Morphology, taxonomy and distribution of Stephanodiscus triporus (Bacillariophyceae) and related taxa

Stephanodiscus triporus was described in 1978, based on a study from the phytoplankton of Volgograd Reservoir that used transmission electron microscopy. This species is small, diameter 3.7–10.6 µm, with 14–30 striae and 30–60 areolae in 10 µm, and differs from other Stephanodiscus species by the presence of three satellite pores in the single central fultoportula. Later a new species similar in morphology to S. triporus, was described from Iowa, USA, namely S. vestibulis. A large population of S. vestibulis was found in Lake Balaton and the species also occurs in different Hungarian and French waters. Detailed comparison of S. triporus and S. vestibulis, based on our results and literature, showed they are very similar. Therefore we reinvestigated the type material of both and compared them with the Hungarian and French specimens. Conventional and geometric morphometric analyses were carried out, also including comparisons with the morphologically closest taxon, S. minutulus. There is a continuum of variation between S. triporus and S. vestibulis (in diameter, the number and morphology of the striae, the position of the valve face fultoportula with three satellite pores, the presence of a vestibulum having more or less the same shape). Hence we suggest that they are conspecific, with S. vestibulis a later synonym of S. triporus

Serum L-arginine and Dimethylarginine Levels in Migraine Patients with Brain White Matter Lesions

Background/Aim Migraine is a risk factor for the formation of silent brain white matter lesions (WMLs) that are possibly ischemic in nature. Although dysfunction of the L-arginine/nitric oxide (NO) pathway has been associated with oxidative stress and endothelial dysfunction in migraine, its role in WML development has not been specifically investigated. Thus, this prospective study aimed to measure the serum concentrations of the NO substrate L-arginine, the NO synthase inhibitor asymmetric dimethylarginine (ADMA), and the L-arginine transport regulator symmetric dimethylarginine (SDMA) in migraine patients in a headache-free period. Methods All participants underwent MR imaging to assess for the presence of WMLs on fluid-attenuated inversion recovery imaging. Altogether 109 migraine patients (43 with lesions, 66 without lesions) and 46 control individuals were studied. High-performance liquid chromatography was used to quantify L-arginine, ADMA and SDMA serum concentrations. Migraine characteristics were investigated, and participants were screened for risk factors that can lead to elevated serum ADMA levels independent of migraine. Results Migraine patients and controls did not differ in regard to vascular risk factors. Migraineurs with WMLs had a longer disease duration ( p &lt; 0.001) and a higher number of lifetime headache attacks ( p = 0.005) than lesion-free patients. Higher L-arginine serum levels were found in both migraine subgroups compared to controls ( p &lt; 0.001). Migraine patients with WMLs showed higher ADMA concentrations than lesion-free patients and controls ( p &lt; 0.001, for both). In migraineurs, the presence of WMLs, aura and increasing age proved to be significant predictors of increased ADMA levels ( p = 0.008, 0.047 and 0.012, respectively). SDMA serum levels of lesional migraineurs were higher than in nonlesional patients ( p &lt; 0.001). The presence of lesions and increasing age indicated an increased SDMA level ( p = 0.017 and 0.001, respectively). Binary logistic regression analysis showed that ADMA level ( p = 0.006), increasing age ( p = 0.017) and the total number of lifetime migraine attacks ( p = 0.026) were associated with an increased likelihood of exhibiting WMLs. There was no significant effect of age on ADMA and SDMA concentrations in controls. Conclusions Elevated ADMA levels may impact the pathogenesis of migraine-related WMLs by influencing cerebrovascular autoregulation and vasomotor reactivity. Higher SDMA concentrations may indirectly influence NO synthesis by reducing substrate availability. Elevated L-arginine serum levels might reflect an increased demand for NO synthesis. </jats:sec

A citokeratin-18 sejthalálmarker vizsgálata sikeres cardiopulmonalis resuscitatión átesett betegpopulációban = The prognostic value of cytokeratin-18 cell death marker in cardiac arrest survivors

Absztrakt: Bevezetés: Citokeratin-18 (CK-18) az újraélesztés kapcsán kialakuló ischaemiás-reperfúziós károsodás kiváltotta teljes sejthalál során kerül a véráramba. Kaszpázok által hasított formája specifikus az apoptózis folyamatára. A markerek számos kórképben prognosztikus értékűnek bizonyultak. Tanulmányunkban elsőként vizsgáltuk prognosztikus értéküket reanimált betegpopulációban. Módszer: 40, sikeresen újraélesztett betegnél határoztuk meg a sejthalálmarkerek szintjét 6 órán belül, 24 és 72 óra múlva. Ezeket összevetettük a 30 napos túléléssel, a neurológiai kimenetellel, a szervfunkciós károsodást jellemző laboratóriumi, fizikális és terápiás jellemzőkkel, valamint a reanimáció körülményeivel. Eredmények: A reanimált betegek CK-18-plazmakoncentrációja a szakirodalomban leírt egészséges, posztoperatív és szeptikus populáció értékeinek a többszöröse volt (3842 vs. 242; 559; 1644 ng/l); a hasított és intakt CK-18 aránya alacsonyabb volt (0,14 vs. 0,58; 0,22; 0,24), ami jelentős sejtkárosodásra és a nekrózis dominanciájára utal. A markerek szintje azonban nem mutatott összefüggést a túléléssel, a neurológiai statusszal és a reanimáció körülményeivel sem. Veseelégtelenség esetén a CK-18 szintjének csökkenése elmaradt. Szignifikáns negatív korrelációt figyeltünk meg a 6 órás hemoglobin- és CK-18-szint között (r = –0,400, p<0,01), a 30 napos túlélésnek mégis az alacsonyabb hemoglobinértékek kedveztek. Következtetés: Várakozásunkkal ellentétben a vizsgált markerek nem bírtak prognosztikus értékkel újraélesztett betegpopulációban. A kimenetelt valószínűleg nem a teljes sejtkárosodás, hanem egy kisebb, a fenti markerekkel szenzitíven nem vizsgálható kritikus szerepű sejtpopuláció károsodása, valamint a beteg tartalékkapacitásai befolyásolják. Orv Hetil. 2020; 161(1): 26–32. | Abstract: Introduction: Cytokeratin-18 (CK-18) is releasing into the blood during systemic cell death due to ischemia-reperfusion injury after cardiac arrest. Its caspase-cleaved form is specific to apoptosis. Previous investigations proved their prognostic value in different conditions. We firstly investigated the prognostic value of these markers after cardiac arrest. Method: Plasma samples of 40 resuscitated patients were collected 6, 24, and 72 hours after successful resuscitation to determine the marker concentrations. We investigated the association of the markers with the 30-day mortality, neurological outcome, circumstances of the cardiac arrest, laboratory and physical parameters. Results: Resuscitated patients had highly elevated CK-18 levels (3842 vs. 242; 559; 1644 ng/L) and decreased caspase-cleaved CK-18/CK-18 ratio (0.14 vs. 0.58; 0.22; 0.24) compared to healthy subjects, septic and postoperative patients suggesting severe grade of cell death, mainly necrosis. Neither the marker concentrations nor their kinetics showed difference between survivors and non-survivors. They did not show association with the length of the resuscitation, the initial rhythm or the neurological outcome either. CK-18 decreased in patients with good renal function in contrast to patients with renal failure. Significant negative correlation was observed between the 6-hour cytokeratin-18 and hemoglobin concentrations (r = –0.400, p<0.01), while the 30-day survival was associated with lower hemoglobin levels. Conclusion: Surprisingly the biomarkers did not show prognostic value among resuscitated population. The outcome is probably not determined by the complete cell damage, but the loss of a small group of cells with critical role and the reserve capacity of the patient. Orv Hetil. 2020; 161(1): 26–32

Plasma Fibrinogen Independently Predicts Hypofibrinolysis in Severe COVID-19

High rates of thrombosis are present in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Deeper insight into the prothrombotic state is essential to provide the best thromboprophylaxis care. Here, we aimed to explore associations among platelet indices, conventional hemostasis parameters, and viscoelastometry data. This pilot study included patients with severe COVID-19 (n = 21) and age-matched controls (n = 21). Each patient received 100 mg aspirin therapy at the time of blood sampling. Total platelet count, high immature platelet fraction (H-IPF), fibrinogen, D-dimer, Activated Partial Thromboplastin Time, von Willebrand factor antigen and von Willebrand factor ristocetin cofactor activity, plasminogen, and alpha2-antiplasmin were measured. To monitor the aspirin therapy, a platelet function test from hirudin anticoagulated whole blood was performed using the ASPI test by Multiplate analyser. High on-aspirin platelet reactivity (n = 8) was defined with an AUC > 40 cut-off value by ASPI tests. In addition, in vitro viscoelastometric tests were carried out using a ClotPro analyser in COVID-associated thromboembolic events (n = 8) (p = 0.071) nor the survival rate (p = 0.854) showed associations with high on-aspirin platelet reactivity status. The platelet count (p = 0.03), all subjects. COVID-19 patients presented with higher levels of inflammatory markers, compared with the controls, along with evidence of hypercoagulability by ClotPro. H-IPF (%) was significantly higher among non-survivors (n = 18) compared to survivors (p = 0.011), and a negative correlation (p = 0.002) was found between H-IPF and plasminogen level in the total population. The platelet count was significantly higher among patients with high on-aspirin platelet reactivity (p = 0.03). Neither the ECA-A10 (p = 0.008), and ECA-MCF (p = 0.016) were significantly higher, while the tPA-CFT (p < 0.001) was significantly lower among patients with high on-aspirin platelet reactivity. However, only fibrinogen proved to be an independent predictor of hypofibrinolysis in severe COVID-19 patients. In conclusion, a faster developing, more solid clot formation was observed in aspirin ‘non-responder’ COVID-19 patients. Therefore, an individually tailored thromboprophylaxis is needed to prevent thrombotic complications, particularly in the hypofibrinolytic cluster

Algological and bacteriological investigations on reed periphyton in Lake Velencei, Hungary

In the shallow Lake Velencei (surface area 24.5 km(2)) reed communities (Scirpo-Phragmitetum) are of great significance due to extensive metabolic activity of algal-bacterial associations developing on their submerged surfaces. Samples for algological and bacteriological studies were taken in April 2000 and July 2001 at five sites of the lake and were analysed with traditional methods as well as with tools of molecular biology (16S rDNA sequencing). These investigations have shown that (i) The original mosaic structure of the lake disappeared; periphytic algae became spatially uniform both in terms of taxonomic composition and abundance. (ii) The biodiversity of the reed periphyton decreased. The dominance of the weed algal species Achnanthes minutissima Kutz. increased significantly. (iii) The most frequent bacteria were members of the genera Pseudomonas, Acinetobacter, Shewanella and Agrobacterium characterised by oxidative chemoorganotrophic heterotrophic- and Aeromonas and Bacillus species with fermentative metabolism. (iv) Among the studied bacterial strains both plant growth promoting bacteria, members of Pseudomonas fluorescens group, and potential plant pathogens (Agrobacterium, Aureobacterium, Curtobacterium) were present