulation treatment compared to nonproliferative retinopathy (p<0.05). CONCLUSION: Diabetes mellitus itself and diabetic retinopathy progression affects choroidal thickness significantly. Choroidal thickness is affected significantly by systemic risk factors (age, the presence of hypertension, disease duration). Choroidal thinning proved to be correlated with panretinal photocoagulation treatment of diabetic retinopathy. Orv Hetil. 2020; 161(35): 1475-1482.

Adverse ocular effects to systemic drug therapy / Szisztémás gyógyszerek szemészeti mellékhatásai

Systemic medications of various diseases can have adverse effects on the eye that range from asymptomatic lesions to potentially blinding complications such as toxic retinopathy and optic neuropathy. In the course of ophthalmological screening, with the early detection of toxic effects, the majority of drug-induced eye disorders can be prevented and even be reversed. Our review focuses on major drugs with common and significant ocular side effects. Physicians prescribing medications need to be keenly aware of ocular toxicity risks and the importance of regular screening. Orv Hetil. 2020; 161(23): 951-961.

The effect of image quality on the reliability of OCT angiography measurements in patients with diabetes.

BACKGROUND: This study aimed to determine the relationship between image quality and measurement repeatability of optical coherence tomography angiography (OCTA) parameters in patients with non-proliferative diabetic retinopathy. METHODS: A total of 100 eyes of 50 patients were included in the study. Three OCTA images were obtained consecutively during one session of imaging in all patients using the RTVue AngioVue OCTA device. We applied the signal strength index (SSI) provided by the RTVue system to define scan quality. Superficial vessel density (VD) in the central 3 × 3 mm macular and in the perifoveal region, as well as foveal avascular zone (FAZ) area were evaluated by the AngioAnalytics software for each scan from three consecutive measurements, whereby measurement repeatability of the OCTA parameters were calculated. The effect of SSI value on OCTA parameters, as well as on measurement errors was assessed. RESULTS: Values of SSI ranged from 30 to 85 with an overall mean of 61.79 ± 10.38. Mean SSI values showed significant positive correlation with the mean retinal capillary vessel density values, but not with non-flow area. Repeatability of OCTA parameters was generally improved with higher SSI values. We calculated a mean correction factor of 0.22% (95% CI 0.20-0.24 µm; p < 0.001) for VD at the 3 × 3 mm macular scan, 0.23% (95% CI 0.21-0.26%; p < 0.001) for perifoveal VD and - 0.001 mm2 (95% CI - 0.001 to 0.002; p = 0.001) for the non-flow area for each unit increase in SSI for the comparison of images with different SSI values. CONCLUSIONS: The influence of image quality on OCTA metrics should be considered for image comparisons during follow-up to avoid misinterpretation of small changes in OCTA parameters in patients with diabetes.

[Systemic biological treatment in ophthalmology]. / Biológiai terápia szisztémás alkalmazása a szemészetben.

We present herewith cases of non-infectious uveitis with biological treatment where the ocular complaints were the initial symptoms indicating a multi-organ autoimmune disease. The first case was a patient with panuveitis and Vogt-Koyanagi-Harada disease, the second case was also a panuveitic patient with sarcoidosis and the third case was a patient with intermediate uveitis and inflammatory bowel disease. In all cases, emerging new, biological therapy (adalimumab) was necessary to achieve permanent inactive period of uveitis and the autoimmune disease. Introducing systemic biological treatment (adalimumab) in ophthalmology is crucial in the therapy of immune-mediated, non-infectious uveitis in order to preserve visual acuity. Orv Hetil. 2019; 160(44): 1744-1750.

[Ocular manifestations and management of Fusarium and Sarocladium infections]. / Fusarium és Sarocladium okozta fertozések szemészeti vonatkozásai és azok kezelése.

Since 2017, the nomenclature of Fusarium, Acremonium and Sarocladium species have changed, as these morphologically homogeneous, but phylogenetically heterogeneous species and species complexes may be differentiated using MALDI-TOF MS examination, analyzing nucleotic sequences. This resulted in taxonomical changes. We summarize the clinical course, diagnostic and therapeutic options of keratitis caused by Fusarium and Sarocladium. The challenge of Fusarium and Sarocladium keratitis management for an ophthalmologist lies in delayed diagnosis and therapy, fulminant progression and penetration of the Descemet's membrane, restricted availability, poor penetration of antifungal agents and therapy resistance. The diagnosis is based on the clinical history of corneal trauma or contact lens wear, PCR and MALDI-TOF MS, confocal microscopic examination, microbiological culture and light-microscopic analysis of corneal scrapings. As primary conservative treatment, 5% natamycin eye drops have to be used and with results of an antimycogram, topical 1% voriconazole or 0.15-0.25% amphotericin B, in some cases 0.02% polyhexamethylene-biguanide (PHMB) may be applied. Fusarium keratitis may benefit from additional 2 × 200 mg oral voriconazole treatment, daily. In therapy resistant cases, early, large diameter penetrating keratoplasty (PKP) has to be performed, with complete removal of the infected area. With late diagnosis, delayed specific treatment and surgery, mycotic hyphae may penetrate the Descemet's membrane, leading to the loss of vision and enucleation in about every fourth patient. In our paper, we also present the heterogeneous clinical history of five Fusarium and Sarocladium keratitis cases. Orv Hetil. 2019; 160(1): 2-11.

DECREASED RETINAL CAPILLARY DENSITY IS ASSOCIATED WITH A HIGHER RISK OF DIABETIC RETINOPATHY IN PATIENTS WITH DIABETES.

PURPOSE: To quantify retinal microvascular alterations using optical coherence tomography angiography in diabetic patients, and to evaluate the accuracy of decreased vessel density (VD) in predicting early diabetic retinopathy (DR). METHODS: One hundred and two eyes of 51 diabetic patients and 92 eyes of 46 individuals without diabetes were examined. Duration of diabetes, insulin therapy, blood pressure, HbA1C, dyslipidemia, axial length, and the presence of DR were recorded. Retinal VD was measured using optical coherence tomography angiography. The effect of risk factors on VD and on DR was assessed using multivariable regression analyzes. RESULTS: Compared with controls, VD was lower in diabetic patients (P < 0.05) and correlated with diabetes duration (P = 0.02). Decreased VD was associated with a higher risk of DR (odds ratio: 1.24, P = 0.009) after controlling for systemic and ocular confounding variables. Eyes with a VD of <50% had an odds ratio of 4.55 (P = 0.003) for DR and an odds ratio of 3.22 (P = 0.03) for decreased visual acuity (<20/25) after controlling for systemic and ocular confounding factors. CONCLUSION: The risk of DR and vision loss is substantially higher in eyes with lower VD, suggesting that optical coherence tomography angiography metrics may serve as prognostic biomarkers for the prediction of early onset DR.

Intrasession and Between-Visit Variability of Retinal Vessel Density Values Measured with OCT Angiography in Diabetic Patients.

In clinical practice the measurement error of an instrument has special importance in analyzing and interpreting data, and acknowledging limitations. The purpose of this study was to evaluate intrasession and between-visit reproducibility of OCT angiography measurements in diabetic patients. A total of 54 eyes of 27 diabetic patients underwent OCT angiography imaging. Foveal avascular zone (FAZ) area and superficial retinal vessel density (VD) at 3 mm were calculated using the AngioAnalytics software. Three consecutive images were acquired at first visit and one image 1 month later. Intrasession and between-visit reproducibility of parameters were characterized by intraclass correlation coefficient (ICC), coefficient of variation (CV), and coefficient of repeatability (CR) values. We measured excellent (>0.90) ICC values both in intrasession and between-visit comparisons. CV was higher for the FAZ area compared to VD both in intrasession (7.79% vs. 2.87%) and in between-visit (12.33% vs. 2.95%) comparisons. Between-visit CR value for VD was 4.53% (95% CI: 3.72-5.79%). These data suggest that OCT angiography shows excellent repeatability in diabetic patients, indicating that this non-invasive technology might be suitable for longitudinal assessment of microvascular complications.

Choroidal thickness changes in non-treated eyes of patients with diabetes: swept-source optical coherence tomography study.

AIMS: To measure choroidal thickness (CT) in diabetic eyes and its correlation with metabolic status and the severity of diabetic retinopathy (DR). MATERIALS AND METHODS: Prospective cross-sectional study using swept-source optical coherence tomography. CT maps of 96 treatment naïve eyes of 48 patients with diabetes were compared to 46 eyes of 23 healthy controls. CT changes and their relation to diabetes, age, gender, disease duration, hypertension (HT), hemoglobin A1c level, type and severity of DR were evaluated. RESULTS: A significantly thinner choroid was measured in patients with diabetes compared to controls (p < 0.009). In the diabetic group age, gender, disease duration and HT were significantly correlated with CT in univariable regression models (p < 0.05). In multivariable analysis, the duration of diabetes significantly negatively correlated with CT (p = 0.02). According to analysis of variance, there was a significant difference among means of CT in different stages of DR (p = 0.002), with thinner CT in cases with more advanced DR. In a multivariable predictive model, thinner CT was associated with an increased risk for the presence of DR (p = 0.02). CONCLUSIONS: Diabetes mellitus itself and the severity of DR affect CT significantly, even after adjusting for the effects of confounding systemic factors. Disease duration seems to be associated with a reduction of choroidal thickness. Decreased CT proved to be correlated with the severity of DR.

[Placoid chorioretinopathy in systemic infections]. / Placoid chorioretinopathiák szisztémás fertozésekben.

INTRODUCTION AND AIM: To present two cases of placoid chorioretinopathy (ocular syphilis and ocular tuberculosis) and underline the importance of differential diagnosis. METHOD: Two young female patients presented with unilateral loss of vision. Fundus examination showed yellowish placoid lesions in the posterior pole in both cases. RESULTS: Performing fluorescein angiography and laboratory investigations, ocular syphilis was diagnosed in our first case and intraocular tuberculosis was diagnosed in our second case. CONCLUSION: It is important to determine the etiology of the placoid choriaretinopathies due to the different prognosis and therapy and the exclusion of systemic diseases. A comprehensive evaluation of these patients is inevitable for the correct diagnosis and appropriate management. Orv Hetil. 2018; 159(22): 863-869.

[Evaluation of diabetic microangiopathy using optical coherence tomography angiography]. / Diabeteses kisér-károsodás vizsgálata optikai koherencia tomográfián alapuló angiográfiával.

INTRODUCTION: Optical coherence tomography angiography is a non-invasive imaging technique that is able to visualize the different retinal vascular layers using motion contrast to detect blood flow without intravenous dye injection. This method might help to assess microangiopathy in diabetic retinopathy during screening and follow-up. AIM: To quantify retinal microvasculature alterations in both eyes of diabetic patients in relation to systemic risk factors using optical coherence tomography angiography. METHOD: Both eyes of 36 diabetic patients and 45 individuals without diabetes were examined. Duration of diabetes, insulin therapy, blood pressure, HbA1c, dyslipidemia, axial length and the presence of diabetic retinopathy were recorded. Retinal vessel density was measured by optical coherence tomography angiography. The effect of risk factors on vessel density and between-eye asymmetry was assessed using multivariable regression analysis. RESULTS: Vessel density was significantly lower and between-eye difference was significantly higher in diabetic patients compared to controls (p<0.05). Both vessel density and between-eye asymmetry significantly correlated with diabetes duration (p<0.05) after controlling for the effect of risk factors. The between-eye asymmetry in vessel density was significantly higher in patients without clinically detectable diabetic retinopathy compared to control subjects (p<0.001). CONCLUSIONS: There is a decrease in retinal vessel density and an increase in between-eye asymmetry in patients with diabetes compared to healthy subjects. By using optical coherence tomography angiography, the detection of these microvascular alterations is possible before clinically detectable diabetic retinopathy and might serve as a useful tool in both screening and timing of treatment. Orv Hetil. 2018; 159(8): 320-326.

Differential effects of α7 nicotinic receptor agonist PHA-543613 on spatial memory performance of rats in two distinct pharmacological dementia models.

The aim of the present study was to compare the cognitive enhancer potential of a recently identified highly selective α7 nicotinic receptor agonist PHA-543613 in scopolamine induced cholinergic and in MK-801 induced glutamatergic transient amnesia models in adult male Wistar rats. Spontaneous alternation paradigm in the T-maze was used as it is considered a reliable measure of spatial working memory and as T-maze performance is highly dependent on the functioning of the hippocampus and the prefrontal cortex. Scopolamine (0.5 mg/kg) and MK-801 (0.1 mg/kg) caused similar decrease of alternation rate and increased locomotion. Prior administration of PHA-543613 (1 or 3 mg/kg) dose dependently and completely reversed scopolamine induced impairment of alternation. However, PHA-543613 had lower efficacy in the MK-801 induced transient amnesia model, as the pharmacologically induced memory deficit was only partially reversed and an inverted U-shaped dose-response was found. PHA-543613 did not modulate either scopolamine or MK-801 induced increased locomotor activity or decreased choice latency. Results suggest that the α7 nicotinic receptor agonist had better efficacy to alleviate working memory deficits of rats caused by cholinergic receptor dysfunction, when NMDA receptors were not primarily targeted. On the other hand, the same memory enhancer strategy through α7 cholinergic receptors was apparently less effective when glutamatergic transmission (via NMDARs) was directly impaired by MK-801 treatment. The present results provide data supporting the need of parallel comprehensive testing of novel drug-candidates for cognitive impairment in distinct preclinical models of memory deficits.

Unique picoeukaryotic algal community under multiple environmental stress conditions in a shallow, alkaline pan.

Winter phytoplankton communities in the shallow alkaline pans of Hungary are frequently dominated by picoeukaryotes, sometimes in particularly high abundance. In winter 2012, the ice-covered alkaline Zab-szék pan was found to be extraordinarily rich in picoeukaryotic green algae (42-82 × 10(6) cells ml(-1)) despite the simultaneous presence of multiple stressors (low temperature and light intensity with high pH and salinity). The maximum photosynthetic rate of the picoeukaryote community was 1.4 µg C µg chlorophyll a (-1) h(-1) at 125 µmol m(-2) s(-1). The assimilation rates compared with the available light intensity measured on the field show that the community was considerably light-limited. Estimated areal primary production was 180 mg C m(-2) d(-1). On the basis of the 18S rRNA gene analysis (cloning and DGGE), the community was phylogenetically heterogeneous with several previously undescribed chlorophyte lineages, which indicates the ability of picoeukaryotic communities to maintain high genetic diversity under extreme conditions.