Dorsal Vessel Research Articles

New data on the polyphyletic Marionina genus (Annelida, Enchytraeidae): description of three new species from European shore habitats

Marionina (Michaelsen in Pfeffer, 1890) is a worldwide distributed genus of small enchytraeids living in mainly aquatic habitats. The genus is polyphyletic, including about 100 species with diverse morphological characters and cryptic lineages; therefore, taxonomic revisions were performed recently, and further actions are needed in the future. In our study, Marionina individuals were investigated from decaying seagrass debris collected from seashores in Croatia and Italy using morphological characters and molecular markers involving the COI and H3 genes and the ITS region. Descriptions of two new Marionina species, M. puntaalanensissp. nov. and M. orbiferasp. nov., are presented in this paper, and in addition, the description of a third new Marionina species, M. reichartisp. nov., from the shore of the freshwater Lake Balaton (Hungary) is provided here. All three new species are small (2–3.5 mm in vivo with less than 30 segments), their clitellum is saddle-shaped, the dorsal anterior blood vessel bifurcation is in III, and the spermatheca is attached to the oesophagus. The main diagnostic features of M. puntaalanensissp. nov. are: brain incised posteriorly; dorsal vessel from the clitellar region; two chaetae in all bundles; three pairs of preclitellar nephridia; small subneural glands in XIII–XIV; seminal vesicle absent or small; ectal duct of spermatheca surrounded along the length by glands and one larger. The main features of M. orbiferasp. nov. are: brain truncate posteriorly; dorsal vessel from the clitellar region; two chaetae in all bundles; two pairs of preclitellar nephridia; subneural glands in XIII–XIV; seminal vesicle well developed; the lumen of the spermathecal ampulla is characteristically full with many spherical sperm rolls. In M. reichartisp. nov.: brain incised posteriorly, dorsal vessel origin in XII, maximum five chaetae per bundle, often the middle chaetae slightly smaller than the ental ones, three pairs of preclitellar nephridia, subneural glands absent, spermathecal ampulla globular, ectal duct surrounded along the length by glands, and one large sessile gland at the orifice.

Oscillatory contractile forces refine endothelial cell-cell interactions for continuous lumen formation governed by Heg1/Ccm1.

The formation and organization of complex blood vessel networks rely on various biophysical forces, yet the mechanisms governing endothelial cell-cell interactions under different mechanical inputs are not well understood. Using the dorsal longitudinal anastomotic vessel (DLAV) in zebrafish as a model, we studied the roles of multiple biophysical inputs and cerebral cavernous malformation (CCM)-related genes in angiogenesis. Our research identifies heg1 and krit1 (ccm1) as crucial for the formation of endothelial cell-cell interfaces during anastomosis. In mutants of these genes, cell-cell interfaces are entangled with fragmented apical domains. A Heg1 live reporter demonstrated that Heg1 is dynamically involved in the oscillatory constrictions along cell-cell junctions, whilst a Myosin live reporter indicated that heg1 and krit1 mutants lack actomyosin contractility along these junctions. In wild-type embryos, the oscillatory contractile forces at junctions refine endothelial cell-cell interactions by straightening junctions and eliminating excessive cell-cell interfaces. Conversely, in the absence of junctional contractility, the cell-cell interfaces become entangled and prone to collapse in both mutants, preventing the formation of a continuous luminal space. By restoring junctional contractility via optogenetic activation of RhoA, contorted junctions are straightened and disentangled. Additionally, haemodynamic forces complement actomyosin contractile forces in resolving entangled cell-cell interfaces in both wild-type and mutant embryos. Overall, our study reveals that oscillatory contractile forces governed by Heg1 and Krit1 are essential for maintaining proper endothelial cell-cell interfaces and thus for the formation of a continuous luminal space, which is essential to generate a functional vasculature.

A safe zone of dorsal scaphoid approach: an anatomic study of proximal dorsal vessel foramina.

The dorsal approach to the scaphoid carries a risk of injuring its nutrient vessels. This cadaveric study identified a safe zone dorsally, which extends from the proximal pole to 11.3 mm distally along the scaphoid axis.Level of evidence: Level V.

How to give a spider a heart attack: Evaluating cardiac stress reactions of Trichonephila and Argiope spiders

AbstractAll animal species, from arthropods to vertebrates, must deal with occasional stressors in their lives, though most research on this has been focused on vertebrates. Meanwhile, our understanding of stress reactions in arthropod species like spiders is nascent. In the United States, a non‐native orb‐weaving spider, Trichonephila clavata (‘jorō’ spider), is spreading as is its already‐established cousin in the United States, T. clavipes (golden silk spider). Prior study has revealed how these two species have a unique behavioural reaction to physical stressors, whereby they remain in a thanatosis state for a prolonged period compared with other species. Here, we investigate the physiological stress reactions of these Trichonephila spiders by evaluating how each species' dorsal vessel contractions (heart rates) become elevated after being subjected to a non‐lethal stressor. For comparison, we also evaluate two similarly‐sized orb weavers, Argiope aurantia (garden spider) and A. trifasciata (banded garden spider). We record baseline heart rates of inactive, resting, spiders in our lab, then restrain them under an electronic, ‘optocardiographic’, sensor for 10 min, to record their ‘stressed’ heart rates. Argiope aurantia has a pronounced heart rate elevation, for reasons unknown. We observe that all spider heart rates increase during restraint, though each has a species‐specific pattern of elevation over time under restraint. Notably, heart rates of both Trichonephila spiders are less variable under stress, since they tend not to struggle during restraint. Meanwhile, both Argiope spiders frequently struggle, leading to marked fluctuations in cardiac output. The stress reactions of Trichonephila spiders could be characterized as ‘even‐tempered’, which may factor into their ability to live in habitats with frequent disturbances.

Mechanisms controlling haemolymph circulation under resting conditions in the Chagas disease vector Rhodnius prolixus.

Chagas disease vectors can ingest several times their own volume in blood with each meal. This ad libitum feeding causes an intense process of diuresis, inducing the insect to eliminate a large quantity of urine and faeces. To ensure diuresis, the speed of circulation of the haemolymph is increased. The Triatominae circulatory system is quite simple, including the dorsal vessel, which pumps haemolymph in an anterograde direction. The return is caused by peristaltic contractions of the anterior midgut. Triatominae insects can spend several weeks without feeding, meaning that most of the time, the insect is in a resting condition. Although the mechanisms controlling the circulation of the haemolymph during post-prandial diuresis have been largely analysed, the mechanisms controlling it during resting conditions are poorly understood. In this study, we analysed several canonical pathways (i.e. L-type VGCC, GPCR, RyR, IP3R) and a novel system represented by the recently characterized Piezo proteins. Our results show that during the resting condition, haemolymph circulation depends on a cross-talk between myogenic activity, inhibitory and stimulatory cellular messengers, and Piezo proteins. This report also unveils for the first time the existence of a putative Piezo protein in Hemiptera.

Organization of the blood system of rhynchonellid brachiopod Hemithiris psittacea (Brachiopoda: Rhynchonelliformea).

The brachiopods are sessile invertebrates with an unusual blood system, which consists of a long-branched dorsal vessel. It is still unknown how blood circulates in this system. In the present study, for the first time we propose the circulation of blood in brachiopod Hemithiris psittacea based on morphological and experimental data. The main heart is located on the dorsal side of the stomach and divides the dorsal vessel into anterior and posterior parts. The anterior part enters the lophophore, where it gives off blind branches to each tentacle. The posterior part passes by the funnels of the nephridia and forms a blindly closed network in the gonads. We suggest that the circulation of blood includes three successive stages. During the first phase of systole of the main heart, blood flows through the anterior dorsal vessel. During the second phase of systole, blood flows through the posterior dorsal vessel. During diastole, blood flows from the anterior and posterior vessels and fills the main heart. The origin of a peculiar blood system in brachiopods can be explained by reduction of the ventral vessel, which is probably correlates with the reduction of the ventral side of the brachiopod ancestor's body. Another peculiarity of brachiopod blood system is the presence of an ampullar heart, which functions as a blood depot and allows blood to move in the vessels in two directions in an oscillatory mode. The brachiopod blood system contains vessels lacking true endothelium and can be classified as an "incompletely closed" type.

Is Galleria mellonella model a good alternative to study virulence in Staphylococcus aureus from bovine mastitis?

Staphylococcus aureus is one of the agents of bovine mastitis of hardest control due to a complex pathogenesis comprising a variety of virulence factors, which ensures its persistence in the mammary gland, causing significant health and economic losses. Therefore, understanding the pathogenesis of this agent is imperative. Galleria mellonella has stood out as an invertebrate animal model for the study of infectious diseases that affect several hosts. This work aimed to evaluate G. mellonella larvae as an experimental model for the study of virulence phenotypes in an S. aureus population isolated from bovine mastitis. Thirty genetically divergent S. aureus strains were chosen based on PFGE analysis. After experimental infection, larvae survival rates, bacterial growth in hemolymph, melanization intensity of the dorsal vessel, and histological characteristics of the infected tissues were evaluated. The G. mellonella model showed a clear diversity in the S. aureus pathogenicity pattern, allowing the differentiation of strains with virulence phenotypes ranging from high to low degrees. Histological analysis confirmed that the strains tested were capable of inducing the formation of nodules and melanization spots in the dorsal vessels of the larvae in different magnitudes. The strains 16S-717, 19C-828, and 31S-1443 presented the highest virulence intensity among the bacteria tested and will be used further for the generation of S. aureus mutant populations to prospect genetic targets aimed to develop control strategies of bovine mastitis. Altogether, our results suggest that G. mellonella is an attractive and low-cost animal model for characterizing virulence phenotypes of large S. aureus populations.

Toxicity of environmentally relevant concentration of PFAS chemicals in Lumbriculus variegatus (Oligochaeta, Lumbriculidae) – A multi-bioindicator study

PFAS, or per- and polyfluoroalkyl substances, are a family of man-made chemicals found in a variety of products from non-stick cookware and food wrappers to firefighting foams. PFAS are persistent and widely distributed in the environment, including aquatic environments. In this study we examined the impact of PFAS chemicals on the physiological and behavioral endpoints of Lumbriculus variegatus (i.e., blackworms). Lumbriculus variegatus is a species of freshwater annelid worm that plays key roles in shallow freshwater ecosystems. At an environmentally relevant concentration of 1 μg/L, 12-day aqueous exposure to long chain PFAS, including PFOA, PFOS and PFDA, each markedly slowed the pulse rate of the dorsal blood vessel in L. variegatus, indicating a suppressive effect on blood circulation. The mean pulse rate was reduced from 9.6 beats/minute to 6.2 and 7.0 beats/min in PFOA and PFOS, respectively (P < 0.0001). Further, PFOA, PFOS and PFDA reduced the escape responsiveness of L. variegatus to physical stimulation. The percentage of worms showing normal escape behavior was reduced from 99.0% in control to 90.6% in the PFOS exposed group (P < 0.01). In a chronic (4 week) growth study, exposure to overlying water and sediment spiked with PFOA, PFOS or PFDA reduced the total biomass and the number of worms, indicating a suppressive effect on worm population growth. For instance, PFOA and PFDA reduced the total dry biomass by 26.3% and 28.5%, respectively, compared to the control (P < 0.05). The impact of PFAS on blackworm physiology is accompanied by an increase in lipid peroxidation. The level of malondialdehyde (MDA), an indicator of lipid peroxidation, and catalase, a major antioxidant enzyme, were markedly increased in PFOA, PFOS and PFDA exposed groups. Interestingly, exposure to PFHxA, a short chain PFAS, had no detectable effect on any of the measured endpoints. Our results demonstrate that L. variegatus is highly sensitive to the toxic impact of long chain PFAS chemicals as measured by multiple endpoints including blood circulation, behavior, and population growth. Such toxicity may have a detrimental impact on L. variegatus and the freshwater ecosystems where it resides.

Allatotropic peptides modulate muscle contraction of the female reproductive system in Rhodnius prolixus (STÄL)

Allatotropin (AT) acts as a myoregulator at the level of the dorsal vessel (DV) and midgut (MG) in triatominae insects. Previous analyses of the expression of the AT receptor in Rhodnius prolixus showed that AT is expressed in the DV and MG, but also in the reproductive system in females. To further study the activity of AT on female reproductive organs we analyzed the response by adult females in different physiological conditions, including unfed (virgin and mated), and fed mated females (gravid), to doses ranging between 10-14 and 10-6M. Myoregulatory activity was evaluated in vivo, by recording independently the frequency of contractions of each organ after treatment. The results show that the effect of AT varies depending on the organs and on the physiological state of the female. Whilst unfed virgin females did not show response to the peptide for neither of the applied doses, the ovaries showed a differential response, presenting the highest frequency of contractions in gravid individuals. An increase in the frequency of contractions of the oviducts was only observed in mated females. Uterus and spermathecae responded in both gravid and mated females, with maximum activity in the latter. In the bursa, responses were only detected in gravid females. The differential response of the organs seems to be associated to particular moments along the reproductive cycle, such as with the spermathecae that reacted to AT in both unfed mated and gravid females, when the movement of spermatozoids is physiologically crucial. Testes and accessory glands of the male, expressed the mRNA of AT precursor, suggesting that the male would modulate the contractile behavior of the female reproductive system after copula. The ovaries also expressed AT mRNA suggesting the existence of a paracrine/autocrine system modulating muscle contraction.

Early destruction of cockroach respiratory system and heart by emerald jewel wasp larvae

In the 1880s, Henri Fabre was captivated by the "special art of eating", whereby a parasitoid wasp larva fed selectively on host internal organs, avoiding the heart (dorsal vessel) and tracheal system (respiratory system) to preserve life. In Fabre's words: "The ruling feature in this scientific method of eating, which proceeds from parts less to the parts more necessary to preserve a remnant of life, is none the less obvious"1. Subsequent investigators have reported the same for many parasitoid wasps2,3, including for the emerald jewel wasp (Ampulex compressa)4. Here it is reported that larval jewel wasps destroy the dorsal vessel and tracheae (respiratory system) in the thorax of their cockroach host (Periplaneta americana) at their earliest opportunity. Moreover, the broken tracheae release air into the host, which the larval jewel wasp inspires. An increase in larval chewing rate, cotemporaneous with the sudden release of air from the host's broken tracheae, suggests the larva taps into the host respiratory system to support its metabolism while rapidly consuming the host. VIDEO ABSTRACT.

A Comparative Analysis of RNAi Trigger Uptake and Distribution in Mosquito Vectors of Disease.

In mosquitoes, the utilization of RNAi for functional genetics is widespread, usually mediated through introduced double-stranded RNAs (dsRNAs) with sequence identity to a gene of interest. However, RNAi in mosquitoes is often hampered by inconsistencies in target gene knockdown between experimental setups. While the core RNAi pathway is known to function in most mosquito strains, the uptake and biodistribution of dsRNAs across different mosquito species and life stages have yet to be extensively explored as a source of variation in RNAi experiments. To better understand mosquito-RNAi dynamics, the biodistribution of a dsRNA to a heterologous gene, LacZ (iLacZ), was tracked following various routes of exposure in the larval and adult stages of Aedes aegypti, Anopheles gambiae, and Culex pipiens. iLacZ was largely limited to the gut lumen when exposed per os, or to the cuticle when topically applied, but spread through the hemocoel when injected. Uptake of dsRNA was noted in a subset of cells including: hemocytes, pericardial cells of the dorsal vessel, ovarian follicles, and ganglia of the ventral nerve cord. These cell types are all known to undergo phagocytosis, pinocytosis, or both, and as such may actively take up RNAi triggers. In Ae. aegypti, iLacZ was detected for up to one week post exposure by Northern blotting, but uptake and degradation drastically differed across tissues. The results presented here reveal that the uptake of RNAi triggers is distinct and specific to the cell type in vivo.

Svep1 is a binding ligand of Tie1 and affects specific aspects of facial lymphatic development in a Vegfc-independent manner

Multiple factors are required to form functional lymphatic vessels. Here, we uncover an essential role for the secreted protein Svep1 and the transmembrane receptor Tie1 during the development of subpopulations of the zebrafish facial lymphatic network. This specific aspect of the facial network forms independently of Vascular endothelial growth factor C (Vegfc) signalling, which otherwise is the most prominent signalling axis in all other lymphatic beds. Additionally, we find that multiple specific and newly uncovered phenotypic hallmarks of svep1 mutants are also present in tie1, but not in tie2 or vegfc mutants. These phenotypes are observed in the lymphatic vasculature of both head and trunk, as well as in the development of the dorsal longitudinal anastomotic vessel under reduced flow conditions. Therefore, our study demonstrates an important function for Tie1 signalling during lymphangiogenesis as well as blood vessel development in zebrafish. Furthermore, we show genetic interaction between svep1 and tie1 in vivo, during early steps of lymphangiogenesis, and demonstrate that zebrafish as well as human Svep1/SVEP1 protein bind to the respective Tie1/TIE1 receptors in vitro. Since compound heterozygous mutations for SVEP1 and TIE2 have recently been reported in human glaucoma patients, our data have clinical relevance in demonstrating a role for SVEP1 in TIE signalling in an in vivo setting.

Complex hemolymph circulation patterns in grasshopper wings

An insect’s living systems—circulation, respiration, and a branching nervous system—extend from the body into the wing. Wing hemolymph circulation is critical for hydrating tissues and supplying nutrients to living systems such as sensory organs across the wing. Despite the critical role of hemolymph circulation in maintaining healthy wing function, wings are often considered “lifeless” cuticle, and flows remain largely unquantified. High-speed fluorescent microscopy and particle tracking of hemolymph in the wings and body of the grasshopper Schistocerca americana revealed dynamic flow in every vein of the fore- and hindwings. The global system forms a circuit, but local flow behavior is complex, exhibiting three distinct types: pulsatile, aperiodic, and “leaky” flow. Thoracic wing hearts pull hemolymph from the wing at slower frequencies than the dorsal vessel; however, the velocity of returning hemolymph (in the hindwing) is faster than in that of the dorsal vessel. To characterize the wing’s internal flow mechanics, we mapped dimensionless flow parameters across the wings, revealing viscous flow regimes. Wings sustain ecologically important insect behaviors such as pollination and migration. Analysis of the wing circulatory system provides a template for future studies investigating the critical hemodynamics necessary to sustaining wing health and insect flight.

A new species of Enchytraeus (Enchytraeidae, Clitellata) from sewage sludge of a plum processing plant in Japan.

Enchytraeus ohtakai sp. nov. (Enchytraeidae, Clitellata, Oligochaeta) was discovered in the organic matter of a wastewater treatment facility of a plums processing plant in Honshu, Japan. The wastewater is characterized by high organic matter content and low salt concentration. Morphological analysis and DNA-sequencing of a fragment of the COI barcoding gene show that the new species belongs to the E. albidus species group. Within this group it differs in: vasa deferentia restricted to XII, preclitellar bundles with mostly three chaetae, postclitellar bundles with two or three, dorsal blood vessel from XII or XIII, spermathecal ectal duct completely glandular. spermatheca with a large diverticulum, accessory sexual glands present in XII, clitellum ventrally almost absent. The individual gene trees of COI analysis recovered this new species as a monophyletic group within the genus Enchytraeus, closely related to E. albidus species group.

The ant abdomen: The skeletomuscular and soft tissue anatomy of Amblyopone australis workers (Hymenoptera: Formicidae).

Recent studies of insect anatomy evince a trend towards a comprehensive and integrative investigation of individual traits and their evolutionary relationships. The abdomen of ants, however, remains critically understudied. To address this shortcoming, we describe the abdominal anatomy of Amblyopone australis Erichson, using a multimodal approach combining manual dissection, histology, and microcomputed tomography. We focus on skeletomusculature, but additionally describe the metapleural and metasomal exocrine glands, and the morphology of the circulatory, digestive, reproductive, and nervous systems. We describe the muscles of the dorsal vessel and the ducts of the venom and Dufour's gland, and characterize the visceral anal musculature. Through comparison with other major ant lineages, apoid wasps, and other hymenopteran outgroups, we provide a first approximation of the complete abdominal skeletomuscular groundplan in Formicidae, with a nomenclatural schema generally applicable to the hexapod abdomen. All skeletal muscles were identifiable with their homologs, while we observe potential apomorphies in the pregenital skeleton and the sting musculature. Specifically, we propose the eighth coxocoxal muscle as an ant synapomorphy; we consider possible transformation series contributing to the distribution of states of the sternal apodemes in ants, Hymenoptera, and Hexapoda; and we address the possibly synapomorphic loss of the seventh sternal-eighth gonapophyseal muscles in the vespiform Aculeata. We homologize the ovipositor muscles across Hymenoptera, and summarize demonstrated and hypothetical muscle functions across the abdomen. We also give a new interpretation of the proximal processes of gonapophyses VIII and the ventromedial processes of gonocoxites IX, and make nomenclatural suggestions in the context of evolutionary anatomy and ontology. Finally, we discuss the utility of techniques applied and emphasize the value of primary anatomical research.

Svep1 stabilises developmental vascular anastomosis in reduced flow conditions.

ABSTRACTMolecular mechanisms controlling the formation, stabilisation and maintenance of blood vessel connections remain poorly defined. Here, we identify blood flow and the large extracellular protein Svep1 as co-modulators of vessel anastomosis during developmental angiogenesis in zebrafish embryos. Both loss of Svep1 and blood flow reduction contribute to defective anastomosis of intersegmental vessels. The reduced formation and lumenisation of the dorsal longitudinal anastomotic vessel (DLAV) is associated with a compensatory increase in Vegfa/Vegfr pERK signalling, concomittant expansion of apelin-positive tip cells, but reduced expression of klf2a. Experimentally, further increasing Vegfa/Vegfr signalling can rescue the DLAV formation and lumenisation defects, whereas its inhibition dramatically exacerbates the loss of connectivity. Mechanistically, our results suggest that flow and Svep1 co-regulate the stabilisation of vascular connections, in part by modulating the Vegfa/Vegfr signalling pathway.

Abstract P4-11-18: Arm lymphatic pulsing changes after mastectomy or breast-conserving surgery with axillary lymph node dissection, detected with near-infrared fluorescence lymphatic imaging

Abstract Introduction: Axillary lymph node dissection (ALND) that accompanies mastectomy or breast-conserving surgery is assumed to disrupt arm lymphatic fluid pumping that normally flows in a one-way, distal-to-proximal path to transit cellular waste, immune cells, and large molecules to the thorax. Any resulting stagnation of lymph is surmised to drive the development of lymphedema (LE), with potential lifelong, detrimental effects on quality of life for breast cancer survivors, yet the majority of breast cancer survivors receiving ALND never encounter LE. To date, no objective before-and-after-ALND lymphatic pumping data has been published. Methods: In a prospective, ongoing, longitudinal clinical study (NCT02949726) of breast cancer patients undergoing neoadjuvant chemotherapy, axillary lymph node dissection (ALND) with mastectomy or breast-conserving surgery, and radiation treatment (RT), we used near-infrared fluorescence lymphatic imaging (NIRF-LI) to observe changes in arm lymphatics anatomy and pulsing. NIRF-LI, using a custom-built imaging system, with indocyanine green (ICG) contrast, allows “see through the skin” visualization of arm lymph pumping through lymphatic vessels, and captured videos of 58 locally advanced breast cancer patients before and approximately four weeks after mastectomy or breast-conserving surgery with ALND. Lymphatic pumping frequencies (pulses per minute) were determined from fluorescence intensity fluctuations through regions of interest (ROIs) along lymphatic vessels, quantitated with ImageJ (NIH) free software. Ipsilateral and contralateral arm dorsal, ventral, and axillary-feeding (ventral upper arm) vessel pulsing was classified as 1) static or improved to normal range (improved), or 2) transitioning to abnormal ranges (worsened) after surgery. The number of vessels in each category were tallied and reported herein. Results: After ALND, arm lymphatic pulsing frequencies improved or worsened as shown in Table 1. Conclusions: NIRF-LI allowed objective quantitation of arm lymphatic pumping frequencies captured before and after ALND accompanying mastectomy or breast-conserving surgery for breast cancer. Pulsing frequencies in detectable vessels improved in more axilla-feeding vessels, surprisingly, but worsened or did not change in more ipsilateral and ventral vessels, on both ipsilateral and contralateral sides. While cancer surgery with ALND may be associated with increased risk of BCRL, other factors, such as neoadjuvant chemotherapy, cancer severity, and radiation treatment may contribute to LE etiology. Table 1.Anatomical position (arm)# of Vessels Improved# of Vessels WorsenedIpsilateral dorsal6499Ipsilateral ventral73107Ipsilateral axilla-feeding5626Contralateral dorsal97112Contralateral ventral8988Contralateral axilla-feeding10323 Citation Format: Melissa B Aldrich, Meghan E McWain, Wenyaw Chan, John C Rasmussen, Sarah DeSnyder, Eva M Sevick-Muraca, Simona F Shaitelman. Arm lymphatic pulsing changes after mastectomy or breast-conserving surgery with axillary lymph node dissection, detected with near-infrared fluorescence lymphatic imaging [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-11-18.

Computational simulations of the 4D micro-circulatory network in zebrafish tail amputation and regeneration.

Wall shear stress (WSS) contributes to the mechanotransduction underlying microvascular development and regeneration. Using computational fluid dynamics, we elucidated the interplay between WSS and vascular remodelling in a zebrafish model of tail amputation and regeneration. The transgenic Tg (fli1:eGFP; Gata1:ds-red) zebrafish line was used to track the three-dimensional fluorescently labelled vascular endothelium for post-image segmentation and reconstruction of the fluid domain. Particle image velocimetry was used to validate the blood flow. Following amputation to the dorsal aorta and posterior cardinal vein (PCV), vasoconstriction developed in the dorsal longitudinal anastomotic vessel (DLAV) along with increased WSS in the proximal segmental vessels (SVs) from amputation. Angiogenesis ensued at the tips of the amputated DLAV and PCV where WSS was minimal. At 2 days post amputation (dpa), vasodilation occurred in a pair of SVs proximal to amputation, followed by increased blood flow and WSS; however, in the SVs distal to amputation, WSS normalized to the baseline. At 3 dpa, the blood flow increased in the arterial SV proximal to amputation and through anastomosis with DLAV formed a loop with PCV. Thus, our in silico modelling revealed the interplay between WSS and microvascular adaptation to changes in WSS and blood flow to restore microcirculation following tail amputation.

The Clinical Effect of Digital Dorsal Fascial Island Flap Combined With Crossfinger Flap for Repairing Distal Degloving Injury and Sensory Reconstruction.

BackgroundTo explore the clinical effect of digital dorsal fascial island flap combined with crossfinger flap to repair distal degloving injury and sensory reconstruction.MethodsA total of 19 patients with distal fingertip degloving injuries treated with digital dorsal fascial island flap combined with crossfinger flap in our hospital from April 2018 to August 2020 were retrospectively included. Semmes–Weinstein (SW) monofilament and static two-point discrimination (S-2PD) tests, active range-of-motion (ROM) of the fingers, cold intolerance, visual analog scale (VAS) score patient complications, and patient satisfaction were evaluated.ResultsFive cases with post-operative flap blisters were treated at the time of dressing changes until successful scab formation. Three cases with post-operative arterial crisis of finger arterial dorsal branch vessel were relieved after suture removal and tension reduction. All other skin flaps and skin grafts survived. Nineteen patients received follow-up between 3 and 26 months (average 14.6 months). The active ROM of metacarpophalangeal (MCP) and interphalangeal (IP) joints of the injured fingers were satisfactory.ConclusionThe digital dorsal fascial island flap combined with the crossfinger flap for repairing the distal degloving injury of the distal segment of the finger is a good surgical method, which is simple and easy to operate, can repair a large area of soft tissue defect, and obtain a satisfactory effect.

Effect of a 110 ppb mercury exposition on neotropical bumble bee workers, Bombus atratus: in situ localization of Hsp70 and Hsp90 and general morphological changes of hepato-nephrocitic cells

We analyzed the effect of mercury (Hg) on the hepato-nephrocitic system (HNS) of Bombus atratus workers exposed to an estimated concentration similar to that found in honey stores of neotropical bees (110 ppb). The bees were divided into control and experimental groups. A solid mixture of honey, pollen and organic soy was offered to both experimental groups, ad libitum. The control group received distilled water and the exposed group received a 110 µg.L−1 (110 ppb) Hg solution. After 48 h of exposure, the bees were cryo-anesthetized, and the dorsal vessel was dissected directly in 4% paraformaldehyde. The samples were prepared for routine morphological analysis (HE), fluorescent histochemical staining (Acridine Orange and F-actin + DAPI), and in situ immunohistochemical labeling (Hsp70 and Hsp90). Our results showed that both the trophocytes and oenocytes of bees exposed to mercury exhibited chromatin damages. The Hg exposure also induced trophocytes deactivation of the nucleus-cytoplasm exchange as a result of branched contour loss of the nuclei. The pericardial cells were predominantly found at stage IV with pyknotic nuclei. Although the fluorescence intensity of both Hsp70 and Hsp90 was reduced in the exposed group compared to the control group, there was an indication of misfolded proteins. In conclusion, our results showed that the concentration of 110 µg.L−1Hg, which can be found in the honey stores of B. atratus colonies, has severely damaged the HNS of B. atratus workers. These effects can trigger major damage to their populations, contributing to bee declines in natural environments worldwide.