In vitro antibacterial activity and cytocompatibility of magnesium-incorporated poly(lactide-co-glycolic acid) scaffolds.

BACKGROUND: Bone defects are often combined with the risk of infection in the clinic, and artificial bone substitutes are often implanted to repair the defective bone. However, the implant materials are carriers for bacterial growth, and biofilm can form on the implant surface, which is difficult to eliminate using antibiotics and the host immune system. Magnesium (Mg) was previously reported to possess antibacterial potential. METHODS: In this study, Mg was incorporated into poly(lactide-co-glycolic acid) (PLGA) to fabricate a PLGA/Mg scaffold using a low-temperature rapid-prototyping technique. All scaffolds were divided into three groups: PLGA (P), PLGA/10 wt% Mg with low Mg content (PM-L) and PLGA/20 wt% Mg with high Mg content (PM-H). The degradation test of the scaffolds was conducted by immersing them into the trihydroxymethyl aminomethane-hydrochloric acid (Tris-HCl) buffer solution and measuring the change of pH values and concentrations of Mg ions. The antibacterial activity of the scaffolds was investigated by the spread plate method, tissue culture plate method, scanning electron microscopy and confocal laser scanning microscopy. Additionally, the cell attachment and proliferation of the scaffolds were evaluated by the cell counting kit-8 (CCK-8) assay using MC3T3-E1 cells. RESULTS: The Mg-incorporated scaffolds degraded and released Mg ions and caused an increase in the pH value. Both PM-L and PM-H inhibited bacterial growth and biofilm formation, and PM-H exhibited higher antibacterial activity than PM-L after incubation for 24 and 48 h. Cell tests revealed that PM-H exerted a suppressive effect on cell attachment and proliferation. CONCLUSIONS: These findings demonstrated that the PLGA/Mg scaffolds possessed favorable antibacterial activity, and a higher content of Mg (20%) exhibited higher antibacterial activity and inhibitory effects on cell attachment and proliferation than low Mg content (10%).

An An Open-Label, Single Center, Retrospective Study to Evaluate Clinical Outcomes with Surgical Sealant in Bentall Procedures: A Cohort Study.

BACKGROUND: Cardiovascular surgery is associated with substantial risk for postoperative bleeding with increased patient morbidity and mortality. Numerous intraoperative techniques have been utilized to reduce this risk. This study was to assess postoperative bleeding-related parameters following Bentall procedures and to examine the impact of intraoperative surgical sealant application. METHOD: The medical/surgical records of 100 consecutive Bentall procedure cases were examined retrospectively for perioperative surgical sealant use and postoperative bleeding-related outcomes. RESULTS: Of the 100 patient cases, three died during the postoperative period, and 97 were evaluable. Surgical sealant was utilized in 56 patient cases (57.8%). The utilization versus no utilization of surgical sealant was associated with significant reductions in most postoperative bleeding-related parameters, including less drainage (P = .028), resternotomy for hemorrhage (P = .036), transfusion of red blood cells (P = .022 at 48 hours; P = .027 total in-hospital), transfusion of fresh frozen plasma (P = .04 at 48 hours; P = .004 total in-hospital), and a higher percentage of cases not needing blood transfusion (P = .002). The surgical sealant group had longer cardiopulmonary bypass circuit (P = .016) and aortic cross-clamp time (P = .001), with no significant between-group differences in intubation time (P = .636) or intensive care unit duration (P = .294). When excluding urgent cases or Stanford type A aortic dissections, intensive care unit duration significantly was shorter in the surgical sealant group (P = .017). Surgical sealant use was not associated with any adverse events. CONCLUSION: The application of surgical sealant to the anastomosis suture line in Bentall procedures reduces postoperative drainage, bleeding, and transfusion utilization. Further studies are warranted to investigate these benefits in prospective, randomized clinical trials.

Alteromonas lipolytica sp. nov., a poly-beta-hydroxybutyrate-producing bacterium isolated from surface seawater.

Strain JW12T, isolated from surface seawater of the Arabian Sea, was subjected to characterization by a polyphasic taxonomic approach. Cells of the isolate were Gram-stain-negative, aerobic and rod-shaped. It accumulated poly-ß-hydroxybutyrate. On the basis of 16S rRNA gene sequence analysis, strain JW12T was closely related to Alteromonas confluentis, with 16S rRNA gene sequence similarity of 98.0 %. Phylogenetic analysis revealed that it fell within the cluster of the genus Alteromonas and represented one independent lineage with A. confluentis. The average nucleotide identity (ANI) value and the genome-to-genome distance between strain JW12T and A. confluentis KCTC 42603T were 70.0 and 21.3 %, respectively. The sole respiratory quinone was ubiquinone-8 (Q8). The principal fatty acids were summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH), C16 : 0 and C18 : 1ω7c. The major polar lipids included phosphatidylethanolamine, phosphatidylglycerol, two unidentified glycolipids and one aminophospholipid. The DNA G+C content was 48.4 mol%. Differential phylogenetic distinctiveness and chemotaxonomic differences, together with phenotypic properties obtained in this study, revealed that strain JW12T could be differentiated from the closely related species. Therefore, it is proposed that strain JW12T represents a novel species in the genus Alteromonas, for which the name Alteromonas lipolytica sp. nov. (type strain, JW12T=CGMCC 1.15735T=KCTC 52408T=MCCC 1K03175T), is proposed.

Core decompression in combination with nano-hydroxyapatite/polyamide 66 rod for the treatment of osteonecrosis of the femoral head.

BACKGROUND: The aim of this study was to investigate the effectiveness of core decompression in combination with a nano-hydroxyapatite/polyamide 66 (n-HA/PA66) rod and a porous bioglass bone graft for the treatment of osteonecrosis of the femoral head (ONFH). METHODS: Sixty-four patients (84 hips) with ONFH were allocated to a program of either core decompression (CD) in combination with a n-HA/PA66 rod and a porous bioglass bone graft (treatment group) or CD with an autologous cancellous bone graft (control group). Clinical and radiographic retrospective follow-ups were performed on all patients with the prospectively collected data. RESULTS: The overall clinical failure rate in the treatment group (9/38, 23.68%) was lower than that of the control group (24/46, 52.17%) (p < 0.05). Harris hip scores (HHS) were significantly increased in both groups post-surgery (p < 0.05). There was a significant difference between the two groups on HHS improvement for Steinberg IIC and IIIA (p < 0.05 and p < 0.001, respectively). The visual analogue scale (VAS) was significantly decreased in both groups post-surgery (p < 0.05). Especially, significant difference in the VAS improvement was observed between the groups for IIB, IIC and IIIA (p < 0.05, p < 0.05 and p < 0.01, respectively). CONCLUSIONS: Core decompression combined with the implantation of a n-HA/PA66 rod and a bioglass bone graft can significantly decrease hip pain, improve hip function, and prevent the collapse of the femoral head in patients with ONFH. As the effectiveness of this approach appears to vary with Steinberg stage, we suggest that this treatment procedure may be suitable for patients with early to middle stage ONFH.

Electrospun compliant heparinized elastic vascular graft for improving the patency after implantation.

The low patency rate after artificial blood vessel replacement is mainly due to the ineffective use of anticoagulant factors and the mismatch of mechanical compliance after transplantation. Electrospun nanofibers with biomimetic extracellular matrix three-dimensional structure and tunable mechanical strength are excellent carriers for heparin. In this work, we have designed and synthesized a series of biodegradable poly(ester-ether-urethane)ureas (BEPU), following compound with optimized constant concentration of heparin by homogeneous emulsion blending, then spun into the hybrid BEPU/heparin nanofibers tubular graft for replacing rats' abdominal aorta in situ for comprehensive performance evaluation. The results in vitro demonstrated that the electrospun L-PEUUH (LDI-based PEUU with heparin) vascular graft was of regular microstructure, optimum surface wettability, matched mechanical properties, reliable cytocompatibility, and strongest endothelialization in situ. Replacement of resected abdominal artery with the L-PEUUH vascular graft in rat showed that the graft was capable of homogeneous hybrid heparin and significantly promoted the stabilization of vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs), as well as stabilizing the blood microenvironment. This research demonstrates the L-PEUUH vascular graft with substantial patency, indicating their potential for injured vascular healing.

Construction of a high-throughput aorta smooth muscle-on-a-chip for thoracic aortic aneurysm drug screening.

Thoracic aortic aneurysm (TAA), in which arteries enlarge asymptomatically over time until dissection or rupture occurs, is a serious health risk. The mainstay of TAA treatment remains surgical repair due to the lack of effective drugs. The complex etiology and pathogenesis of TAA, including hemodynamic alterations and genetic factors, lead to inaccuracies in preclinical models for drug screening. Previously, our group designed an aorta smooth muscle-on-a-chip to emulate human aorta physiology and pathophysiology and screened three promising therapeutic drugs targeting mitochondrial dynamics in TAA. On this foundation, we updated the one-channel chip to an eighteen-well chip platform with four polydimethylsiloxane layers. Benefiting from this high-throughput chip, we rapidly screened multiple drugs simultaneously using distinct cell lines in vitro. In addition, we observed the abnormal activation of hypoxia-inducible factor 1-alpha (HIF-1alpha) in aortas from TAA patients by Western blot and bioinformatics analyses. Intriguingly, this phenomenon was replicated only when smooth muscle cells (SMCs) were strained on the chip. We then screened seven specific HIF-1alpha inhibitors and selected the two most effective drugs (2-methoxyestradiol and digoxin) by quantitative PCR and colorimetric methods. The results demonstrated that these two drugs can improve respiratory chain function and rescue the SMC contractile phenotype, showing applicability for the clinical treatment of TAA. This high-throughput aorta smooth muscle-on-a-chip will become a potential preclinical model for TAA drug screening.

Oceanobacillus neutriphilus sp. nov., isolated from activated sludge in a bioreactor.

A Gram-stain-positive, neutrophilic, rod-shaped bacterium, strain A1g(T), was isolated from activated sludge of a bioreactor and was subjected to a polyphasic taxonomic characterization. The isolate grew in the presence of 0-17.0 % (w/v) NaCl and at pH 6.0-9.0; optimum growth was observed in the presence of 3.0-5.0 % (w/v) NaCl and at pH 7.0. Strain A1g(T) was motile, formed cream-coloured colonies, was catalase- and oxidase-positive and was able to hydrolyse aesculin, Tween 40 and Tween 60. Chemotaxonomic analysis revealed menaquinone-7 as the predominant respiratory quinone and anteiso-C15:0, anteiso-C17:0, iso-C16:0 and iso-C15:0 as major fatty acids. The genomic DNA G+C content of strain A1g(T) was 36.3 mol%. Comparative 16S rRNA gene sequence analysis revealed that the new isolate belonged to the genus Oceanobacillus and exhibited closest phylogenetic affinity to the type strains of Oceanobacillus oncorhynchi subsp. incaldanensis (97.9 % similarity) and O. oncorhynchi subsp. oncorhynchi (97.5 %), but less than 97 % sequence similarity with respect to the type strains of other recognized Oceanobacillus species. Levels of DNA-DNA relatedness between strain A1g(T) and reference strains O. oncorhynchi subsp. incaldanensis DSM 16557(T), O. oncorhynchi subsp. oncorhynchi JCM 12661(T) and Oceanobacillus iheyensis DSM 14371(T) were 29, 45 and 38 %, respectively. On the basis of phenotypic and genotypic data, strain A1g(T) is considered to represent a novel species of the genus Oceanobacillus, for which the name Oceanobacillus neutriphilus sp. nov. is proposed. The type strain is A1g(T) (=CGMCC 1.7693(T) =JCM 15776(T)).

Microplastic pollution in deep-sea sediments and organisms of the Western Pacific Ocean.

Microplastics are ubiquitous in marine environments. Sediments and marine organisms are recognized as the carriers and final destinations of microplastics. However, research on the concentration and abundance of microplastics in deep-sea sediments and organisms is limited. In this study, samples of sediments and organisms were collected from deep-sea locations of the western Pacific Ocean, with the depth ranging from 4601 m to 5732 m. Microplastics were extracted from the samples and analyzed by micro-Fourier-transform infrared spectroscopy. The average abundance of microplastics in the sediments was 240 items per kg dry weight of sediment. The microplastics were predominantly fibrous in shape (52.5%), blue in color (45.0%), and less than 1 mm in size (90.0%). The most commonly detected polymers were poly(propylene-ethylene) copolymer (40.0%) and polyethylene terephthalate (27.5%). The concentrations of polychlorinated biphenyls (PCBs), which are representatives of persistent organic pollutants, in the pore water of sediment samples were also investigated. A significant correlation between the distribution of microplastics and the PCB concentrations in sediments was found (P = 0.016). Microplastics were also detected in deep-sea organisms (i.e., Crinoidea, Pheronematidae, Ophiuroidea, and Gammaridea) in the sampling region, with an abundance of 0-3 items per individual biological sample. This assessment of microplastics in deep-sea sediments and benthic organisms of the western Pacific Ocean confirms that microplastic pollution exists in the deep-sea ecosystems of this region.

Interaction between microbial communities and various plastic types under different aquatic systems.

This study investigated the physicochemical surface changes of various plastics caused by indigenous communities. The first invading microbes on plastics in 4 different aquatic communities including seawater, freshwater, marine sediments and lake sediments were developed in microcosm incubation experiments. A mixture of weathered plastics (PE, PS, PET) was incubated with different indigenous communities under their respective habitat simulations. All microbial communities were able to form populations on all plastic surfaces with time-dependent development. Biofilm also affected floatation of plastics and the communities on PE foam (PF) were dominated by genera affiliated with plastic and hydrocarbon degraders. The results showed that indigenous populations were able to degrade plastic pieces and utilize them as carbon sources where the weight of PF was reduced more effectively than PS and PET. Besides, carbonyl groups that were seen with FTIR on initial PF disappeared after microbial treatment along with signs of bioerosion on the plastic surface.

Using Multilayered Hydrogel Bioink in Three-Dimensional Bioprinting for Homogeneous Cell Distribution.

During the extrusion-based three-dimensional bioprinting process, liquid-like bioinks with low viscosity can protect cells from membrane damage induced by shear stress and improve the survival of the encapsulated cells. However, rapid gravity-driven cell sedimentation in the reservoir could lead to an inhomogeneous cell distribution in bioprinted structures and therefore hinder the application of liquid-like bioinks. Here, we developed a novel multilayered modified strategy for liquid-like bioinks (e.g., gelatin methacryloyl with low viscosity) to prevent the sedimentation of encapsulated cells. Multiple liquid interfaces were manipulated in the multilayered bioink to provide interfacial retention. Consequently, the cell sedimentation action going across adjacent layers in the multilayered system was retarded in the bioink reservoir. It was found that the interfacial retention was much higher than the sedimental pull of cells, demonstrating a critical role of the interfacial retention in preventing cell sedimentation and promoting a more homogeneous dispersion of cells in the multilayered bioink.

Prefabrication of vascularized porous three-dimensional scaffold induced from rhVEGF(165): a preliminary study in rats.

BACKGROUND/AIMS: Several shortcomings have limited the routine use of autogenous vascularized bone graft. The present study investigates the prefabrication of vascularized scaffold with the desired shape and microarchitecture combined with recombinant human vascular endothelial growth factor 165 (rhVEGF(165)) to mimic autogenous vascularized bone graft. METHODS: Eighty-five porous calcium phosphate cement scaffolds constructed by rapid prototyping technology were divided into four groups: group A [rhVEGF(165)-fibrin sealant (FS) scaffold], group B (hVEGF(165) scaffold), group C (FS scaffold), and group D (scaffold alone). The release of rhVEGF(165) from the scaffolds was examined in vitro. The vessel density, relative functionalized vessels, vessel diameter and relative vessel area were also measured. RESULTS: The sustained release of hVEGF(165) lasted 14 days in the absence of plasmin and 12 days in the presence of plasmin in group A and 10 days in group B. There was no statistical difference between groups A and B at 2 or 4 weeks in terms of vessel density, relative functionalized vessels, vessel diameter, and relative vessel area, as between groups C and D. However, the above parameters were greater in groups A and B than groups C and D. CONCLUSION: The scaffolds with the desired shape and microarchitecture combined with rhVEGF(165) could shorten the time needed for the construction of prefabricated vascularized grafts and accelerate the maturation of the vessels.

A new glass sponge genus (Hexactinellida: Euplectellidae) from abyssal depth of the Yap Trench, northwestern Pacific Ocean.

In this article we report on a hexactinellid sponge new to science, Rhizophyta yapensis gen. et sp. nov., which was collected from the Yap Trench in the northwestern Pacific Ocean at an abyssal depth of 4159-4779 m. Its fungus-like body form with long peduncle and absence of hypodermalia suggest placement within the euplectellid subfamily Bolosominae Tabachnick, 2002, whereas molecular phylogenetic evidence suggests that it is sister to all remaining Euplectellidae Gray, 1867. Its rhizophytous method of attachment to the substrate, hitherto unknown from bolosomine Euplectellidae, a veil of pentactins covering the peduncle, and the presence of toothed discohexasters as the only type of microscleres, clearly characterize it as a new genus. The intraspecific divergence between holotype and paratypes of the new species is examined with both morphological and molecular approaches. This report represents the first record of a hexactinellid sponge from the Yap Trench.

Microplastics in offshore sediment in the Yellow Sea and East China Sea, China.

Microplastic particles are a global concern due to their widespread and growing threat to marine and coastal environments. To improve knowledge of microplastic pollution in China, we investigated 25 sediment samples collected with a box corer in the Southern Yellow Sea and East China Sea off the coast of China. The microplastics were extracted from sediments via density separation, after which they were observed under a microscope and characterized according to shape, color, and size, while polymer type identification was performed using micro-Fourier transform infrared spectroscopy. The abundance of microplastics in the offshore region of the Southern Yellow Sea and East China Sea was mapped. The mean concentration of microplastics at the 25 sites was 13.4 ±â€¯0.6 particles 100 g-1 dry weight (range: 6.0-24.0 particles 100 g-1 dry weight). Based on the categorization according to shape, color, and size, fiber (77%) was the most abundant shape, while blue (35%) and transparent (29%) were the most prevalent colors. In addition, the dominant size of microplastics was smaller than 1000 µm which accounted for 89%. Finally, polyethylene, polyethylene terephthalate, acrylic, polyester, cellulose, and cellophane were the most abundant types of microplastics identified. Our result highlighted the presence of microplastics in offshore sediments from the Yellow Sea and East China Sea, and provided useful information for evaluating the environmental risks posed by microplastics in China.

New Hexactinellid Sponge Chaunoplectella megapora sp. nov. (Lyssacinosida: Leucopsacidae) from Clarion-Clipperton Fracture Zone, Eastern Pacific Ocean.

The new Hexactinellid sponge Chaunoplectella megapora sp. nov. reported in this study was collected from the COMRA contract area, the western part of Clarion-Clipperton Fracture Zone (CCFZ) in the eastern Pacific Ocean at a depth of 5258 m. This sponge's extraordinary multiporous body with the presence of unique codonhexasters, sigmatocomes, toothed discohexasters and hemidiscohexasters, as well as stellate disocohexasters, characterizes it as a new species in the genus Chaunoplectella. This report presents the first record of family Leucopsacidae at this site in the eastern Pacific Ocean.

A General Strategy for Extrusion Bioprinting of Bio-Macromolecular Bioinks through Alginate-Templated Dual-Stage Crosslinking.

The recently developed 3D bioprinting technology has greatly improved the ability to generate biomimetic tissues that are structurally and functionally relevant to their human counterparts. The selection of proper biomaterials as the bioinks is a key step toward successful bioprinting. For example, viscosity of a bioink is an important rheological parameter to determine the flexibility in deposition of free-standing structures and the maintenance of architectural integrity following bioprinting. This requirement, however, has greatly limited the selection of bioinks, especially for those naturally derived due to their commonly low mechanical properties. Here the generalization of a mechanism for extrusion bioprinting of bio-macromolecular components, mainly focusing on collagen and its derivatives including gelatin and gelatin methacryloyl, is reported. Specifically, a templating strategy is adopted using a composite bioink containing both the desired bio-macromolecular component and a polysaccharide alginate. The physically crosslinkable alginate component serves as the temporal structural support to stabilize the shape of the construct during bioprinting; upon subsequent chemical or physical crosslinking of the bio-macromolecular component, alginate can be selectively removed to leave only the desired bio-macromolecule. It is anticipated that this strategy is general, and can be readily expanded for use of a wide variety of other bio-macromolecular bioinks.

A new species of deep-sea sponge-associated shrimp from the North-West Pacific (Decapoda, Stenopodidea, Spongicolidae).

A new species of the deep-sea spongicolid genus Spongicoloides Hansen, 1908 is described and illustrated based on material from the northwestern Pacific. Spongicoloides weijiaensissp. n. was found inside a hexactinellid sponge, Euplectella sp., sampled by the Chinese manned submersible "Jiaolong" at depths of 2279 m near the Weijia Guyot, in the Magellan Seamount Chain. The new species can be distinguished from all congeneric species by several morphological features, involving gill formula, spination of the carapace, antennal scale, third pereiopod, telson and uropod, posteroventral teeth of the pleura, and dactyli of the fourth and fifth pereiopods. An identification key to the Pacific species of Spongicoloides is provided.

A new species of Ophryotrocha (Annelida, Eunicida, Dorvilleidae) from hydrothermal vents on the Southwest Indian Ridge.

Dorvilleids were collected from hydrothermal vents on the Southwest Indian Ridge by manned submersible Jiaolong. These represent a new species of Ophryotrocha that is here described as Ophryotrocha jiaolongisp. n. This is the first dorvilleid described from vents on the Southwest Indian Ridge. It most closely resembles another vent species, Ophryotrocha akessoni Blake, 1985 from the Galapagos Rift, but can be distinguished by its antennae, palps, jaw structure. The new species has particularly distinctive mandibles, which allow it to be easily identified.

Implantable and Biodegradable Macroporous Iron Oxide Frameworks for Efficient Regeneration and Repair of Infracted Heart.

The construction, characterization and surgical application of a multilayered iron oxide-based macroporous composite framework were reported in this study. The framework consisted of a highly porous iron oxide core, a gelatin-based hydrogel intermediary layer and a matrigel outer cover, which conferred a multitude of desirable properties including excellent biocompatibility, improved mechanical strength and controlled biodegradability. The large pore sizes and high extent of pore interconnectivity of the framework stimulated robust neovascularization and resulted in substantially better cell viability and proliferation as a result of improved transport efficiency for oxygen and nutrients. In addition, rat models with myocardial infraction showed sustained heart tissue regeneration over the infract region and significant improvement of cardiac functions following the surgical implantation of the framework. These results demonstrated that the current framework might hold great potential for cardiac repair in patients with myocardial infraction.

A new species of the thorid genus Paralebbeus Bruce & Chace, 1986 (Crustacea: Decapoda: Caridea) from the deep sea of the Northwestern Pacific Ocean.

During recent dives by the Chinese manned submersible "Jiaolong", some shrimp specimens were sampled from the deep sea of the Northwestern Pacific Ocean. A new species of the caridean family Thoridae, Paralebbeus jiaolongi sp. nov., is described and illustrated in this study. The rostrum armed with only one subterminal ventral tooth can easily distinguish the new species from its congeners.

A new species of Munidopsis Whiteaves, 1874 (Crustacea: Decapoda: Anomura) from the Northwest Indian Ocean Ridge.

A new species, Munidopsis militaris n. sp., from the Carlsberg Ridge, Northwest Indian Ocean Ridge is described herein. The species belongs to a group of species having a pair of epigastric spines, mesial and lateral eye-spines, abdominal tergites unarmed, five or six spines on the lateral margin of the carapace, and a denticulate carina on the distolateral margin of the P1 fixed finger. It can be distinguished from its relatives by the spinous lateral margin of the palm and dorsal carinae on the P2-4 propodus. The Munidopsis fauna of the Indian Ocean Ridge is seldom reported on; this new species is the sixth member of this genus found inhabiting the Indian Ocean Ridge.