Emergent Total Endovascular Arch Repair for Contained Aortic Arch Rupture: Another Tool in the Box.

To date, emergent total endovascular aortic arch repair has not been described in the literature. We present a 67-year-old female with a poorly differentiated posterior mediastinal sarcoma. Imaging obtained was concerning for intravascular extension of the tumor into the thoracic aorta. While awaiting radiation therapy, the patient complained of worsening chest and arm pain, vital signs demonstrating tachypnea and hypoxia. Subsequent imaging revealed an increase in vascular erosion, concerning for a contained rupture, with complete obliteration of the left mainstem bronchus. The patient was emergently taken for percutaneous endovascular repair of her aortic arch. A three-vessel physician modified fenestrated graft was created and deployed with concurrent stenting of the innominate, left carotid, and left subclavian arteries. Interval computed tomography angiography revealed patency in all stented vessels, with no endoleak and no evidence of pseudoaneurysm. The patient was able to undergo chemotherapy with favorable decrease in tumor burden. Total endovascular aortic arch repair, when planned carefully, is an attractive option in high-risk patients who are otherwise not ideally suited for open total arch replacement.

Intravascular ultrasound imaging for diagnosis and characterization of the popliteal compression syndrome.

Objective: Functional popliteal artery entrapment syndrome (fPAES) is a rare form of nonatherosclerotic claudication most often seen in young athletic patients. Diagnosis remains challenging, with various imaging modalities showing equivocal or subtle findings that may be missed. We sought to critically examine and quantitate the utility of intravascular ultrasound (IVUS) imaging, a common diagnostic tool for vascular compression syndromes, in diagnosis and characterization of fPAES. Methods: Patients presenting to a single tertiary care center between 2019 and 2022 with symptoms of PAES but without an anatomic etiology or equivocal workup were selected. Angiogram and IVUS with maneuvers were performed on affected extremities at rest, active plantarflexion/dorsiflexion, and plantarflexion/dorsiflexion against resistance. IVUS examination was recorded using a pull-back technique from the tibial vessels to the superficial femoral artery. The degree, length, and anatomic location of compression using the two imaging modalities were compared. Results: Angiogram and IVUS with maneuvers were performed on 17 lower extremities (9 left, 8 right) in 15 patients (88% female; mean age, 21.2 years). Evidence of arterial compression on angiography was noted in 88.2% (n = 15) of limbs (66.7% complete contrast cessation and 20% popliteal artery tapering); 13.3% (n = 2) only demonstrated sluggish flow as possible evidence of compression. Arterial compression was seen on IVUS imaging in 15 of 17 limbs, and all completely compressed around the IVUS catheter. The IVUS-measured mean length of compression was 10.5 cm ± 4.2 (median, 11 cm; range, 4-23 cm). Compression involved only the popliteal vessels in 86.7% (n = 13); one patient had both popliteal and tibioperoneal trunk compression, whereas another had tibioperoneal trunk and peroneal artery compression. Popliteal vein compression was 100%. The contrast cessation point on angiography and the proximal point of compression on IVUS imaging differed in 80% of cases (P < .05). The distal extent of compression was unable to be determined by angiogram findings but was clearly delineated by IVUS imaging in all cases. Conclusions: IVUS imaging is a more sensitive diagnostic and descriptive imaging modality compared with angiogram in patients with possible fPAES. IVUS and angiogram findings are greatly discordant; moreover, IVUS imaging can provide detailed information such as the precise extent and anatomic location of the arterial compression, which may be useful in aiding surgical planning. IVUS imaging should be considered the gold standard for diagnosing and characterizing fPAES before intervention planning.

Structure and proteomic analysis of the crown-of-thorns starfish (Acanthaster sp.) radial nerve cord.

The nervous system of the Asteroidea (starfish or seastar) consists of radial nerve cords (RNCs) that interconnect with a ring nerve. Despite its relative simplicity, it facilitates the movement of multiple arms and numerous tube feet, as well as regeneration of damaged limbs. Here, we investigated the RNC ultrastructure and its molecular components within the of Pacific crown-of-thorns starfish (COTS; Acanthaster sp.), a well-known coral predator that in high-density outbreaks has major ecological impacts on coral reefs. We describe the presence of an array of unique small bulbous bulbs (40-100 µm diameter) that project from the ectoneural region of the adult RNC. Each comprise large secretory-like cells and prominent cilia. In contrast, juvenile COTS and its congener Acanthaster brevispinus lack these features, both of which are non-corallivorous. Proteomic analysis of the RNC (and isolated neural bulbs) provides the first comprehensive echinoderm protein database for neural tissue, including numerous secreted proteins associated with signalling, transport and defence. The neural bulbs contained several neuropeptides (e.g., bombyxin-type, starfish myorelaxant peptide, secretogranin 7B2-like, Ap15a-like, and ApNp35) and Deleted in Malignant Brain Tumor 1-like proteins. In summary, this study provides a new insight into the novel traits of COTS, a major pest on coral reefs, and a proteomics resource that can be used to develop (bio)control strategies and understand molecular mechanisms of regeneration.

Ruptured Iliac Arteriovenous Fistula Presenting With Thigh Pain and Swelling: Case Report.

The presentation of abdominal arteriovenous fistulas is classically described as a triad of a pulsatile abdominal mass with a bruit, high-output heart failure, and regional venous hypertension with primarily open operative therapy. In the following case, we present the treatment of a patient who arrived with acute right heart failure and renal failure due to an arteriovenous fistula and who was successfully treated with endovascular repair.

Multi-Level Lower Extremity Arterial Revascularization Via Retrograde Pedal Access Under Local Anesthesia in a Patient With Severe Cardiopulmonary Comorbidities: A Case Report.

BACKGROUND: Chronic limb-threatening ischemia is a severe form of peripheral artery disease that leads to high rates of amputation and mortality if left untreated. Bypass surgery and antegrade endovascular revascularization through femoral artery access from either side are accepted as conventional treatment modalities for critical limb ischemia. The retrograde pedal access revascularization is an alternative treatment modality useful in specific clinical scenarios; however, these indications have not been well described in literature. This case report highlights the use of retrograde pedal access approach as primary treatment modality in a patient with an extensive comorbidities precluding general anesthesia nor supine positioning. CASE PRESENTATION: The patient is a 60-year-old female with multiple severe cardiopulmonary comorbidities presenting with dry gangrene of the right great toe. Her comorbidities and inability to tolerate supine positioning precluded her from receiving open surgery, general anesthesia or monitored sedation, or percutaneous femoral access. Rather, the patient underwent ankle block and retrograde endovascular revascularization via dorsalis pedis artery access without post-operative complications. DISCUSSION: The prevalence of comorbidities related to peripheral artery disease is increasing and with it the number of patients who are not optimal candidates for conventional treatment methods for critical limb ischemia. The retrograde pedal access revascularization as initial treatment modality offers these patients an alternative limb salvaging treatment option.

Syntheses and Structures of trans-bis(Alkenylacetylide) Ruthenium Complexes.

A series of ruthenium alkenylacetylide complexes trans-[Ru{C≡CC(=CH2 )R}Cl(dppe)2 ] (R=Ph (1 a), c C4 H3 S (1 b), 4-MeS-C6 H4 (1 c), 3,3-dimethyl-2,3-dihydrobenzo[b]thiophene (DMBT) (1 d)) or trans-[Ru{C≡C-c C6 H9 }Cl(dppe)2 ] (1 e) were allowed to react with the corresponding propargylic alcohol HC≡CC(Me)R(OH) (R=Ph (A), c C4 H3 S (B), 4-MeS-C6 H4 (C), DMBT (D) or HC≡C-c C6 H10 (OH) (E) in the presence of TlBF4 and DBU to presumably give alkenylacetylide/allenylidene intermediates trans-[Ru{C≡CC(=CH2 )R}{C=C=C(Me)}(dppe)2 ]PF6 ([2]PF6 ). These complexes were not isolated but deprotonated to give the isolable bis(alkenylacetylide) complexes trans-[Ru{C≡CC(=CH2 )R}2 (dppe)2 ] (R=Ph (3 a), c C4 H3 S (3 b), 4-MeS-C6 H4 (3 c), DMBT (3 d)) and trans-[Ru{C≡C-c C6 H9 }2 (dppe)2 ] (3 e). Analogous reactions of trans-[Ru(CH3 )2 (dmpe)2 ], featuring the more electron-donating 1,2-bis(dimethylphosphino)ethane (dmpe) ancillary ligands, with the propargylic alcohols A or C and NH4 PF6 in methanol allowed isolation of the intermediate mixed alkenylacetylide/allenylidene complexes trans-[Ru{C≡CC(=CH2 )R}{C=C=C(Me)}(dmpe)2 ]PF6 (R=Ph ([4 a]PF6 ), 4-MeS-C6 H4 ([4 c]PF6 ). Deprotonation of [4 a]PF6 or [4 c]PF6 gave the symmetric bis(alkenylacetylide) complexes trans-[Ru{C≡CC(=CH2 )R}2 (dmpe)2 ] (R=Ph (5 a), 4-MeS-C6 H4 (5 c)), the first of their kind containing the dmpe ancillary ligand sphere. Attempts to isolate bis(allenylidene) complexes [Ru{C=C=C(Me)R}2 (PP)2 ]2+ (PP=dppe, dmpe) from treatment of the bis(alkenylacetylide) species 3 or 5 with HBF4 ⋅ Et2 O were ultimately unsuccessful.

Regional Anaesthesia Alone is Reasonable for Major Lower Extremity Amputation in High Risk Patients and May Initiate a More Efficacious Enhanced Recovery Programme.

OBJECTIVE: Major limb amputations are physiologically stressful and subject patients to peri-operative cardiovascular risk. Up to 90% of major lower extremity amputations (LEAMP) are being performed under general anaesthesia, despite regional anaesthesia being an acceptable option in most cases. Obtaining a better understanding of who would benefit from regional vs. general anaesthesia could reduce complications and help establish best evidence based practice. It was hypothesised that patients undergoing LEAMP with regional anaesthesia would have better post-operative outcomes than patients receiving general anaesthesia. METHODS: This retrospective cohort study used the U.S. Vascular Quality Initiative lower extremity amputation module to identify patients (≥18 years) who underwent LEAMP from 2013 to 2018. Outcomes included 30 day incidence of major adverse cardiac events (MACE) and all cause mortality. Multivariable logistic regression models were used to compute odds ratios (OR) and 95% confidence intervals (CI). Time to death was analysed using standard survival analysis. RESULTS: The final sample included 5 567 patients (median age: 65 years, 67% white, 65% male). Only 719 (13%) of patients received regional anaesthesia. Compared with patients undergoing general anaesthesia, patients in the regional group were older (67 vs. 65 years, p < .001) and more likely to have diabetes (78% vs. 69%; p < .001), end stage renal disease (26% vs. 18%; p < .001), congestive heart failure (33% vs. 27%; p < .01) and coronary artery disease (35% vs. 30%; p < .01). The overall incidence of MACE, death, and MACE or death was 5%, 6%, and 9%, respectively. There was no statistically significant difference by anaesthesia groups for MACE (OR 0.98, 95% CI 0.69-1.39) or mortality (HR 1.03, 95% CI 0.90-1.17). CONCLUSION: There was no difference in outcomes between regional or general anaesthesia techniques in patients undergoing LEAMP, despite the regional group having more comorbidities. Regional anaesthesia may be under used for high risk patients undergoing LEAMP. Further studies are needed to establish best practices in LEAMP procedures.

Further Evidence for 'Extended' Cumulene Complexes: Derivatives from Reactions with Halide Anions and Water.

Reactions of [Ru{C=C(H)-1,4-C6 H4 C≡CH}(PPh3 )2 Cp]BF4 ([1 a]BF4 ) with hydrohalic acids, HX, results in the formation of [Ru{C≡C-1,4-C6 H4 -C(X)=CH2 }(PPh3 )2 Cp] [X=Cl (2 a-Cl), Br (2 a-Br)], arising from facile Markovnikov addition of halide anions to the putative quinoidal cumulene cation [Ru(=C=C=C6 H4 =C=CH2 )(PPh3 )2 Cp]+ . Similarly, [M{C=C(H)-1,4-C6 H4 -C≡CH}(LL)Cp ]BF4 [M(LL)Cp'=Ru(PPh3 )2 Cp ([1 a]BF4 ); Ru(dppe)Cp* ([1 b]BF4 ); Fe(dppe)Cp ([1 c]BF4 ); Fe(dppe)Cp* ([1 d]BF4 )] react with H+ /H2 O to give the acyl-functionalised phenylacetylide complexes [M{C≡C-1,4-C6 H4 -C(=O)CH3 }(LL)Cp'] (3 a-d) after workup. The Markovnikov addition of the nucleophile to the remote alkyne in the cations [1 a-d]+ is difficult to rationalise from the vinylidene form of the precursor and is much more satisfactorily explained from initial isomerisation to the quinoidal cumulene complexes [M(=C=C=C6 H4 =C=CH2 )(LL)Cp']+ prior to attack at the more exposed, remote quaternary carbon. Thus, whilst representative acetylide complexes [Ru(C≡C-1,4-C6 H4 -C≡CH)(PPh3 )2 Cp] (4 a) and [Ru(C≡C-1,4-C6 H4 -C≡CH)(dppe)Cp*] (4 b) reacted with the relatively small electrophiles [CN]+ and [C7 H7 ]+ at the ß-carbon to give the expected vinylidene complexes, the bulky trityl ([CPh3 ]+ ) electrophile reacted with [M(C≡C-1,4-C6 H4 -C≡CH)(LL)Cp'] [M(LL)Cp'=Ru(PPh3 )2 Cp (4 a); Ru(dppe)Cp* (4 b); Fe(dppe)Cp (4 c); Fe(dppe)Cp* (4 d)] at the more exposed remote end of the carbon-rich ligand to give the putative quinoidal cumulene complexes [M{C=C=C6 H4 =C=C(H)CPh3 }(LL)Cp']+ , which were isolated as the water adducts [M{C≡C-1,4-C6 H4 -C(=O)CH2 CPh3 }(LL)Cp'] (6 a-d). Evincing the scope of the formation of such extended cumulenes from ethynyl-substituted arylvinylene precursors, the rather reactive half-sandwich (5-ethynyl-2-thienyl)vinylidene complexes [M{C=C(H)-2,5-c C4 H2 S-C≡CH}(LL)Cp']BF4 ([7 a-d]BF4 add water readily to give [M{C≡C-2,5-c C4 H2 S-C(=O)CH3 }(LL)Cp'] (8 a-d)].

Differences in Small Molecule Neurotransmitter Profiles From the Crown-of-Thorns Seastar Radial Nerve Revealed Between Sexes and Following Food-Deprivation.

Neurotransmitters serve as chemical mediators of cell communication, and are known to have important roles in regulating numerous physiological and metabolic events in eumetazoans. The Crown-of-Thorns Seastar (COTS) is an asteroid echinoderm that has been the focus of numerous ecological studies due to its negative impact on coral reefs when in large numbers. Research devoted to its neural signaling, from basic anatomy to the key small neurotransmitters, would expand our current understanding of neural-driven biological processes, such as growth and reproduction, and offers a new approach to exploring the propensity for COTS population explosions and subsequent collapse. In this study we investigated the metabolomic profiles of small molecule neurotransmitters in the COTS radial nerve cord. Multivariate analysis shows differential abundance of small molecule neurotransmitters in male and female COTS, and in food-deprived individuals with significant differences between sexes in gamma-aminobutyric acid (GABA), histamine and serotonin, and significant differences in histamine and serotonin between satiation states. Annotation established that the majority of biosynthesis enzyme genes are present in the COTS genome. The spatial distribution of GABA, histamine and serotonin in the radial nerve cord was subsequently confirmed by immunolocalization; serotonin is most prominent within the ectoneural regions, including unique neural bulbs, while GABA and histamine localize primarily within neuropil fibers. Glutamic acid, which was also found in high relative abundance and is a precursor of GABA, is known as a spawning inhibitor in seastars, and as such was tested for inhibition of ovulation ex-vivo which resulted in complete inhibition of oocyte maturation and ovulation induced by 1-Methyladenine. These findings not only advance our knowledge of echinoderm neural signaling processes but also identify potential targets for developing novel approaches for COTS biocontrol.

Chemical Ecology of Chemosensation in Asteroidea: Insights Towards Management Strategies of Pest Species.

Within the Phylum Echinodermata, the class Asteroidea, commonly known as starfish and sea stars, encompasses a large number of benthos inhabiting genera and species with various feeding modalities including herbivores, carnivores, omnivores and detritivores. The Asteroidea rely on chemosensation throughout their life histories including hunting prey, avoiding or deterring predators, in the formation of spawning aggregations, synchronizing gamete release and targeting appropriate locations for larval settlement. The identities of many of the chemical stimuli that mediate these physiological and behavioural processes remain unresolved even though evidence indicates they play pivotal roles in the functionality of benthic communities. Aspects of chemosensation, as well as putative chemically-mediated behaviours and the molecular mechanisms of chemoreception, within the Asteroidea are reviewed here, with particular reference to the coral reef pest the Crown-of-Thorns starfish Acanthaster planci species complex, in the context of mitigation of population outbreaks.

Assessing Interest and Barriers for Resident and Faculty Involvement in Global Surgery.

BACKGROUND: Multiple institutions have developed international electives and sustainable global surgery initiatives to facilitate clinical, research, and outreach opportunities with hospitals in resource-poor areas. Despite increasing interest among programs, many institutions have not successfully reached potential involvement. OBJECTIVE: This study evaluates the experiences of Yale residents and faculty, measures interest in the development of an international surgical elective, and enumerates barriers to developing or participating in these opportunities. This was performed to develop a formalized elective and assess interest and capacity for surgical global health initiatives, as a seemingly increasing number of trainee applicants and residents were expressing interest in working in resource-poor settings. METHODS: Electronic survey of Yale Surgery residents and faculty analyzed using SPSS and Graphpad Prism. RESULTS: Among residents, previous global experience correlates with current interest in international opportunities, with 100% remaining interested, and 78% of those without prior experience also expressing interest (p = 0.018). Barriers to pursuing these activities included the use of vacation time, funding, scheduling, family obligations, and concern for personal safety. Among faculty, 28% of respondents have been involved internationally, and most (86%) expressed interest in additional opportunities and all were willing to take residents. Barriers to faculty participation included funding, relative value unit target reduction, protected time, and the desire for institutional support for such activities. CONCLUSIONS: A substantial proportion of residents and faculty have experience in global health and motivation to pursue additional opportunities. The main barriers to participation are not a lack of interest, but rather needs for funding support, protected time, and institutional recognition of academic contributions. These findings are being used to develop a global surgery elective and establish long-term partnerships with international colleagues.

The neuropeptidome of the Crown-of-Thorns Starfish, Acanthaster planci.

Outbreaks of Crown-of-Thorns Starfish (COTS; Acanthaster planci) are a major cause of destruction of coral communities on the Australian Great Barrier Reef. While factors relating to population explosions and the social interactions of COTS have been well studied, little is known about the neural mechanisms underlying COTS physiology and behaviour. One of the major classes of chemical messengers that regulate physiological and behavioural processes in animals is the neuropeptides. Here, we have analysed COTS genome and transcriptome sequence data to identify neuropeptide precursor proteins in this species. A total of 48 neuropeptide precursors were identified, including homologs of neuropeptides that are evolutionarily conserved throughout the Bilateria, and others that are novel. Proteomic mass spectrometry was employed to confirm the presence of neuropeptides in extracts of radial nerve cords. These transcriptomic and proteomic resources provide a foundation for functional studies that will enable a better understanding of COTS physiology and behaviour, and may facilitate development of novel population biocontrol methods. SIGNIFICANCE: The Crown-of-Thorns Starfish (COTS) is one of the primary factors leading to coral loss on the Great Barrier Reef, Australia. Our combined gene and proteomic findings of this study reveal the COTS neuropeptidome, including both echinoderm-like neuropeptides and novel putative neuropeptides. This represents the most comprehensive neuropeptidome for an echinoderm, contributing to the evolving knowledge of the COTS molecular neurobiology that may assist towards the development of biocontrol methods.

Identification of putative olfactory G-protein coupled receptors in Crown-of-Thorns starfish, Acanthaster planci.

BACKGROUND: In marine organisms, and in particular for benthic invertebrates including echinoderms, olfaction is a dominant sense with chemosensation being a critical signalling process. Until recently natural product chemistry was the primary investigative approach to elucidate the nature of chemical signals but advances in genomics and transcriptomics over the last decade have facilitated breakthroughs in understanding not only the chemistry but also the molecular mechanisms underpinning chemosensation in aquatic environments. Integration of these approaches has the potential to reveal the fundamental elements influencing community structure of benthic ecosystems as chemical signalling modulates intra- and inter-species interactions. Such knowledge also offers avenues for potential development of novel biological control methods for pest species such as the predatory Crown-of-Thorns starfish (COTS), Acanthaster planci which are the primary biological cause of coral cover loss in the Indo-Pacific. RESULTS: In this study, we have analysed the COTS sensory organs through histological and electron microscopy. We then investigated key elements of the COTS molecular olfactory toolkit, the putative olfactory rhodopsin-like G protein-protein receptors (GPCRs) within its genome and olfactory organ transcriptomes. Many of the identified Acanthaster planci olfactory receptors (ApORs) genes were found to cluster within the COTS genome, indicating rapid evolution and replication from an ancestral olfactory GPCR sequence. Tube feet and terminal sensory tentacles contain the highest proportion of ApORs. In situ hybridisation confirmed the presence of four ApORs, ApOR15, 18, 25 and 43 within COTS sensory organs, however expression of these genes was not specific to the adhesive epidermis, but also within the nerve plexus of tube feet stems and within the myomesothelium. G alpha subunit proteins were also identified in the sensory organs, and we report the spatial localisation of Gαi within the tube foot and sensory tentacle. CONCLUSIONS: We have identified putative COTS olfactory receptors that localise to sensory organs. These results provide a basis for future studies that may enable the development of a biological control not only for COTS, but also other native pest or invasive starfish.

CD44 Promotes Inflammation and Extracellular Matrix Production During Arteriovenous Fistula Maturation.

OBJECTIVE: Arteriovenous fistulae (AVF) remain the optimal conduit for hemodialysis access but continue to demonstrate poor patency and poor rates of maturation. We hypothesized that CD44, a widely expressed cellular adhesion molecule that serves as a major receptor for extracellular matrix components, promotes wall thickening and extracellular matrix deposition during AVF maturation. APPROACH AND RESULTS: AVF were created via needle puncture in wild-type C57BL/6J and CD44 knockout mice. CD44 mRNA and protein expression was increased in wild-type AVF. CD44 knockout mice showed no increase in AVF wall thickness (8.9 versus 26.8 µm; P=0.0114), collagen density, and hyaluronic acid density, but similar elastin density when compared with control AVF. CD44 knockout mice also showed no increase in vascular cell adhesion molecule-1 expression, intercellular adhesion molecule-1 expression, and monocyte chemoattractant protein-1 expression in the AVF compared with controls; there were also no increased M2 macrophage markers (transglutaminase-2: 81.5-fold, P=0.0015; interleukin-10: 7.6-fold, P=0.0450) in CD44 knockout mice. Delivery of monocyte chemoattractant protein-1 to CD44 knockout mice rescued the phenotype with thicker AVF walls (27.2 versus 14.7 µm; P=0.0306), increased collagen density (2.4-fold; P=0.0432), and increased number of M2 macrophages (2.1-fold; P=0.0335). CONCLUSIONS: CD44 promotes accumulation of M2 macrophages, extracellular matrix deposition, and wall thickening during AVF maturation. These data show the association of M2 macrophages with wall thickening during AVF maturation and suggest that enhancing CD44 activity may be a strategy to increase AVF maturation.

The crown-of-thorns starfish genome as a guide for biocontrol of this coral reef pest.

The crown-of-thorns starfish (COTS, the Acanthaster planci species group) is a highly fecund predator of reef-building corals throughout the Indo-Pacific region. COTS population outbreaks cause substantial loss of coral cover, diminishing the integrity and resilience of reef ecosystems. Here we sequenced genomes of COTS from the Great Barrier Reef, Australia and Okinawa, Japan to identify gene products that underlie species-specific communication and could potentially be used in biocontrol strategies. We focused on water-borne chemical plumes released from aggregating COTS, which make the normally sedentary starfish become highly active. Peptide sequences detected in these plumes by mass spectrometry are encoded in the COTS genome and expressed in external tissues. The exoproteome released by aggregating COTS consists largely of signalling factors and hydrolytic enzymes, and includes an expanded and rapidly evolving set of starfish-specific ependymin-related proteins. These secreted proteins may be detected by members of a large family of olfactory-receptor-like G-protein-coupled receptors that are expressed externally, sometimes in a sex-specific manner. This study provides insights into COTS-specific communication that may guide the generation of peptide mimetics for use on reefs with COTS outbreaks.

Increased Oxidative Stress and Hypoxia Inducible Factor-1 Expression during Arteriovenous Fistula Maturation.

BACKGROUND: The poor clinical results that are frequently reported for arteriovenous fistulae (AVF) for hemodialysis are typically due to failure of AVF maturation. We hypothesized that early AVF maturation is associated with generation of reactive oxygen species and activation of the hypoxia-inducible factor-1 (HIF-1) pathway, potentially promoting neointimal hyperplasia. We tested this hypothesis using a previously reported mouse AVF model that recapitulates human AVF maturation. METHODS: Aortocaval fistulae were created in C57Bl/6 mice and compared with sham-operated mice. AVFs or inferior vena cavas were analyzed using a microarray, Amplex Red for extracellular H2O2, quantitative polymerase chain reaction, immunohistochemistry, and immunoblotting for HIF-1α and immunofluorescence for NOX-2, nitrotyrosine, heme oxygenase-1 (HO-1), and vascular endothelial growth factor (VEGF)-A. RESULTS: Oxidative stress was higher in AVF than that in control veins, with more H2O2 (P = 0.007) and enhanced nitrotyrosine immunostaining (P = 0.005). Immunohistochemistry and immunoblot showed increased HIF-1α immunoreactivity in the AVF endothelium; HIF-1 targets NOX-2, HO-1 and VEGF-A were overexpressed in the AVF (P < 0.01). AVF expressed increased numbers of HIF-1α (P < 0.0001) and HO-1 (P < 0.0001) messenger RNA transcripts. CONCLUSIONS: Oxidative stress increases in mouse AVF during early maturation, with increased expression of HIF-1α and its target genes NOX-2, HO-1, and VEGF-A. These results suggest that clinical strategies to improve AVF maturation could target the HIF-1 pathway.

Crown-of-thorns starfish have true image forming vision.

BACKGROUND: Photoreceptors have evolved numerous times giving organisms the ability to detect light and respond to specific visual stimuli. Studies into the visual abilities of the Asteroidea (Echinodermata) have recently shown that species within this class have a more developed visual sense than previously thought and it has been demonstrated that starfish use visual information for orientation within their habitat. Whereas image forming eyes have been suggested for starfish, direct experimental proof of true spatial vision has not yet been obtained. RESULTS: The behavioural response of the coral reef inhabiting crown-of-thorns starfish (Acanthaster planci) was tested in controlled aquarium experiments using an array of stimuli to examine their visual performance. We presented starfish with various black-and-white shapes against a mid-intensity grey background, designed such that the animals would need to possess true spatial vision to detect these shapes. Starfish responded to black-and-white rectangles, but no directional response was found to black-and-white circles, despite equal areas of black and white. Additionally, we confirmed that starfish were attracted to black circles on a white background when the visual angle is larger than 14°. When changing the grey tone of the largest circle from black to white, we found responses to contrasts of 0.5 and up. The starfish were attracted to the dark area's of the visual stimuli and were found to be both attracted and repelled by the visual targets. CONCLUSIONS: For crown-of-thorns starfish, visual cues are essential for close range orientation towards objects, such as coral boulders, in the wild. These visually guided behaviours can be replicated in aquarium conditions. Our observation that crown-of-thorns starfish respond to black-and-white shapes on a mid-intensity grey background is the first direct proof of true spatial vision in starfish and in the phylum Echinodermata.

DNA barcoding the phyllosoma of Scyllarides squammosus (H. Milne Edwards, 1837) (Decapoda: Achelata: Scyllaridae).

Scyllarides has the largest number of species with commercial importance within the Scyllaridae family. As for other achelate lobsters, however, little is known of the unique long-lived planktonic phyllosoma stages of any of these tropical and temperate species. Recently, a large and diverse collection of Scyllaridae phyllosoma, compiled from cruises along the Coral Sea and spanning several years, has been analysed. Molecular evidence from DNA-barcoding and phylogenetic analyses is provided here on the identity of S. squammosus phyllosoma larvae, including stages that were previously undescribed or poorly known. As a consequence, the growth and morphological changes that occur during the mid- to late-stages of S. squammosus larval development is now well-documented. Furthermore, an additional collection of S. squammosus larvae, described by Alain Michel and thought to be no longer extant, were discovered in the crustacean collection of the Muséum national d'Histoire naturelle, Paris. This new molecular and morphological information is complemented by a review of the literature. As a result, descriptions of key larval characters by a number of authors were evaluated and appear to suggest the existence of distinct groups of larvae within Scyllarides. From a combination of adult and larval morphology, and molecular data, the results presented here revealed inconsistencies with regard to the affinities of species assigned to Scyllarides. This new evidence will contribute to future studies addressing the phylogenetic relationships within the genus.