Histopathological Evaluation of Bipolar and Microneedle Radiofrequency Energy on the Skin and Fat of the Abdominal Region of the Rat.

BACKGROUND: Radiofrequency (RF)-based devices are frequently used in plastic surgeries. In the current literature, no comparative experimental study has demonstrated the histological and immunological effects of these devices that are frequently used in the facial area. In this study, we investigated the histological and immunological effects of Bipolar RF (BodyTite) and Microneedle RF (Morpheus 8) devices in the rat abdominal region. METHODS: 24 rats were used in this study. The rats were divided into four groups: group I: Control. In group II, BodyTite was applied to the abdominal region. Group III: Morpheus 8 was applied to the abdominal region. Group IV: Both Morpheus 8 and BodyTite were applied to the abdominal region. The histological and immunological features of the tissues in the groups were examined using light microscopy, and collagen formation and desmosome structures were examined using light microscopy. RESULTS: Collagens in Group II were thinner than those in the other groups. In addition, there were fewer vessels in Group III. The collagen scores were as follows: Group II:1.5; Group III:2; and Group IV:3. The VEGF scores were II:2.5, group III:2, and IV:3, respectively. The collagen score in group II and VEGF score in group III were significantly lower than those in the other groups. In addition, the bonds between desmosomes in group III were found to be looser using electron microscopy. Collagen morphology in groups III and IV was found to be similar to that in group I. CONCLUSIONS: The conclusion of comparison RF-based devices increased tissue regeneration and healing. CLINICAL RELEVANCE STATEMENT: The use of radiofrequency devices has increased in plastic surgery practice over the past two decades, particularly emerging as a unique alternative for non-surgical candidates. There is a lack of experimental studies concerning these commonly used devices in clinical practice.

Evaluation of graphene oxide-doped poly-lactic-co-glycolic acid (GO-PLGA) nanofiber absorbable plates and titanium plates for bone stability and healing in mandibular corpus fractures: An experimental study.

BACKGROUND: Open reduction with internal fixation is the preferred treatment option for displaced facial bone fractures. The superior mechanical properties of metallic plates have made them the most widely used material in existing bone fixation systems. However, after the healing period, these permanent plates can cause various problems. Alternative bioresorbable materials are being investigated to reduce these potential problems. This study compares bone stability and viability by using graphene oxide (GO)-doped poly-lactic-co-glycolic acid (PLGA) nanofiber plates and titanium plates for rats with fractured mandibles. MATERIALS AND METHODS: The study included 20 male Sprague-Dawley rats, divided into four groups: a control group (Group I), a mandibular fracture group with no additional application (Group II), a mandibular fracture group repaired with titanium plates (Group III), and a mandibular fracture group repaired with GO-PLGA plates (Group IV). After 2 months, all of the rats were euthanized. A bone compression test was performed to assess bone stability, and a histological examination was performed to evaluate bone healing. RESULTS: The osteocyte lacunae, Haversian ducts, canaliculi, and vascular structures of Group IV were found to be higher. In the compression test, vertical compression was applied to the bone axis, and Group IV had a higher maximum load and maximum stretch. GO-PLGA plates were found to be statistically superior to titanium plates in terms of both bone stability and bone healing (p < 0.05). CONCLUSIONS: The present study found that GO-PLGA plates are more effective than titanium plates for the treatment of mandibular corpus fractures.

Surface characteristics of additively manufactured CoCr and Ti6Al4V dental alloys: The effects of carbon and gold thin film coatings, and alkali-heat treatment.

This study investigates the impact of surface modifications on additively manufactured CoCr and Ti6Al4V dental alloys, focusing on surface properties. Thin film carbon (C) and gold (Au) coatings, as well as alkali-heat treatment, were applied to the high- and low-polished specimens. Scanning electron microscopy (SEM) showed that thin film coatings retained the underlying surface topography, while the alkali-heat treatment induced distinct morphological changes. Energy-dispersive x-ray spectroscopy (EDS) analysis revealed that C-coating enriched surfaces with C, and Au-coating introduced detectable amounts of Au. Nevertheless, signs of coating delamination were observed in the high-polished specimens. Alkali-heat treatment led to the formation of a sodium titanate layer on Ti6Al4V surfaces, confirmed by sodium presence and Fourier transform infrared spectroscopy (FTIR) results showing carbonate bands. Surface roughness measurements with atomic force microscopy (AFM) showed that C-coating increased surface roughness in both high- and low-polished alloys. Au-coating slightly increased roughness, except for low-polished Au-coated Ti6Al4V, where a decrease in roughness was observed compared to low-polished bare Ti6Al4V, likely due to surface defects present in the latter resulting from the additive manufacturing process. Alkali-heat treatment led to a pronounced increase in roughness for both alloys, particularly for Ti6Al4V. Both thin film coatings decreased the water contact angles in all specimens in varying magnitudes, indicating an increase in wettability. However, the alkali-heat treatment caused a substantial decrease in contact angles, resulting in a highly hydrophilic state for Ti6Al4V. These findings underscore the substantial impact of surface modifications on additively manufactured dental alloys, potentially influencing their clinical performance. RESEARCH HIGHLIGHTS: Thin film coatings and chemical/heat treatment modify the surface properties of additively manufactured dental alloys. The surfaces of the alloys get rougher and more hydrophilic after alkali-heat treatment. Thin gold coatings exhibit potential adhesion challenges.

Characterization of Collagen from Jellyfish Aurelia aurita and Investigation of Biomaterials Potentials.

Marine collagen sources are potent alternatives due to abundant yield, low pathogen infection risk, high biocompatibility, and any religious and ethical restrictions compared to terrestrial collagen sources. In this research, we aim to investigate the biomaterials potential of the collagen from Aurelia aurita, which is a native jellyfish species in the Marmara Sea. Spectroscopic techniques were used to investigate the structure of jellyfish collagen (JCol) from acid-soluble fraction and compared to Jellagen® from Rhizostoma pulmo. MALDI-TOF showed the main peak of Jellagen® at 276,765.161 Da and jellyfish collagen at 276,761.687 Da. SDS-PAGE indicated α1 and α2 bands at about 122 kDa and 140 kDa, respectively. In FTIR and Raman spectra, the locations of amide bands of both species were almost the same. The pI of JCol was determined as 4.46. The particle size decreased abruptly at 43 oC from 890 to 290 nm. Water, organic and inorganic ratios of collagen were determined at 7.14%, 63.59, and 29.27 respectively. In DSC, the denaturation temperature (Td) of JCol was found at 43.7 oC and found to be higher than that of the collagens from jellyfishes that have been reported so far in the literature. Biocompatibility testing by metabolic assay revealed significantly higher fibroblast proliferation on collagen film than on the Tissue Culture Plate. To conclude, Aurelia aurita collagen would be a suitable source of collagen when biomaterials are needed to have high biocompatibility and unique macromolecular properties such as high denaturation temperatures.

Evaluation of photochemically cross-linked collagen/gold nanoparticle composites as potential skin tissue scaffolds.

Collagen type I is the main structural unit in skin tissue and is therefore used preferentially in skin tissue scaffolds. However, collagen-based 3D scaffolds have weak aqueous stability and degradation profiles in their uncross-linked states and chemical cross-linking reagents arise toxicity concerns, which generally restrict the spectrum of their biomedical applicability. Here, the research goal is to photochemically cross-link collagen type I with rose bengal (RB) when subjected to green laser light and to investigate the effect of silk sericin-capped gold nanoparticles (S-AuNP) when incorporated into scaffolds on the cross-linking process and thus on the scaffold properties. All the collagen scaffolds, that is plain collagen (C), collagen/S-AuNP (C-Au), cross-linked collagen (C-RBL), and cross-linked collagen/S-AuNP (C-AuRBL) were characterized for their potential as skin tissue scaffolds. C-AuRBL group had the best thermal stability, resistance to enzymatic degradation, and more uniform pore size distribution. None of the groups had cytotoxicity (cell viability > 70%) regarding the microscopic observations and MTT cell viability assays for L929 fibroblasts. L929 fibroblasts and primary adult human epidermal keratinocytes (HEKa) were also separately seeded on C-AuRBL scaffolds and according to microscopy results, they could support the stimulation of adhesion, morphological changes, and spreading of both cells, thereby encouraging the usage of this fabrication strategy for prospective skin tissue scaffolds.

Histological and Immunological Evaluation of the Osteogenic Effects of Compact Bone-Delivered Stem Cell on Spongiosis Bone in the Rat Zygomatic Arch Defect Model.

BACKGROUND: In stem cell applications, apart from bone marrow and adipose tissue, compact bone is also used as an alternative. However, studies on this subject are limited. In our study, we investigated the effect of stem cell derived from compact bone on rat zygomatic arch defect. METHODS: Fifteen rats were included in the study. Five rats were killed to obtain stem cells before the experiment. The rats were divided into 2 groups with 5 rats each. In group 1, compact bone-derived stem cell was applied. In group 2, adipose tissue-derived stem cell was applied. Right zygomatic arch defect was created in rats in both groups. Zygomatic bones were decellularized by cryosurgery. Stem cells were transferred to zygomatic bones. The number of stem cells, stem cell differentiation, and superficial markers obtained from the groups were examined. Histologically, cell structure, osteocyte count and osteopontin scores, elemental composition of the groups, percentages of resemblance to intact bone, osteocytes numbers, and cells were examined by electron microscopy of the bones in the groups after killing. RESULTS: The number of stem cells administered to the groups was 5 × 107 and 3.2 × 107 for group 1 and group 2, respectively (P > 0.05). Histologically, the morphology of the cells in group 1 was found to be healthier than group 2. The number of osteocytes was 97.56 ± 15.4 and 132.93 ± 10.8 in group 1 and group 2, respectively (P < 0.05). The osteopontin score was 3.47 ± 0.73 and 65 ± 0.64 in group 1 and group 2, respectively (P < 0.05). In the electron microscope examination, the morphologies of the cells in group 1 were seen more normal. The Ca/P ratio of the groups was 1.51 and 1.59 in group 1 and group 2, respectively (P > 0.05). Osteocyte counts were 10.7 ± 2.8 and 6.1 ± 1.2 in group 1 and group 2, respectively (P < 0.05). Morphological similarity percentages to normal bone were 88.4% and 79.6% in group 1 and group 2, respectively (P > 0.05). CONCLUSION: Stem cells obtained from compact bone gave positive results in zygomatic arch defect. This method can also be used as an alternative in stem cell applications.

Determination of the degree of conversion, the diffuse reflectance, and the color stability after different aging processes of gingiva-colored composite resins.

PURPOSE: To determine the degree of conversion (DC) and spectral diffuse reflectance of four different gingiva-colored composites and to evaluate their color stability after various aging processes. MATERIALS AND METHODS: The gingiva-colored composites were assigned to four experimental groups (Anaxgum (AG), Crea.lign paste Gum (CB), Gradia Gum (GR), SR Nexco Gum (NC)). A total of 120 disc-shaped specimens (10 × 2 mm) (n = 30/group) were polymerized in a Teflon mold. The nature of chemical bonding was studied by Fourier transform infrared spectroscopy (FTIR). Diffuse reflection spectra of the polymerized specimens were gathered using an ultraviolet-visible-near infrared (UV-Vis-NIR) spectrophotometer. Specimens subjected to aging methods were divided into three subgroups (n = 10): ultraviolet aging, hydrothermal aging, and autoclave aging. Color differences (ΔE*ab and ΔE00 ) were determined by colorimetry before and after aging. The statistical analysis was done using a two-way ANOVA along with paired sample t-test and Bonferroni's post hoc test. RESULTS: Conversion degrees varied between 26.9% and 59.7% and all groups showed 3 or 4 maxima at different positions in the visible region of the spectrum. Both ΔE*ab and ΔE00 values were significantly different from the groups of different brands for all types of aging processes. Similarly, there were significantly different ΔE*ab and ΔE00 values according to the aging procedure for all groups of particular brands, except for ΔE00 of SR Nexco Gum (NC). CONCLUSIONS: The aging procedures resulted in significant color differences between similar shades of four commercial gingiva-colored composites. The composite resins showed different degrees of conversion and diffuse reflectance spectra. The aging conditions tested affected the color stability. Patients with gingiva-colored indirect restorations should be informed about time-dependent discoloration.

Co-axial electrospinning of PLLA shell, collagen core nanofibers for skin tissue engineering.

The main functions of wound dressing biomaterials are to promote a moist environment in the wound while protecting the area from mechanical injury and microbial contamination. Furthermore, the scaffold used for skin tissue engineering must mimic epidermal and dermal layers as well as support the growth of keratinocytes and fibroblasts. In this study, PLLA (shell) and EGF-encapsulated collagen (core) nanofibers were produced by coaxial electrospinning at 25 kV potential, 12 cm collector distance, and 0.125 mL/h flow rate of PLLA (15%) and collagen (4%). The bilayer structure was produced by gelling GeIMA in between two nanofiber membranes to imitate the epidermal and dermal layers of skin. Cytocompatibility properties of nanofiber membrane and bilayer structure were characterized by mono- and coculture of keratinocytes (HaCaT) and fibroblasts (3T3), respectively. TEM revealed that the PLLA shell and collagen core thicknesses were about 60 and 115 nm, respectively. Oxygen and water vapor could pass through the GeIMA- integrated bilayer nanofiber membranes. The presence of EGF in nanofibers could increase cell proliferation. Fluorescence and SEM imaging showed that HaCaT and 3T3 could cover the membrane after 14 days of monoculture. Cocultures showed a reduction in the proliferation of cells in the first week and a recovery during the second and third weeks. In a mechanical bioreactor, cocultured bilayer membranes formed interlocked polygonal keratinocyte cells. These results showed that the bilayer nanofiber membrane and GeIMA combination provided cell compatibility. Furthermore, the use of a mechanical reactor was found to be effective in the formation of a functional keratinocyte layer by stimulating cells.

Bacterial content of the human pancreatic duct: An observational study.

Background: Pancreatic fistula/PF is a challenging surgical complication. We could recently show that intestinal bacteria such as Enterobacterales colonize the PF fluid even after a "sterile" operation like distal pancreatectomy/DP. Therefore, we explored the bacterial flora of the human pancreatic duct in a patient collective undergoing pancreatic surgery. Methods: In this observational study, upon transection of the pancreas during surgery, a swab was inserted into the main duct, and the micro-organismal content was correlated with clinical characteristics. Results: Between February 2017 and February 2020, an intraoperative swab from the pancreatic duct was obtained from a total of 54 patients who underwent pancreatico-duodenectomy/PD or DP. The swabs were sterile in 39 cases (72.2%), detected intestinal bacteria in 10 cases (18.5%), and other bacteria in 5 cases (9.3%). There was no correlation of the micro-organismal content of the pancreatic duct swab with bacteria detected in the PF fluid or bile. Preoperative ERCP was associated with a higher frequency of bacterial colonization of the pancreatic duct (33.3% vs. 6.7%, p = 0.005). There was no correlation of the pancreatic duct swabs with postoperative complications. Discussion: The human main pancreatic duct is usually sterile, and its bacterial colonization does not correlate with the occurrence of PF. Therefore, the mechanisms leading to infection of PF warrant in-depth, mechanistic investigation.

Mathematical surface function-based design and 3D printing of airway stents.

BACKGROUND: Three-dimensional (3D) printing is a method applied to build a 3D object of any shape from a digital model, and it provides crucial advantages especially for transferring patient-specific designs to clinical settings. The main purpose of this study is to introduce the newly designed complex airway stent models that are created through mathematical functions and manufactured with 3D printing for implementation in real life. METHODS: A mathematical modeling software (MathMod) was used to design five different airway stents. The highly porous structures with designated scales were fabricated by utilizing a stereolithography-based 3D printing technology. The fine details in the microstructure of 3D printed parts were observed by a scanning electron microscope (SEM). The mechanical properties of airway stents with various designs and porosity were compared by compression test. RESULTS: The outputs of the mathematical modeling software were successfully converted into 3D printable files and airway stents with a porosity of more than 85% were 3D printed. SEM images revealed the layered topography of high-resolution 3D printed parts. Compression tests have shown that the mathematical function-based design offers the opportunity to adjust the mechanical strength of airway stents without changing the material or manufacturing method. CONCLUSIONS: A novel approach, which includes mathematical function-based design and 3D printing technology, is proposed in this study for the fabrication of airway stents as a promising tool for future treatments of central airway pathologies.

Comparison of 3 Cell-Free Matrix Scaffolds Used to Treat Osteochondral Lesions in a Rabbit Model.

BACKGROUND: Various cell-free scaffolds are already in use for the treatment of osteochondral defects (OCDs); however, a gold standard material has not yet been defined. PURPOSE: This study compared the macroscopic, histological, and scanning electron microscopy (SEM) characteristics of Chondro-Gide (CG), MaioRegen (MA), and poly-d,l-lactide-co-caprolactone (PLCL) cell-free scaffolds enhanced with small-diameter microfractures (SDMs) for OCDs in a rabbit model. STUDY DESIGN: Controlled laboratory study. METHODS: In total, 54 knees from 27 rabbits were used in this study. Three rabbits were sacrificed at the beginning of the study to form an intact cartilage control group (group IC). An OCD model was created at the center of the trochlea, and SDMs were generated in 24 rabbits. Rabbits with OCDs were divided into 4 groups (n = 12 knees per group) according to the cell-free scaffold applied: CG (group CG), MA (group MA), PLCL (group PLCL), and a control group (group SDM). Half of the rabbits were sacrificed at 1 month after treatment, while the other half were sacrificed at 3 months after treatment. Healed cartilage was evaluated macroscopically (using International Cartilage Regeneration & Joint Preservation Society [ICRS] classification criteria) and histopathologically (using modified O'Driscoll scores and collagen staining). Additionally, cell-free scaffold morphologies were compared using SEM analysis. RESULTS: ICRS and modified O'Driscoll classification and staining with collagen type 1 and type 2 demonstrated significant differences among groups at both 1 and 3 months after treatment (P < .05). The histological characteristics of the group IC samples were superior to those of all other groups, except group PLCL, at 3 months after treatment (P < .05). In addition, the histological properties of group PLCL samples were superior to those of group SDM samples at both 1 and 3 months after treatment in terms of the modified O'Driscoll scores and type 1 collagen staining (P < .05). Concerning type 2 collagen staining intensity, the groups were ranked from highest to lowest at 3 months after treatment as follows: group PLCL (30.3 ± 2.6) > group MA (26.6 ± 1.2) > group CG (23.3 ± 2.3) > group SDM (18.9 ± 0.9). CONCLUSION: OCDs treated with enhanced SDM using cell-free PLCL scaffolds had superior histopathological and microenvironmental properties, more hyaline cartilage, and more type 2 collagen compared with those treated using CG or MA scaffolds. CLINICAL RELEVANCE: OCDs treated with PLCL cell-free scaffolds may have superior histopathological properties and contain more type 2 collagen than do OCDs treated with CG or MA cell-free scaffolds.

3D porous PCL-PEG-PCL / strontium, magnesium and boron multi-doped hydroxyapatite composite scaffolds for bone tissue engineering.

Bioceramic/polymer composite systems have gained importance in treating hard tissue damages using bone tissue engineering (BTE). In this context, it was aimed to develop 3D porous composite PCL-PEG-PCL scaffolds containing different amounts of B, Sr and Mg multi-doped HA that can provide bone regeneration in the bone defect area and to investigate the effect of both the amount of inorganic phase and the porosity on the mechanical and the biological properties. B-Sr-Mg multi-doped HA and PCL-PEG-PCL copolymer were successfully synthesized. PCL-PEG-PCL composite scaffolds containing different amounts of hydroxyapatite (HA) (10% and 20 wt%) were produced with the desired porosity (50% and 60%) by compression-molding and particulate leaching method. The porosity of the scaffolds was determined between 47% and 59%. HA/PCL-PEG-PCL composite scaffolds were subjected to a 3-week degradation test and showed negligible (0.2-0.5%) degradation. The water uptake percentage of the composite scaffolds with 60% porosity was the highest among all groups. Presence of HA in the scaffolds improved the water adsorption and the mechanical properties. Compressive strength of the scaffolds was between 9.32 and 24.27 MPa and 20% 2Sr0.5BHA scaffolds were found to have the maximum compressive strength. Compressive strength of 50% porous samples was higher than that of 60% porous samples. In the relative cell viability (%) test, the highest viability was observed on the scaffolds with HA and 2Sr0.5BHA. The specific ALP activity level of the cells on the scaffolds containing 2Sr0.5BHA was significantly higher (2.6 times) than that of the control group. The amount of porosity did not make a significant difference in cellular response. It was concluded that PCL-PEG-PCL composite scaffolds with 2Sr0.5BHA have the potential to be used in BTE.

Future directions in preclinical and translational cancer neuroscience research.

Recent advances in cancer neuroscience necessitate the systematic analysis of neural influences in cancer as potential therapeutic targets in oncology. Here, we outline recommendations for future preclinical and translational research in this field.

Surface modification strategies for hemodialysis catheters to prevent catheter-related infections: A review.

Insertion of a central venous catheter is one of the most common invasive procedures applied in hemodialysis therapy for end-stage renal disease. The most important complication of a central venous catheter is catheter-related infections that increase hospitalization and duration of intensive care unit stay, cost of treatment, mortality, and morbidity rates. Pathogenic microorganisms, such as, bacteria and fungi, enter the body from the catheter insertion site and the surface of the catheter can become colonized. The exopolysaccharide-based biofilms from bacterial colonies on the surface are the main challenge in the treatment of infections. Catheter lock solutions and systemic antibiotic treatment, which are commonly used in the treatment of hemodialysis catheter-related infections, are insufficient to prevent and terminate the infections and eventually the catheter needs to be replaced. The inadequacy of these approaches in termination and prevention of infection revealed the necessity of coating of hemodialysis catheters with bactericidal and/or antiadhesive agents. Silver compounds and nanoparticles, anticoagulants (e.g., heparin), antibiotics (e.g., gentamicin and chlorhexidine) are some of the agents used for this purpose. The effectiveness of few commercial hemodialysis catheters that were coated with antibacterial agents has been tested in clinical trials against catheter-related infections of pathogenic bacteria, such as Staphylococcus aureus and Staphylococcus epidermidis with promising results. Novel biomedical materials and engineering techniques, such as, surface micro/nano patterning and the conjugation of antimicrobial peptides, enzymes, metallic cations, and hydrophilic polymers (e.g., poly [ethylene glycol]) on the surface, has been suggested recently.

Synthesis and sintering of B, Sr, Mg multi-doped hydroxyapatites: Structural, mechanical and biological characterization.

Hydroxyapatite (HA, Ca10(PO4)6(OH)2) is the main constituent mineral of bone and teeth in mammals. Due to its outstanding biocompatibility and osteoconductive capabilities, it is preferred for bone repair and replacement. Owing to high potential to have excellent biological properties, ternary ions-doped HAs have just begun to be investigated in the biomedical field and preparing multi-doped HAs is a fairly new approach. Boron (B, BO33-), strontium (Sr, Sr2+) and magnesium (Mg, Mg2+) provide a beneficial effect on bone growth, bone strength, biocompatibility and positively affect bone microstructure. The motivation of this study is taking advantages of the potential of the combine effects of these bivalent ions. In this study, 8 different compositions of BO33-, Sr2+, Mg2+ multi-doped HAs were synthesized by microwave irradiation method to investigate the structural, mechanical and biological features of bone substitutes. This is the first time we report the effect of boron, strontium and magnesium ions multi-doping on the structure of HA and its biological properties. Samples were sintered at 700, 900 and 1100 °C. The effect of varying ion contents and sintering temperature on structural and biological properties of the multi-doped samples was investigated. B, Sr and Mg ions were successfully doped into the HA structure according to X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analyses. A biphasic structure was obtained with increasing amount of ion-doping. Increasing the sintering temperature affected the crystallinity and the density of the samples gradually. Vicker's microhardness and diametral strength of the samples increased at high sintering temperatures. B-Sr-Mg multi-doped HA promoted osteoblast-like Saos-2 cell proliferation, and as the sintering temperatures of the samples increased, the osteogenic differentiation level of the cultured cells also increased. Overall, results showed that the biological properties of HA were improved with the doping of Sr, Mg and B ions, and for bone implant applications samples sintered at 1100 °C were suggested to have potential as a biomaterial.

Clinically Actionable Strategies for Studying Neural Influences in Cancer.

Neuro-glial activation is a recently identified hallmark of growing cancers. Targeting tumor hyperinnervation in preclinical and small clinical trials has yielded promising antitumor effects, highlighting the need of systematic analysis of neural influences in cancer (NIC). Here, we outline the strategies translating these findings from bench to the clinic.

Live surgical demonstrations for minimally invasive colorectal training.

PURPOSE: Live surgical demonstrations are considered an effective educational tool providing a chance for trainees to observe a real-time decision-making process of expert surgeons. No data exists evaluating the impact of live surgical demonstrations on the outcomes of minimally invasive colorectal surgery. This study evaluates perioperative and short-term postoperative outcomes in patients undergoing minimally invasive colorectal surgery in the setting of live surgical demonstrations. METHODS: Patients undergoing minimally invasive colorectal surgery which was performed as live surgical demonstrations (the study group) performed between 2006 and 2018 were reviewed. These patients were case-matched with those undergoing operations in routine practice (the control group). The study and control group were compared for intraoperative and short-term postoperative outcomes. RESULTS: Thirty-nine live surgery cases in the study group were case-matched with its thirty-nine counterparts as the control group. Operating time was longer (200 vs 165 min; p = 0.002) and estimated intraoperative blood loss was higher in the study group (100 vs 55 ml; p = 0.008). Patients in the study group stayed longer in the hospital (6 vs 5 days; p = 0.001). While conversion (n = 4 vs n = 1, p = 0.358) and intraoperative complications (n = 6 vs n = 2, p = 0.2) were more frequent in the study group, these outcomes did not reach statistical significance. Overall complications were higher in the study group (n = 22 vs n = 9, p = 0.003). One patient underwent a reoperation due to postoperative bleeding, and one mortality occurred in the live surgery group. CONCLUSIONS: Live surgical demonstrations in minimally invasive colorectal surgery seem to be associated with increased risk of operative morbidity.

Bioprinting Technologies in Tissue Engineering.

Bioprinting technology is a strong tool in producing living functional tissues and organs from cells, biomaterial-based bioinks, and growth factors in computer-controlled platform. The aim of this chapter is to present recent progresses in bioprinting of nerve, skin, cardiac, bone, cartilage, skeletal muscle, and other soft tissues and highlight the challenges in these applications. Various composite bioinks with bioactive ceramic-based scaffolds having patient-specific design and controlled micro-architectures were used at clinical and preclinical applications successfully for regeneration of bone. In nerve tissue engineering, bioprinting of alginate- and gelatin-based gel bioinks by extrusion presented a controllable 3D microstructures and showed satisfactory cytocompatibility and axonal regeneration. Bioprinting of cardiac progenitors in biopolymers resulted in limited success, while the use of bioinks from extracellular matrix induced satisfactory results in cardiac regeneration. Osteochondral scaffold bioprinting is challenging due to the complex hierarchical structure and limited chondral regeneration. Therefore, current approaches focused on osteochondral scaffold with vascular network and mimicking hierarchical structures. The applications of bioprinting in other types of tissues were also studied, and results showed significant potentials in regeneration of tissues such as cornea, liver, and urinary bladder.

Investigation of surface structure and biocompatibility of chitosan-coated zirconia and alumina dental abutments.

BACKGROUND: For long-term success of dental implants, it is essential to maintain the health of the surrounding soft tissue barrier, which protects the bone-implant interface from the microorganisms. Although implants based on titanium and its alloys still dominate the dental implant market, alumina (Al2 O3 ) and zirconia (ZrO2 ) implant systems are widely used in the area. However, they provide smooth and bioinert surfaces in the transmucosal region, which poorly integrate with the surrounding tissues. OBJECTIVE: The main aim of this research was to investigate the surface characteristics and biocompatibility of chitosan-coated alumina and zirconia surfaces. MATERIALS AND METHODS: The substrates were coated via solution casting technique. Additionally, an aging process with a thermocycle apparatus was applied on the coated materials to mimic the oral environment. To define the morphology and chemical composition of the surfaces of untreated, chitosan-coated, and chitosan-coated-aged samples, scanning electron microscopy and energy dispersive X-ray spectrometry were used. The phases and bonds characterized by Fourier transform infrared spectroscopy and X-ray diffraction analysis. The human gingival fibroblast cells were used to evaluate cytocompatibility by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium salt assay. RESULTS: It was observed that both substrates were successfully coated with chitosan and the aging process did not significantly affect the integrity of the coating. The attachment and proliferation of human gingival fibroblast cells were shown to be good on both kinds of chitosan-coated surfaces. CONCLUSION: Coating zirconia and alumina surfaces with chitosan is an efficient surface modification for increasing biocompatibility and bioactivity of these materials in vitro.