N-butyl-2 cyanoacrylate (NBCA) embolus in the graft portal vein after portosystemic collateral embolization in liver transplantation recipient: what is the clinical significance?

Background An N-butyl-2 cyanoacrylate (NBCA) embolus in the graft portal vein was frequently observed after an intraoperative embolization of portosystemic collaterals performed to prevent portal steal in liver transplant (LT) recipients. The radiological and clinical features of NBCA emboli have not yet been described. Purpose To describe radiological and clinical features of NBCA embolus in graft portal vein after portosystemic collateral embolization in LT recipients. Material and Methods A total of 165 consecutive LT recipients who had undergone intraoperative NBCA embolization of varix were found in single institution's computerized databases of a clinical cohort of LT. Patients were evaluated for NBCA emboli (categorized into major and minor emboli according to location) on first postoperative computed tomography (CT). All electronic medical records and radiologic studies including follow-up was evaluated to determine any radiological and clinical abnormality associated with NBCA embolus. Results NBCA emboli were found in 24% (39/165) of recipients. Although most patients had minor emboli (77%, 30/39) without remarkable ultrasonography (US) abnormalities, seven (78%) of nine recipients with major emboli showed intraluminal echogenic lesions in graft portal vein on grayscale US, and five of them (71%) showed partial portal flow obstruction, although none exhibited any abnormality on contrast-enhanced US. Recipients with NBCA portal emboli showed no significant clinical abnormalities and were discharged safely. NBCA embolus eventually disappeared mostly within six months (82%, 32/39). Conclusion NBCA emboli are frequently observed after portosystemic collateral embolization in LT recipients and are not associated with poor clinical outcome. They may mimic ordinary thromboemboli on US.

Microbial Activation of Bacillus subtilis-Immobilized Microgel Particles for Enhanced Oil Recovery.

Microbially enhanced oil recovery involves the use of microorganisms to extract oil remaining in reservoirs. Here, we report fabrication of microgel particles with immobilized Bacillus subtilis for application to microbially enhanced oil recovery. Using B. subtilis isolated from oil-contaminated soils in Myanmar, we evaluated the ability of this microbe to reduce the interfacial tension at the oil-water interface via production of biosurfactant molecules, eventually yielding excellent emulsification across a broad range of the medium pH and ionic strength. To safely deliver B. subtilis into a permeable porous medium, in this study, these bacteria were physically immobilized in a hydrogel mesh of microgel particles. In a core flooding experiment, in which the microgel particles were injected into a column packed with silica beads, we found that these particles significantly increased oil recovery in a concentration-dependent manner. This result shows that a mesh of microgel particles encapsulating biosurfactant-producing microorganisms holds promise for recovery of oil from porous media.

Simethicone to prevent colonic bubbles during CT colonography performed with polyethylene glycol lavage and iohexol tagging: a randomized clinical trial.

OBJECTIVE: The purpose of this study was to determine whether the occurrence of numerous colonic bubbles during CT colonography (CTC) performed with polyethylene glycol cleansing and oral iohexol fecal/fluid tagging could be prevented by use of simethicone. SUBJECTS AND METHODS: Adults with suspected colonic neoplasia who had been randomly assigned to control and simethicone intervention groups underwent CTC after cleansing with 4 L of polyethylene glycol, tagging with 50 mL of 350 mg I/mL oral iohexol, and without (control) or with (intervention) oral administration of 200 mg of simethicone. Colonic segments in the control and intervention groups were evaluated for amount of colonic bubbles during CTC. A 6-point grading system was used in which 0 indicated no bubbles and 5 indicated that more than three fourths of the air-distended mucosa was covered with bubbles. The primary endpoint was a per-patient colonic bubble grade, derived as an average of the segmental grades. RESULTS: Eighty adults with suspected colonic neoplasia were randomly assigned to the control (40 patients) and simethicone intervention (40 patients) groups. A total of 659 colonic segments in the control group and 689 segments in the intervention group were evaluated for amount of colonic bubbles during CTC. The per-patient colonic bubble score was significantly lower in the simethicone intervention group than in the control group. The mean score was 0.0±0.1 (SD) versus 1.2±0.8 (p<0.001; 95% CI for the mean difference, -1.4 to -1.0). In the intervention group, 673 (97.7%) segments were grade 0, and 16 (2.3%) were grade 1. In contrast, in the control group, 226 (34.3%) segments were grade 0; 173 (26.3%), grade 1; 175 (26.6%), grade 2; 45 (6.8%), grade 3; 23 (3.5%), grade 4; and 17 (2.6%), grade 5. CONCLUSION: The colonic bubbles associated with fecal/fluid tagging with iohexol can be successfully prevented by adding simethicone to the colonic preparation.

Effect of Gamma Irradiation on the Osteoinductivity of Demineralized Dentin Matrix for Allografts: A Preliminary Study.

Demineralized dentin matrix (DDM) treated with gamma irradiation (GR) has shown promising results as an allograft without any adverse effects in in vivo and clinical studies. The purpose of this study was to evaluate the effects of 15 and 25 kGy GR on the osteoinductive properties of DDM at extra-skeletal sites. As a control group, non-irradiated DDM powder was implanted into the right subcutaneous tissues of the dorsal thigh muscles of 20 nude mice. DDM powder irradiated with 15 and 25 kGy was implanted into the left side. After two and four weeks, the bone mineral density (BMD) was measured with dual-energy X-ray absorptiometry. After confirming osteoblast- and osteoclast-specific activities by alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) staining, a histological analysis was performed to measure the new bone formation and the number of osteoblasts and osteoclast-like cells on the surface of the DDMs. Histomorphometry was used to calculate the new bone formation area on the surface of the DDM particles (DDMs). The BMD in all the groups increased from two and four weeks without statistically significant differences. The osteoblasts were dominantly activated on DDM without GR, and DDM treated with 25 kGy compared to DDM treated with 15 kGy. Among the groups, new bone formation was identified in all the groups at each time point. In conclusion, GR at doses of 15 and 25 kGy does not affect the osteoinductive properties of DDM powder.

Effects of Caries Activity on Compositions of Mutans Streptococci in Saliva-Induced Biofilm Formed on Bracket Materials.

This study aimed to investigate effects of caries activity on composition of mutans streptococci in saliva-induced biofilms formed on bracket materials. Three bracket materials were used as specimens: ceramic, metal, and plastic. After saliva was collected using a spitting method from caries-active (CA, decayed, missing, filled teeth (DMFT) score ≥ 10) and caries-free (CF, DMFT score = 0) subjects, saliva was mixed with growth media in a proportion of 1:10. The saliva solution was then incubated with each bracket material. After a saliva-induced biofilm was developed on the surface of the bracket material, the amounts of total bacteria and mutans streptococci were determined using real-time polymerase chain reaction. The results showed that biofilms from CA saliva contained more mutans streptococci but less total bacteria than biofilms from CF saliva, regardless of material type. Adhesion of total bacteria to ceramic was higher than to plastic, regardless of caries activity. Mutans streptococci adhered more to ceramic than to metal and plastic in both biofilms from CA and CF saliva, but there was a difference in adhesion between Streptococcus mutans and Streptococcus sobrinus. The amount of S. mutans was higher than that of S. sobrinus in biofilms from CA saliva despite similar amounts of the two strains in biofilms from CF saliva. The stronger adhesion of S. mutans to ceramic than to metal and plastic was more evident in biofilms from CA saliva than in biofilms from CF saliva. This study suggests that caries activity and material type significantly influenced composition of mutans streptococci in biofilms formed on bracket materials.

Surface Induced nanofiber growth by self-assembly of a silk-elastin-like protein polymer.

Many synthetic and natural peptides are known to self-assemble to form various nanostructures. During the self-assembling process, environmental conditions such as salt concentration, pH, temperature, and surface characteristics play a critical role by influencing intermolecular interactions, and hence the process of self-assembly. Here we studied the self-assembly of a genetically engineered protein polymer composed of silk-like and elastin-like repeats on a mica surface. Silk-elastin-like protein polymers (SELPs) consist of tandem repeats of Gly-Ala-Gly-Ala-Gly-Ser from Bombyx mori (silkworm) and Gly-Val-Gly-Val-Pro from mammalian elastin. At a very low polymer concentration of 1 mug/mL, SELPs self-assembled into nanofibrous structures on a mica surface. Examination using atomic force microscopy (AFM) and dynamic light scattering techniques showed that SELPs self-assembled into nanofibers in the presence of the mica surface but not in the bulk state. Ionic strength had a significant influence on nanofiber growth, indicating the importance of electrostatic interactions between the polymer and the mica surface. At low ionic strength, the kinetics of nanofiber growth showed that the mica surface effectively removed a lag phase by providing nucleating sites, facilitating nanofiber self-assembly of SELPs. Furthermore, self-assembly on additional substrates such as silicon and a hydrophobic pyrolytic carbon surface revealed that the charged hydrophilic surface provides the optimal surface to facilitate self-assembly of SELPs.