Effectiveness of hemocoagulase, tranexamic acid, and their combination for reducing blood loss in bimaxillary orthognathic surgery: a retrospective study.

Objectives: Orthognathic surgery is a corrective intervention for maxillofacial deformities. Bleeding is a major concern for oral and maxillofacial surgeons. Various agents, such as hemocoagulase, tranexamic acid, and aprotinin have been developed to reduce intraoperative bleeding and transfusion requirements. Therefore, in this study we aimed to investigate the effects of hemocoagulase and tranexamic acid, as well as their simultaneous use, to reduce bleeding during orthognathic surgery. Patients and. Methods: This retrospective study included patients who had undergone simultaneous orthognathic surgery of the maxilla and mandible between January 2013 and September 2022 and were classified into three groups based on drugs administered: hemocoagulase (Botropase), tranexamic acid, and a combination of both drugs. We recorded patient age, sex, weight, blood loss, and duration of surgery. Red blood cell (RBC), hemoglobin, hematocrit, and platelet levels were measured before, immediately after, and one day after surgery. Results: No statistically significant differences were found in blood loss, RBC, hemoglobin, hematocrit, or platelet levels between any of the groups. There were no differences in the drug effects between Le Fort I and bilateral mandibular sagittal split osteotomies, with or without double genioplasty. However, there were significant reductions in RBC, hemoglobin, hematocrit, and platelet levels during genioplasty. Conclusion: Tranexamic acid, hemocoagulase, and their combination had similar efficacy in patients who underwent Le Fort Ⅰ and bilateral mandibular sagittal split osteotomies with and without genioplasty.

Omni-directional wind-driven triboelectric nanogenerator with cross-shaped dielectric film.

Triboelectric nanogenerators (TENGs) are actively being researched and developed to become a new external power unit for various electronics and applications. Wind is proposed as a mechanical energy source to flutter the dielectric film in wind-driven TENGs as it is clean, abundant, ubiquitous, and sustainable. Herein, we propose a TENG structure with dielectric films bent in four directions to collect the wind energy supply from all directions, unlike the conventional wind-driven TENGs which can only harvest the wind energy from one direction. Aluminum (Al) layer was intercalated within the dielectric film to improve electrostatic induction, resulting in improved triboelectric performances. Maximum open-circuit voltage (Voc) of 233 V, short-circuit current (Isc) of 348 µA, and output power density of 46.1 W m- 2 at an external load of 1 MΩ under a wind speed of 9 m s- 1 were revealed, and it faithfully lit "LED" characters composed of 25 LEDs.

Investigation of Pathogenic Escherichia coli Contamination of Vegetables Distributed in a Korean Agricultural Wholesale Market.

The purpose of this study was to investigate the monthly contamination rate of pathogenic Escherichia coli, a major cause of food poisoning, in vegetables sold in agricultural wholesale markets, which distribute vegetables from all over the country, in the Incheon Metropolitan City area, South Korea, and to identify a source of the pathogen. In total, 1739 vegetables of 80 types, along with 109 soil, 67 manure, and 33 livestock feces samples, were tested for pathogenic E. coli using polymerase chain reaction, from September 2016 through August 2017. The average annual prevalence rate of vegetables was 5.8%, and the prevalence rate was above 5% from June through October. The highest prevalence rate (15.7%) was recorded in July. Water dropwort showed the highest prevalence rate (28.6%) among the vegetables examined. Pathogenic E. coli was detected in >20 types of the vegetables that were to be consumed without cooking. Among these, the prevalence rates of ponytail radish (n = 21), crown daisy (n = 86), young radish (n = 68), romaine lettuce (n = 133), perilla leaf (n = 103), Korean leek (n = 43), young Chinese cabbage (n = 68), and Chinese cabbage (n = 30) were 9.5%, 8.1%, 7.4%, 6.8%, 4.9%, 4.7%, 4.4%, and 3.3%, respectively. Among the vegetables cooked before consumption, prevalence rates were 28.6%, 27.3%, and 25.0% in wormwood, sweet potato stalk, and edible mountain vegetables (Saussurea sp., etc.), respectively. In soil, manure, and livestock feces, 36.7%, 26.9%, and 90.6% prevalence rates were confirmed, respectively. This study confirmed the pathogenic E. coli contamination of vegetables to be consumed without cooking. Therefore, to produce agricultural products that do not induce food poisoning and are safe for consumption, it is important to develop a process for killing the pathogenic microorganisms and set up a sanitary environment for effectively managing compost. In addition, it is necessary to establish surveillance systems to monitor the production chain.

Comparative Study of the Effect of Paranasal Augmentation With Autologous Bone in Orthognathic Surgery.

PURPOSE: The purpose of the present study was to compare the effectiveness of the 3 orthognathic surgical options among the patients who had had mandibular prognathism with a concave midfacial profile. PATIENTS AND METHODS: A total of 72 patients with mandibular prognathism with a concave midfacial profile were divided into 3 groups. We compared the lateral profile changes using lateral cephalograms. The images were taken before surgery (T0) and at least 6 months to 1 year after surgery (T1). After computerization of the preoperative cephalograms (T0), the surgical changes (T1 minus T0) were measured by computerizing the postoperative cephalograms. Group 1 (n = 21) had undergone bilateral sagittal split osteotomies, group 2 (n = 36) had undergone bilateral sagittal split osteotomy with autologous bone paranasal augmentation, and group 3 (n = 15) had undergone bilateral sagittal split osteotomies and Le Fort I osteotomy. RESULTS: After surgery, all the landmarks and values showed changes. Among them, quantitative changes could be observed in all the cheek points and cheek lines. The average of the overall cheek points had increased by ∼0.56 mm in group 1, ∼1.85 mm in group 2, and ∼2.39 mm in group 3, horizontally. CONCLUSIONS: The results of the present study suggest approximately comparative values among the 3 surgical options for patients and surgeons considering orthognathic surgery. In addition, autologous bone paranasal augmentation can be considered as an alternative for Le Fort I osteotomy in specific conditions.

New method for an evaluation of the esthetical improvements resulting from a mandibular angle reduction.

OBJECTIVES: This paper proposes Han's ratio as an objective and quantitative comparative result obtained from pre and postoperative data in patients with a mandibular angle reduction. MATERIALS AND METHODS: Thirty patients, 12 men and 18 women, who visited the Department of Oral and Maxillofacial Surgery with the chief complaints of skeletal mandibular prognathism and prominent mandibular angle were selected. The subjects were classified into 3 groups according to the types of surgical procedures involved. Group A consisted of patients who underwent mandibular angle resection and mandibular setback. Group B was comprised of patients with mandibular angle resection, mandibular setback and genioplasty. Group C consisted of patients with mandibular angle resection, mandibular setback, Le Fort I osteotomy, and genioplasty. The landmarks placed in pre and postoperative frontal photographs were used to obtain the Han's ratio in each group. The Han's ratios were compared pre- and postoperation and according to the surgical techniques applied. RESULTS: Of the 3 groups who had undergone a mandibular angle resection, all showed a statistically significant increase in Han's ratio. On the other hand, there was no statistically significant difference based on the surgical techniques used. CONCLUSION: The ratio of the lateral lower face proposed in this study is a potential indicator of postoperative esthetic enhancement in mandibular angle reduction surgery.

Comparison of the effects on the pharyngeal airway space of maxillary protraction appliances according to the methods of anchorage.

BACKGROUND: The purpose of the study is to compare the effects on the pharyngeal airway space of skeletal anchored face mask with those of tooth-borne facemask. METHODS: We used two types of facemask for maxillary protraction, the tooth-borne facemask (TBFM) and the skeletal anchored facemask (SAFM), and evaluated the effects of each facemask on the pharyngeal airway. Twenty-eight patients (mean age 10.3 years) were treated with the TBFM and 24 patients (mean age 11.2 years) were treated with the SAFM. Lateral cephalometric radiographs were taken before treatment (T1) and after treatment (T2) to assess changes in the dimensions of the upper airway. Statistical analysis was performed with independent t tests, matched t tests, Mann-Whitney U tests, and Kruskal-Wallis tests. RESULTS: There were marked increases in upper airway dimensions in both groups following treatment, but the SAFM group had a significantly greater increase in airway dimensions than the TBFM group. Also, the SAFM subgroups showed more improved airway measurements than the TBFM subgroups in both the superior and inferior pharyngeal airways. CONCLUSIONS: SAFM is more effective than TBFM in increasing upper airway dimensions.

Cranial bone regeneration according to different particle sizes and densities of demineralized dentin matrix in the rabbit model.

BACKGROUND: The objective of this study was to place bone graft materials in cranial defects in a rabbit model and compare their bone regenerating ability according to the size and density of demineralized dentin matrix (DDM). METHODS: We selected nine healthy male rabbits that were raised under the same conditions and that weighed about 3 kg. Two circular defects 8 mm in diameter were created in each side of the cranium. The defects were grafted with DDM using four different particle sizes and densities: 0.1 mL of 0.25- to 1.0-mm particles (group 1); 0.2 mL of 0.25- to 1.0-mm particles (group 2); 0.1 mL of 1.0- to 2.0-mm particles (group 3); and 0.2 mL of 1.0- to 2.0-mm particles (group 4). After 2, 4, and 8 weeks, the rabbits were sacrificed, and bone samples were evaluated by means of histologic, histomorphometric, and quantitative RT-PCR analysis. RESULTS: In group 1, osteoblast activity and bone formation were greater than in the other three groups on histological examination. In groups 2, 3, and 4, dense connective tissue was seen around original bone even after 8 weeks. Histomorphometric analysis of representative sections in group 1 showed a higher rate of new bone formation, but the difference from the other groups was not statistically significant. RT-PCR analysis indicated a correlation between bone formation and protein (osteonectin and osteopontin) expression. CONCLUSIONS: DDM with a space between particles of 200 µm was effective in bone formation, suggesting that materials with a small particle size could reasonably be used for bone grafting.

Extracellular Protease Inhibition Alters the Phenotype of Chondrogenically Differentiating Human Mesenchymal Stem Cells (MSCs) in 3D Collagen Microspheres.

Matrix remodeling of cells is highly regulated by proteases and their inhibitors. Nevertheless, how would the chondrogenesis of mesenchymal stem cells (MSCs) be affected, when the balance of the matrix remodeling is disturbed by inhibiting matrix proteases, is incompletely known. Using a previously developed collagen microencapsulation platform, we investigated whether exposing chondrogenically differentiating MSCs to intracellular and extracellular protease inhibitors will affect the extracellular matrix remodeling and hence the outcomes of chondrogenesis. Results showed that inhibition of matrix proteases particularly the extracellular ones favors the phenotype of fibrocartilage rather than hyaline cartilage in chondrogenically differentiating hMSCs by upregulating type I collagen protein deposition and type II collagen gene expression without significantly altering the hypertrophic markers at gene level. This study suggests the potential of manipulating extracellular proteases to alter the outcomes of hMSC chondrogenesis, contributing to future development of differentiation protocols for fibrocartilage tissues for intervertebral disc and meniscus tissue engineering.

Protease inhibitors enhance extracellular collagen fibril deposition in human mesenchymal stem cells.

INTRODUCTION: Collagen is a widely used naturally occurring biomaterial for scaffolding, whereas mesenchymal stem cells (MSCs) represent a promising cell source in tissue engineering and regenerative medicine. It is generally known that cells are able to remodel their environment by simultaneous degradation of the scaffolds and deposition of newly synthesized extracellular matrix. Nevertheless, the interactions between MSCs and collagen biomaterials are poorly known, and the strategies enhancing the extracellular matrix deposition are yet to be defined. In this study, we aim to investigate the fate of collagen when it is in contact with MSCs and hypothesize that protease inhibition will enhance their extracellular deposition of collagen fibrils. METHODS: Specifically, human MSCs (hMSCs) were exposed to fluorescence-labeled collagen with and without intracellular or extracellular protease inhibitors (or both) before tracing the collagen at both intracellular and extracellular spaces. RESULTS: Collagen were internalized by hMSCs and degraded intracellularly in lysosomes. In the presence of protease inhibitors, both intracellular collagen fibril growth and extracellular deposition of collagen fibrils were enhanced. Moreover, protease inhibitors work synergistically with ascorbic acid, a well-known matrix deposition-enhancing reagent, in further enhancing collagen fibril deposition at the extracellular space. CONCLUSION: These findings provide a better understanding of the interactions between hMSCs and collagen biomaterials and suggest a method to manipulate matrix remodeling and deposition of hMSCs, contributing to better scaffolding for tissue engineering and regenerative medicine.

Molecular mechanism of type I collagen homotrimer resistance to mammalian collagenases.

Type I collagen cleavage is crucial for tissue remodeling, but its homotrimeric isoform is resistant to all collagenases. The homotrimers occur in fetal tissues, fibrosis, and cancer, where their collagenase resistance may play an important physiological role. To understand the mechanism of this resistance, we studied interactions of alpha1(I)(3) homotrimers and normal alpha1(I)(2)alpha2(I) heterotrimers with fibroblast collagenase (MMP-1). Similar MMP-1 binding to the two isoforms and similar cleavage efficiency of unwound alpha1(I) and alpha2(I) chains suggested increased stability and less efficient unwinding of the homotrimer triple helix at the collagenase cleavage site. The unwinding, necessary for placing individual chains inside the catalytic cleft of the enzyme, was the rate-limiting cleavage step for both collagen isoforms. Comparative analysis of the homo- and heterotrimer cleavage kinetics revealed that MMP-1 binding promotes stochastic helix unwinding, resolving the controversy between different models of collagenase action.

Carcinomas contain a matrix metalloproteinase-resistant isoform of type I collagen exerting selective support to invasion.

Collagen fibers affect metastasis in two opposing ways, by supporting invasive cells but also by generating a barrier to invasion. We hypothesized that these functions might be performed by different isoforms of type I collagen. Carcinomas are reported to contain alpha1(I)(3) homotrimers, a type I collagen isoform normally not present in healthy tissues, but the role of the homotrimers in cancer pathophysiology is unclear. In this study, we found that these homotrimers were resistant to all collagenolytic matrix metalloproteinases (MMP). MMPs are massively produced and used by cancer cells and cancer-associated fibroblasts for degrading stromal collagen at the leading edge of tumor invasion. The MMP-resistant homotrimers were produced by all invasive cancer cell lines tested, both in culture and in tumor xenografts, but they were not produced by cancer-associated fibroblasts, thereby comprising a specialized fraction of tumor collagen. We observed the homotrimer fibers to be resistant to pericellular degradation, even upon stimulation of the cells with proinflammatory cytokines. Furthermore, we confirmed an enhanced proliferation and migration of invasive cancer cells on the surface of homotrimeric versus normal (heterotrimeric) type I collagen fibers. In summary, our findings suggest that invasive cancer cells may use homotrimers for building MMP-resistant invasion paths, supporting local proliferation and directed migration of the cells whereas surrounding normal stromal collagens are cleaved. Because the homotrimers are universally secreted by cancer cells and deposited as insoluble, MMP-resistant fibers, they offer an appealing target for cancer diagnostics and therapy.

Segregation of type I collagen homo- and heterotrimers in fibrils.

Normal type I collagen is a heterotrimer of two alpha1(I) and one alpha2(I) chains, but various genetic and environmental factors result in synthesis of homotrimers that consist of three alpha1(I) chains. The homotrimers completely replace the heterotrimers only in rare recessive disorders. In the general population, they may compose just a small fraction of type I collagen. Nevertheless, they may play a significant role in pathology; for example, synthesis of 10-15% homotrimers due to a polymorphism in the alpha1(I) gene may contribute to osteoporosis. Homotrimer triple helices have different stability and less efficient fibrillogenesis than heterotrimers. Their fibrils have different mechanical properties. However, very little is known about their molecular interactions and fibrillogenesis in mixtures with normal heterotrimers. Here we studied the kinetics and thermodynamics of fibril formation in such mixtures by combining traditional approaches with 3D confocal imaging of fibrils, in which homo- and heterotrimers were labeled with different fluorescent colors. In a mixture, following a temperature jump from 4 to 32 degrees C, we observed a rapid increase in turbidity most likely caused by formation of homotrimer aggregates. The aggregates promoted nucleation of homotrimer fibrils that served as seeds for mixed and heterotrimer fibrils. The separation of colors in confocal images indicated segregation of homo- and heterotrimers at a subfibrillar level throughout the process. The fibril color patterns continued to change slowly after the fibrillogenesis appeared to be complete, due to dissociation and reassociation of the pepsin-treated homo- and heterotrimers, but this remixing did not significantly reduce the segregation even after several days. Independent homo- and heterotrimer solubility measurements in mixtures confirmed that the subfibrillar segregation was an equilibrium property of intermolecular interactions and not just a kinetic phenomenon. We argue that the subfibrillar segregation may exacerbate effects of a small fraction of alpha1(I) homotrimers on formation, properties, and remodeling of collagen fibers.