Biosynthesis of allene oxides in Physcomitrella patens

Background: The moss Physcomitrella patens contains C-18- as well as C-20-polyunsaturated fatty acids that can be metabolized by different enzymes to form oxylipins such as the cyclopentenone cis(+)-12-oxo phytodienoic acid. Mutants defective in the biosynthesis of cyclopentenones showed reduced fertility, aberrant sporophyte morphology and interrupted sporogenesis. The initial step in this biosynthetic route is the conversion of a fatty acid hydroperoxide to an allene oxide. This reaction is catalyzed by allene oxide synthase (AOS) belonging as hydroperoxide lyase (HPL) to the cytochrome P450 family Cyp74. In this study we characterized two AOS from P. patens, PpAOS1 and PpAOS2. Results: Our results show that PpAOS1 is highly active with both C-18 and C-20-hydroperoxy-fatty acid substrates, whereas PpAOS2 is fully active only with C-20-substrates, exhibiting trace activity (similar to 1000-fold lower k(cat)/K-M) with C-18 substrates. Analysis of products of PpAOS1 and PpHPL further demonstrated that both enzymes have an inherent side activity mirroring the close inter-connection of AOS and HPL catalysis. By employing site directed mutagenesis we provide evidence that single amino acid residues in the active site are also determining the catalytic activity of a 9-/13-AOS - a finding that previously has only been reported for substrate specific 13-AOS. However, PpHPL cannot be converted into an AOS by exchanging the same determinant. Localization studies using YFP-labeled AOS showed that PpAOS2 is localized in the plastid while PpAOS1 may be found in the cytosol. Analysis of the wound-induced cis(+)-12-oxo phytodienoic acid accumulation in PpAOS1 and PpAOS2 single knock-out mutants showed that disruption of PpAOS1, in contrast to PpAOS2, results in a significantly decreased cis(+)-12-oxo phytodienoic acid formation. However, the knock-out mutants of neither PpAOS1 nor PpAOS2 showed reduced fertility, aberrant sporophyte morphology or interrupted sporogenesis. Conclusions: Our study highlights five findings regarding the oxylipin metabolism in P. patens: (i) Both AOS isoforms are capable of metabolizing C-18- and C-20-derived substrates with different specificities suggesting that both enzymes might have different functions. (ii) Site directed mutagenesis demonstrated that the catalytic trajectories of 9-/13-PpAOS1 and PpHPL are closely inter-connected and PpAOS1 can be inter-converted by a single amino acid exchange into a HPL. (iii) In contrast to PpAOS1, PpAOS2 is localized in the plastid where oxylipin metabolism takes place. (iv) PpAOS1 is essential for wound-induced accumulation of cis(+)-12-oxo phytodienoic acid while PpAOS2 appears not to be involved in the process. (v) Knock-out mutants of neither AOS showed a deviating morphological phenotype suggesting that there are overlapping functions with other Cyp74 enzymes

Ten Misconceptions from the History of Analysis and Their Debunking

The widespread idea that infinitesimals were "eliminated" by the "great triumvirate" of Cantor, Dedekind, and Weierstrass is refuted by an uninterrupted chain of work on infinitesimal-enriched number systems. The elimination claim is an oversimplification created by triumvirate followers, who tend to view the history of analysis as a pre-ordained march toward the radiant future of Weierstrassian epsilontics. In the present text, we document distortions of the history of analysis stemming from the triumvirate ideology of ontological minimalism, which identified the continuum with a single number system. Such anachronistic distortions characterize the received interpretation of Stevin, Leibniz, d'Alembert, Cauchy, and others.Comment: 46 pages, 4 figures; Foundations of Science (2012). arXiv admin note: text overlap with arXiv:1108.2885 and arXiv:1110.545

A modified surgical approach to women with obstetric anal sphincter tears by separate suturing of external and internal anal sphincter. A modified approach to obstetric anal sphincter injury

<p>Abstract</p> <p>Background</p> <p>Long-term results after obstetric anal sphincter injury (OASI) are poor. We aimed to improve the long-term outcome after OASI by lessening symptoms of anal incontinence.</p> <p>Methods</p> <p>In a prospective study at Malmö University Hospital, twenty-six women with at least grade 3B OASI were classified and sutured in a systematic way, including separate suturing of the internal and external sphincter muscles with monofilament absorbable sutures. The principal outcome assessed by answers given to six questions, was a difference in anal incontinence score, between the study group and two control groups (women with prior OASI [n = 180] and primiparous women delivered vaginally without a diagnose of OASI [n = 100]).</p> <p>Results</p> <p>An anal incontinence score of zero (i.e., no symptoms) was found in 74% of the study group, 47% of the OASI control group, and 66% of the vaginal control group (<it>p </it>= 0.02 and 0.5, as compared to the study group).</p> <p>Conclusions</p> <p>A modified suturing technique was followed by significant improved one-year symptoms of anal incontinence as compared to historical cases.</p

СТРЕСС-ОТВЕТ ПРИ РАДИКАЛЬНЫХ ОПЕРАЦИЯХ ПО ПОВОДУ РАКА ЖЕЛУДКА

The purpose of the study was to evaluate the anesthetic effect of the combination of xenon and dexmedetomidine during surgery for gastric cancer. Material and methods. The prospective randomized study included 53 patients with operable II–III stage gastric cancer. The age range was from 26 to 75 years. The patients underwent gastrectomy (n=21) and subtotal distal gastrectomy (n=32). The study group comprised 27 patients who received anesthesia with xenon and dexmedetomidine combined with epidural analgesia. The control group consisted of 26 patients who received anesthesia with sevoflurane in combination with epidural analgesia. Intraoperative patient monitoring was performed according to Harvard intraoperative monitoring standards. Plasma levels of ACTH, STH cortisole, IL-1β, IL-6, and CRP as well as cytokine profile were used to evaluate the effect of two anesthetic methods. Results. In the perioperative period, the combination of xenon and dexmedetomidine in combination with epidural analgesia was characterized by significant inhibition of systemic inflammatory reactions and a lower release of stress hormones as components of a surgical stress response expressed by a lower level of pro-inflammatory cytokines and somatotropic hormone. The frequency of postoperative inflammatory complications was lower in the xenon group than in the control group. Conclusion. The use of the combination of xenon and dexmedetomidine during surgery for gastric cancer provides a more adequate course of the perioperative period. Цель исследования – оценить эффективность анестезиологического пособия комбинацией ксенона и дексмедетомидина при операциях по поводу рака желудка. Материал и методы. В проспективное рандомизированное исследование включены 53 пациента с операбельным раком желудка II–III стадий, в возрасте 26–75 лет, ASA I–II, которым были выполнены операции в объеме гастрэктомии (n=21), субтотальной дистальной резекции желудка (n=32). В I (основной) группе (n=27) проводилась комбинированная анестезия ксеноном и дексмедетомидином в сочетании с эпидуральной аналгезией. Во II (контрольной) группе (n=26) проводилась анестезия севорфлюраном в сочетании с эпидуральной аналгезией. Проводился стандартный интраоперационный мониторинг по Гарвардскому стандарту. Эффективность сравниваемых методов анестезиологического пособия оценивали по уровеню АКТГ, СТГ, кортизола, IL-1β, IL-6 и СРБ и цитокиновому профилю. Результаты. Комбинация ксенона и дексмедетомидина в сочетании с эпидуральной аналгезией на всех этапах периоперационного периода характеризовалась значимым торможением системных воспалительных реакций и меньшим выбросом гормонов стресса как компонентов хирургической стрессовой реакции, выражающейся более низким уровнем провоспалительных цитокинов и соматотропного гормона. В основной группе отмечена меньшая частота послеоперационных нехирургических осложнений, обусловленных системной воспалительной реакцией. Заключение. Применение комбинированного анестезиологического пособия с использованием ксенона и дексмедетомидина при операциях по поводу рака желудка обеспечивает более адекватное течение периоперационного периода.

A weak scientific basis for gaming disorder: let us err on the side of caution

We greatly appreciate the care and thought that is evident in the 10 commentaries that discuss our debate paper, the majority of which argued in favor of a formalized ICD-11 gaming disorder. We agree that there are some people whose play of video games is related to life problems. We believe that understanding this population and the nature and severity of the problems they experience should be a focus area for future research. However, moving from research construct to formal disorder requires a much stronger evidence base than we currently have. The burden of evidence and the clinical utility should be extremely high, because there is a genuine risk of abuse of diagnoses. We provide suggestions about the level of evidence that might be required: transparent and preregistered studies, a better demarcation of the subject area that includes a rationale for focusing on gaming particularly versus a more general behavioral addictions concept, the exploration of non-addiction approaches, and the unbiased exploration of clinical approaches that treat potentially underlying issues, such as depressive mood or social anxiety first. We acknowledge there could be benefits to formalizing gaming disorder, many of which were highlighted by colleagues in their commentaries, but we think they do not yet outweigh the wider societal and public health risks involved. Given the gravity of diagnostic classification and its wider societal impact, we urge our colleagues at the WHO to err on the side of caution for now and postpone the formalization