Essential amino acid residues and catalytic mechanism of trans-epoxysuccinate hydrolase for production of meso-tartaric acid.

OBJECTIVES: This study aimed to discuss the essential amino acid residues and catalytic mechanism of trans-epoxysuccinate hydrolase from Pseudomonas koreensis for the production of meso-tartaric acid. RESULTS: The optimum conditions of the enzyme were 45 °C and pH 9.0, respectively. It was strongly inhibited by Zn2+, Mn2+ and SDS. Michaelis-Menten enzyme kinetics analysis gave a Km value of 3.50 mM and a kcat of 99.75 s-1, with an exceptional EE value exceeding 99.9%. Multiple sequence alignment and homology modeling revealed that the enzyme belonged to MhpC superfamily and possessed a typical α/ß hydrolase folding structure. Site-directed mutagenesis indicated H34, D104, R105, R108, D128, Y147, H149, W150, Y211, and H272 were important catalytic residues. The 18O-labeling study suggested the enzyme acted via two-step catalytic mechanism. CONCLUSIONS: The structure and catalytic mechanism of trans-epoxysuccinate hydrolase were first reported. Ten residues were critical for its catalysis and a two-step mechanism by an Asp-His-Asp catalytic triad was proposed.

Transcription factor Krüppel-like factor 4 upregulated G protein-coupled receptor 30 alleviates intestinal inflammation and apoptosis, and protects intestinal integrity from intestinal ischemia-reperfusion injury.

INTRODUCTION: Intestinal ischemia/reperfusion (I/R) injury is a common clinical event occurring during multiple clinical pathological processes. Here, we designed this paper to discuss the role of G protein-coupled receptor 30 (GPR30) playing in intestinal I/R injury. METHODS: An oxygen-glucose deprivation/reoxygenation (OGD/R) cell model was established to simulate the pathological process of I/R injury. With the application of enzyme-linked immunosorbent assay, TUNEL, and transepithelial electrical resistance (TEER) assays, the levels of inflammatory cytokines, cell apoptosis, and intestinal integrity were estimated. The corresponding proteins were estimated by applying western blot. Immunofluorescence was conducted to examine N-terminal Gasdermin D (GSDMD-N) expression. The interplay between KLF4 and GPR30 was demonstrated by dual-luciferase reporter assay and chromatin immunoprecipitation. RESULTS: The results showed that GPR30 was downregulated in Caco-2 cells exposed to OGD/R. GPR30 overexpression reduced the production of TNF-α, IL-6, IL-1ß, and IL-18, the TUNEL-positive cells, as well as the contents of p-p65, Cox-2, Inos, Bax, and cleaved-PARP, but elevated the expression of Bcl-2 in OGD/R-induced Caco-2 cells. In addition, OGD/R-induced the reduction of TEER value and reduced expression of tight junction proteins in Caco-2 cells, which was partially restored by GPR30 overexpression. Furthermore, GPR30 suppressed nod-like receptor pyrin 3 inflammasome and GSDMD-N expression. It was evidenced that Krüppel-like factor 4 (KLF4) could directly bind to GPR30 promoter and positively regulate GPR30 expression. The regulation of GPR30 overexpression above was weakened by KLF4 knockdown. CONCLUSION: Collectively, our findings suggested that KLF4 could transcriptionally upregulate GPR30, and GPR30 prevented intestine I/R injury by inhibiting inflammation and apoptosis, and maintaining intestinal integrity that provides potential targets for mitigating the I/R injury.

Preparation of a Bi6O5(OH)3(NO3)5·2H2O/AgBr composite and its long-lasting antibacterial efficacy.

A novel Bi6O5(OH)3(NO3)5·2H2O/AgBr (6535BBN/AgBr) composite with long-lasting antibacterial efficacy was prepared. The microstructure of the composite was characterized. AgBr nanoparticles (NPs) were sandwiched in 6535BBN nanosheets (NSs) or loaded on their surfaces. The utilization of 6535BBN as carriers contributed to the long-term lasting antibacterial activity of the composite after storage in water or 0.9% NaCl. The antibacterial activity was evaluated by inhibition zones against E. coli. The inhibition zone diameters of 6535BBN/AgBr stored in water for 0 h, 8 h, 16 h, and 48 h were measured as 22.50, 21.71, 20.43, and 20.29 mm, respectively. The activity of the composite after storage in water for 48 h remained 90.2% of that in the beginning. After storing in 0.9% NaCl for 16 h, the activity was determined to be 90.1% of that in the beginning. In comparison with the rapid decrease in the antibacterial activity of pure AgBr, the slow reduction of 6535BBN/AgBr after storage indicates long-lasting efficacy. The excellent dispersion states of 6535BBN/AgBr powders after storage in solutions were revealed, and the positive relationship between the dispersion state and its long-lasting antibacterial activity was suggested. Based on the unique load-on-carrier (LOC) structure, the long-lasting antibacterial performance was promoted by the synergy of the sharp-edge-cutting effect of 6535BBN NSs, prolonged ROS antibacterial effect, and restrained sterilization effects of silver ions caused by their slow release.

[Oral health and hygiene behavior in chronic renal failure patients].

PURPOSE: To investigate the oral health and hygiene behavior of chronic renal failure(CRF) patients in Shenzhen, so as to provide basis for formulating education for them. METHODS: The history of renal failure, oral health status and oral health care behavior of 336 patients with chronic renal failure(CRF) in the hemodialysis center of Shenzhen Second People's Hospital were investigated by questionnaire and oral examinations. RESULTS: At an average, dialysis was required for 3.2 years. The main cause of renal failure was glomerulonephritis in 49.11% of patients, hypertensive kidney lesion in 19.35% and diabetic nephropathy in 15.77% of patients; 77.8% of them kept brushing teeth two or more than two times every day; 72.9% patients suffered from oral problems such as toothache in recent 12 months. The rate of visiting a dentist when having complaints was 21.7%. CONCLUSIONS: The state of oral health of CRF is worse than the general population of comparable age in China, while their hygiene behavior is better than the corresponding reference general population. However, their consciousness of dental treatment is poor. Therefore, health education for CRF patients should include knowledge about oral diseases complicated with CRF and correct medical philosophy.

Study on the application of oral digital design in aesthetic restoration of anterior teeth of cleft lip/palate patients.

OBJECTIVES: A study was conducted to investigate the clinical effects of oral digital design on the aesthetic restoration of anterior teeth of cleft lip/palate patients. METHODS: Nine adult cleft lip/palate patients who need aesthetic restoration of anterior teeth were recruited. Digital information of patients' dental arches, the surrounding soft tissue and face were captured by digital camera and scanner. The aesthetic analysis and design were conducted using keynote and 3shape software and were demonstrated to the patients. The optimized treatment plan was ensured by communicating with the patients. Digital wax-up models were exported and printed into resin diagnostic models, which were then utilized in the treatment process to guide the doctors and the technicians in tooth preparation and in making the final restorations, respectively. The adhesive procedure was completed after satisfactory try-in. Aesthetics assessment was conducted in accordance with the anterior esthetic evaluation form. The scores of patient's satisfaction were recorded on a questionnaire containing six items of aesthetic index and doctor-patient communication. Patients were interviewed and examined after 1, 3, 6, and 12 months, respectively, and the clinical effects of restorations were evaluated. RESULTS: All nine patients had satisfactory clinical results. The aesthetic defects of the patients were effectively addressed. All treatments met the requirements of the preoperative digital designs. The patients' scores were all above 90 on the satisfaction scale. At 12 months after the operation, the clinical effects of restorations of all cases achieved A class in each evaluation indicator. CONCLUSIONS: For cleft lip/palate patients with esthetic defect in the anterior teeth, the digital design plays an important role in optimizing the treatment plan and guides the whole treatment process. This design can help clinicians achieve predictable satisfactory aesthetic results.

FAK Promotes Early Osteoprogenitor Cell Proliferation by Enhancing mTORC1 Signaling.

Focal adhesion kinase (FAK) has important functions in bone homeostasis but its role in early osteoprogenitor cells is unknown. We show herein that mice lacking FAK in Dermo1-expressing cells exhibited low bone mass and decreased osteoblast number. Mechanistically, FAK-deficient early osteoprogenitor cells had decreased proliferation and significantly reduced mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling, a central regulator of cell growth and proliferation. Furthermore, our data showed that the pharmacological inhibition of FAK kinase-dependent function alone was sufficient to decrease the proliferation and compromise the mineralization of early osteoprogenitor cells. In contrast to the Fak deletion in early osteoprogenitor cells, FAK loss in Col3.6 Cre-targeted osteoblasts did not cause bone loss, and Fak deletion in osteoblasts did not affect proliferation, differentiation, and mTORC1 signaling but increased the level of active proline-rich tyrosine kinase 2 (PYK2), which belongs to the same non-receptor tyrosine kinase family as FAK. Importantly, mTORC1 signaling in bone marrow stromal cells (BMSCs) was reduced if FAK kinase was inhibited at the early osteogenic differentiation stage. In contrast, mTORC1 signaling in BMSCs was not affected if FAK kinase was inhibited at a later osteogenic differentiation stage, in which, however, the concomitant inhibition of both FAK kinase and PYK2 kinase reduced mTORC1 signaling. In summary, our data suggest that FAK promotes early osteoprogenitor cell proliferation by enhancing mTORC1 signaling via its kinase-dependent function and the loss of FAK in osteoblasts can be compensated by the upregulated active PYK2. © 2020 American Society for Bone and Mineral Research.

Bidirectional Effects of Pyrrolidine Dithiocarbamate on Severe Acute Pancreatitis in a Rat Model.

INTRODUCTION: The mechanism by which intestinal mucosal barrier is damaged in severe acute pancreatitis (SAP)-associated impairment is not fully understood. METHODS: We established an l-arginine-induced SAP rat model, pretreated with or without pyrrolidine dithiocarbamate (PDTC). Hematoxylin and eosin staining was performed to evaluate the pathological alterations. Western blotting was conducted to detect the expression of autophagy-related proteins. Oxidative stress was assessed by the levels of malondialdehyde and superoxide dismutase. RESULTS: We found significant injury of the intestinal mucosal barrier in SAP rats, with overexpression of Beclin-1, LC3, and p65. Pyrrolidine dithiocarbamate showed a bidirectional effect in protecting SAP rats. A high dose of PDTC aggravated disease in rats, while a low or medium dose of PDTC pretreatment, was able to alleviate tissue damage. Pyrrolidine dithiocarbamate changed the expression of Beclin-1, LC3, and p65 in the intestines. The fatty acid-binding protein level was increased in SAP rats with high-dose PDTC or without PDTC pretreatment and was reduced in SAP rats with low- or medium-dose PDTC exposure. CONCLUSIONS: Autophagy is involved in the impairment of intestinal mucosal barrier during SAP. A suitable dose of PDTC (1 or 10 mg/kg) may decrease the severity of SAP by inhibiting autophagy in intestinal mucosal cells.

Metabolism of Peptide Drugs and Strategies to Improve their Metabolic Stability.

BACKGROUND: Despite the therapeutic use of peptides is limited because of their metabolism in vivo, there are no systematic reviews explaining degradation of peptides by peptidases. This review summarizes peptidases present in the tissues and metabolic characteristics of peptides, and provides recent strategies for improving the metabolic stability of peptides. METHOD: We reviewed a number of peptidases including their functional groups, tissue localization and cleavage specificity. Given the broad distribution of peptidases in the body, several tissues, such as the liver, kidney, lung, blood, nasal epithelial cells, placenta and skin, have the capacity to metabolize peptides. We compared the metabolic characteristics of peptides in these tissues and then summarized strategies for improving peptide stability. RESULTS: In addition to the primary organs including liver, kidney, gastrointestinal tract and blood involved in peptide metabolism, other organs such as the lung, skin, placenta and nasal mucosa may also play a role in peptide degradation. At present, the main measures to improve the stability of the peptide include N- and/or C-terminal modification or substitution, D-amino acid or unnatural amino acid substitution, cyclization, backbone modification, nanoparticle formulations and increased molecular mass. CONCLUSION: This review summarized the key in vivo peptidases and their tissue distribution characteristics, and presented strategies to improve the metabolic stability and bioavailability of peptide drugs. These viewpoints will benefit the further development and utilization of peptide drugs.

Evaluation of osteoinductive calcium phosphate ceramics repairing alveolar cleft defects in dog model.

BACKGROUND: Alveolar cleft repair is an important step in the sequence of treatments for cleft lip and palate. Intrinsically osteoinductive materials have been the subject of research interest. OBJECTIVE: The aim of this study was to explore the use of osteoinductive biphasic calcium phosphate (BCP) ceramics to repair alveolar cleft defects in dogs. METHODS: We prepared two kinds of BCP ceramic with different physical characteristics: osteoinductive BCP (OBCP) and non-osteoinductive BCP (NBCP). Bilateral alveolar cleft models were surgically established in dogs. On one side, OBCP was implanted in the defect; on the opposite side NBCP was implanted as a control. The materials were also implanted in the femoral muscles to test their properties at non-osseous sites. The osteogenic ability of materials was evaluated with imaging, spiral CT, histology and fluorescent dye tests. RESULTS: At the muscular implantation sites, new bone formed in all of the OBCP samples, but none in the NBCP samples. Imaging and spiral CT revealed good appearance and continuity of the alveolar cleft postoeration, with normal eruption of the bilateral permanent teeth in the groups. Histological and fluorescent dye testing revealed new bone formation in both groups in situ. However, earlier osteogenesis initiation and bone remodeling were superior with OBCP. Osteogenic process in the intramuscular samples with OBCP was similar to that seen in situ. CONCLUSIONS: Our findings indicated that osteoinductive biphasic calcium phosphate ceramics (OBCP) have superior characteristics in alveolar cleft repair compared with non-osteoinductive calcium phosphate ceramics (NBCP).

Involvement of Nucleotide-Binding and Oligomerization Domain-Like Receptors in the Intestinal Injury of Severe Acute Pancreatitis in Rats.

OBJECTIVES: The aim of the study was to observe the role of nucleotide-binding and oligomerization domain (NOD)-like receptors (NLR) in intestinal injury of severe acute pancreatitis (SAP) in rats. METHODS: Severe acute pancreatitis was induced by retrograde infusion of sodium taurocholate into the biliopancreatic duct. Rats were divided into the following 6 groups: sham operation, SAP treated with saline, and SAP treated with interleukin 1ß (IL-1ß)-converting enzyme inhibitor, killed at 6 or 12 hours after operation. Serum IL-18 and IL-1ß concentrations were measured. mRNA expression and protein levels of NOD1, NOD2, and NLRP3 in the intestine were measured. RESULTS: Severe acute pancreatitis resulted in significantly higher serum IL-18 and IL-1ß concentration, higher mRNA expression, and protein levels of NOD1, NOD2, and NLRP3 in intestine in SAP treated with saline groups compared with sham operation groups. This effect was attenuated by administration of IL-1ß-converting enzyme inhibitor. CONCLUSIONS: The NLRs, including NOD1, NOD2, and NLRP3, were involved in the intestinal injury in SAP through a caspase-1 pathway.

Roles of PRF and IGF-1 in promoting alveolar osteoblast growth and proliferation and molecular mechanism.

Background: Fibrin and cytokines in platelet-rich fibrin (PRF) can be combined into a powerful biological scaffold, which is an integrated reservoir of growth factors involved in tissue regeneration. Insulin-like growth factor-1 (IGF-1) is a kind of effective mitogenic protein, which can enhance osteogenic differentiation of periodontal ligament fibroblasts. However, whether PRF and IGF-1 can stimulate the osteogenic differentiation and osteogenesis of human periodontal ligament stem cells (PDLSCs) remains unclear. This study aims to investigate the osteogenic capability of PDLSCs in vitro and in vivo after being separated from human PDL tissues, purified with STRO-1 and treated with PRF and IGF-1. Methods: The proliferative capabilities of PDLSCs under different conditions were analyzed via methyl thiazolyl tetrazolium (MTT), growth curve, alkaline phosphatase activity, reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively. Results: PRF and IGF-1 significantly promoted the growth, proliferation and differentiation of PDLSCs, up regulated the expressions of Runt-related transcription factor 2 (RUNX2), osterix (OSX) and osteocalcin (OCN), phosphorylated extracellular signal-regulated kinase (ERK) and phosphorylated c-Jun N-terminal kinase (JNK) in stem cells. Conclusion: Our data indicate that PRF and IGF-1 facilitate the proliferation of alveolar osteoblast via the activation of the mitogen-activated protein kinase (MAPK) signaling pathway.

Effect of Presurgical Nasoalveolar Molding on Nasal Symmetry in Unilateral Complete Cleft Lip/Palate Patients after Primary Cheiloplasty without Concomitant Nasal Cartilage Dissection: Early Childhood Evaluation.

OBJECTIVE: The objective of this study was to assess the efficacy of presurgical nasoalveolar molding (PNAM) on long-term nasal symmetry and shaping after primary cheiloplasty in patients with unilateral complete cleft lip/palate (UCL/P). DESIGN: This was a two-group, parallel, retrospective, randomized clinical trial. SETTING: The setting for this study was the Chang Gung Craniofacial Center in Taoyuan, Taiwan. PATIENTS: Patients were divided into one of the following two groups: infants with UCL/P who underwent PNAM (PNAM group, n = 42) and infants with UCL/P who did not undergo PNAM (non-PNAM group, n = 42). INTERVENTIONS: Interventions included PNAM and primary cheiloplasty without nasal cartilage dissection. MAIN OUTCOME MEASURES: In this study, 4- to 5-year postoperative full-face and submental oblique photographs were taken of all patients and scored from 1 to 5 points by 10 medical evaluators. The scores were statistically analyzed using repeated-measures analysis of variance, and P < .05 was considered to represent statistical significance. RESULTS: After 1 to 3 months of PNAM but before primary cheiloplasty, the displaced nasal and alveolar cartilage showed obvious improvement. However, the scores in the PNAM and non-PNAM groups at 4 to 5 years postoperatively were 66.62 ± 14.25 and 66.31 ± 15.08, respectively. There was no significant difference between the two groups ( F = 0.009, P = .923). CONCLUSION: PNAM as an early-stage adjunctive therapy for nasal deformity correction is beneficial before primary cheiloplasty, but it is insufficient to maintain long-term nostril symmetry after primary cheiloplasty without nasal cartilage dissection.

Simultaneous determination of five novel luteinizing hormone-releasing hormone antagonists by LC-MS and pharmacokinetics in rats following cassette dosing.

Long acting luteinizing hormone-releasing hormone (LHRH) antagonists designed to be protease-resistant were a series of novel decapeptides structurally similar to LHRH. In the present work, a high-throughput method based on a LC-MS/MS has been developed for the simultaneous determination of pharmacokinetics of five LHRH antagonists in rat via cassette dosing. The method was performed under selected reaction monitoring (SRM) in positive ion mode. The analytes were extracted from rat plasma by liquid-liquid extraction with acetonitrile. Chromatographic separation of the analytes was successfully achieved on a Hypersil Gold (100mm×2.1mm, 3µm) using a mobile phase composed of acetonitrile-water (30:70) containing 0.05% (v/v) formic acid. The result showed good linearity and selectivity were obtained for all antagonists. The limits of quantification of the five LHRH antagonists were from 5 to 10ng/mL. The average extract recoveries in the rat plasma were all over 72%. The intra-day and inter-day precisions (R.S.D. %) were all within 10% and the accuracy was ranged from 92.54 to 109.05%. This method has been successfully applied to the pharmacokinetic studies of the five LHRH antagonists. The results indicated that the plasma drug concentrations versus time curves after intravenous injection of five antagonists via cassette dosing were all fitted to a two-compartment model. The pharmacokinetic parameters of five LHRH antagonists suggested that LY616 could be the more stable candidate drugs and optimized as the candidate drug for further study. Our studies enabled high-throughput rapid screening for pharmacokinetic assessment of new peptide candidates, and provided abundant information on the metabolic properties of these LHRH antagonists.

Structural elucidation of the metabolites of lapachol in rats by liquid chromatography-tandem mass spectrometry.

Lapachol is a natural naphthoquinone compound derived from Bignoniaceae (Tabebuia sp.) that possesses a range of significant biological activities. Nine phase I and four phase II metabolites of lapachol in rat bile were firstly elucidated and identified using a sensitive LC-ESI-MS(n) method. The molecular structures of the metabolites have been presented on the basis of the characteristics of their precursor and product ions, as well as their fragmentation mechanisms and chromatographic retention times. The results indicated that the phase I metabolites were predominantly biotransformed by the hydroxylation, semiquinone hydrogenation at the oxygen position or a side chain rearrangement. The phase II metabolites were identified as the glucuronidated conjugates which showed a characteristic neutral loss of 176Da. Based on the results of this research, we have proposed the metabolic pathways for lapachol in rats. This work has provided novel information for the in vivo lapachol metabolism which could be used to develop a novel drug candidate, as well as a better understanding of the safety and efficacy of the drug.

Metabolic stability of long-acting luteinizing hormone-releasing hormone antagonists.

Long-acting luteinizing hormone-releasing hormone (LHRH) antagonists designed to be protease resistant consisted of a series of novel decapeptides structurally similar to LHRH. The aim of this study was to evaluate the in vitro metabolic stability of the LHRH decapeptides using pancreatin and homogenates models and identify the metabolites in rat liver homogenate for the purpose of illustrating the metabolic features of the decapeptides. The major metabolites in rat liver homogenate were identified by LC-ESI-MS(n). The half-lives of the 11 LHRH decapeptides were from 44 to 330 min in the pancreatin model. The half-lives of the five decapeptides in rat liver, kidney and lung homogenates were between 8 and 462 min. The most stable decapeptides were the LY616 and LY608 peptides with half-lives of 36 min in liver homogenate. Two major cleavage sites were found by analysing the metabolites of the LY618 peptide in rat liver homogenate, between the Pal(3)-Ser(4) and the Leu(7)-Ilys(8) peptide bonds. The major metabolites were produced via cleavages of peptide bonds at these sites, and further metabolic reactions such as hydroxylation, oxidative dechlorination, alcohol dehydration and isopropyl dealkylation were also observed.

1-Bromo-2-(4-methoxy-phen-oxy)ethane.

In the crystal structure of the title compound, C(9)H(11)BrO(2), mol-ecules are stacked parallel to the b-axis direction, forming double layers in which the molecules are arranged head-to-head, with the bromo-methyl groups pointing towards each other.

Osteogenic induction of adipose-derived stromal cells: not a requirement for bone formation in vivo.

Osteogenic induction was regarded as an indispensable step for adipose-derived stromal cells (ADSCs) to have osteogenic ability. Non-induced ADSCs can also produce bone in vivo and heal skeletal defects. The present study aimed to compare the bone-forming ability of osteogenically induced ADSCs and non-induced ADSCs in vivo. Tissue-engineered constructs were prepared from osteogenically induced or non-induced ADSCs and porous hydroxyapatite/beta-tricalcium phosphate scaffolds. A scaffold without cells and an empty defect group were used as control. All were implanted in rat critical calvarial defects. After implantation for 6 and 12 weeks, bone formation was analyzed using histomorphometry and microcomputed tomography; there were no significant differences in the formation of new bone between osteogenically induced ADSCs and non-induced ADSCs (P > 0.05). In conclusion, osteogenic induction of ADSCs is not an indispensable step for bone formation in vivo. Non-induced ADSCs can also be used as seeding cells to construct bone tissue.

Ectopic bone formation in adipose-derived stromal cell-seeded osteoinductive calcium phosphate scaffolds.

The phenomenon of osteoinduction by biomaterials has been proven and used in animals. However, whether the ability of a biomaterial to initiate bone formation in ectopic implantation sites improves the performance of such osteoinductive biomaterial as a scaffold for tissue-engineered (TE) bone remains unclear. In this study, we compared ectopic bone formation by combining autologous adipose-derived stromal cells (ADSCs) with an osteoinductive and a nonosteoinductive biphasic calcium phosphate (BCP) ceramic to create a tissue engineering construct in the muscle of dogs. Two groups of BCP scaffolds (BCP1 and BCP2) were prepared. In each group, ADSCs were seeded, and the scaffolds without seeded cells served as controls. All implants were implanted in the back muscle of 10 adult dogs for 8 weeks and 12 weeks. Microcomputed tomography (Micro-CT) analysis and histomorphometry were performed to evaluate and quantify ectopic bone formation. The results indicated that the osteoinductive BCP1 performed significantly better compared to the nonosteoinductive BCP2 in cell-based TE bone formation ectopically. The ADSCs had a significantly positive effect on the ectopic bone formation. In addition, the usefulness of Micro-CT for the efficient and nondestructive analysis of mineralized bone and calcium phosphate scaffold was confirmed.

A novel technique to reconstruct a boxlike bone defect in the mandible and support dental implants with In vivo tissue-engineered bone.

The purpose of this study was to investigate the feasibility of using in vivo tissue-engineered (TE) bone to repair boxlike mandibular defect and support dental implant, and then provide experimental evidence for the future application of the novel technique in the clinical setting. The TE bone graft was constructed in vivo by implanting osteoinductive calcium phosphate (Ca-P) ceramics in the femoral muscles of dog for 8 weeks, then was transplanted to repair the autogeneic boxlike bone defect site created in one side of the mandible and simultaneously support a dental implant, while in the opposite side of the mandibular defect, the same ceramic was used directly as control. 8 weeks after transplantation, samples were harvested for analysis. The results demonstrated that the technique of in vivo tissue engineering improved the mechanical and biologic properties of ceramics significantly. After transplantation, the in vivo TE ceramic-bone grafts were involved in bone metabolism of the host and fused well with the host bone. The dental implants were stable and had been integrated with both TE bone grafts and autologous bone. Therefore, it is feasible to construct a live bone graft with osteoinductive Ca-P ceramics in vivo, then repair a mandibular bone defect, and support a dental implant. In conclusion, in vivo TE bone is a promising technique for bone repair.

2-(2,4,6-Trichloro-phen-oxy)ethyl bromide.

In the title compound, C(8)H(6)BrCl(3)O, there is a weak intra-molecular C-H⋯Cl hydrogen bond involving the O bound methylene group. Intermolecular Cl⋯Cl contacts [3.482 (2) Å] are present in the crystal structure.