3D-Printed Auxetic Skin Scaffold for Decreasing Burn Wound Contractures at Joints.

For patients with severe burns that consist of contractures induced by fibrous scar tissue formation, a graft must adhere completely to the wound bed to enable wound healing and neovascularization. However, currently available grafts are insufficient for scar suppression owing to their nonuniform pressure distribution in the wound area. Therefore, considering the characteristics of human skin, which is omnidirectionally stretched via uniaxial stretching, we proposed an auxetic skin scaffold with a negative Poisson's ratio (NPR) for tight adherence to the skin scaffold on the wound bed site. Briefly, a skin scaffold with the NPR effect was fabricated by creating a fine pattern through 3D printing. Electrospun layers were also added to improve adhesion to the wound bed. Fabricated skin scaffolds displayed NPR characteristics (-0.5 to -0.1) based on pulling simulation and experiment. Finger bending motion tests verified the decreased marginal forces (<50%) and deformation (<60%) of the NPR scaffold. In addition, the filling of human dermal fibroblasts in most areas (>95%) of the scaffold comprising rarely dead cells and their spindle-shaped morphologies revealed the high cytocompatibility of the developed scaffold. Overall, the developed skin scaffold may help reduce wound strictures in the joints of patients with burns as it exerts less pressure on the wound margin.

Influence of body shape on health-related quality of life in Korean adults: The mediating effect of self-rated health.

A Body Shape Index (ABSI) predicts mortality independent of body mass index and had a negative relationship with self-rated health (SRH), which had a positive effect on the EuroQol (EQ)-5D index. This study aimed to investigate the relationship between ABSI and the EQ-5D index and to verify the mediating effect of SRH in Korean adults. This study included 13,381 participants aged ≥20 years from the 7th (2016-2018) Korean National Health and Nutrition Examination Survey (KNHANES). The participants were classified into tertile groups based on the ABSI (T1, T2, and T3 groups). Demographic characteristics, health-related factors, ABSI, SRH, and EQ-5D scores were evaluated. Women (p<0.001), rural areas (p<0.001), married persons (p<0.001), low education level (p<0.001), low income (p<0.001), and older age (p<0.001) were higher in the T3 group. The monthly drinking (p<0.001), current smoking (p<0.001), and mental stress rates (p<0.001) were the highest in the T1 group. The overall average SRH scores and EQ-5D index were 3.08 points and 0.94 points, respectively. ABSI and SRH (r = -0.161, p<0.001) and ABSI and EQ-5D (r = -0.229, p<0.001) showed a negative correlation. However, SRH and EQ-5D scores (r = 0.433, p<0.001) were positively correlated. The overall effect of the independent variable ABSI on the dependent variable EQ-5D was -0.959. SRH partially mediated the effect of ABSI on EQ-5D (indirect effect coefficient = -0.200). These results can be used as basic data to develop strategies and programs to improve health-related quality of life by adjusting ABSI and SRH.

Bone Regeneration with 3D-Printed Hybrid Bone Scaffolds in a Canine Radial Bone Defect Model.

BACKGROUND: The repair of large bone defects remains a significant challenge in clinical practice and requires bone grafts or substitute materials. In this study, we developed a unique hybrid bone scaffold comprising a three dimensional (3D)-printed metal plate for weight bearing and a biodegradable polymer tube serving as bone conduit. We assessed the long-term effect of the hybrid bone scaffold in repairing radial bone defects in a beagle model. METHODS: Bone defects were created surgically on the radial bone of three beagle dogs and individually-tailored scaffolds were used for reconstruction with or without injection of autologous bone and decellularized extracellular matrix (dECM). The repaired tissue was evaluated by X-ray, micro-computed tomography, and histological observation 6 months after surgery. The functional integrity of hybrid bone scaffold-mediated reconstructions was assessed by gait analysis. RESULTS: In vivo analysis showed that the hybrid bone scaffolds maintained the physical space and bone conductivity around the defect. New bone was formed adjacent to the scaffolds. Addition of autologous bone and dECM in the polymer tube improved healing by enhancing bone induction and osteoconduction. Furthermore, the beagles' gait appeared normal by 4 months. CONCLUSION: The future of bone healing and regeneration is closely related to advances in tissue engineering. Bone production using autologous bone and dECM loaded on 3D-printed hybrid bone scaffolds can successfully induce osteogenesis and provide mechanical force for functional bone regeneration, even in large bone defects.

PCL/Sodium-Alginate Based 3D-Printed Dual Drug Delivery System with Antibacterial Activity for Osteomyelitis Therapy.

Chronic osteomyelitis is mostly caused by bacteria such as S. aureus, and is often treated with oral antibiotics or injections to suppress the bacteria. In severe cases, however, surgical treatment using antibiotic beads and metal supports may be required. In these surgeries, bacterial attachment to the metal may lead to biofilm formation and reduce antibiotics' penetration to the bacteria. Reoperation must be performed to prevent bacterial inflammatory reactions and antibiotic resistance. Thus, in this study, we developed a dual-drug-releasing PCL/sodium-alginate-based 3D-printed scaffold to effectively treat osteomyelitis by removing the biofilm. We proposed an antibiotic-loaded biodegradable polymer scaffold using 3D printing, which was encapsulated by a second antibiotic-containing hydrogel. Then, we successfully established a dual-drug-based scaffold that consisted of a cefazolin (CFZ)-containing polycaprolactone 3D scaffold and a rifampicin (RFP)-loaded alginate hydrogel encapsulating the 3D scaffold. Our scaffold showed a synergistic effect, whereby biofilm formation was inhibited by RFP, which is an external drug, and bacterial activity was inhibited by CFZ, which is an internal drug that increases antibacterial activity. We also confirmed that the dual-drug-based scaffold did not affect the proliferation of human osteoblasts. Our findings suggest that this dual drug delivery system may serve as a new therapeutic treatment for osteomyelitis that overcomes the limitations of individual drugs.

Phlebosclerotic Colitis in a Healthy Young Woman.

Phlebosclerotic colitis is a rare disease of intestinal ischemia and differentiating it from the typical ischemic colitis. It is caused by venous obstruction due to colonic and mesenteric venous calcification. We report a 36-year-old woman presenting with intermittent abdominal pain. Initial radiologic findings showed multiple tortuous thread-like calcifications in the region of the right side of the colon and transverse colon on plain abdominal radiographs and computed tomography images. In the colonoscopy, edematous dark-bluish colonic mucosa, sclerotic colon wall, and multiple ulcers without clear boundaries were observed from the ascending colon to the transverse colon. In the sigmoid colon only showed the edematous dark-bluish colonic mucosa, sclerotic colon wall. On the basis of these findings, we diagnosed the patient as having phlebosclerotic colitis. We report a rare case of phlebosclerotic colitis in healthy young woman.

Does dexmedetomidine reduce postoperative pain after laparoscopic cholecystectomy with multimodal analgesia?

BACKGROUND: Pain after laparoscopy is multifactorial and different treatments have been proposed to provide pain relief. Multimodal analgesia is now recommended to prevent and treat post-laparoscopy pain. Dexmedetomidine, an α2 agonist, has well-known anesthetic and analgesic-sparing effects. We evaluated the analgesic effect of perioperative dexmedetomidine infusion during laparoscopic cholecystectomy with multimodal analgesia. METHODS: Forty-two patients aged 20 to 60 years old were allocated randomly into one of 2 groups (n = 21, in each). All patients underwent laparoscopic cholecystectomy under multimodal analgesia. The patients in group P received dexmedetomidine 1 µg/kg during 10 min before induction and then 0.5 µg/kg/h continuously until the removal of the gall bladder while the patients in the group C received saline by the same methods as group P. Total analgesic consumption and VAS score were recorded for the first 24 hr. RESULTS: There were no significant differences in VAS scores between group P and group C during 24 hr after laparoscopic cholecystectomy. VAS scores of group P were lower than that of group C during the 1st hr after operation. The amount of ketorolac required during the 24 hr after the operation was significantly less in group P compared to group C. CONCLUSIONS: The administration of dexmedetomidine during laparoscopic cholecystectomy with multimodal analgesia has minimal benefits on the reduction of the postoperative pain score. The amount of ketorolac requirements during 24 hr after the operation showed significant difference. Dexmedetomidine might be helpful for the postoperative pain after laparoscopic cholecystectomy with multimodal analgesia.

Comparison of surgical conditions during propofol or desflurane anesthesia for endoscopic sinus surgery.

BACKGROUND: Reduction of intraoperative bleeding is necessary to achieve the ideal surgical field for the endoscopic sinus surgery (ESS). Intraoperative intra nasal bleeding is influenced by various anesthetics. This study compared surgical field condition between propofol/remifentanil (PR) based anesthesia and desflurane/remifentanil (DR) based anesthesia. METHODS: American Society of Anesthesiologists physical status class I or II patients undergoing ESS were randomly assigned to group PR (n = 36) or group DR (n = 32). The extent of the preoperative surgical lesion was classified as high (> 12) and low (≤ 12) Lund-Mackay (LM) scores according to the computed tomography findings. The target mean blood pressure was maintained at 70-80 mmHg. Only one surgeon was involved in rating the visibility of the surgical field on a numeric rating scale (NRS) every 10 minutes. RESULTS: There was a different surgical field grade from PR to DR. The mean (SD) surgical field score of NRS for the PR and DR was 2.3 (0.57) and 2.7 (0.67), respectively (P = 0.006). Especially in the high-LM score patients, the mean (SD) of surgical field score for the PR and DR was 2.4 (0.67) and 3.0 (0.63), respectively (P = 0.012). CONCLUSIONS: In the high-LM score patients, PR based anesthesia resulted in better surgical field condition for ESS than DR based anesthesia. In ESS, PR based anesthesia is considered to be helpful.

Dexmedetomidine and remifentanil in the perioperative management of an adolescent undergoing resection of pheochromocytoma -A case report-.

A 15-year-old adolescent with unilateral multiple adrenal pheochromocytoma had an episode of subcortical intracerebral hemorrhage and seizure 6 weeks before the surgery. He was pretreated with terazosin, losartan, atenolol and levetiracetam for 2 weeks. Dexmedetomidine was started in the preoperative waiting area, and a combination of dexmedetomidine and remifentanil was continuously infused for most of anesthetic time. To control blood pressure, bolus injection of remifentanil and low-dose infusion of sodium nitroprusside, nicardipine, and esmolol were administered during three adrenergic crises. There was minimal post-resection hypotension, and his trachea was extubated safely 20 min after the surgery. He was discharged without noticeable complication. His catecholamine levels showed the steadily decreasing pattern during the operation in this case. Though a combination of dexmedetomidine and remifentanil may not prevent the hemodynamic instability impeccably during the tumor manipulation, this combination seems to be the way of interrupting release of catecholamines and minimizing hemodynamic fluctuations.

Heat-killed Lactobacillus acidophilus La205 enhances NK cell cytotoxicity through increased granule exocytosis.

Heat-killed lactic acid bacteria (LAB) are known to be important immunomodulators that stimulate tumor necrosis factor-α (TNF-α) and nitric oxide (NO) production as well as increase phagocytic activity in macrophages. NK cells play a critical role in innate immune response and induce spontaneous killing of tumor cells and virus-infected cells. However, the effect of heat-killed LAB on NK cells is still unclear. In this study, we investigated the effect of heat-killed Lactobacillus acidophilus La205 (La205) on NK cytolytic activity. We found that heat-killed La205 directly stimulated NK cytolytic activity in dose- and time-dependent manners. To determine the mechanism underlying heat-killed La205-enhanced NK cytotoxicity, the expression of NK activating receptors was tested. Heat-killed La205 did not affect the expression of NK activating receptors. To investigate whether NK degranulation is related to heat-killed La205-enhanced NK cytotoxicity, NK degranulation inhibitor concanamycin A (CMA) was used. CMA effectively blocked heat-killed La205-induced NK cytotoxicity, and an assay for detection of a degranulation marker, CD107a, showed that heat-killed La205 increased granule exocytosis approximately 2-fold in comparison to non-treated NK cells. In addition, heat-killed La205 dramatically elevated mRNA expression of granulysin, a component of the cytolytic granule contents, in NK cells. However, other granule contents, including perforin and granzymes, were not changed by heat-killed La205. From these data, we concluded that heat-killed La205 stimulated NK cytolytic activity through enhancement of granule exocytosis, and granulysin may be a critical mediator in heat-killed La205-induced granule exocytosis.

Effect of thermal degradation of SFF-based PLGA scaffolds fabricated using a multi-head deposition system followed by change of cell growth rate.

Solid free-form fabrication (SFF) technology is used to fabricate scaffolds with controllable characteristics including well-defined pore size and porosity. The multi-head deposition system (MHDS), one form of SFF technology, may be more advantageous than others for fabricating scaffolds because a MHDS does not require the use of a cytotoxic solvent. This method, however, may induce the thermal degradation of raw materials and a subsequent decrease in the material's molecular weight, whereby hydrolytic degradation, resulting in acidic by-products, might be accelerated. This study investigated whether fabrication of poly(lactic-co-glycolic acid) (PLGA) scaffolds using a MHDS with various residence times in the heating step induces thermal degradation and affects the proliferation of cells seeded on the scaffold in vitro. To answer this question, we fabricated porous three-dimensional PLGA scaffolds using residence times of 1, 3, 5 and 7 days for groups 1 through 4, respectively. Degradation behavior of the scaffolds was observed for 7 weeks in phosphate-buffered saline solution (pH 7.4) at 37 degrees C. The molecular weight, glass transition temperature and mechanical properties were compared for PLGA scaffolds fabricated with each of the four residence times at 120 degrees C. The proliferation rate of MC3T3-E1 cells grown on each group of scaffolds was compared to investigate the effect of acidic by-products on the growth of seeded cells in vitro. The heat process applied in fabrication of SFF-based PLGA scaffolds induced considerable thermal degradation followed by a decrease in molecular weight and mechanical compressive strength of the scaffolds in groups 3 and 4, which had more than 3 days residence time. Moreover, the cell proliferation rate was significantly higher for group 1 than for groups 3 and 4.

Synchrotron X-ray bioimaging of bone regeneration by artificial bone substitute of MegaGen Synthetic Bone and hyaluronate hydrogels.

Synchrotron X-ray bioimaging was successfully carried out to observe bone regeneration by a novel artificial bone substitute of bioactive MegaGen Synthetic Bone (MGSB) and hyaluronate (HA) hydrogels. A biphasic calcium phosphate of MGSB was prepared by chemical precipitation method, with a porous spherical morphology. On the basis of the fact that HA plays important roles in bone regeneration and promotes the differentiation, vascularization, and migration of stem cells, HA-cystamine (CYS) hydrogels with cleavable disulfide linkages were prepared to supply HA continuously for effective bone regeneration by their controlled degradation in vivo. Among seven different samples using Bio-OSS®, MGSB, and/or several kinds of HA hydrogels, MGSB/HA-CYS hydrogels resulted in the most significant bone regeneration in the calvarial critical bone defect of New Zealand white rabbits. Histological and histomorphometric analyses revealed that the bone regeneration by MGSB/HA-CYS hydrogels was as high as 43%, occupying 71% of the bone defect area with MGSB in the form of a calvarial bone plate in 4 weeks. After that, MGSB was bioabsorbed and replaced gradually with regenerated bones as observed in 8 weeks. Synchrotron X-ray imaging clearly confirmed the effective bone regeneration by MGSB/HA-CYS hydrogels, showing three-dimensional micron-scale morphologies of regenerated bones interconnected with MGSB. In addition, sequential nondestructive synchrotron X-ray tomographic analysis results from anterior to posterior of the samples were well matched with the histomorphometric analysis results. The clinically feasible artificial bone substitutes of MGSB/HA-CYS hydrogels will be investigated further for various bone tissue engineering applications using the synchrotron X-ray bioimaging systems.

Effect of cross-linking reagents for hyaluronic acid hydrogel dermal fillers on tissue augmentation and regeneration.

A novel, biocompatible, and nontoxic dermal filler using hyaluronic acid (HA) hydrogels was successfully developed for tissue augmentation applications. Instead of using highly reactive cross-linkers such as divinyl sulfone (DVS) for Hylaform, 1,4-butanediol diglycidyl ether (BDDE) for Restylane, and 1,2,7,8-diepoxyoctane (DEO) for Puragen, HA hydrogels were prepared by direct amide bond formation between the carboxyl groups of HA and hexamethylenediamine (HMDA) with an optimized carboxyl group modification for effective tissue augmentation. The HA-HMDA hydrogels could be prepared within 5 min by the addition of HMDA to HA solution activated with 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide (EDC) and 1-hydroxybenzotriazole monohydrate (HOBt). Five kinds of samples, a normal control, a negative control, a positive control of Restylane, adipic acid dihydrazide grafted HA (HA-ADH) hydrogels, and HA-HMDA hydrogels, were subcutaneously injected to wrinkled model mice. According to the image analysis on dorsal skin augmentation, the HA-HMDA hydrogels exhibited the best tissue augmentation effect being stable longer than 3 months. Furthermore, histological analyses after hematoxylin-eosin (H&E) and Masson's trichrome staining revealed the excellent biocompatibility and safety of HA-HMDA hydrogels. The dermal thickness and the dermal collagen density in wrinkled mice after treatment with HA-HMDA hydrogels for 12 weeks were comparable to those of normal mice. Compared with HA-DVS hydrogels and Restylane, the excellent tissue augmentation by HA-HMDA hydrogels might be ascribed to the biocompatible residues of amine groups in the cross-linker of HMDA. The HA-HMDA hydrogels will be investigated further as a novel dermal filler for clinical applications.

Guided bone regeneration by poly(lactic-co-glycolic acid) grafted hyaluronic acid bi-layer films for periodontal barrier applications.

A novel protocol for the synthesis of biocompatible and degradation controlled poly(lactic-co-glycolic acid) grafted hyaluronic acid (HA-PLGA) was successfully developed for periodontal barrier applications. HA was chemically modified with adipic acid dihydrazide (ADH) in the mixed solvent of water and ethanol, which resulted in a high degree of HA modification up to 85 mol.%. The stability of HA-ADH to enzymatic degradation by hyaluronidase increased with ADH content in HA-ADH. When the ADH content in HA-ADH was higher than 80 mol.%, HA-ADH became soluble in dimethyl sulfoxide and could be grafted to the activated PLGA with N,N'-dicyclohexyl carbodiimide and N-hydroxysuccinimide. The resulting HA-PLGA was used for the preparation of biphasic periodontal barrier membranes in chloroform. According to in vitro hydrolytic degradation tests in phosphate buffered saline, HA-PLGA/PLGA blend film with a weight ratio of 1/2 degraded relatively slowly compared to PLGA film and HA coated PLGA film. Four different samples of a control, OSSIX(TM) membrane, PLGA film, and HA-PLGA/PLGA film were assessed as periodontal barrier membranes for the calvarial critical size bone defects in SD rats. Histological and histomorphometric analyses revealed that HA-PLGA/PLGA film resulted in the most effective bone regeneration compared to other samples with a regenerated bone area of 63.1% covering the bone defect area.

Application of microstereolithography in the development of three-dimensional cartilage regeneration scaffolds.

Conventional methods for fabricating three-dimensional (3-D) tissue engineering scaffolds have substantial limitations. In this paper, we present a method for applying microstereolithography in the construction of 3-D cartilage scaffolds. The system provides the ability to fabricate scaffolds having a pre-designed internal structure, such as pore size and porosity, by stacking photopolymerized materials. To control scaffold structure, CAD/CAM technology was used to generate a scaffold pattern algorithm. Since tissue scaffolds must be constructed using a biocompatible, biodegradable material, scaffolds were synthesized using liquid photocurable TMC/TMP, followed by acrylation at the terminal ends, and photocured under UV light irradiation. The solidification properties of the TMC/TMP polymer were also assessed. To assess scaffold functionality, chondrocytes were seeded on two types of 3-D scaffold and characterized for cell adhesion. Results indicate that scaffold geometry plays a critical role in chondrocyte adhesion, ultimately affecting the tissue regeneration utility of the scaffolds. These 3-D scaffolds could eventually lead to optimally designed constructs for the regeneration of various tissues, such as cartilage and bone.

Synthesis and degradation test of hyaluronic acid hydrogels.

Hyaluronic acid (HA) hydrogels prepared with three different crosslinking reagents were assessed by in vitro and in vivo degradation tests for various tissue engineering applications. Adipic acid dihydrazide grafted HA (HA-ADH) was synthesized and used for the preparation of methacrylated HA (HA-MA) with methacrylic anhydride and thiolated HA (HA-SH) with Traut's reagent (imminothiolane). (1)H NMR analysis showed that the degrees of HA-ADH, HA-MA, and HA-SH modification were 69, 29, and 56 mol%, respectively. HA-ADH hydrogel was prepared by the crosslinking with bis(sulfosuccinimidyl) suberate (BS(3)), HA-MA hydrogel with dithiothreitol (DTT) by Michael addition, and HA-SH hydrogel with sodium tetrathionate by disulfide bond formation. According to in vitro degradation tests, HA-SH hydrogel was degraded very fast, compared to HA-ADH and HA-MA hydrogels. HA-ADH hydrogel was degraded slightly faster than HA-MA hydrogel. Based on these results, HA-MA hydrogels and HA-SH hydrogels were implanted in the back of SD rats and their degradation was assessed according to the pre-determined time schedule. As expected from the in vitro degradation test results, HA-SH hydrogel was in vivo degraded completely only in 2 weeks, whereas HA-MA hydrogels were degraded only partially even in 29 days. The degradation rate of HA hydrogels were thought to be controlled by changing the crosslinking reagents and the functional group of HA derivatives. In addition, the state of HA hydrogel was another factor in controlling the degradation rate. Dried HA hydrogel at 37 degrees C for a day resulted in relatively slow degradation compared to the bulk HA hydrogel. There was no adverse effect during the in vivo tests.

Augmentation of sodium butyrate-induced apoptosis by phosphatidylinositol 3-kinase inhibition in the human cervical cancer cell-line.

PURPOSE: Sodium butyrate (NaBT) is principally a histone deacetylase (HDAC) inhibitor, and it has the potential to arrest HPV-positive carcinoma cells at the G1 to S phase transition of the cell cycle. The aim of study was to determine whether phosphatidylinositol 3-kinase (PI3K) inhibition can enhance the inhibitory effect of NaBT on a human cervical cancer cell line (HeLa). MATERIALS AND METHODS: Cervical cancer cells (HeLa) were treated with NaBT alone or in combination with the PI3K inhibitors wortmannin or LY294002. Cell viability analysis and FACS analysis were carried out. The expressions of the cell cycle related proteins were evaluated by Western-blot analysis. RESULTS: Inhibition of PI3K enhanced NaBT-mediated apoptosis and this decreased the HeLa cell viability. Either wortmannin or LY294002, combined with NaBT, enhanced the activation of caspase 3 and caspase 9, and this enhanced the subsequent cleavage of poly (ADP-ribose) polymerase (PARP). Cervical cancer cells were arrested in the subG1 and G2/M phase, as was detected by FACS analysis. NaBT treatment in combination with PI3K inhibitors showed the increased expression of the CDK inhibitors p21(Cip1/Waf1) and p27(Kip1), in a p53 dependent manner, and also the increased dephosphorylation of Rb whereas there was a reduction in the expression levels of cyclin A, cyclin D1 and cyclin B1. CONCLUSION: The results demonstrate that inhibition of PI3K enhances NaBT-mediated cervical cancer cell apoptosis through the activation of the caspase pathway. Moreover, these findings will support future investigation using the PI3K inhibitors in combination with adjuvant treatment for treating carcinoma of the cervix.