Bacteriopheophytin triplet state in <i>Rhodobacter sphaeroides</i> reaction centers

It is well established that photoexcitation of Rhodobacter sphaeroides reaction centers (RC) with reduced quinone acceptors results in the formation of a triplet state localized on the primary electron donor P with a significant yield. The energy of this long-lived and therefore potentially damaging excited state is then efficiently quenched by energy transfer to the RC spheroidenone carotenoid, with its subsequent decay to the ground state by intersystem crossing. In this contribution, we present a detailed transient absorption study of triplet states in a set of mutated RCs characterized by different efficiencies of triplet formation that correlate with lifetimes of the initial charge-separated state P(+)H(A)(−). On a microsecond time scale, two types of triplet state were detected: in addition to the well-known spheroidenone triplet state with a lifetime of ~4 μs, in some RCs we discovered a bacteriopheophytin triplet state with a lifetime of ~40 μs. As expected, the yield of the carotenoid triplet increased approximately linearly with the lifetime of P(+)H(A)(−), reaching the value of 42 % for one of the mutants. However, surprisingly, the yield of the bacteriopheophytin triplet was the highest in RCs with the shortest P(+)H(A)(−) lifetime and the smallest yield of carotenoid triplet. For these the estimated yield of bacteriopheophytin triplet was comparable with the yield of the carotenoid triplet, reaching a value of ~7 %. Possible mechanisms of formation of the bacteriopheophytin triplet state are discussed

Just Bone Tired: Equine Bone Stress

The field of biophotoelectrochemistry and its application in biophotovoltaics and biosensors has gained more and more attention in recent years. Knowledge of the redox potentials of the catalytically active protein cofactors in biophotovoltaic devices is crucial for accurate modelling and in discerning the mechanisms of their operation. Here, for the first time, we used spectroelectrochemical methods to investigate thermodynamic parameters of a biophotoelectrode in situ. We determined redox potentials of two elements of the system: the primary electron donor in photosynthetic reaction centers (RCs) of the bacterium Rhodobacter sphaeroides and osmium-complex based redox mediators that are bound to a hydrogel matrix. We observe that the midpoint potential of the primary donor is shifted towards more positive potentials in comparison to literature data for RCs solubilized in buffered water solution, likely due to interaction with the polymer matrix. We also demonstrate that the osmium-complex modified redox polymer efficiently wires the RCs to the electrode, maintaining a high Internal Quantum Efficiency with approximately one electron per two photons generated (IQE=50±12%). Overall, this biophotoelectrode may be attractive for controlling the redox state of the protein when performing other types of experiments, e.g. time resolved absorption or fluorescence measurements, in order to gain insights into kinetic limitations and thereby help in the rational design of bioelectronic devices

Left main disease management strategy: Indications and revascularization methods in particular groups of subjects

Surgical revascularization with coronary artery by-pass grafting is still recommended in vast majority of patients with unprotected left main disease. The aim of the paper was to analyze optimal treatment of left main disease in selected groups of patients, on the basis of current guidelines and information gained from literature data. We focused on data in relation to treatment of elderly patients, diabetics and those hemodynamically unstable. Additionally we discussed the issue of anti-platelet therapy and informed consent. As far as efficacy of treatment is concerned, not only method of revascularization but also general condition of the patient, the factors influencing peri-operative risk and optimal pharmacotherapy should be taken into account. Therefore establishment of the heart team is crucial when choosing the most suitable method of invasive treatment of left main disease

Skuteczna alkoholowa ablacja guza insulinowego trzustki, obserwacja 4-letnia. Opis przypadku i przegląd literatury

Introduction: EUS-guided ethanol ablation of insulinoma is a new method of treatment of this neuroendocrine tumour. Ablation is recommended in patients who are poor surgical candidates or refuse surgery. We present a case of an 81-year-old female with symptomatic insulinoma, treated successfully with EUS-guided alcoholic ablation, along with a literature review including 28 other previously described cases. The effectiveness, safety of the therapy, and technical procedure-related issues are summarised. To the best of our knowledge, this is the first described case of successful insulinoma EUS-guided ablation in Poland. Material and methods: We searched the PubMed/Medline database to identify cases of EUS-guided alcoholic ablation. Our analysis included 14 articles (case reports or case series), with a total of 27 patients and 31 tumours described, published before February 2017. Results: The described tumours were relatively small (mean 13 mm), and the most common location was pancreatic head. The mean ethanol volume injected to the tumour was 1.8 ml and the concentration of infused alcohol varied from 95% to 98%.Side effects were observed in six cases; apart from one, they were mild and self-limiting. There was only one severe adverse event, treated conservatively with success. The median follow-up was 14.4 months (2–55 months). In all described cases ablation led to improvement of the symptoms and normalisation of glycaemia. Conclusions: The EUS-guided alcoholic ablation of insulinoma is a safe and effective method of treatment in patients who are poor surgical candidates and/or refuse surgery. The adverse effects are rare and mild and were observed when the volume of injected ethanol was equal to or above 3.0 ml. However, the data is limited, the follow-up is relatively short, and prospective studies are needed to confirm the long-term effects of treatment. The study shows also that there are important procedural differences (concentration and volume of alcohol, needle gauge, number of sessions) between the endoscopists, which should be specified.Wstęp: Przedstawiono 81-letnią chorą z objawowym guzem insulinowym głowy trzustki. Pacjentka, z uwagi na liczne choroby współistniejące, została zdyskwalifikowana z leczenia chirurgicznego. Leczona diazoksydem, ciągłymi wlewami z glukozy, analogami somatostatyny bez istotnej poprawy(obserwowano działania niepożądane). Następnie pod kontrolą EUS wykonano alkoholową ablację zmiany. Nie obserwowano powikłań. Odstawiono diazoksyd, obserwując normalizację glikemii. Pacjentka w 4-letniej obserwacji pozostaje bez objawów klinicznych hipoglikemii. Według naszej wiedzy jest to pierwszy opisany przypadek skutecznej alkoholowej ablacji guza insulinowego w Polsce. W pracy przeprowadzono przegląd literatury i podsumowanie wcześniej przeprowadzonych i opisanych zabiegów alkoholowej ablacji guzów insulinowych, ze szczególnym naciskiem na skuteczność i bezpieczeństwo, czas obserwacji po leczeniu i szczegóły techniczne przeprowadzenia procedury. Materiał i metody: Przeszukano bazę Pub Med/Medline, aby zidentyfikować opisane przypadki alkoholowej ablacji guza insulinowego trzustki. Do analizy włączono 14 artykułów opublikowanych przed końcem lutego 2017, w których opisano łącznie 27 przypadków i 31 guzów insulinowych. Wyniki: Opisane guzy były stosunkowo małymi zmianami (średnio 13 mm), ich najczęstsza lokalizacją była głowa trzustki. Średnia objętość podawanego alkoholu to 1,8 ml, a stężenie wynosiło 95–98%. Efekty uboczne obserwowano w 6 przypadkach, poza jednym były one łagodne i ustępowały samoistnie. Zaobserwowano tylko jedno poważne powikłanie leczone zachowawczo z sukcesem. Średni czas obserwacji pacjenta wyniósł 14,4 miesiąca (od 2 do 55 miesięcy). U wszystkich opisanych chorych ablacja doprowadziła do ustąpienia objawów i normalizacji glikemii. Wnioski: Alkoholowa ablacja guza insulinowego trzustki pod kontrolą EUS jest bezpieczną i skuteczną metoda leczenia tego guza u pacjentów z przeciwwskazaniami do zabiegu lub takich, którzy nie godzą się na zabieg. Większość powikłań ma charakter łagodny i były one obserwowane, gdy objętość podawanego do guza etanolu przekraczała 3,0 ml. Krótki czas obserwacji pacjentów i niewielka liczba opisanych przypadków, sprawiają że konieczne jest zaplanowanie badań prospektywnych, które mogłyby potwierdzić długoterminowe efekty leczenia. Analiza pokazuje również, że występują istotne różnice pomiędzy endoskopistami w zakresie sposobu przeprowadzenia samej procedury (stężenie i objętość alkoholu, rozmiar igły, liczba sesji). Powinno dążyć się do sprecyzowania sposobu jej wykonania.

Safety and feasibility of minimally invasive coronary artery bypass surgery early after drug eluting stent implantation due to acute coronary syndrome

Background: The evidence of performing minimally invasive coronary artery surgery early after drug eluting stent (DES) implantation due to acute coronary syndrome (ACS) is limited. Aim: The aim of the study is to determine the safety and feasibility of this approach. Methods: This registry includes 115  (78% male) patients from 2013‒2018, who underwent non-LAD percutaneous coronary intervention (PCI) due to ACS with contemporary DES implantation (39% diagnosed with myocardial infarction at baseline), followed by endoscopic atraumatic coronary artery bypass (EACAB) surgery within 180 days, after temporary P2Y12 inhibitor discontinuation. Primary composite endpoint of MACCE (Major Adverse Cardiac and Cerebrovascular Events), defined as death, myocardial infarction (MI), cerebrovascular incident and repeat revascularization was evaluated in long- term follow-up. The follow-up was collected via telephone survey and with National Registry for Cardiac Surgery Procedures. Results: Median (interquartile range [IQR]) time interval separating both procedures was 100.0 (62.0‒136.0) days. Median (IQR) follow-up duration was 1338.5 (753.0‒2093.0) days and was completed from all patients with regard to mortality. Eight patients (7%) died; 2 (1.7%) had a stroke; 6 (5.2%) suffered from MI and 12 (10.4%) required repeat revascularization. Overall, the incidence of MACCE was 20 (17.4%). Conclusions: EACAB is a safe and feasible method of LAD revascularization in patients who received DES for ACS within 180 days prior to surgery, despite early dual antiplatelet therapy discontinuation. The adverse event rate is low and acceptable

State-of-the-art of transcatheter treatment of aortic valve stenosis and the overview of the InFlow project aiming at developing the first Polish TAVI system

Initial experience of transcatheter aortic valve implantation (TAVI) or replacement (TAVR) has ap-peared as a promising minimally invasive technology for patients disqualified from surgical treatment (SAVR). Safety and efficacy of TAVI has been analyzed and assessed through numerous registries and trials. Furthermore, results obtained from comparative TAVI vs. SAVR trials proved that both treat¬ments can be considered equal in terms of post-procedural mortality and morbidity in high-risk, as well as lower risk patients. However, there are still some issues that have to be addressed, such as higher chance of paravalvular leakage, vascular injuries, conduction disturbances, malpositioning and the yet unmet problem of insufficient biological valves durability. Recent technological developments along with the learning curve of operators prove a great potential for improvement of TAVI and a chance of surpassing SAVR in various groups of patients in the near future. In pursuit of finding new solutions, the CardValve Consortium consisting of leading scientific and research institutions in Poland has been created. Under the name of InFlow and financial support from the National Center for Research and Development, they have started a project with the aim to design, create and implement into clinical practice the first, Polish, low-profile TAVI valve system, utilizing not only biological but also artificial, polymeric-based prosthesis. This review focuses on current developments in TAVI technologies including the InFlow project

The influence of SGLT2 inhibitors on oxidative stress in heart failure and chronic kidney disease in patients with type 2 diabetes

There is increasing interest in sodium-glucose cotransporter 2 inhibitors (SGLT2i) as not only a new oral glucose-lowering drug class but also one with cardio- and nephroprotective potential. Understanding the underlying mechanisms is therefore of great interest, and postulated benefits have included increased natriuresis, lower blood pressure, increased haematocrit, enhanced cardiac fatty acid utilization, reduced low-grade inflammation, and decreased oxidative stress. In particular, redox homeostasis seems to be crucial in the pathogenesis of heart and kidney disease in diabetes, and there is accumulating evidence that SGLT2i have beneficial effects in this perspective. In this review, we aimed to summarize the potential mechanisms of the influence of SGLT2i on oxidative stress parameters in animal and human studies, with a special focus on heart failure and chronic kidney disease in diabetes mellitus