The utilization of efficacious hemostatic agents in surgical procedures has the potential to enhance operational efficacy, expedite patient recovery, and diminish the need for blood transfusions. However, in cases of excessive bleeding, few commercial hemostatic agents can maintain contact with the bleeding site and perform hemostatic functions effectively. In the present work, we propose a mesh-shaped absorbable lyophilized hemostatic hydrogel patch with excellent biodegradability, wet tissue adhesion ability, strong structural properties, and good blood coagulation activity by integrating the beneficial properties of two marine organism-derived bioengineered protein biomaterials, sea anemone silk-like protein (aneroin) and mussel adhesive protein (MAP). The hemostatic efficacy of the developed hydrogel patch was thoroughly evaluated using in vitro and in vivo experiments. The mesh-shaped hemostatic hydrogel patch exhibited the ability to absorb plasma upon contact with blood, adhere to surfaces, and facilitate aggregation of blood components, hence enhancing the process of blood coagulation. Using animal liver damage models, we confirmed that the hemostatic hydrogel patch could significantly enhance hemostatic capabilities by reducing clotting time and blood loss while exhibiting minimal inflammation and toxicity when remaining within the body. Thus, our proposed absorbable hemostatic hydrogel patch demonstrated great potential for use as a novel adhesive hemostatic agent for application in visceral surgery.

Topical hemostatic agents are preferred for application to sensitive bleeding sites because of their immediate locoregional effects with less tissue damage. However, the majority of commercial hemostatic agents fail to provide stable tissue adhesion to bleeding wounds or act as physical barriers against contaminants. Hence, it has become necessary to investigate biologically favorable materials that can be applied and left within the body post-surgery. In this study, a dual-sided nanofibrous dressing for topical hemostasis is electrospun using a combination of two protein materials: bioengineered mussel adhesive protein (MAP) and silk fibroin (SF). The wound-adhesive inner layer is fabricated using dihydroxyphenylalanine (DOPA)-containing MAP, which promotes blood clotting by aggregation of hemocytes and activation of platelets. The anti-adhesive outer layer is composed of alcohol-treated hydrophobic SF, which has excellent spinnability and mechanical strength for fabrication. Because both proteins are fully biodegradable in vivo and biocompatible, the dressing would be suitable to be left in the body. Through in vivo evaluation using a rat liver damage model, significantly reduced clotting time and blood loss are confirmed, successfully demonstrating that the proposed dual-sided nanofibrous dressing has the right properties and characteristics as a topical hemostatic agent having dual functionality of hemostasis and physical protection.

Background: Decellularized extracellular matrix (dECM) is a non-cellular scaffold with various functions in tissue engineering and regenerative medicine. Elastin is related to tissue elasticity and scarless wound healing, abundantly found in lung and blood vessel tissues. We studied the characteristics of blood vessel-derived dECM (VdECM) and its effect in wound healing.Methods:VdECM was prepared from porcine blood vessel tissue. Weight percentages of elastin of VdECM and atelocollagen were analyzed. Migratory potential of VdECM was tested by scratch assay. VdECM in hydrogel form was microscopically examined, tested for fibroblast proliferation, and examined for L/D staining. Cytokine array of various growth factors in adipocyte-derived mesenchymal stem cell (ASC) media with VdECM was done. Animal wound model showed the wound healing effect of VdECM hydrogel in comparison to other topical agents.Results:VdECM contained 6.7 times more elastin than atelocollagen per unit weight. Microscopic view of 0.35% VdECM hydrogel showed consistent distribution. Compared to 3% atelocollagen, 0.35% VdECM showed superior results in fibroblast migration. Fluorescent microscopic findings of L/D assay had highest percentage of cell survival in 1% VdECM compared to atelocollagen. Growth factor expression was drastically amplified when VdECM was added to ASC media. In the animal study model, epithelialization rate in the VdECM group was higher than that of control, oxytetracycline, and epidermal growth factor ointments.Conclusion:VdECM contains a high ratio of elastin to collagen and amplifies expressions of many growth factors. It promotes fibroblast migration, proliferation, and survival, and epithelialization comparable to other topical agents.

Background: The purpose of this study was to demonstrate the usefulness of 3D image-based virtual reduction by validating the evaluation criteria according to guidelines suggested by the AO Surgery Reference. Methods: For this experiment, 19 intact radial ORTHObones (ORTHObones radius, 3B Scientific, Germany, Hamburg) without any fractures were prepared. All ORTHObones with six cortical marking holes (three points on the distal part and three points on the proximal part) were scanned using a CT scanner twice (before/after intentional fracture of the ORTHObone). After the virtual reduction of all 19 ORTHObones, accuracy evaluations using the four criteria (length variation, apposition variation, alignment variation, Rotation Variation) suggested in the AO Surgery Reference were performed. Results: The mean (M) length variation was 0.42 mm, with 0.01 mm standard deviation (SD). The M apposition variation was 0.48 mm, with 0.40 mm SD. The M AP angulation variation (for alignment variation) was 3.24°, with 2.95° SD. The M lateral angulation variation (for alignment variation) was 0.09°, with 0.13° SD. The M angle of axial rotation was 1.27° with SD: 1.19°. Conclusions: The method of accuracy evaluation used in this study can be helpful in establishing a reliable plan.

Reconstructive treatments of heel defects usually involve regional flap techniques such as medial plantar flap procedures due to the limited availability of adjacent soft tissues. Although free flaps have advantages in terms of function and aesthetics, they remain challenging due to the longer operation time required than for regional flaps. Thus, we introduce an appropriate 2-team surgical protocol to reconstruct plantar defects after wide excision of malignant melanoma using free flap coverage. From 2015 to 2020, a retrospective study was performed including 21 patients who underwent free flap surgeries to reconstruct defects due to plantar malignant melanoma. Lymphoscintigraphy was performed to localize sentinel lymph nodes, and the procedure was carried out by 2 teams working together, a tumor-ablative team and a reconstructive team. The present study is adhered to the STROBE guidelines for cohort studies. The average operation time was 241.4 minutes and was not significantly different even in cases with inguinal dissection (P value: 0.641). All flaps survived after 2 cases of venous insufficiency and 1 case of hematoma were resolved by immediate revision surgery. The 2-team approach to surgically reconstruct heel defects after wide excision of malignant melanoma using free flap coverage offers favorable results and lower morbidity than regional flap approaches.

A composite comprising Ti and NaCl powders was sintered similar to a three-dimensional (3D)-printed patient-customized artificial bone scaffold. Additionally, a proper microstructure of the mimetic scaffold and the optimum processing parameters for its development were analyzed. The mechanical properties of the metal-based porous-structured framework used as an artificial bone scaffold were an optimum replacement for the human bone. Thus, it was confirmed that patient-customized scaffolds could be manufactured via 3D printing. The 3D-printed mimetic specimens were fabricated by a powder-sintering method using Ti for the metal parts, NaCl as the pore former, and polylactic acid as the biodegradable binder. Scanning electron microscopy (SEM) images showed that pores were formed homogeneously, while X-ray computed tomography confirmed that open pores were generated. The porosity and pore size distribution were measured using a mercury porosimeter, while the flexural strength and flexural elastic modulus were calculated using the three-point bending test. Based on these measurements, a pore-former content of 15 vol % optimized the density and flexural strength to 2.52 g cm(-2) and 283 MPa, respectively, similar to those of the actual iliac bone. According to the 3D-printing production method, a selective laser-sintering process was applied for the fabrication of the mimetic specimen, and it was determined that the microstructure and properties similar to those of previous metal specimens could be achieved in the as-prepared specimen. Additionally, a decellularized extracellular matrix (dECM) was used to coat the surfaces and interiors of the specimens for evaluating their biocompatibilities. SEM image analysis indicated that the adipose-derived stem cells grew evenly inside the pores of the coated specimens, as compared with the bulky Ti specimens without the dECM coating. The doubling time at 65% was measured at 72, 75, and 83 h for specimens with pore-former contents of 5, 10, and 15 vol %, respectively. The doubling time without the pore former was 116 h. As compared with the specimens without the pore former (73 h), 15% of the dECM-coated specimens showed a doubling time of 64%, measured at 47 h.

Surgical intervention after traumatic peripheral nerve injury relies heavily on sutures. While the suture method often burdens functional nerve regeneration by causing secondary traumatic damage and eliciting prolonged inflammatory immune responses, replacing sutures has rarely been considered because secure anastomosis between severed nerve ends has been the utmost priority in neurorrhaphy. In the present work, a macrophage-polarizing sutureless neurorrhaphy system was proposed by using an in situ visible light-crosslinkable protein-based bioadhesive hydrogel containing a functional neurotransmitter peptide. The efficacy of the proposed bioadhesive hydrogel as a successful sutureless neurorrhaphy system was intensively evaluated in vitro and in vivo. Using a rat sciatic nerve defect model, our findings suggested that this macrophage-polarizing bioadhesive hydrogel offered effective sutureless anastomosis and the capability to induce M2 macrophage polarization for effective tissue remodeling, significantly enhancing functional nerve regeneration compared with conventional sutures. Taken together, these results suggest that our macrophage-polarizing functional bioadhesive hydrogel system can be utilized as a promising alternative to surgical sutures for nerve regenerative medicine applications.

Background: Vulvovaginal reconstruction is challenging. In this study, we evaluated the outcomes of vulvovaginal reconstruction with "perineal perforator switch flap" (PPSF) and compared it with other conventional flaps. In addition, the long-term esthetic results were compared with the perineal perforator propeller flap (PPPF), which we previously used.Methods: We retrospectively reviewed the clinical data of 16 patients (27 flaps) who underwent vulvovaginal reconstruction with PPSF. After tumor resection, perineal perforators close to the genitofemoral sulcus were identified. The flap was designed as an island with the perforator at the center. The flap was elevated while preserving the soft tissue surrounding the pedicle, and transferred to the defect via the subcutaneous tunnel without pedicle skeletonization.Results: All flaps survived and no major surgical complications were observed. The total follow-up period was 16.13 +/- 3.38 months. The mean operation time was 79.38 +/- 19.65 min, and the initiation of walking and the length of hospitalization were 1.69 +/- 0.79 and 5.69 +/- 0.79 days, respectively. Perineal function was well preserved. Comparison of esthetic results with PPPF showed that PPSF showed better results in symmetrical and labial shape (2.29 +/- 0.73 vs. 3.13 +/- 0.81; p = 0.015, 2.43 +/- 1.02 vs. 3.25 +/- 0.68; p = 0.031, respectively), and in total score. (10.29 +/- 2.16 vs. 12.31 +/- 1.82; p = 0.017).Conclusion: PPSF was technically simple and significantly reduced the duration of operation and the overall recovery time. PPSF also prevented delay in radiation. Therefore, PPSF is a promising method for vulvovaginal reconstruction.(c) 2022 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by El-sevier Ltd. All rights reserved.

Firing patterns of 15 dopamine neurons in the rat substantia nigra were studied. These cells alternated between two firing modes, single-spike and bursting, which interwove to produce irregular, aperiodic interspike interval (ISI) patterns. When examined by linear autocorrelation analysis, these patterns appeared to reflect a primarily stochastic or random process. However, dynamical analysis revealed that the sequential behavior of a majority of these cells expressed "higher-dimensional" nonlinear deterministic structure. Dimensionality refers to the number of degrees of freedom or complexity of a time series. Bursting was statistically associated with some aspects of nonlinear ISI sequence dependence. Controlling for the effects of nonstationarity substantially increased overall predictability of ISI sequences. We hypothesize that the nonlinear deterministic structure of ISI firing patterns reflects the neuron's response to coordinated synaptic inputs emerging from neural circuit interactions.

Impedance-based microfluidic cytometry has proven its potential for applications in point-of-care tests and clinical diagnosis. In this work, we have developed a three-electrode microfluidic potentiometric cytometry system for robust cell size and concentration measurement. A pair of planar electrodes applies a constant voltage drop as a sensing electrode detects the potential changes caused by particle translocation events through a microchannel. The microchannel geometry was optimized based on numerical simulation to provide signal amplitudes of particles independent of cross-sectional position as well as buffer conductivity. Additionally, the signal amplitude shows non-linear characteristics with respect to particle diameter, enabling stem cell selective counting without further signal processing. Experimental results from measurements of the concentration of polystyrene particles as well as stem cells in a stromal vascular fraction (SVF) showed good agreement with manual hemocytometry (error < 2.1%). The developed system is applicable to point-of-care cell, bacteria, and microparticle analyses for global health and environmental monitoring.

In article number 2001693 by Dong-Woo Cho and co-workers, the assembling of dual cell-laden tissue modules is proposed for engineering a volumetric and non-hypoxic soft tissue construct with the combination of planar and rotational 3D cell printing techniques. The engineered softtissue construct possessing flexibility, increased capillary formation, and the adipogenic effect is a potential platform for soft tissue reconstruction in the future.

Background: Angiogenesis and vasculogenesis are essential processes for successful tissue regeneration in tissue engineering and regenerative medicine. The adipose-derived stromal vascular fraction (SVF) is not only a source of adipose stem cells (ASC) but also a suitable source of microvascular endothelial cells because it is a rich capillary network. So, we propose a new hypothesis for isolating adipose-derived human microvascular endothelial cells (HMVEC-A) from the SVF and developed a dual isolation system that isolates two cell types from one tissue. Method: To isolate HMVEC-A, we analyzed the supernatant discarded when ASC is isolated from the adipose-derived SVF. Based on this analysis, we assumed that the SVF adherent to the bottom of the culture plate was divided into two fractions: the stromal fraction as the ASC-rich fraction, and the vascular fraction (VF) as the endothelial cells-rich fraction floating in the culture supernatant. VF isolation was optimized and the efficiency was compared, and the endothelial cells characteristics of HMVEC-A were confirmed by flow cytometric analysis, immunocytochemistry (ICC), a DiI-acetylated low-density lipoprotein (DiI-Ac-LDL) uptake, and in vitro tube formation assay. Results: Consistent with the hypothesis, we found a large population of HMVEC-A in the VF and isolated these HMVEC-A by our isolation method. Additionally, this method had higher yields and shorter doubling times than other endothelial cells isolation methods and showed typical morphological and phenotypic characteristics of endothelial cells. Conclusion: Cells obtained by the method according to our hypothesis can be applied as a useful source for studies such as tissue-to-tissue networks, angiogenesis and tissue regeneration, patient-specific cell therapy, and organoid chips.

A hypertrophic scar is a common dermal fibroproliferative lesion usually treated with topical silicone. Verapamil, a type of calcium channel blocker, is considered a candidate drug for the treatment of hypertrophic scars. Here, we report that the addition of verapamil to topical silicone gel enhances treatment outcomes of hypertrophic scars. Upon creation of hypertrophic scars with the rabbit ear model, varying concentrations of verapamil-added silicone gel (0.1, 1, and 10 mg/g) were applied daily for 28 days. After the animals were euthanised, microscopic measurement was performed for (a) scar elevation index (SEI), (b) fibroblast count, and (c) capillary count. On gross analysis, features of hypertrophic scars were significantly alleviated in the verapamil-added groups. On histologic examination, verapamil-added groups showed (a) reduced SEI (1.93 (1.79-2.67) for control vs 1.34 (1.21-1.51) for silicone only and 1.13 (1.01-1.65) for verapamil-added silicone), (b) fibroblast count 700.5 (599.5-838.5) for control, 613.25 (461-762.5) for silicone only, and 347.33 (182.5-527) for verapamil-added silicone), and (c) capillary formation (52 (35.5-96.5) for control, 46 (28-64.5) for silicone only, and 39.83(24-70) for verapamil-added silicone) (Kruskal-Wallis test, P < .05). On western blot, expression levels of collagen I protein was lower in the 1 mg/g and 10 mg/g verapamil-added silicone compared with control. Therefore, we suggest a therapeutic concentration of verapamil-added silicone gel of at least over 1 mg/g. Further study regarding maximally effective concentration and deeper insight into the mechanism of action should follow.

Background. In microvascular anastomosis, size discrepancy is common and can increase thrombotic complications. If size differences can be predicted, then vessels of the appropriate size can be selected. This study documented the difference in diameter between the thoracodorsal (TD) vessel and deep inferior epigastric perforator (DIEP) pedicle in each patient who underwent breast reconstruction using free tissue transfer. Patients and Methods. This retrospective study included 32 anastomoses (27 breasts including five cases of supercharged anastomosis) of breast reconstruction with the free DIEP flap and TD recipient between August 2018 and June 2019. In the microscopic view, the caliber of the TD vessel, the largest branch to the serratus anterior muscle, the descending branch, the largest and the second largest branches to the latissimus dorsi muscle, and the DIEP pedicle were measured. Results. The diameter of the deep inferior epigastric artery was similar to that of the descending branch, and their anastomosing rate was 56.3%. The diameter of the deep inferior epigastric vein was similar to the branch to the serratus anterior muscle and the descending branch, and their anastomosing rates were 29.3% and 29.3%, respectively. All flaps were survived; however, in one case, a reoperation was needed to remove the hematoma, in which case fat necrosis occurred as the only complication. Conclusion. TD branches of similar size to the DIEP pedicle were prioritized in anastomosis. The descending branch and the branch to the serratus anterior muscle are expected to be good candidates as recipients in breast reconstruction with DIEP free flap. Moreover, supercharged anastomosis of DIEP pedicles can be achieved within TD branches.

Background: The stromal vascular fraction (SVF) isolated from adipose tissue, which contains stem cells as well as other cell types, has been applied in various research fields. Although different enzymatic concentrations and treatment durations have been applied to isolate the SVF, optimal conditions have not been established. Thus, we aimed to establish the optimal conditions for isolation of the SVF from adipose tissue by automated systems. Methods: The SVF was collected from removed adipose tissues of five donors during surgery. The SVF was treated with 0.1% or 0.2% collagenase type I for 20, 40, or 60 min. Then, colony forming unit (CFU) assays and flow cytometry were performed to characterize the adipose stem cells (ASCs). A cytokine array was used to investigate the correlation between colony-formation ability and the secretion of isolated ASCs. Results: Treatment with 0.1% collagenase type I for 60 min resulted in a higher SVF yield, whereas treatment with 0.1% collagenase for 40 min resulted in higher CFU values. In addition, expression of interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1 in the SVF was higher in the high-CFU group than in the low-CFU group. Conclusion: The optimal conditions for isolation of the SVF from adipose tissue were treatment with 0.1% collagenase type I for 40 min. We identified the conditions required for efficient SVF isolation based on high CFU values, and our results will facilitate the development of automated systems.

Purpose . To reconstruct a zygomaticomaxillary complex (ZMC) fracture, zygomaticofrontal (ZF) suture is the most reliable site to assess anatomical alignment and to secure rigidity. It has been chosen primary site to be fixed, but approach through the lateral eyebrow incision may leave a visible scar. This study suggests altered two-point fixation of ZMC fracture without accessing the ZF suture. Methods . In the retrospective study, a total of 40 patients with ZMC fracture were divided into two groups (group 1, two-point fixation and group 2, three-point fixation). Patient demographics and follow-up were evaluated, and degree of reduction including cortical gaps of ZF and inferior orbital (IO) area, protruding difference of zygoma, and malar difference using asymmetry index were measured through preoperative and postoperative CT. Results . Preoperatively, the means of ZF displacement, IO displacement, protruding difference of zygoma, and facial asymmetry index between the groups were not statistically different. The result was the same after the operation. However, all variables were significantly different before and after surgery within each group. Moreover, mean operation time was significantly different between groups (P value = 0.026). Conclusion . Altered two-point fixation in ZMC fracture excluding incision approaching the ZF provides surgical efficacy and similar surgical outcomes to three-point fixation but offers reduced operation time and fewer complications.

BACKGROUND:The Breslow depth is an important parameter to determine the excision margin and prognosis of melanoma. However, it is difficult to accurately determine the actual Breslow depth before surgery using the existing ocular micrometer and biopsy technique. OBJECTIVES:To evaluate the use of 3D wide-field multispectral photoacoustic imaging to non-invasively measure depth and outline the boundary of melanomas for optimal surgical margin selection. METHODS:Six melanoma patients were examined in vivo using the 3D multispectral photoacoustic imaging system. For five cases of melanomas (one in situ, three nodular, and one acral lentiginous type melanoma), the spectrally unmixed photoacoustic depths were calculated and compared against histopathological depths. RESULTS:Spectrally unmixed photoacoustic depths and histopathological depths match well within a mean absolute error of 0.36 mm. In particular, the measured minimum and maximum depths in the in situ and nodular type of melanoma were 0.6 and 9.1 mm, respectively. In the 3D photoacoustic image of one metastatic melanoma, feeding vessels were visualized in the melanoma, suggesting the neovascularization around the tumour. CONCLUSIONS:The 3D multispectral photoacoustic imaging not only provides well-measured depth and sizes of various types of melanomas, it also visualizes the metastatic type of melanoma. Obtaining accurate depth and boundary information of melanoma before surgery would play a useful role in the complete excision of melanoma during surgery.