Improved radiation resistance of an Er-doped silica fiber by a preform pretreatment method.

We report a novel pretreatment method to improve the radiation resistance of Er-doped fiber (EDF). The processing object of this method is EDF preform, and the pretreatment processing involves three steps: deuterium loading, pre-irradiation, and thermal annealing. The effects of pretreatment conditions on the optical loss, gain performance, and radiation resistance of EDF were systematically studied. The relevant mechanisms were revealed using Fourier transform infrared (FTIR), radiation-induced absorption (RIA), and electron paramagnetic resonance (EPR) spectroscopies. The results show that the pretreatment can not only greatly reduce the hydroxyl content of the EDF core, but it can also effectively improve the radiation resistance of EDF. The online test results show that the gain of the commercial, pristine, and pretreated EDFs were reduced by 19.0, 4.2, and 1.3 dB, respectively, corresponding to a decrease of 68.1, 16.2, and 4.7% after 98 krad X-rays irradiation. The high vacuum experiments show that the pretreatment method can maintain long-term stable high radiation resistance. This work provides a reference for the development of high-performance radiation resistant EDFs for use in the lower, middle, and geosynchronous earth orbit.

Evaluation of GnRH antagonist pretreatment before ovarian stimulation in a GnRH antagonist protocol in normal ovulatory women undergoing IVF/ICSI: a randomized controlled trial.

BACKGROUND: Synchronization of follicles is key to improving ovulation stimulation with the gonadotropin-releasing hormone (GnRH) antagonist protocol. GnRH antagonist administration in the early follicular phase can quickly decrease gonadotrophin (Gn) levels and achieve downregulation before stimulation, which may improves synchronization. A previous small randomized controlled study (RCT) showed that pretreatment with a GnRH antagonist for 3 days before stimulation may increase oocyte retrieval but cannot increase the pregnancy rate. This study investigated whether the GnRH antagonist pretreatment protocol in ovulatory women can increase the synchronization of follicles and pregnancy outcomes compared with the conventional GnRH antagonist protocol. METHODS: This RCT included 136 normal ovulatory women undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI). Both groups were treated with recombinant follicle-stimulating hormone (r-FSH) and a flexible GnRH antagonist protocol. The women were randomized into two equal groups with or without GnRH antagonist administration from day 2 of the menstrual cycle for 3 days before stimulation. Our primary outcome was the number of retrieved oocytes. Secondary outcomes included the pregnancy rate and live birth rate. RESULTS: Both groups had similar baseline characteristics. The number of retrieved oocytes in the study group was comparable to that in the control group (9.5 [8.0-13.0] vs. 11.0 [7.0-14.8], P = 0.469). There was no significant difference in the follicle size. The fertilization rate, number of good-quality embryos, implantation rate, pregnancy rate, ongoing pregnancy rate, live birth rate per embryonic transfer cycle, and miscarriage rate were similar between the two groups. CONCLUSION: This large RCT analysed GnRH antagonist pretreatment with the GnRH antagonist protocol applied to normal ovulatory women undergoing IVF/ICSI. The number of retrieved oocytes and pregnancy outcomes did not significantly vary. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1800019730 . Registered 26 November 2018.

[A Novel Chemically Defined Medium Enhanced the Osteogenic Potential and Periodontal Bone Regeneration of Dental Papilla Cells].

OBEJECTIVE: To investigate the role of a novel chemically defined medium (CDM) in the regulation of dental papilla cells (DPCs) functional phenotype in vitro and periodontal bone regeneration in vivo. METHODS: DPCs were isolated and cultured in conventional medium (CM) or CDM. The surface makers, and the proliferation, migration and osteogenic differentiation abilities of DPCs were evaluated. In vivo, the DPCs that mixed with collagen gel were implanted into the model rats in the defect of periodontal to repair the periodontal tissue. Regeneration of the tissues was examined by microcomputed tomography and histological observation. RESULTS: DPCs in the CM group and CDM group showed similar surface markers. Compared to the CM group, the CDM significantly enhanced the proliferation, colony-forming efficiency and migration of DPCs in vitro. In addition, real time PCR showed that the expression levels of osteogenesis-related genes, Runx2, Alp and Opn. were significantly enhanced in DPCs in the CDM group. DPCs cells treated with CDM also exhibited higher alkaline phosphatase activity and stronger ability of formation of mineralized nodules in vitro. In vivo, DPCs from CDM group significantly enhanced the periodontal bone regeneration and the reconstruction of periodontal bone tissues in rat periodontal defect model. CONCLUSION: CDM is a suitable medium to culture DPCs for periodontal bone regeneration. This research provided a substitute for basic research and set the stage for future clinical application of stem cell transplantation.

Therapeutic potential of HERS spheroids in tooth regeneration.

Hertwig's epithelial root sheath (HERS) plays indispensable roles in tooth root development, including controlling the shape and number of roots, dentin formation, and helping generate the cementum. Based on these characteristics, HERS cell is a potential seed cell type for tooth-related tissue regeneration. However, the application is severely limited by a lack of appropriate culture methods and small cell numbers. Methods: Here, we constructed a 3D culture method to expand functional HERS cells into spheroids, and investigated characteristics and application of dental tissue regeneration of these spheroids. HERS spheroids and HERS cells (2D monolayer culture) were compared in terms of biological characteristics (such as proliferation, self-renewal capacity, and stemness) in vitro and functions (including differentiation potential and inductive ability of dentin formation) both in vitro and in vivo. Further, transcriptome analysis was utilized to reveal the molecular mechanisms of their obvious differences. Results: HERS spheroids showed obvious superiority in biological characteristics and functions compared to 2D monolayers of HERS cells in vitro. In vivo, HERS spheroids generated more mineralized tissue; when combined with dental papilla cells (DPCs), HERS spheroids contributed to dentin-like tissue formation. Moreover, the generation and expansion of HERS spheroids rely to some degree on the HIF-1 pathway. Conclusion: HERS spheroid generation is beneficial for functional HERS cell expansion and can provide a useful cell source for further tooth regeneration and mechanistic research. Notably, HIF-1 pathway plays a critical role in HERS spheroid formation and function.

Exosome-like vesicles derived from Hertwig's epithelial root sheath cells promote the regeneration of dentin-pulp tissue.

Background: The formation of dentin-pulp involves complex epithelial-mesenchymal interactions between Hertwig's epithelial root sheath cells (HERS) and dental papilla cells (DPCs). Earlier studies have identified some of the regulatory molecules participating in the crosstalk between HERS and DPCs and the formation of dentin-pulp. In the present study we focused on the role of HERS-secreted exosomes in DPCs and the formation of dentin-pulp. Specifically, we hypothesized that exosome-like vesicles (ELVs) might mediate the function of HERS and trigger lineage-specific differentiation of dental mesenchymal cells. To test our hypothesis, we evaluated the potential of ELVs derived from a HERS cell line (ELVs-H1) in inducing in vitro and in vivo differentiation of DPCs. Methods: ELVs-H1 were characterized using transmission electron microscopy and dynamic light scattering. The proliferation, migration, and odontoblast differentiation of DPCs after treatment with ELVs-H1, was detected by CCK8, transwell, ALP, and mineralization assays, respectively. Real time PCR and western blotting were used to detect gene and protein expression. For in vivo studies, DPC cells were mixed with collagen gel combined with or without ELVs and transplanted into the renal capsule of rats or subcutaneously into nude mice. HE staining and immunostaining were used to verify the regeneration of dentin-pulp and expression of odontoblast differentiation markers. Results: ELVs-H1 promoted the migration and proliferation of DPCs and also induced odontogenic differentiation and activation of Wnt/ß-catenin signaling. ELVs-H1 also contributed to tube formation and neural differentiation in vitro. In addition, ELVs-H1 attached to the collagen gel, and were slowly released and endocytosed by DPCs, enhancing cell survival. ELVs-H1 together with DPCs triggered regeneration of dental pulp-dentin like tissue comprised of hard (reparative dentin-like tissue) and soft (blood vessels and neurons) tissue, in an in vivo tooth root slice model. Conclusion: Our data highlighted the potential of ELVs-H1 as biomimetic tools in providing a microenvironment for specific differentiation of dental mesenchymal stem cells. From a developmental perspective, these vesicles might be considered as novel mediators facilitating the epithelial-mesenchymal crosstalk. Their instructive potency might be exploited for the regeneration of dental pulp-dentin tissues.

Evaluation of Endovascular Therapy Combined with Bowel Resection Treatment on Patients with Acute Mesenteric Venous Thrombosis.

BACKGROUND: This retrospective study aims to investigate the effects of the endovascular and surgical strategy for treating patients with acute mesenteric venous thrombosis (AMVT). METHODS: We retrospectively studied 68 patients with AMVT who underwent treatment in Jinling Hospital during the period from January 2009 to December 2014. The mean age was 45 ± 12 years (range 20-72 years). All patients were treated by using the combined treatment that included endovascular treatment, damage control surgery, surgical intensive care, and intestinal rehabilitation treatment. Clinical outcomes and complications were compared during the follow-up period. RESULTS: All the 68 cases received anticoagulant treatment. However, only 24 received the endovascular intervention, 19 received surgical resection, and 25 patients received endovascular treatment combined with bowel resection. The overall mortality rate was 2.94% (2 cases). Bowel resection range significantly decreased (92 ± 14 cm vs. 162 ± 27 cm, t = -2.377, P = 0.022) in the combination therapy group, when compared with the surgery group. During the 1-year follow-up period, 4 cases suffered from short bowel syndrome. CONCLUSIONS: Our study indicates that AMVT can be successfully treated with the early improvement of intestinal blood circulation. Further, our applied combined approach showed a favorable outcome in mesenteric thrombosis patients and reduced the mortality rate by improving the prognosis significantly.

Immortalized Hertwig's epithelial root sheath cell line works as model for epithelial-mesenchymal interaction during tooth root formation.

Hertwig's epithelial root sheath (HERS) is critical for epithelial-mesenchymal interaction (EMI) during tooth root formation. However, the exact roles of HERS in odontogenic differentiation by EMI have not been well characterized, because primary HERS cells are difficult to obtain. Immortalized cell lines constitute crucial scientific tools, while there are few HERS cell lines available. Our previous study has successfully established immortalized HERS cell lines. Here, we confirmed the phenotype of our HERS-H1 by verifying its characteristics and functions in odontogenic differentiation through EMI. The HERS-H1-conditioned medium (CM-H1) effectively enhanced odontogenic differentiation of dental papilla cells (DPCs) in vitro. Furthermore, Smad4 and p-Smad1/5/8 were significantly activated in DPCs treated with CM-H1, and this activation was attenuated by noggin. In vivo, our implanted recombinants of HERS-H1 and DPCs exhibited mineralized tissue formation and expression of Smad4, p-Smad1/5/8, and odontogenic differentiation markers. Our results indicated that HERS-H1 promoted DPCs odontoblastic differentiation via bone morphogenetic protein/Smad signaling. HERS-H1 exhibits relevant key molecular characteristics and constitutes a new biological model for basic research on HERS and the dental EMI during root development and regeneration.

Effects of incident light intensity and light path length on cell growth and oil accumulation in Botryococcus braunii (Chlorophyta).

Botryococcus braunii was cultured in different light path length under different incident light intensity to investigate the effect of light on alga growth as well as hydrocarbon and fatty acid accumulation. Results indicated that longer light path length required higher incident light intensity in order to meet the light requirement of algal growth and hydrocarbon accumulation during the course of cultivation. However, hydrocarbon profile was only affected by the incident light intensity and not influenced by the light path length. High incident light intensity enhanced the accumulation of hydrocarbons with longer carbon chains. Besides, the fatty acid content and profiles were significantly influenced by both incident light intensity and light path. Higher fatty acid content and higher percentage of C18 and monounsaturated fatty acid components were achieved at the higher incident light intensity and lower light path length. Taken together, these results are benefit to improve its biomass and oil productivity through the optimization of light and photobioreactor design.

Open Abdomen Improves Survival in Patients With Peritonitis Secondary to Acute Superior Mesenteric Artery Occlusion.

BACKGROUND: Damage control surgery and open abdomen (OA) have been extensively used in the severe traumatic patients. However, there was little information when extended to a nontrauma setting. The purpose of this study was to evaluate whether the liberal use of OA as a damage control surgery adjunct improved the clinical outcome in acute superior mesenteric artery occlusion patients. STUDY DESIGN: A single-center, retrospective cohort review was performed in a national tertiary surgical referral center. RESULTS: Forty-four patients received OA (OA group) and 65 patients had a primary fascial closure (non-OA group) after diagnosed as peritonitis secondary to acute superior mesenteric artery occlusion from January, 2005 to June, 2016. Revascularization was achieved through endovascular aspiration embolectomy, open embolectomy, or percutaneous stent. No difference of bowel resection length was found between groups in the first emergency surgery. However, more non-OA patients (35.4%) required a second-look enterectomy to remove the residual bowel ischemia than OA patients (13.6%, P<0.05). OA was closed within a median of 7 days (4 to 15 d). There was a mean of 134 cm residual alive bowel in OA, whereas 96 cm in non-OA. More non-OA patients suffered from intra-abdominal sepsis (23.1% vs. 6.8%, P<0.01), intra-abdominal hypertension (31% vs. 0, P<0.01), and acute renal failure (53.8% vs. 31.8%, P<0.05) than OA group after surgery. Short-bowel syndrome occurred infrequently in OA than non-OA patients (9.1% vs. 36.9%, P<0.01). OA significantly decreased the 30-day (27.3% vs. 52.3%, P<0.01) and 1-year mortality rate (31.8 % vs. 61.5%, P<0.01) compared with non-OA group. CONCLUSIONS: Liberal use of OA, as a damage control adjunct avoided the development of intra-abdominal hypertension, reduced sepsis-related complication, and improved the clinical outcomes in peritonitis secondary to acute SMA occlusion.

Effects of early enteral nutrition supplemented with collagen peptides on post-burn inflammatory responses in a mouse model.

The effect of early enteral nutrition (EN) supplemented with Alaska pollock skin-derived collagen peptides (CPs) on post-burn inflammatory responses was investigated in a mouse model. Male blab/c mice were randomly assigned to four groups: a sham burn (SB) group, a control group (burn + EN + glycine, BE), a positive control group (burn + EN + glutamine, BEG) and a treatment group (burn + EN + CPs, BEC). Burn-induced increases of serum endotoxin level, and systemic and intestinal concentration of TNF-α and IL-6 were attenuated in BEG and BEC at post-burn day (PBD) 1, 3 and 7 (p < 0.05 vs. BE). Notably, BEC revealed a prominent decrease of the serum endotoxin level, TNF-α and IL-6 as compared to BEG at PBD 7 (p < 0.05). Furthermore, EN supplemented with CPs diminished the phosphorylation of intestinal NF-κB p65 and simultaneously down-regulated the mRNA expression of TNF-α and IL-6 in small intestine (p < 0.05 vs. BE). Also, it demonstrated a comparable effect with glutamine in ameliorating post-burn inflammatory responses in mice with burns. Therefore, CPs could be considered as a potential immunonutrient supplement in EN to improve post-burn outcomes in burn patients.

Protective effect of gelatin peptides from pacific cod skin against photoaging by inhibiting the expression of MMPs via MAPK signaling pathway.

Chronic exposure to ultraviolet (UV) irradiation causes skin photoaging. This study was undertaken to identify the anti-photoaging mechanisms of gelatin hydrolysate (CH) derived from pacific cod skin. Quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) and ELISA assays were used to investigate the effects of CH on matrix metalloproteinases (MMPs) and the signaling pathways after UV irradiation by using a mice skin photoaging model. The average molecular weight of CH was 1200Da, and 273/1000 residues were hydrophobic, Gly-Pro and Gly-Leu sequences and Arg at C-terminus appeared frequently in CH. CH improved pathological changes of collagen fibers and significantly inhibited collagen content reduction in photoaging skin. Moreover, CH blocked the up-regulated expression of interstitial collagenase (MMP-1), stromelysin 1 (MMP-3), and gelatinase (MMP-9) in photoaging skin. Besides, CH suppressed the activities of MMPs by increasing the contents of tissue inhibitors of matrix metalloproteinases (TIMPs). CH significantly reduced the UV irradiation-dependent up-regulated phosphorylation of ERK and p38 in the mitogen-activated protein kinase (MAPK) signaling pathway. Furthermore, it inhibited the activation of activator protein 1 (AP-1) by down-regulating the mRNA level of c-Jun and c-Fos, which are the two transcription factors responsible for the regulation of MMPs expression. CH can effectively protect against UV irradiation-induced skin photoaging by inhibiting the expression and the activity of MMPs.