[Bioinformatic analysis of CCND2 expression in papillary thyroid carcinoma and its impact on immune infiltration].

OBJECTIVE: To investigate cyclin D2 (CCND2) expression in papillary thyroid carcinoma (PTC) and its association with the clinicopathological features. METHODS: The public databases TCGA, TIMER 2.0 and UALCAN were used to explore CCND2 expression level in PTC and adjacent tissues, and its diagnostic value for PTC was analyzed using ROC curves. GO enrichment analysis of CCND2-related differentially expressed genes (DEGs) in PTC was performed, and tumor immune infiltration of CCND2 in thyroid cancer was analyzed using TIMER database and CIBERSORT data source. RT-qPCR and Western blot were used to detect CCND2 expression in normal human thyroid cell line Nthy-ori-3-1 and human PTC cell lines TPC-1 and BCPAP. CCND2 expression was also detected in clinical specimens of PTC and adjacent tissues by immunohistochemistry, and its correlation with clinicopathological features of the patients were analyzed. RESULTS: Informatic analysis revealed significantly higher CCND2 mRNA expression in thyroid cancer than in the adjacent tissues (P < 0.001) in close correlation with tumor stage, gender, age, pathological subtype, and lymph node involvement (P < 0.05). ROC curve analysis showed that at the cutoff value of 4.983, the diagnostic sensitivity, specificity, and accuracy of CCND2 expression for PTC was 83.6%, 94.9%, and 78.5%, respectively. CCND2 expression was positively correlated with B cells, CD4+ T cells, and macrophages (P < 0.001) and negatively with CD8+ T cells (P < 0.01), and also correlated with memory B-cell infiltration, CD4+ T-cell memory activation, M2 macrophages, resting mast cells, and mast cell activation (P < 0.05). RT-qPCR, Western blot and immunohistochemistry showed significantly higher CCND2 expression in the PTC cells than in Nthy-ori-3-1 cells (P < 0.01) and also in clinical PTC tissues than in the adjacent tissues (P < 0.05) in correlation with tumor size, lymph node metastasis and TNM stage (P < 0.05). CONCLUSION: CCND2 overexpression is closely correlated with tumor progression and immune cell infiltration in PTC patients..

[Non-muscle myosin heavy chain 9 gene-related disorders with thrombocytopenia: report of two pedigrees and literature review].

Objective: To summarize the clinical characteristics and gene variants of 2 pedigrees of non-muscle myosin heavy chain 9 related diseases (MYH9-RD) in children. Methods: The basic information, clinical features, gene variants and laboratory tests of MYH9-RD patients from 2 pedigrees confirmed in the First Affiliated Hospital of Zhengzhou University in November 2021 and July 2022 were analyzed retrospectively. "Non-muscle myosin heavy chain 9 related disease" "MYH9" and "children" were used as key words to search at Pubmed database, CNKI and Wanfang database up to February 2023. The MYH9-RD gene variant spectrum and clinical data were analyzed and summarized. Results: Proband 1 (male, 11 years old) sought medical attention due to epistaxis, the eldest sister and second sister of proband 1 only showed excessive menstrual bleeding, the skin and mucous membrane of the their mother were prone to ecchymosis after bumping, the uncle of proband 1 had kidney damage, and the maternal grandmother and maternal great-grandmother of proband 1 had a history of cataracts. There were 7 cases of phenotypic abnormalities in this pedigree. High-throughput sequencing showed that the proband 1 MYH9 gene had c.279C>G (p.N93K) missense variant, and family verification analysis showed that the variant was inherited from the mother. A total of 4 patients including proband 1 and family members were diagnosed with MYH9-RD. The proband 2 (female, 1 year old) sought medical attention duo to fever and cough, and the father's physical examination revealed thrombocytopenia. There were 2 cases of phenotypic abnormalities in this pedigree. High-throughput sequencing showed that there was a c.4270G>A (p.D1424N) missense variant in the proband 2 MYH9 gene, and family verification analysis showed that the variant was inherited from the father. A total of 2 patients including proband 2 and his father were diagnosed with MYH9-RD. A total of 99 articles were retrieved, including 32 domestic literatures and 67 foreign literatures. The MYH9-RD cases totaled 149 pedigrees and 197 sporadic patients, including 2 pedigrees in our study. There were 101 cases with complete clinical data, including 62 sporadic cases and 39 pedigrees. There were 56 males and 45 females, with an average age of 6.9 years old. The main clinical manifestations were thrombocytopenia, skin ecchymosis, and epistaxis. Most patients didn't receive special treatment after diagnosis. Six English literatures related to MYH9-RD caused by c.279C>G mutation in MYH9 gene were retrieved. Italy reported the highest number of cases (3 cases). Twelve literatures related to MYH9-RD caused by c.4270G>A mutation in MYH9 gene were retrieved. China reported the highest number of cases (9 cases). Conclusions: The clinical manifestations of patients in the MYH9-RD pedigrees varied greatly. MYH9 gene c.279C>G and c.4270G>A mutations are the cause of MYH9-RD.

Bilateral double site (calvarial and mandibular) critical-size bone defect model in rabbits for evaluation of a craniofacial tissue engineering constructs.

Most existing preclinical models for evaluating the biosafety and bone-regeneration efficacy of innovative bone substitute materials (BSMs) or tissue engineering (TE) constructs only consisted of a single-site defect and the anatomical locations of defect varied drastically. While the compelling evidence showed that the bone healing pattern is location-dependent, owing to developmental, structural, and functional differences of anatomical locations, this is particularly true for the craniofacial region. Taking this into account, the bone healing efficiency of a BSM shown at one anatomical defect location cannot ensure the same impact at another. This prompted us to develop, for the first time, a model of bilateral critical-sized defect (CSD) at two distinctly different locations (non-load-bearing parietal calvaria and load-bearing mandibular body) co-existing in one rabbit to reduce the number of animals needed and avoid the influence of interindividual variability and evaluation bias on comparisons. 24 healthy adult male New Zealand White rabbits were randomly assigned to a group, either control, autograft (considered the "gold standard") or a clinically relevant BSM (biphasic calcium phosphate granules) (BCPg, Mastergraft®, Medronics). The full-thickness cylindrical calvarial defect (ø10 mm) on frontoparietal region and mandibular composite defect (ø11 mm) on the body of the mandible were created bilaterally using low-speed drilling with saline irrigation. The defect on one side was filled with autograft debris or BCPg, and the other side was no graft (empty). Following the euthanasia of animals at the predetermined intervals (4w and 12w), the defect zones were examined macroscopically and then sampled and processed for microcomputed tomography (microCT) and histological analysis. All surgeries went uneventfully, and all rabbits recovered slowly but steadily. No symptoms of infection or inflammation associated with the defect were observed during the experiment. At 4w and 12w, macroscopic views of all defect sites were clean without any signs of necrosis or abscess, and no intraoral communication was found. The analysis of microCT and histological findings showed the non-healing nature of the empty defect, thereby both calvaria and mandible CSDs can be validated. The study of the application of BCPg in this defect model highlighted good osteointegration and excellent osteoconductive properties but compromised the osteoinductive properties of this material (compared with autograft). To conclude, this novel double-site CSD model holds great promise in the application for preclinical evaluation of BSMs, TE construct, etc. With a reduced number of animals in use, and lower interindividual variability and evaluation bias for comparisons.

Designed sponges based on chitosan and cyclodextrin polymer for a local release of ciprofloxacin in diabetic foot infections.

Diabetic foot infections are the most common complications requiring hospitalisation of patients with diabetes. They often result in amputation to extremities and are associated with high morbi-mortality rates, especially when bone is infected. Treatment of these complications is based on surgical procedures, nursing care and systemic antibiotic therapy for several weeks, with a significant risk of relapse. Due to low blood flow and damage caused by diabetic foot infection, blood supply is decreased, causing low antibiotic diffusion in the infected site and an increase of possible bacterial resistance, making this type of infection particularly difficult to treat. In this context, the aim of this work was to develop a medical device for local antibiotic release. The device is a lyophilized physical hydrogel, i.e a sponge based on two oppositely charged polyelectrolytes (chitosan and poly(cyclodextrin citrate)). Cyclodextrins, via inclusion complexes, increase drug bioavailability and allow an extended release. Using local release administration increases concentrations in the wound without risk of toxicity to the body and prevents the emergence of resistant bacteria. The hydrogel was characterised by rheology. After freeze-drying, a curing process was implemented. The swelling rate and cell viability were evaluated, and finally, the sponge was impregnated with a ciprofloxacin solution to evaluate its drug release profile and its antibacterial activity.

[The analysis of mutations in non-syndromic deafness gene SLC26A4 by next generation sequencing technology].

Objective:To analogize the distribution of nonsyndromic deafness gene SLC26A4 mutation and to characterize clinical profiles in patients with SLC26A4 mutation in order to understand their hereditary etiologies and provide evidence for deafness screening and accurate genetic counseling. Method: SLC26A4 gene was first analized by MALDI-TOF-MS technology to detect the hot mutation c.919-2A>G in 57 cases. There were 3 cases with homozygous mutation and 7cases with heterozygous mutation. Then 54 cases except for 3 cases with homozygous mutation were analyzed by targeted genomic capturing and next generation sequencing technologies(targeted DNA-Hiseq), 81 non-syndromic deafness genes and the chondiogene was designed to all their exons and their flanking intron(±10 bp) sequences. Sanger sequencing was used to confirm the variant by analyzing the DNAs sequences. Result: The carrying rates of SLC26A4 gene in the deafness were 26.32%, but SLC26A4 homozygous genes and compound heterozygous genes were 19.30%. They included 3 cases with c.919-2A>G and 1 case with c.754T>C pathogenic homozygous mutations. While in 7 cases with compound heterozygous there were 6 cases with two pathogenic mutation, there was 1 case with c.2168A>G pathogenic mutation the other likely pathogenic mutation c.1545-1546insC. The 11 cases all were diagnosed large vestibular aqueduct syndrome(LVAS). There were 4 cases with heterozygous that were not found large vestibular aqueduct. Conclusion: Pathogenic mutation of SLC26A4 is closely related to clinical phenotype of LVAS. The hot pathogenic mutation was c.919-2A>G of SLC26A4 gene. The next generation sequencing technology is available for the diagnosis of inherited hearing loss especially for LVAS.

Numerical optimization of cell colonization modelling inside scaffold for perfusion bioreactor: A multiscale model.

Part of clinically applicable bone graft substitutes are developed by using mechanical stimulation of flow-perfusion into cell-seeded scaffolds. The role of fluid flow is crucial in driving the nutrient to seeded cells and in stimulating cell colonization. A common numerical approach is to use a multiscale model to link some physical quantities (wall shear stress and inlet flow rate) that act at different scales. In this study, a multiscale model is developed in order to determine the optimal inlet flow rate to cultivate osteoblast-like cells seeded in a controlled macroporous biomaterial inside a perfusion bioreactor system. We focus particularly on the influence of Wall Shear Stress on cell colonization to predict cell colonization at the macroscale. Results obtained at the microscale are interpolated at the macroscale to determine the optimal flow rate. For a macroporous scaffold made of interconnected pores with pore diameters of above 350 µm and interconnection diameters of 150 µm, the model predicts a cell colonization of 325% after a 7-day-cell culture with a constant inlet flow rate of 0.69 mL·min-1. Furthermore, the strength of this protocol is the possibility to adapt it to most porous biomaterials and dynamic cell culture systems.

Cyclodextrin modified PLLA parietal reinforcement implant with prolonged antibacterial activity.

The use of textile meshes in hernia repair is widespread in visceral surgery. Though, mesh infection is a complication that may prolong the patient recovery period and consequently presents an impact on public health economy. Such concern can be avoided thanks to a local and extended antibiotic release on the operative site. In recent developments, poly-l-lactic acid (PLLA) has been used in complement of polyethyleneterephthalate (Dacron®) (PET) or polypropylene (PP) yarns in the manufacture of semi-resorbable parietal implants. The goal of the present study consisted in assigning drug reservoir properties and prolonged antibacterial effect to a 100% PLLA knit through its functionalization with a cyclodextrin polymer (polyCD) and activation with ciprofloxacin. The study focused i) on the control of degree of polyCD functionalization of the PLLA support and on its physical and biological characterization by Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC) and cell viability, ii) on the understanding of drug/meshes interaction using mathematic model and iii) on the correlation between drug release studies in phosphate buffer saline (PBS) and microbiological evaluation of meshes and release medium against E. coli and S. aureus. All above mentioned tests highlighted the contribution of polyCD on the improved performances of the resulting antibacterial implantable material. STATEMENT OF SIGNIFICANCE: 1. We managed for the first time, with well-defined parameters in terms of temperature and time of treatment, to functionalize a bio-absorbable synthetic material to improve drug sorption and drug release properties without affecting its mechanical properties. 2. We analyzed for the first time the degradation of our coating products by mass spectroscopy to show that only citrate and cyclodextrin residues (and glucose units) without any cytotoxicity are formed. 3. We managed to improve the mechanical properties of the PLA with the cyclodextrin polymer to form a composite. The assembly (cyclodextrin polymer and PLLA) remains biodegradable.

[An analysis of the mutation in GJB2，GJB3，SLC26A4 and mtDNA12SrRNA in new born].

Objective:To analyze deafness gene mutation in GJB2，GJB3，SLC26A4 and mtDNA12SrRNA in newborn and to explore the significance of genetic test and potential correlations between the genotype and clinical phenotype.Method:Blood samples were collected with a standard protocol and DNA templates are extracted from 501 newborn in Longgang of Shenzhen.MALDI-TOF-MS Technology was used to detect the coding region twenty mutations sites of GJB2，GJB3，SLC26A4 AND mtDNA12SrRNA，includingSLC26A4(1226G>A,1229C>T,281C>T,589G>A,IVS7-2A>T,1174A>T,IVS15+5G>A,1975G>C,2027T>A,2162C>T,2168A>G),GJB2(176-191del16,35delG,167delT,235 delC,299-300 delAT),GJB3(547G>A,538C>T),mtDNA12SrRNA(1555A>G,1494C>T).While two-step hearing screening was carried by using AABR（automatedauditory brainstem response）and DPOAE. Result:In the 501 newborns,26 cases were found have one or two allele mutations of deafness-susceptibility genes.GJB2 gene mutation(n=9,1.796%) all were 235 delC single heterozygosity mutation.GJB3 gene mutation(n=3,0.599%). SLC26A4 gene mutation(n=12,2.395%) included IVS7-2A>G heterozygosity mutation(n=5). MtDNA 12Rrna gene mutation was found in 3 child(n=3,0.599%). Finally one of 26 infants was diagnosed enlarged vestibular aqueduct syndrome. The infant was detected 2168A>G heterozygosity mutation. Conclusion:235delC is the main mutation form of GJB2 gene,while it is the hottest mutation in People. But SLC26A4 gene mutations are the main type in newborn. MtDNA 12Rrna gene mutation was found in 3 child.This genetic epidemiological study demonstrated that genetic screening is helpful for determining high risk individuals and early discovering possible late-onset hearing loss. Moreover pationts and family member can acquire more effective genetic counseling.

A novel anatomical ceramic root canal simulator for endodontic training.

INTRODUCTION: Endodontic therapy is often complicated and technically demanding. The aim of this study was to develop a reproducible biomimetic root canal model for pre-clinical and postgraduate endodontic training. MATERIAL AND METHODS: A specific ceramic shaping technique (3D printing and slip casting of a root canal mould) was developed to reproduce canal systems with the desired shape and complexity using a microporous hydroxyapatite (HAp)-based matrix. The microstructural morphology, pore size and porosity, as well as the Vickers microhardness of the ceramic simulators (CS) were assessed and were compared with natural dentin and commercial resin blocks. The reproducibility of the root canal shapes was assessed using the Dice-Sørensen similarity index. Endodontic treatments, from refitting the access cavity to obturation, were performed on the CS. Each step was controlled by radiography. RESULTS: Many properties of the CS were similar to those of natural dental roots, including the mineral component (HAp), porosity (20%, porous CS), pore size (3.4 ± 2.6 µm) and hardness (120.3 ± 18.4 HV). DISCUSSION: We showed that it is possible to reproduce the radio-opacity of a tooth and variations in root canal morphology. The endodontic treatments confirmed that the CS provided good tactile sensation during instrumentation and displayed suitable radiological behaviour. CONCLUSIONS: This novel anatomic root canal simulator is well suited for training undergraduate and postgraduate students in endodontic procedures.

Visceral mesh modified with cyclodextrin for the local sustained delivery of ropivacaine.

The aim of the study was to develop a polyester visceral implant modified with a cyclodextrin polymer for the local and prolonged delivery of ropivacaine to reduce post operatory pain. Therefore, we applied a coating of an inguinal mesh with a crosslinked polymer of hydroxypropyl-ß-cyclodextrin (HPßCD) whose specific host-guest complex forming properties were expected to improve the adsorption capacity of the implant toward anesthetic, and then to release it within a sustained period. The modification reaction of the textile with cyclodextrin was explored through the study of the influence of the pad/dry/cure process parameters and the resulting implant (PET-CD) was characterized by solid state NMR and SEM. Besides, the inclusion complex between ropivacaine and CD was studied by NMR and capillary electrophoresis in PBS medium. Finally, ropivacaine sorption test showed that a maximum of 30 mg/g of ropivacaine could be adsorbed on the functionalized samples. In dynamic batch tests in PBS at pH 7.4, the release could be observed up to 6h. The cytocompatibility of the PET-CD loaded with ropivacaine was also studied and reached 65% cell vitality after 6 days.

Porous silicon-cyclodextrin based polymer composites for drug delivery applications.

One of the main applications of porous silicon (PSi) in biomedicine is drug release, either as a single material or as a part of a composite. PSi composites are attractive candidates for drug delivery systems because they can display new chemical and physical characteristics, which are not exhibited by the individual constituents alone. Since cyclodextrin-based polymers have been proven efficient materials for drug delivery, in this work ß-cyclodextrin-citric acid in-situ polymerization was used to functionalize two kinds of PSi (nanoporous and macroporous). The synthesized composites were characterized by microscopy techniques (SEM and AFM), physicochemical methods (ATR-FTIR, XPS, water contact angle, TGA and TBO titration) and a preliminary biological assay was performed. Both systems were tested as drug delivery platforms with two different model drugs, namely, ciprofloxacin (an antibiotic) and prednisolone (an anti-inflammatory), in two different media: pure water and PBS solution. Results show that both kinds of PSi/ß-cyclodextrin-citric acid polymer composites, nano- and macro-, provide enhanced release control for drug delivery applications than non-functionalized PSi samples.

Dyeing and antibacterial activation with methylene blue of a cyclodextrin modified polyester vascular graft.

The aim of this study was to develop an antiseptic and blue dyed polyester (PET) vascular graft in order to reach two distinct properties: (i) the prevention of postoperative infections, (ii) the improvement of the graft compatibility with the coelioscopy surgical technique. This work consisted of dyeing a vascular prosthesis with methylene blue (MB) which is known as a cationic dye with antiseptic properties. Therefore, the functionalization of the PET fibers of the prosthesis with a cyclodextrin-citric acid polymer (PolyCD) was achieved in order to improve its sorption capacity. The NMR experiments demonstrated that a 1:2 complex occurred between hydroxypropyl ß-cyclodextrin (HP-ßCD) and MB. Kinetic and sorption isotherm studies showed that an impregnation of the polyCD modified prosthesis (PET-CD) in a 1 g L(-1) of MB solution for 150 min was sufficient to reach the saturation of the device. Results proved that the adsorption mechanism followed the Langmuir model and a maximum of 20 mg g(-1) of MB on the graft. A sustained release of MB in batch tests was observed in PBS and in vitro microbiological assays displayed a prolongation of the bactericidal effect of PET-CD whose extent varied with the amount of MB preliminarily adsorbed onto the PET-CD.

Validating the poly-cyclodextrins based local drug delivery system on plasma-sprayed hydroxyapatite coated orthopedic implant with toluidine blue O.

Local antibiotics delivery is an efficient solution to reduce the risk of infections associated with orthopedic implant. This study aims to functionalize plasma-sprayed hydroxyapatite coated titanium (Ti-HA) hip joint implant material with cyclodextrins-polymer (polyCD)-based local drug delivery system for loading therapeutic molecules (e.g. antibiotics), to offer a sustainable drug delivery. The process of polyCD coating on Ti-HA material was optimized with the help of model guest molecule - toluidine blue O (TBO) for evaluating the efficacy of polyCD system. The obtained results clearly showed that polyCD's treatment can firmly coat on the Ti-HA material under the optimized processing parameters concerning the type of CD, thermal treatment temperature and duration. PolyCD system has been proven to have a high capacity of TBO adsorption and long release duration. In vitro study also showed non-cytotoxicity of polyCD functionalized samples to osteoblastic cells. Trial study with gentamicin revealed very promising potential of polyCD system for sustained delivery of antibiotics. To conclude, the study substantiates the prospective flexibility of drug choice when applying polyCD treated implants including antibiotics, antimitotic agents or other therapeutical molecules. One or more drugs can be loaded, thus synergism and multi-factorial effects are feasible.

Calcite as a bone substitute. Comparison with hydroxyapatite and tricalcium phosphate with regard to the osteoblastic activity.

Close to the bone mineral phase, the calcic bioceramics, such as hydroxyapatite (HA) and ß-tricalcium phosphate (ß-TCP), are commonly used as substitutes or filling materials in bone surgery. Besides, calcium carbonate (CaCO3) is also used for their excellent biocompatibility and bioactivity. However, the problem with the animal-origin aragonite demands the new technique to synthesize pure calcite capable of forming 3D bone implant. This study aims to manufacture and evaluate a highly-pure synthetic crystalline calcite with good cytocompatibility regarding to the osteoblasts, comparing to that of HA and ß-TCP. After the manufacture of macroporous bioceramic scaffolds with the identical internal architecture, their cytocompatibility is studied through MC3T3-E1 osteoblasts with the tests of cell viability, proliferation, vitality, etc. The results confirmed that the studied process is able to form a macroporous material with a controlled internal architecture, and this synthesized calcite is non-cytotoxic and facilitate the cell proliferation. Indeed requiring further improvement, the studied calcite is definitely an interesting alternative not only to coralline aragonite but also to calcium phosphate ceramics, particularly in bone sites with the large bone remodelling.

Carotid revascularization in patient with asymptomatic unilateral carotid stenosis undergoing coronary bypass--a futile effort!

The best management of asymptomatic carotid artery disease in patient who needs coronary bypass remains controversial. We report the neurological outcome of four patients with asymptomatic unilateral significant carotid artery disease who underwent conventional coronary bypass without carotid revascularization. Our review highlighted the risk of perioperative stroke is not increased despite carotid revascularization was not performed. Asymptomatic carotid artery disease is not the cause for cerebral infarct but soft aortic atheroma encountered during surgery is the main culprit.

Anticoagulant and antimicrobial finishing of non-woven polypropylene textiles.

The aim of this work is to prepare non-woven polypropylene (PP) textile functionalized with bioactive molecules in order to improve its anticoagulation and antibacterial properties. This paper describes the optimization of the grafting process of acrylic acid (AA) on low-pressure cold-plasma pre-activated PP, the characterization of the modified substrates and the effect of these modifications on the in vitro biological response towards cells. Then, the immobilization of gentamicin (aminoglycoside antibiotic) and heparin (anticoagulation agent) has been carried out on the grafted samples by either ionic interactions or covalent linkages. Their bioactivity has been investigated and related to the nature of their interactions with the substrate. For gentamicin-immobilized AA-grafted samples, an inhibition radius and a reduction of 99% of the adhesion of Escherichia coli have been observed when gentamicin was linked by ionic interactions, allowing the release of the antibiotic. By contrast, for heparin-immobilized AA-grafted PP samples, a strong increase of the anticoagulant effect up to 35 min has been highlighted when heparin was covalently bonded on the substrate, by contact with the blood drop.

Selective biological response of human pulmonary microvascular endothelial cells and human pulmonary artery smooth muscle cells on cold-plasma-modified polyester vascular prostheses.

The aim of this work was to improve the hemocompatibility and the selectivity according to cells of non-woven poly(ethylene terephthalate) (PET) membranes. Non-woven PET membranes were modified by a combined plasma-chemical process. The surface of these materials was pre-activated by cold-plasma treatment and poly(acrylic acid) (PAA) was grafted by the in situ free radical polymerization of acrylic acid (AA). The extent of this reaction and the number of carboxylic groups incorporated were evaluated by colorimetric titration using toluidine blue O. All samples were characterized by SEM, AFM and thermogravimetric analysis, and the mechanical properties of the PAA grafted sample were determined. A selective cell response was observed when human pulmonary artery smooth muscle cells (HPASMC) or human pulmonary micro vascular endothelial cells (HPMEC) were seeded on the modified surfaces. HPASMC proliferation decreased about 60%, while HPMEC proliferation was just reduced about 10%. PAA grafted samples did not present hemolytic activity and the platelet adhesion decreased about 28% on PAA grafted surfaces.

[Engineering a bone free flap for maxillofacial reconstruction: technical restrictions]. / Ingénierie d'un lambeau osseux vascularisé à destinée maxillofaciale : les limites techniques.

Vascularisation is a key for success in bone tissue engineering. Creating a functional vascular network is an important concern so as to ensure vitality in regenerated tissues. Many strategies were developed to achieve this goal. One of these is cellular growth technique by perfusion bioreactor chamber. These new technical requirements came along with improved media and chamber receptacles: bioreactors (chapter 2). Some bone tissue engineering processes already have clinical applications but for volumes limited by the lack of vascularisation. Resorbable or non-resorbable membranes are an example. They are used separately or in association with bone grafts and they protect the graft during the revascularization process. Potentiated osseous regeneration uses molecular or cellular adjuvants (BMPs and autologous stem cells) to improve osseous healing. Significant improvements were made: integration of specific sequences, which may guide and enhance cells differentiation in scaffold; nano- or micro-patterned cell containing scaffolds. Finally, some authors consider the patient body as an ideal bioreactor to induce vascularisation in large volumes of grafted tissues. "Endocultivation", i.e., cellular culture inside the human body was proven to be feasible and safe. The properties of regenerated bone in the long run remain to be assessed. The objective to reach remains the engineering of an "in vitro" osseous free flap without morbidity.

[Bone substitutes: Classification and concerns]. / Les biomatériaux de substitution osseuse : classification et intérêt.

Autograft is considered as the "gold standard" for bone reconstruction. It provides osteoinductive factors, osteogenic cells, and appropriate osteoconductive scaffold. Donor site morbidity is the main limitation of autograft. Donor disease transmission limits the use of allograft. Synthetic bone substitutes still lack osteoinductive or osteogenic properties. Composite bone substitutes combining synthetic scaffold and biochemical substances initiating proliferation and cell differentiation, and possibly osteogenesis. Bone substitutes and grafts intended for clinical use are listed.