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.

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-β-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.

Choroidal thickness changes in patients with diabetes

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 (β -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.

Szisztémás gyógyszerek szemészeti mellékhatásai

A különböző szerveket érintő betegségek gyógyításában szisztémásan alkalmazott gyógyszerek szemészeti mellékhatásai lehetnek tünetmentes elváltozások, azonban látást veszélyeztető kórképek is, mint a toxikus retinopathia vagy az opticus neuropathia. A szemészeti szűrővizsgálatok során a mellékhatások korai felismerésével a további progresszió és a maradandó látáskárosodás az esetek többségében megelőzhető. Összefoglaló közleményünkben a klinikai gyakorlatban széles körben használt gyógyszerek leggyakoribb és legjelentősebb szemészeti mellékhatásait ismertetjük. Célunk a gyógyszereket felíró orvosok tájékoztatása a terápia lehetséges szemészeti szövődményeiről, a szemészeti vizsgálatok fontosságáról és rendszerességéről. Orv Hetil. 2020; 161(23): 951–961.

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.

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]

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.

Fusarium és Sarocladium okozta fertőzések szemészeti vonatkozásai és azok kezelése

Abstract:

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.

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]

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.

Diabeteses kisér-károsodás vizsgálata optikai koherencia tomográfián alapuló angiográfiával

Abstract:

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.

Highly efficient dehydrogenation of formic acid in aqueous solution catalysed by an easily available water-soluble iridium(iii) dihydride

Water-soluble cis-mer-[IrH₂Cl(mtppms)₃] selectively dehydrogenated formic acid with a TOF of 298 000 h⁻¹, a final pressure of 140 bar, and a TON_max of 674 000.

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.

LCT 13910 C/T polymorphism, serum calcium, and bone mineral density in postmenopausal women

SUMMARY

LCT 13910 CC genotype is associated with lactose intolerance, a condition often resulting in reduced milk intake. Women with the CC genotype were found to have decreased serum calcium and reduced bone mineral density.

INTRODUCTION

The CC genotype of the 13910 C/T polymorphism of the LCT gene is linked to lactose intolerance and low calcium intake.

METHODS

We studied 595 postmenopausal women, including 267 osteoporotic, 200 osteopenic, and 128 healthy subjects. Genotyping, osteodensitometry, and laboratory measurements were carried out.

RESULTS

Frequency of aversion to milk consumption was 20% for CC genotype and 10% for TT + TC genotypes (p = 0.03). The albumin-adjusted serum calcium was 2.325 +/- 0.09 mmol/L for CC genotype and 2.360 +/- 0.16 mmol/L for TT + TC genotypes (p = 0.031). Bone mineral density (BMD; Z score) was lower in the CC than TT + TC genotypes, respectively, at the radius (0.105 +/- 1.42 vs 0.406 +/- 1.32; p = 0.038), at the total hip (-0.471 +/- 1.08 vs -0.170 +/- 1.09; p = 0.041), and at the Ward's triangle (-0.334 +/- 0.87 vs -0.123 +/- 0.82; p = 0.044).

CONCLUSION

LCT 13910 C/T polymorphism is associated with decreased serum calcium level and lower BMD in postmenopausal women.