The induction of heme oxygenase 1 decreases contractility in human internal thoracic artery and radial artery grafts

ObjectiveSpasm remains a potential problem encountered during the use of arterial grafts in coronary artery bypass surgery. Heme oxygenase plays a role in the control of arterial vasoreactivity. Heme oxygenase exists in 2 constitutive isoforms (heme oxygenase 2 and 3) and an inducible isoform (heme oxygenase 1). The aim of our study was to induce heme oxygenase 1 by using hemin in human internal thoracic and radial arteries and to evaluate the effect of this induction on the contractility of these arterial grafts.MethodsSegments of human arterial grafts obtained from patients undergoing isolated coronary artery bypass surgery were incubated in organ chambers for 4 hours in the presence of 10−4 mol/L hemin. Concentration-response curves to norepinephrine were obtained in control and hemin-treated arterial rings. Heme oxygenase 1 expression was evaluated by using enzyme-linked immunosorbent assays and immunohistochemical staining.ResultsThe contractility of the arterial rings to norepinephrine was significantly reduced after incubation with hemin. Zinc protoporphyrin (an inhibitor of heme oxygenase) reversed the effect of hemin, whereas the inhibitor of nitric oxide synthase had no effect. The inhibitor of soluble guanylate cyclase blocked the decrease in contractility induced by hemin. Immunohistochemical staining revealed a large expression of heme oxygenase 1 in all vascular layers of hemin-treated internal thoracic artery and radial artery rings. Enzyme-linked immunosorbent assay studies showed a significant increase in heme oxygenase 1 levels in hemin-treated internal thoracic artery and radial artery rings.ConclusionHemin caused in vitro induction of heme oxygenase 1 in human internal thoracic artery and radial artery grafts. This induction resulted in a reduced contractility to norepinephrine, partially through the cyclic guanosine monophosphate–dependent pathway. This effect was independent from nitric oxide synthesis

The influence of structure on reactivity in alkene metathesis

Abstract Alkene metathesis has grown from a niche technique to a common component of the synthetic organic chemistry toolbox, driven in part by the development of more active catalyst systems, or those optimized for particular purposes. While the range of synthetic chemistry achieved has been exciting, the effects of structure on reactivity have not always been particularly clear, and rarely quantified. Understanding these relationships is important when designing new catalysts, reactions, and syntheses. Here, we examine what is known about the effect of structure on reactivity from two perspectives: the catalyst, and the substrate. The initiation of the precatalyst determines the rate at which active catalyst enters the catalytic cycle; the rate and selectivity of the alkene metathesis reaction is dependent on how the substrate and active catalyst interact. The tools deployed in modern studies of mechanism and structure/activity relationships in alkene metathesis are discussed

Calibration with linear programming and spatio-temporal reconstruction from a network of cameras

Le problème de la stéréovision à partir de caméras multiples calibrées capturant une scène fixe est étudié depuis plusieurs décennies. Les résultats présentés dans le benchmark de stéréovision proposé par Strecha et al., attestent de la qualité des reconstructions obtenues. En particulier, les travaux du laboratoire IMAGINE, mènent à des résultats visuellement impressionnant. Aussi, il devient intéressant de calibrer des scènes de plus en plus vastes, afin d'appliquer ces algorithmes de stéréovision de façon optimale. Trois objectifs essentiels apparaissent : – La précision de la calibration doit être améliorée. En effet comme pointé par Yasutaka Furukawa, même les benchmarks de stéréovision fournissent parfois des caméras bruitées à la précision imparfaite. Un des moyen d'améliorer les résultats de stéréovision est d'augmenter la précision de la calibration. – Il est important de pouvoir prendre en compte les cycles dans le graphe des caméras de façon globale. En effet la plupart des méthodes actuelles sont séquentielles, et dérivent. Ainsi ces méthodes ne garantissent pas, pour une très grande boucle, de retrouver cette configuration cyclique, mais peuvent plutôt retrouver une configuration des caméras en spirale. Comme on calibre des réseaux d'images, de plus en plus grand, ce point est donc crucial. – Pour calibrer des réseaux d'images très grands, il convient d'avoir des algorithmes rapides. Les méthodes de calibration que nous proposons dans la première partie, permettent de calibrer des réseaux avec une précision très proche de l'état de l'art. D'autre part elle permettent de gérer les contraintes de cyclicité par le biais d'optimisations linéaires sous contraintes linéaires. Ainsi ces méthodes permettent de prendre en compte les cycles et bénéficient de la rapidité de la programmation linéaire. Enfin, la recherche en stéréovision étant arrivée à maturité, il convient de s'intéresser à l'étape suivante, à savoir la reconstruction spatio-temporelle. La méthode du laboratoire IMAGINE représentant l'état de l'art en stéréovision, il est intéressant de développer cette méthode et de l'étendre à la reconstruction spatio-temporelle, c'est-à-dire la reconstruction d'une scène dynamique capturée par un dôme de caméras. Nous verrons cette méthode dans la seconde partie de ce manuscritThe issue of retrieving a 3D shape from a static scene captured with multiple view point calibrated cameras has been deeply studied these last decades. Results presented in the stereovision benchmark made by Strecha et al., show the high quality of state of the art methods. Particularly, works from IMAGINE laboratory lead to impressive results. So, it becomes convenient to calibrate wider and wider scenes, in order to apply these stereovision algorithms to large scale scenes. Three main objectives appear : – The calibration accuracy should be improved. As stated by Yasutaka Furukawa, even stereovision benchmarks use noisy cameras. So one obvious way to improve stereovision, is to improve camera calibration. – It is crucial to take cycles into account in cameras graph in a global way. Most of nowadays methods are sequential and so present a drift. So these methods do not offer the guarantee to retrieve the loopy configuration for a loop made of a high number of images, but retrieve a spiral configuration. As we aim to calibrate wider and wider cameras networks, this point becomes quite crucial. – To calibrate wide cameras networks, having quick and linear algorithms can be necessary. Calibration methods we propose in the first part, allow to calibrate with an accuracy close to state of the art. Moreover, we take cyclicity constraints into account in a global way, with linear optimisations under linear constraints. So these methods allow to take cycle into account and benefit from quickness of linear programming. Finally, sterovision being a well studied topic, it is convenient to concentrate on the next step, that is, spatio-temporal reconstruction. The IMAGINE' stereovision method being the state of the art, it is interesting to extend this method to spatio-temporal reconstruction, that is, dynamique scene reconstruction captured from a dome of camera

Calibration par programmation linéaire et reconstruction spatio-temporelle à partir de réseaux d’images

The issue of retrieving a 3D shape from a static scene captured with multiple view point calibrated cameras has been deeply studied these last decades. Results presented in the stereovision benchmark made by Strecha et al., show the high quality of state of the art methods. Particularly, works from IMAGINE laboratory lead to impressive results. So, it becomes convenient to calibrate wider and wider scenes, in order to apply these stereovision algorithms to large scale scenes. Three main objectives appear : – The calibration accuracy should be improved. As stated by Yasutaka Furukawa, even stereovision benchmarks use noisy cameras. So one obvious way to improve stereovision, is to improve camera calibration. – It is crucial to take cycles into account in cameras graph in a global way. Most of nowadays methods are sequential and so present a drift. So these methods do not offer the guarantee to retrieve the loopy configuration for a loop made of a high number of images, but retrieve a spiral configuration. As we aim to calibrate wider and wider cameras networks, this point becomes quite crucial. – To calibrate wide cameras networks, having quick and linear algorithms can be necessary. Calibration methods we propose in the first part, allow to calibrate with an accuracy close to state of the art. Moreover, we take cyclicity constraints into account in a global way, with linear optimisations under linear constraints. So these methods allow to take cycle into account and benefit from quickness of linear programming. Finally, sterovision being a well studied topic, it is convenient to concentrate on the next step, that is, spatio-temporal reconstruction. The IMAGINE' stereovision method being the state of the art, it is interesting to extend this method to spatio-temporal reconstruction, that is, dynamique scene reconstruction captured from a dome of camerasLe problème de la stéréovision à partir de caméras multiples calibrées capturant une scène fixe est étudié depuis plusieurs décennies. Les résultats présentés dans le benchmark de stéréovision proposé par Strecha et al., attestent de la qualité des reconstructions obtenues. En particulier, les travaux du laboratoire IMAGINE, mènent à des résultats visuellement impressionnant. Aussi, il devient intéressant de calibrer des scènes de plus en plus vastes, afin d'appliquer ces algorithmes de stéréovision de façon optimale. Trois objectifs essentiels apparaissent : – La précision de la calibration doit être améliorée. En effet comme pointé par Yasutaka Furukawa, même les benchmarks de stéréovision fournissent parfois des caméras bruitées à la précision imparfaite. Un des moyen d'améliorer les résultats de stéréovision est d'augmenter la précision de la calibration. – Il est important de pouvoir prendre en compte les cycles dans le graphe des caméras de façon globale. En effet la plupart des méthodes actuelles sont séquentielles, et dérivent. Ainsi ces méthodes ne garantissent pas, pour une très grande boucle, de retrouver cette configuration cyclique, mais peuvent plutôt retrouver une configuration des caméras en spirale. Comme on calibre des réseaux d'images, de plus en plus grand, ce point est donc crucial. – Pour calibrer des réseaux d'images très grands, il convient d'avoir des algorithmes rapides. Les méthodes de calibration que nous proposons dans la première partie, permettent de calibrer des réseaux avec une précision très proche de l'état de l'art. D'autre part elle permettent de gérer les contraintes de cyclicité par le biais d'optimisations linéaires sous contraintes linéaires. Ainsi ces méthodes permettent de prendre en compte les cycles et bénéficient de la rapidité de la programmation linéaire. Enfin, la recherche en stéréovision étant arrivée à maturité, il convient de s'intéresser à l'étape suivante, à savoir la reconstruction spatio-temporelle. La méthode du laboratoire IMAGINE représentant l'état de l'art en stéréovision, il est intéressant de développer cette méthode et de l'étendre à la reconstruction spatio-temporelle, c'est-à-dire la reconstruction d'une scène dynamique capturée par un dôme de caméras. Nous verrons cette méthode dans la seconde partie de ce manuscri

Molecular characterization of the penile microbiome of Dorper rams (Ovis aries)

Thesis (MScAgric)--Stellenbosch University, 2017.ENGLISH ABSTRACT: Characterizing the bacterial community inhabiting the penile environment of Dorper rams may provide insight into the aetiology of ulcerative balanoposthitis (UB), a venereal disease of unknown aetiology, which occurs predominantly in this breed, and that is of great economic importance to the mutton industry in South Africa. Profiling of the bacteria present in the penile environment of healthy and diseased rams was carried out previously using culture-based methods. These culture-based studies identified Mycoplasma mycoides mycoides large colony (MMMLC) and Trueperella pyogenes as potentially contributing to the incidence of UB. Although cultured-based methods have been described as the gold standard for identification of bacteria, many bacteria are uncultivable or grow slowly and poorly in-vitro. The advent of high throughput next generation sequencing (HT-NGS), a culture-independent bacterial identification approach, has offered high coverage and depths in determining the bacterial penile community. Thus, this study aimed to characterize and compare the penile bacterial microbiome of Dorper rams that were healthy and diseased by means of 16S amplicon sequencing, a method of HT-NGS. Swab samples of the preputial and penile mucosa were collected from 113 rams, of which 40 Dorper ram samples (20 infected, 20 healthy) were chosen for further analysis in this study. Genomic DNA was extracted and amplified based on the V3V4 hypervariable region of the 16S rRNA bacterial gene. Bioinformatics analysis was performed using UPARSE and the ecological and statistical analyses such as Principal Coordinate Analysis (PCoA) was performed in QIIME and XLSTAT. Additional analyses comparing the predicted bacterial microbiota in healthy and diseased populations was carried out using LEfSe. A total of 789 OTUs from 9 964 842 sequences of high quality were obtained from the healthy and diseased communities indicating a high bacterial diversity in the penile environment, higher than previously reported and isolated using culture-based bacterial identification methods. The genus Corynebacterium was the most dominant genus identified (20.9%), irrespective of health status. A high inter-sample variation in microbiota was revealed. There were no significant differences in bacterial diversity or community composition between the healthy and diseased ram groups. The microbiota population was thus similar, with a few OTUs of high biological relevance belonging to genera Fusobacterium and Porphyromonas, as well as uncharacterized genera within Aerococaceae and Bacteroidales that were enriched in the diseased community. MMMLC and Trueperella pyogenes were not associated with UB in this study, which is contradictory to previous reports. However, a new Mycoplasma species, Mycoplasma hyopharyngis, not previously isolated in sheep and in cases of UB in Dorper rams, was identified and although not significantly different, had a higher abundance in the diseased population. The prevalence and predominance of Corynebacterium across all samples suggests this genus forms part of the core microbiome of the penile environment. High inter-sample variation in microbiota may depict true biological representation, however, future studies using homogenous ram populations (i.e. same type, same age) under the same environmental factors (i.e. management, feeding regime, etc.) should be conducted to validate these findings. Ulcerative balanoposthitis is not caused as a result of a change in bacterial diversity or community composition but OTUs enriched in the diseased ram population may be disease-specific/disease-associated and their role in UB warrants further investigation. No definitive aetiological agent was thus identified but the OTUs enriched in diseased rams can help direct future studies towards the identification of an aetiological agent of UB.AFRIKAANSE OPSOMMING: Die karakterisering van die bakteriële gemeenskap wat die penis skede omgewing van Dorper ramme kan insig oor die etiologie van ulseratiewe balanoposthitis (UB), 'n geslagsiekte van onbekende etiologie wat hoofsaaklik in dié ras voorkom, verskaf. Die siekte is van groot ekonomiese belang vir die skaapvleis bedryf in Suid-Afrika. Vorige studies oor die karakterisering van die bakterieë in die penis skede omgewing van gesonde en siek ramme was gebaseer op kultuur-gebaseerde metodes. Hierdie kultuur-gebaseerde studies het Mycoplasma mycoides mycoides Large Colony (MMMLC) en Trueperella pyogenes as organismes geïdentifiseer wat moontlik bydra tot die voorkoms van UB. Hoewel kultuur-gebaseerde metodes beskryf word as die goue standaard vir die identifisering van bakterieë, kan baie bakterieë nie in vitro gekweek word nie of swak groei word in vitro waargeneem. Die bekendstelling van 'n hoë deurset volgende generasie volgorde bepalingstegniek (HT-NGS), 'n kultuur-onafhanklike benadering, bied ʼn wye dekking asook besonderse diepte waarmee die bakteriële gemeenskap in die penis skede omgewing bepaal kan word. Dié studie was daarop gemik om die bakteriële mikrobioom van die skede omgewing van siek en gesonde Dorper ramme met behulp van 16S amplikon volgordebepaling, ‘n HT-NGS metode, te karakteriseer en te vergelyk. Depper monsters van die voorvel en penis mukosa omgewing is van 113 ramme versamel, waarvan 40 Dorper ram monsters (20 besmet, 20 gesonde) vir verdere analise in hierdie studie gekies is. Die genomiese DNS is geëkstraheer en versterk gebaseer op die V3V4 hiper-variërende streek van die 16S rRNS bakteriële geen. Bio-informatiese analise is met behulp van UPARSE uitgevoer en die ekologiese en statistiese ontledings soos Hoof Koördinaat Ontleding (PCoA) is uitgevoer in QIIME en XLSTAT. Bykomende ontledings wat die voorspelde bakteriële mikrobiota in gesonde en siek bevolkings vergelyk het, is uitgevoer met behulp van LEfSe. 'n Totaal van 789 operasionele taksonomiese eenhede (OTE’e) van 9 964 842 sekwense van 'n hoë gehalte is verkry uit die gesonde en siek gemeenskappe, wat dui op 'n hoë bakteriële diversiteit in die penis omgewing, hoër as wat voorheen berig en geïsoleer was deur kultuur-gebaseerde bakteriële identifikasie metodes. Die genus Corynebacterium was die mees dominante genus geïdentifiseer (20.9%), ongeag die gesondheidstatus van ʼn ram. 'n Hoë inter-monster variasie in mikrobiota is gevind. Daar was geen betekenisvolle verskille in bakteriële diversiteit of gemeenskapsamestelling tussen die gesonde en siek ram groepe nie. Die mikrobiota bevolking was soortgelyk tussen siek en gesonde ramme, met 'n paar OTE’e van 'n hoë biologiese relevansie (d.i. genera Fusobacterium en Porphyromonas, asook nie-gekarakteriseerde genera binne Aerococaceae en Bacteroidales) wat meer volop in die siek was. Die bakterieë MMMLC en Trueperella pyogenes kon nie in dié studie in verband gebring word met die voorkoms van UB nie, wat teenstrydig is met die vorige verslae. ʼn Nuwe mikoplasma spesie, Mycoplasma hyopharyngis, wat nog nie voorheen in skape en gevalle van UB in Dorper ramme geïsoleer is nie, is geïdentifiseer en alhoewel nie betekenisvol nie, het in hoër getalle in die siek ramme voorgekom. Die voorkoms en oorheersing van Corynebacterium in beide die siek en gesonde ramme dui aan dat dié genus deel vorm van die kern mikrobioom van die penis omgewing. Hoë inter-monster variasie in mikrobiota kan normaal wees, maar daar word aanbeveel dat toekomstige studies waar moontlik homogene ram bevolkings (d.w.s. dieselfde ras, ouderdom, ens.) onder dieselfde omgewingsfaktore (bv. bestuur, voeding, ens.) gedoen moet word om hierdie bevindinge te bevestig. Ulseratiewe balanoposthitis word dus nie veroorsaak deur 'n verandering in bakteriële diversiteit of gemeenskap samestelling nie, maar die OTE’s wat meer volop in die siek ramme voorgekom het mag siekte-spesifiek wees of verband hou met UB. Derhalwe moet hierdie organismes se rol in die voorkoms van UB verder ondersoek word. Geen definitiewe etiologiese agent is dus geïdentifiseer nie, maar die OTE’s geïdentifiseer in hierdie studie kan leiding verskaf oor die ontwerp van toekomstige studies vir die identifisering van 'n etiologiese agent van UB