Endoscopic Submucosal Dissection (ESD) Offers a Safer and More Cost-effective Alternative to Transanal Endoscopic Microsurgery (TEM): An International Collaborative Study.

BACKGROUND: Endoscopic submucosal dissection (ESD) and transanal endoscopic microsurgery (TEM) are minimally invasive procedures that treat early rectal cancer (ERC). Both are effective treatments, yet there are very few studies comparing them. The aim of our study was to identify ideal candidates for each procedure. MATERIALS AND METHODS: Between January 2016 and November 2019, 204 ERC patients were managed with either ESD (n=101) or TEM (n=103) at 7 international centers. Data analyzed included clinical success, tumor characteristics, procedure info, and recurrence rates. RESULTS: Median tumor size was 40 mm±23.9 in the ESD group and 56 mm±27.9 in the TEM group, significantly larger in the latter ( P <0.00001). Average procedure time was 131.5±67.9 minutes in ESD group and 104.9±28.4 minutes in TEM group ( P =0.000347). Average hospital stay was 3.3±2.6 days in the ESD group and 4.7±0.7 days in the TEM group ( P <0.00001). Adverse event rate was 6.8% in the ESD group and 24% in the TEM group. There were no significant difference in the rate of en bloc resection, technical success, tumor location, necessity of additional procedures, and tumor recurrence rates. CONCLUSION: Compared with TEM, ESD is a safer procedure with shorter hospital stay and should be offered for patients who have ERC.

An in vitro model of microbial contamination in the operating room.

Infection associated with tissue-contacting biomedical devices is a compelling clinical problem initiated by the microbial colonization of the device surface. Among the possible sources of contaminating bacteria is the operating room (OR) itself, where viable bacteria in the atmosphere can sediment onto a device surface intraoperatively. We have developed an aerosolizing system that can reproducibly spray small quantities of aerosolized bacteria onto a surface to mimic OR contamination. This paper describes the design of the system and characterizes key aspects associated with its operation. The area density of sprayed bacteria is on the order of 102 /cm2 . Using titanium (Ti) alloy coupons as test substrates contaminated by staphylococci, we quantify the fraction of bacteria that are well adhered to the substrate, those that can be removed by sonication, and those that are not recovered after spraying. Despite the relatively low levels of surface contamination, we furthermore show that such a model is able to demonstrate a statistically significant reduction in colonization of Ti coupons modified by antimicrobial quaternary ammonium compounds relative to unmodified controls.

Optimizing the safety of intradiscal platelet-rich plasma: an in vitro study with Cutibacterium acnes.

Aim: The most common risk associated with intradiscal injection of platelet-rich plasma (PRP) is discitis with Cutibacterium acnes. It is hypothesized that antimicrobial activity of PRP can be enhanced through inclusion of leukocytes or antibiotics in the injectate. Materials & methods: Multiple PRP preparations of varying platelet and leukocyte counts were co-cultured with C. acnes with or without cefazolin, with viable bacterial colony counts being recovered at 0, 4, 24 and 48 hours post-inoculation. Results: A direct correlation between C. acnes recovery and granulocyte counts were observed. Conclusion: We observed the greatest antimicrobial activity with the leukocyte-rich, high platelet PRP preparation combined with an antibiotic in the injectate. However, cefazolin did not completely clear the bacteria in this assay.

Transcatheter Tricuspid Valve-in-Valve Replacement Via Right Internal Jugular Vein Access in a 39-Year-Old Woman.

Transcatheter tricuspid valve-in-valve replacement via right internal jugular is safe and feasible for failed bioprosthetic valve implantation. Challenging aspects include stiff wire advancement into the pulmonary artery for rail establishment and multiple push-pull manipulations for balloon and valve advancement.

Ultrafast electron and energy transfer in dye-sensitized iron oxide and oxyhydroxide nanoparticles.

An emerging area in chemical science is the study of solid-phase redox reactions using ultrafast time-resolved spectroscopy. We have used molecules of the photoactive dye 2',7'-dichlorofluorescein (DCF) anchored to the surface of iron(III) oxide nanoparticles to create iron(II) surface atoms via photo-initiated interfacial electron transfer. This approach enables time-resolved study of the fate and mobility of electrons within the solid phase. However, complete analysis of the ultrafast processes following dye photoexcitation of the sensitized iron(III) oxide nanoparticles has not been reported. We addressed this topic by performing femtosecond transient absorption (TA) measurements of aqueous suspensions of uncoated and DCF-sensitized iron oxide and oxyhydroxide nanoparticles, and an aqueous iron(III)-dye complex. Following light absorption, excited state relaxation times of the dye of 115-310 fs were found for all samples. Comparison between TA dynamics on uncoated and dye-sensitized hematite nanoparticles revealed the dye de-excitation pathway to consist of a competition between electron and energy transfer to the nanoparticles. We analyzed the TA data for hematite nanoparticles using a four-state model of the dye-sensitized system, finding electron and energy transfer to occur on the same ultrafast timescale. The interfacial electron transfer rates for iron oxides are very close to those previously reported for DCF-sensitized titanium dioxide (for which dye-oxide energy transfer is energetically forbidden) even though the acceptor states are different. Comparison of the alignment of the excited states of the dye and the unoccupied states of these oxides showed that the dye injects into acceptor states of different symmetry (Ti t2gvs. Fe eg).

Electron small polarons and their mobility in iron (oxyhydr)oxide nanoparticles.

Electron mobility within iron (oxyhydr)oxides enables charge transfer between widely separated surface sites. There is increasing evidence that this internal conduction influences the rates of interfacial reactions and the outcomes of redox-driven phase transformations of environmental interest. To determine the links between crystal structure and charge-transport efficiency, we used pump-probe spectroscopy to study the dynamics of electrons introduced into iron(III) (oxyhydr)oxide nanoparticles via ultrafast interfacial electron transfer. Using time-resolved x-ray spectroscopy and ab initio calculations, we observed the formation of reduced and structurally distorted metal sites consistent with small polarons. Comparisons between different phases (hematite, maghemite, and ferrihydrite) revealed that short-range structural topology, not long-range order, dominates the electron-hopping rate.

Thin water film formation on metal oxide crystal surfaces.

Reactions taking place at hydrated metal oxide surfaces are of considerable environmental and technological importance. Surface-sensitive X-ray methods can provide structural and chemical information on stable interfacial species, but it is challenging to perform in situ studies of reaction kinetics in the presence of water. We have implemented a new approach to creating a micrometer-scale water film on a metal oxide surface by combining liquid and gas jets on a spinning crystal. The water films are stable indefinitely and sufficiently thin to allow grazing incidence X-ray reflectivity and spectroscopy measurements. The approach will enable studies of a wide range of surface reactions and is compatible with interfacial optical-pump/X-ray-probe studies.

Histopathological characterization of a Cameron lesion.

Cameron lesions are linear erosions located at the neck of a hiatal hernia (HH) in patients with a large HH. The prevalence has been seen in up to 5% of patients with HH who undergo esophagogastroduodenoscopy, and they can be associated with overt gastrointestinal bleeding or anemia. These lesions occur due to vascular compression by the diaphragm in a large sliding HH. Histopathologic changes seen in the biopsy tissue of a Cameron lesion are due to ischemia, but this ischemia is reversible with treatment of HH. The existence of this entity and the histopathologic picture of a Cameron lesion is not well known to pathologists, and therefore, a microscopic picture of a Cameron lesion can be easily confused with ischemic gastritis. Ischemic gastritis is the result of atherosclerosis, usually seen in older people, unrelated to HH, and is not easily reversible. The authors received a gastric biopsy of a hiatal hernia without any associated clinical diagnosis of a Cameron lesion conveyed to the pathologist. This biopsy tissue showed ischemic changes in the gastric mucosa on microscopic examination. Diagnosis of ischemic gastritis was considered but ruled out after the case was discussed with the gastroenterologist. The correct diagnosis was made once the clinical diagnosis of HH with Cameron lesion (ie, a vertical red erosion) was made known to the pathologist. By reporting this case, the authors aim to increase awareness of Cameron lesion among pathologists so that they ask about the presence of a Cameron lesion before making the diagnosis of ischemic gastritis.

Osteoconductivity and osteoinductivity of Puros(R) DBM putty.

Bone graft substitutes have been developed due to the limited supply and morbidity associated with using autogenous graft material. Allogeneic demineralized bone matrix (DBM) has been used extensively as a clinical graft material because of its inherent osteoinductive and osteoconductive properties. Differential enhancement of these properties may optimize the performance of these products for various orthopedic and craniofacial applications. Commercially available bone paste products consist of formulations that combine DBM with a carrier to facilitate handling and containment. In the present study, we present results of a comprehensive in vitro and in vivo characterization of a 100% human DBM putty product, Puros DBM Putty. Results indicate the DBM particles are completely dispersed in the putty. Data are presented showing the porosity of and cell attachment to Puros DBM Putty, thereby demonstrating the osteoconductive properties of this DBM. Puros DBM Putty was also shown to be osteoinductive in the rat ectopic pouch model. We demonstrate here for the first time that Puros DBM Putty maintains its activity to markedly stimulate or induce bone formation over the entire period of its shelf life. Taken together, these data demonstrate that the 100% human allograft derived Puros DBM Putty could be an effective bone graft substitute.

Local antibiotic delivery with bovine cancellous chips.

Infected bone defects and osteomyelitis are encountered frequently in trauma cases. Currently, the standard of care for osteomyelitis cases is prolonged systemic antibiotic therapy and implantation of antibiotic carrier beads. However, this method requires a secondary surgery to remove the beads after the infection has cleared. In the present study a common bone void filler was investigated for its ability to be infused with an antibiotic. This study demonstrates that the xenograft material tested can be loaded with gentamicin and release clinically relevant levels of the drug for at least 14 days in vitro allowing for the inhibition of bacterial growth on the graft. This study also demonstrates that the levels of gentamicin released did not have an adverse effect on primary osteoblast cell proliferation or ability to generate alkaline phosphatase. This bone void filler may represent a viable alternative to current methods of local antibiotic delivery in orthopedic applications.

Incorporation and immunogenicity of cleaned bovine bone in a sheep model.

This study was conducted to determine if a novel cleaning process could extract antigenic material from bovine bone thereby improving incorporation. Cleaned bovine xenograft, untreated bovine xenograft and sheep allograft were implanted into the tibia of mature sheep for 12 and 24 weeks. Inflammation, bone integration and immunological reactions were evaluated via standardized assays. Cleaned bovine bone dowels induced significantly lower inflammatory responses (p < 50.05) when compared to traditionally processed xenograft. Bone integration, measured by in situ biomechanics, was not different between cleaned bovine bone and allograft controls (p = 0.96). A transient antibody response was observed for non-treated xenografts although this response abated by 3 months.

Demineralized bone matrix as an osteoinductive biomaterial and in vitro predictors of its biological potential.

The osteoinductivity of demineralized bone matrix (DBM) varies from donor to donor as a result of varying levels of multiple growth factors, matrix integrity, and artifacts from material processing. Many in vitro assays are currently used for screening the osteoinductivity of DBM. The objectives of this study were to determine the correlation of specific growth factors and in vitro mitotic stimulation to in vivo ectopic bone formation capacity with a large number of DBM samples. Samples were assayed using ELISA methods for BMP-2/4 and TGF-beta1 (n = 304) and cell proliferation using SAOS-2 osteoblasts (n = 239). All samples were then implanted intramuscularly in the abdomen of nude rats. All in vitro assays showed significant variability for any particular level of ostoinductivity determined by in vivo model. A significant, but only very weak, positive correlation to in vivo results was found for TGF-beta1 (r(2) = 0.016), BMP 2/4 (r(2) = 0.065), and SAOS-2 cell proliferation (r(2) = 0.053). The results of this study amplify the notion that a multitude of factors and their relative interplay, rather than a single factor are likely to determine the potency of any particular lot of DBM.

Factors that influence transgene expression and cell viability on DNA-PEI-seeded collagen films.

Gene delivery from tissue-engineering devices has the potential to improve healing, but better regulation of the level and duration of gene expression is needed. We hypothesized that transgene expression could be controlled by varying the fabrication and soaking parameters used in making collagen- based gene delivery scaffolds. Collagen films were made from acid-insoluble type I bovine dermal collagen and seeded with plasmid DNA encoding firefly luciferase, complexed with polyethylenimine. By varying the thickness of the films, the volume of the DNA soak solution, and the pH of the DNA soak solution, and by cross-linking the films, we identified variable combinations that produce significantly different levels of cell number and transgene expression in L-929 cells in vitro. Increasing film thickness or soak volume increased overall reporter gene expression. Decreasing film thickness or soak volume decreased cell number but did not significantly change reporter gene expression per cell. Cross-linking by ultraviolet irradiation (before adding the DNA) significantly decreased transgene expression, probably because of decreased swelling of the collagen film. These results suggest that collagen-based biomaterials may be designed and fabricated to induce, in a controlled fashion, various levels of cellularity and transgene expression.

False aneurysm of the mitral-aortic intervalvular fibrosa after uncomplicated aortic valve replacement.

False aneurysms of the mitral-aortic intervalvular fibrosa are rare and usually complicate aortic valve endocarditis. We report a case of a false aneurysm of the mitral-aortic intervalvular fibrosa after recent bioprosthetic aortic valve replacement in the absence of endocarditis.