Kif9 is an active kinesin motor required for ciliary beating and proximodistal patterning of motile axonemes.

Most motile cilia have a stereotyped structure of nine microtubule outer doublets and a single central pair of microtubules. The central pair of microtubules are surrounded by a set of proteins, termed the central pair apparatus. A specific kinesin, Klp1 projects from the central pair and contributes to ciliary motility in Chlamydomonas. The vertebrate ortholog, Kif9, is required for beating in mouse sperm flagella, but the mechanism of Kif9/Klp1 function remains poorly defined. Here, using Xenopus epidermal multiciliated cells, we show that Kif9 is necessary for ciliary motility and the proper distal localization of not only central pair proteins, but also radial spokes and dynein arms. In addition, single-molecule assays in vitro reveal that Xenopus Kif9 is a long-range processive motor, although it does not mediate long-range movement in ciliary axonemes in vivo. Together, our data suggest that Kif9 is integral for ciliary beating and is necessary for proper axonemal distal end integrity.

Syndiotactic hexamer peptide nanodots.

Spatial confinement of excitons in the nano-crystalline region of semiconducting nanostructures differ significantly from the optoelectronic properties exhibited by the bulk material. We report spike-like absorption observed in the UV spectrum of a phenylalanine hexamer peptide [(Ff)3-OH] nano-assembly, which may be attributed to the spatial confinement of electrons to the dimension of quantum dots. Interdependency of the UV and PLE spectrum of the peptide confirms the existence of quantum confinement in (Ff)3-OH nano-assemblies.

Antibacterial hydrogels of aromatic tripeptides.

Self-assembled peptide hydrogels have emerged as alternatives to the conventional approaches employed in controlled drug release, wound-healing, and drug delivery, and as anti-infective agents. However, peptide hydrogels possessing antibacterial properties are less explored. In this work, we have designed three ultrashort antibacterial peptide hydrogels: Fmoc-FFH-CONH2, Fmoc-FHF-CONH2, and Fmoc-HFF-CONH2. The rheological study showed the higher storage modulus of Fmoc-FFH-CONH2 (30.43 kPa) compared to Fmoc-FHF-CONH2 and Fmoc-HFF-CONH2, which may be attributed to the enhanced aromatic interaction in Fmoc-FFH-CONH2 compared to the other two variants, resulting in more mechanical rigidity. Further, the prepared hydrogels were evaluated for their inherent antibacterial potency against Gram-positive (Staphylococcus aureus, strain MTCC 96) and Gram-negative (Pseudomonas aeruginosa, strain PA01) bacteria. Antibacterial experiments demonstrated the potency of the hydrogels in the order of Fmoc-FFH-CONH2 > Fmoc-FHF-CONH2 > Fmoc-HFF-CONH2. The antibacterial effect of the hydrogels was predominantly due to the osmotic stress and membrane disruption, which was verified by reactive oxygen species (ROS) generation and outer membrane permeabilization assays. Our findings point to the scope of using the synthesized peptide hydrogels as agents for topical applications.

Acute and Chronic Ischemic Disorders of the Small Bowel.

PURPOSE OF REVIEW: Ischemic disorders of the small bowel represent a rare but highly morbid disease process which is often difficult to diagnose and has a complex management course involving multidisciplinary care. Given recent advances in radiologic modalities and surgical/endovascular techniques, this review seeks to provide a disease overview as well as a summary of emerging management strategies. RECENT FINDINGS: In cases of acute mesenteric ischemia without evidence of frank bowel necrosis, an endovascular-first strategy employing thrombolysis, pharmacomechanical thrombectomy, and/or adjunctive angioplasty/stenting has been shown to have positive outcomes. In cases requiring open laparotomy, retrograde open mesenteric stenting may facilitate less dissection and more straightforward revascularization. While endovascular intervention for chronic mesenteric ischemia was historically limited by high rates of restenosis, use of covered stents in these vascular beds has been shown to have excellent patency rates. Ischemia of the small bowel can be acute or chronic in nature-endovascular treatment modalities have been shown to have excellent results given appropriate patient selection and should be an important tool in the armamentarium of management options for this complex disease process.

The Transradial Approach for Lower Extremity Vascular Intervention.

Simultaneous technological advancements in both imaging as well as devices have resulted in an expansion of endovascular options for vascular access. In particular, radial access has traditionally been more favored for coronary interventions; its use in the aortoiliac and lower extremity vasculature has been constrained by the length of devices and the size of sheaths required. However, with increasing catheter shaft lengths, in addition to new thin-walled sheaths allowing for downsizing, the ability to perform transradial interventions on infrainguinal and infrageniculate vessels has been more readily facilitated. In this review, we analyze the potential for transradial therapies in the treatment of peripheral arterial disease (PAD).

Flowtrace: simple visualization of coherent structures in biological fluid flows.

We present a simple, intuitive algorithm for visualizing time-varying flow fields that can reveal complex flow structures with minimal user intervention. We apply this technique to a variety of biological systems, including the swimming currents of invertebrates and the collective motion of swarms of insects. We compare our results with more experimentally difficult and mathematically sophisticated techniques for identifying patterns in fluid flows, and suggest that our tool represents an essential 'middle ground' allowing experimentalists to easily determine whether a system exhibits interesting flow patterns and coherent structures without resorting to more intensive techniques. In addition to being informative, the visualizations generated by our tool are often striking and elegant, illustrating coherent structures directly from videos without the need for computational overlays. Our tool is available as fully documented open-source code for MATLAB, Python or ImageJ at www.flowtrace.org.

Wake-Driven Dynamics of Finite-Sized Buoyant Spheres in Turbulence.

Particles suspended in turbulent flows are affected by the turbulence and at the same time act back on the flow. The resulting coupling can give rise to rich variability in their dynamics. Here we report experimental results from an investigation of finite-sized buoyant spheres in turbulence. We find that even a marginal reduction in the particle's density from that of the fluid can result in strong modification of its dynamics. In contrast to classical spatial filtering arguments and predictions of particle models, we find that the particle acceleration variance increases with size. We trace this reversed trend back to the growing contribution from wake-induced forces, unaccounted for in current particle models in turbulence. Our findings highlight the need for improved multiphysics based models that account for particle wake effects for a faithful representation of buoyant-sphere dynamics in turbulence.

Bilateral cellular flows display asymmetry prior to left-right organizer formation in amniote gastrulation.

A bilateral body plan is predominant throughout the animal kingdom. Bilaterality of amniote embryos becomes recognizable as midline morphogenesis begins at gastrulation, bisecting an embryonic field into the left and right sides, and left-right asymmetry patterning follows. While a series of laterality genes expressed after the left-right compartmentalization has been extensively studied, the laterality patterning prior to and at the initiation of midline morphogenesis has remained unclear. Here, through a biophysical quantification in a high spatial and temporal resolution, applied to a chick model system, we show that a large-scale bilateral counter-rotating cellular flow, termed as 'polonaise movements', display left-right asymmetries in early gastrulation. This cell movement starts prior to the formation of the primitive streak, which is the earliest midline structure, and earlier than expression of laterality genes. The cellular flow speed and vorticity unravel the location and timing of the left-right asymmetries. The bilateral flows displayed a Right dominance after six hours since the start of cell movements. Mitotic arrest that diminishes primitive streak formation resulted in changes in the bilateral flow pattern, but the Right dominance persisted. Our data indicate that the left-right asymmetry in amniote gastrula becomes detectable prior to the point when the asymmetric regulation of the laterality signals at the node leads to the left-right patterning. More broadly, our results suggest that physical processes can play an unexpected but significant role in influencing left-right laterality during embryonic development. Significance Statement: Bilaterians are defined by a bilaterally symmetrical body plan. Vertebrates exhibit external bilateral symmetry but display left-right (LR) asymmetry in their internal organs. In amniote embryos, the initiation of LR symmetry breaking is not well understood. Here, we study LR symmetry breaking in the chick embryo due to its easy accessibility and similarity to human development. Our biophysical approaches to quantify cellular flows inferred that LR symmetry breaking occurs prior to the formation of Hensen's node, a LR organizer, which serves as a signaling center for LR patterning programs. Our work demonstrates that quantitative biophysical parameters can help unravel the initiation of LR symmetry breaking, suggesting involvement of physical mechanisms in this critical biological patterning process.

Coupling and uncoupling of midline morphogenesis and cell flow in amniote gastrulation.

Large-scale cell flow characterizes gastrulation in animal development. In amniote gastrulation, particularly in avian gastrula, a bilateral vortex-like counter-rotating cell flow, called 'polonaise movements', appears along the midline. Here, through experimental manipulations, we addressed relationships between the polonaise movements and morphogenesis of the primitive streak, the earliest midline structure in amniotes. Suppression of the Wnt/planar cell polarity (PCP) signaling pathway maintains the polonaise movements along a deformed primitive streak. Mitotic arrest leads to diminished extension and development of the primitive streak and maintains the early phase of the polonaise movements. Ectopically induced Vg1, an axis-inducing morphogen, generates the polonaise movements, aligned to the induced midline, but disturbs the stereotypical cell flow pattern at the authentic midline. Despite the altered cell flow, induction and extension of the primitive streak are preserved along both authentic and induced midlines. Finally, we show that ectopic axis-inducing morphogen, Vg1, is capable of initiating the polonaise movements without concomitant PS extension under mitotic arrest conditions. These results are consistent with a model wherein primitive streak morphogenesis is required for the maintenance of the polonaise movements, but the polonaise movements are not necessarily responsible for primitive streak morphogenesis. Our data describe a previously undefined relationship between the large-scale cell flow and midline morphogenesis in gastrulation.

Coupling and uncoupling of midline morphogenesis and cell flow in amniote gastrulation.

Large-scale cell flow characterizes gastrulation in animal development. In amniote gastrulation, particularly in avian gastrula, a bilateral vortex-like counter-rotating cell flow, called 'polonaise movements', appears along the midline. Here, through experimental manipulations, we addressed relationships between the polonaise movements and morphogenesis of the primitive streak, the earliest midline structure in amniotes. Suppression of the Wnt/planar cell polarity (PCP) signaling pathway maintains the polonaise movements along a deformed primitive streak. Mitotic arrest leads to diminished extension and development of the primitive streak and maintains the early phase of the polonaise movements. Ectopically induced Vg1, an axis-inducing morphogen, generates the polonaise movements, aligned to the induced midline, but disturbs the stereotypical cell flow pattern at the authentic midline. Despite the altered cell flow, induction and extension of the primitive streak are preserved along both authentic and induced midlines. Finally, we show that ectopic axis-inducing morphogen, Vg1, is capable of initiating the polonaise movements without concomitant PS extension under mitotic arrest conditions. These results are consistent with a model wherein primitive streak morphogenesis is required for the maintenance of the polonaise movements, but the polonaise movements are not necessarily responsible for primitive streak morphogenesis. Our data describe a previously undefined relationship between the large-scale cell flow and midline morphogenesis in gastrulation.

Unleashing the binding interaction of chrysin-Cu(II) complex with the biomacromolecular targets: further studies of cell cytotoxicity and radical scavenging properties.

Flavonoids are significant dietary components and have ability to coordinate with metal ions to produce novel drug discovery leads that are superior to those of the parent flavonoids. Here, in this report, we have synthesized chrysin-Cu(II) complex (as per reported article) and characterized it further with different analytical techniques. The synthesized complex was evaluated for radical scavenging and cell cytotoxicity studies where it exhibited enhanced activity as compared to bare chrysin. The interaction studies of the complex with ct-DNA (Kb ⁓ 105 M-1), human serum albumin (HSA) and ovalbumin (Kb ⁓ 104 M-1) were evaluated using multi-spectroscopic and molecular docking studies. Groove binding mode with ct-DNA was observed as confirmed from competitive displacement studies, viscosity measurement, melting temperature estimation and docking analyses. The complex exhibited comparatively higher affinity towards ct-DNA which indicated it efficient transportation by the carrier proteins and controlled release in the target DNA.Communicated by Ramaswamy H. Sarma.

Extensive iliofemoral and femoropopliteal venous thrombosis in a young patient with iliocaval atresia.

Inferior vena cava (IVC) atresia is a rare congenital anomaly. Standardized treatment is not well defined due to its uncommon presentation, with this pathology associated with an increased risk of unprovoked lower extremity deep vein thrombosis (DVT). We present a case of a 32-year-old man who was admitted for bilateral lower extremity edema and pain and was found to have bilateral extensive iliofemoral and femoropopliteal DVT, absence of IVC filling, and extensive tortuous collateralization arising from the pelvic veins to the azygos vein. Bilateral mechanical thrombectomy and endovascular iliocaval reconstruction was performed. Three months later, the patient demonstrated widely patent iliocaval stents and the absence of DVT. Endovascular treatment of IVC atresia is feasible and optimizes the reduction of thrombus burden.

RevCore thrombectomy system for treatment of chronic left external and common iliac vein stent occlusion.

In recent years, deep venous stenting has increasingly become a treatment strategy for post-thrombotic syndrome. Stent thrombosis can occur, resulting in symptom recurrence despite medical therapy, and there are few options available for durable stent patency restoration. We present a case of a 50-year-old male with prior iliocaval reconstruction that experienced recurrent left lower extremity swelling secondary to occlusion of left external iliac and common iliac vein stents during follow-up. Mechanical thrombectomy with the RevCore System and angioplasty was performed. One month later, the patient demonstrated widely patent bilateral iliac vein stents and complete symptomatic resolution. The RevCore System is a feasible alternative for treatment of chronic in-stent thrombosis.

Open repair of an abdominal aortic and right common iliac artery aneurysm with idiopathic retroperitoneal fibrosis in a 19-month-old infant.

An abdominal aortic aneurysm (AAA) in children is a rare clinical condition, with idiopathic AAAs even more atypical. We report a case of a 19-month-old girl with incidental findings of an infrarenal AAA and right common iliac artery aneurysm during workup for heart failure. Extensive genetic testing was unremarkable for connective tissue disorders. An aortic bi-iliac artery bypass with a Dacron graft from the infrarenal aorta to the right external iliac artery and left common iliac artery was performed. The patient achieved complete recovery and only required one oral hypertensive medication at 30 days of follow-up. Wide patency of the graft was observed on the 3-month follow-up computed tomography angiogram.

Efficient Biosorption of Hexavalent Chromium from Water with Human Hair.

The triphenyl group (trityl radical) possessing three-phenyl rings, self-assembled through aromatic π-π stacking interactions, can form interesting crystalline organic nano-flowers. In this work, we have synthesized a hybrid material of 1,2-bis(tritylthio)ethane and magnetite, which reduces toxic Cr(VI) to non-toxic Cr(III). We validated the efficacy of the hybrid in reducing toxic Cr(VI) along with three other adsorbent systems. Among the five adsorbent systems tested, we observed that human hair has higher Cr removal efficiency, which prompted us to explore further using different mechanical forms of human hair. Pulverized hair (PH), hair powder (HP), and raw hair (RH) were evaluated by employing different reaction factors such as the adsorbent dose, pH, initial Cr(VI) concentration, and contact time. The comparative evaluation showed that PH has greater adsorption capacity (15.14 mg/g), followed by RH (13.27 mg/g) and HP (10.5 mg/g). While investigating the adsorption mechanism, we observed that it follows pseudo-second-order kinetics suggesting chemisorption. The Freundlich isotherm model fitted well for Cr(VI) adsorption by human hair, suggesting a multi-layered adsorption process. Overall, this study promises a cost-effective and eco-friendly bio-adsorbent for Cr(VI), which may be scaled up to design automated industrial waste disposal systems.

Non-Bilaterians as Model Systems for Tissue Mechanics.

In animals, epithelial tissues are barriers against the external environment, providing protection against biological, chemical, and physical damage. Depending on the organism's physiology and behavior, these tissues encounter different types of mechanical forces and need to provide a suitable adaptive response to ensure success. Therefore, understanding tissue mechanics in different contexts is an important research area. Here, we review recent tissue mechanics discoveries in three early divergent non-bilaterian systems-Trichoplax adhaerens, Hydra vulgaris, and Aurelia aurita. We highlight each animal's simple body plan and biology and unique, rapid tissue remodeling phenomena that play a crucial role in its physiology. We also discuss the emergent large-scale mechanics in these systems that arise from small-scale phenomena. Finally, we emphasize the potential of these non-bilaterian animals to be model systems in a bottom-up approach for further investigation in tissue mechanics.

Acute limb ischemia secondary to bullet embolism following a cardiac gunshot wound in a pediatric patient.

Bullet embolism following a gunshot wound to the heart is a very unusual cause of acute limb ischemia. We report the case of a 3-year-old boy who sustained a penetrating cardiac trauma secondary to an accidental self-inflicted gunshot wound with a BB (ball bearing) gun. The BB pellet entered the left ventricle and embolized into the peripheral circulation, lodging at the bifurcation of the left common femoral artery. This resulted in acute left lower extremity ischemia. The patient was successfully treated by open common femoral artery exploration and foreign body removal.

Superior mesenteric artery aneurysm endovascular repair.

Superior mesenteric artery aneurysms are rare and associated with high mortality rates in cases of rupture. Current Society for Vascular Surgery guidelines recommend treatment of all superior mesenteric artery aneurysms regardless of size. A 53-year-old woman who was admitted for abdominal pain was found with a 14-cm, ruptured superior mesenteric artery branch aneurysm. Endovascular approach was performed with microvascular plug embolization of a feeding branch and aneurysm sac exclusion with a stent graft. Four months later, the patient demonstrated a 21% regression of the aneurysm and stent patency. Thus, timely diagnosis and treatment of superior mesenteric artery aneurysms with endovascular techniques can reduce potential complications.

Kommerell's Diverticulum in a Right-Sided Aortic Arch With an Aberrant Left Subclavian Artery Hybrid Repair.

BACKGROUND: Kommerell's diverticulum (KD) with a right aortic arch (RAA) and aberrant left subclavian artery (aLSCA) is a rare congenital anomaly of the aortic arch. Treatment is not well defined due to its uncommon presentation, with rupture and dissection risk rates of up to 53%. CASE SUMMARY: A 54-year-old male with a history of chronic obstructive pulmonary disease (COPD) and hypertension presented with difficulty breathing during exercise without dysphagia. Follow-up computerized tomography angiogram (CTA) revealed the presence of a RAA and aLSCA arising from the descending thoracic aorta with an adjacent 58 × 41-mm KD and tracheal and esophageal displacement. Due to the size of the KD, risk of rupture, unsuitable anatomy for total endovascular aortic repair (EVAR), and high COPD burden, the patient was planned to undergo a hybrid surgical repair. Left common carotid (LCCA) artery to LSCA bypass, full aortic debranching, LSCA embolization and percutaneous thoracic endovascular aortic repair (TEVAR) were performed. Successful device position and exclusion of the diverticulum and aneurysmal aorta were observed after completion thoracic aortogram. 18-month follow-up CTA demonstrated patency of the LSCA to LCCA bypass graft and arch vessel branches, as well as stable exclusion of the KD. Persistence of a type II endoleak originated at the right first posterior intercostal artery has been noted and is being followed conservatively since no sac growth has occurred. CONCLUSION: We highlight the presence of a KD with RAA and aberrant subclavian artery, a rare congenital anatomic variation of the aortic arch with complex anatomy. Surgical planning must be individualized according to comorbidities and anatomical variations identified on imaging and 3D reconstructions.

Coral physiology: Going with the ciliary flow.

Corals have long been known to generate local fluid flows using ciliary beating, but the importance of these ciliary flows is just being discovered. Two new papers shed light on how ciliary-flow physics plays a key role in shaping coral physiology.