Biomaterials and osteoradionecrosis of the jaw: Review of the literature according to the SWiM methodology.

OBJECTIVES: To systematically present and interpret the current literature on research and treatment perspectives for mandibular osteoradionecrosis (mORN) in the field of biomaterials. MATERIAL AND METHODS: A systematic review of the literature using the "Synthesis without meta-analysis" (SWiM) methodology was performed on PubMed, Embase and Cochrane, focusing on the implantation of synthetic biomaterials for bone reconstruction in mORN in humans and/or animal models. The primary endpoints were the composition, efficacy on mORN and tolerance of the implanted synthetic biomaterials. RESULTS: Forty-seven references were obtained and evaluated in full-text by two assessors. Ten (8 in humans and 2 in animal models) met the eligibility criteria and were included for analysis. Materials most often comprised support plates or metal mesh (5 of 10 cases) in combination with grafts or synthetic materials (phosphocalcic ceramics, glutaraldehyde). Other ceramic/polymer composites were also implanted. In half of the selected reports, active compounds (molecules, growth factors, lysates) and/or cells were associated with the reconstruction material. The number of articles referring to implantation of biomaterials for the treatment of mORN was small, and the properties of the implanted biomaterials were generally poorly described, thus limiting a thorough understanding of their role. CONCLUSION: In preventing the morbidity associated with some reconstructive surgeries, basic research has benefitted from recent advances in tissue engineering and biomaterials to repair limited bone loss.

Freeze-casting for PLGA/carbonated apatite composite scaffolds: Structure and properties.

This paper focuses on the fabrication of three-dimensional porous PLGA-biomimetic carbonated apatite composite scaffolds by freeze-casting and using dimethyl carbonate as a solvent. Several charge/polymer ratios were tested in order to finely understand the influence of the filler rate on the scaffold porosity and mechanical and degradation properties using complementary characterization techniques (SEM, mercury porosimetry and X-ray microtomography). It was demonstrated that the apatite ratio within the composite scaffold has a strong influence in terms of architecture, material cohesion, mechanical properties and in vitro degradation properties. An optimum biomimetic apatite ratio was reached to combine good mechanical properties (higher rigidity) and material cohesion. In vitro degradation studies showed that higher apatite filler rates limited PLGA degradation and enhanced the hydrophilicity of the scaffolds which is expected to improve the biological properties of the scaffolds in addition to the bioactivity related to the presence of the apatite analogous to bone mineral.

A multidisciplinary combinatorial approach for tuning promising hydrogen storage materials towards automotive applications.

HyStorM is a multidisciplinary hydrogen-storage project aiming to synthesise and tune materials hydrogen storage properties for automotive applications. Firstly, unique high-throughput combinatorial thin-film technologies are used to screen materials' hydrogen storage properties. Then promising thin-film candidate compositions are synthesised and examined in the bulk. In this paper, we report on our results within the ternary compositions Mg-Ti-B and Ca-Ti-B. Primary screening of the Mg-Ti-B ternary identified a high capacity hotspot corresponding to Mg0.36Ti0.06B0.58, with 10.6 wt% H2 capacity. Partial reversibility has been observed for this material in the thin-film. Bulk Ti-doped Mg(BH4)2 composites show rehydrogenation to MgH2 under the conditions used. The synthesised thin-film Ca-Ti-B ternary showed only low hydrogen storage capacities. In the bulk, Ti-doping experiments on Ca(BH4)2 demonstrated reversible storage capacities up to 5.9 wt% H2. Further characterisation experiments are required to decipher the role of the Ti-dopant in these systems in both films and in the bulk.

Imaging physicochemical reactions occurring at the pore surface in binary bioactive glass foams by micro ion beam analysis.

In this work, the physicochemical reactions occurring at the surface of bioactive sol-gel derived 3D glass scaffolds via a complete PIXE characterization were studied. 3D glass foams in the SiO(2)-CaO system were prepared by sol-gel route. Samples of glass scaffolds were soaked in biological fluids for periods up to 2 days. The surface changes were characterized using particle induced X-ray emission (PIXE) associated to Rutherford backscattering spectroscopy (RBS), which are efficient methods to perform quantitative chemical maps. Elemental maps of major and trace elements at the glass/biological fluids interface were obtained at the micrometer scale for every interaction time. Results revealed interconnected macropores and physicochemical reactions occurring at the surface of pores. The micro-PIXE-RBS characterization of the pores/biological fluids interface shows the glass dissolution and the rapid formation of a Ca rich layer with the presence of phosphorus that came from biological fluids. After 2 days, a calcium phosphate-rich layer containing magnesium is formed at the surface of the glass scaffolds. We demonstrate that quantities of phosphorus provided only by the biological medium have a significant impact on the development and the formation of the phosphocalcic layer.

Influence of Mg doping on the early steps of physico-chemical reactivity of sol-gel derived bioactive glasses in biological medium.

The aim of this study is to highlight the influence of magnesium doping on the surface reactivity of binary (SiO(2)-CaO) and ternary (SiO(2)-CaO-P(2)O(5)) bioactive glasses, prepared by sol-gel chemistry, in biological conditions. These materials were produced in powder form, and their compositional and textural properties characterized. They were then soaked in biological fluids for different delays from 0 to 4 days. The surface changes were characterized using Particles Induced X-ray Emission (PIXE) associated with Rutherford Backscattering Spectroscopy (RBS), which are efficient methods for multi-elemental analysis. Elemental maps of major and trace elements were obtained at a micrometer scale and revealed the formation of a calcium phosphate-rich layer after a few days of interaction. We demonstrate that the presence of magnesium in the material has an impact on the development and the formation rate of the bone-like apatite layer.

[Use of peak systolic velocity of the middle cerebral artery in the management of fetal anemia due to fetomaternal erythrocyte alloimmunization]. / Intérêt pratique du pic systolique de vélocité à l'artère cérébrale moyenne dans la prise en charge des anémies foetales par allo-immunisation érythrocytaire.

OBJECTIVE: To assess the peak systolic velocity in the middle cerebral artery (PSV-MCA) in the prediction of fetal anemia in case of severe red-cell alloimmunization. METHODS: A prospective study, from January 2003 to April 2006, of 47 consecutive pregnancies with severe alloimmunization. Fetal surveillance was based on titration and dosage of antibodies, ultrasound scans, and doppler for PSV-MCA measurement up to twice a week. A fetal blood sampling and in utero transfusion was performed in case of increase in PSV-MCA above 1.5 multiples of the median (MoM), and/or signs of hydrops on ultrasound. Severe fetal anemia was defined by fetal hemoglobin below 0.55MoM for gestational age. Analyses performed included the correlation between PSV-MCA and fetal hemoglobin, the value of PSV-MCA in the prediction of severe fetal anemia, and the determination of adequate threshold for intervention based on ROC curve analysis. RESULTS: Four hundred and eighty-five PSV-MCA were performed in 47 high-risk pregnancies, of which 125 were coupled with hemoglobin measurement by fetal blood sampling. There is a significant negative correlation between PSV-MCA and fetal hemoglobin (R2=0.6545 ; p<0.0001). Based on all prospective data, the negative predictive value of PSV-MCA was 97.8 %, sensitivity was 86.7 %, with a false positive rate of 12.2%. Area under the ROC curve was 0.85 (IC 95 %, 0.742-0.927 ; p<0.0001), suggesting an excellent value of this test. When switching the threshold for intervention from 1.5 to 1.6MoM, the positive predictive value increased, without decrease in sensitivity or negative predictive value. CONCLUSION: This study confirms the correlation between PSV-MCA and fetal hemoglobin. It allows a decrease of invasive procedures in the follow-up of pregnancies with severe red-cell alloimmunization.

[Disseminated tuberculosis and profound thrombopenia]. / Tuberculose disséminée et thrombopénie profonde.

Thrombocytopenia within the context of disseminated tuberculosis can lead to complications requiring rapid treatment. Although the origin is generally central, thrombocytopenia can arise from an immune disorder. We hereby report a case of disseminated tuberculosis associated with thrombocytopenia, which required, in addition to antituberculosis therapy initiated before bacteriological proof, corticosteroid treatment and multiple platelet transfusions. The discovery of anti-platelet antibodies along with the success of immunomodulator therapy confirmed the auto-immune origin of this thrombocytopenia.

Sequential multiple probe fluorescence in-situ hybridization analysis of human oocytes and polar bodies by combining centromeric labelling and whole chromosome painting.

The incidence of chromosomal aneuploidy was analysed in 104 unfertilized human oocytes and 56 first polar bodies using a double-label fluorescence in-situ hybridization (FISH) procedure. Combinations of centromeric (or locus-specific) DNA probes and whole chromosome painting probes for chromosomes 9, 13, 16, 18, 21 and X were applied on oocyte preparations, in a sequential FISH protocol. This combined approach allowed a precise in-situ identification of both chromosomes and free chromatids, and consequently a reliable analysis of chromosomal segregation errors. Of the 104 analysed oocytes, 84 (80.7%) displayed a normal chromosome constitution. Three cases of chromosome non-disjunction (2.8%) were found, whereas seven oocytes (6.7%) presented extra single chromatids. In addition, 12 oocytes (11.5%) showed balanced pre-division of one pair of sister chromatids. Although this phenomenon was not classified as aneuploidy, it could lead to aneuploidy at anaphase II. Abnormalities were observed in all the targetted chromosomes. The present data confirm that both whole chromosome non-disjunction and premature chromatid separation constitute the two major mechanisms of aneuploidy in human female meiosis.

High rate of GB virus type C/HGV transmission from mother to infant: possible implications for the prevalence of infection in blood donors.

BACKGROUND: Because GB virus type C(GBV-C)/HGV (GBV-C/HGV) is blood-borne and sexually transmitted, persons at risk of infection with such viruses have a high prevalence of GBV-C/HGV markers. However, adults with no apparent risk factors, such as blood donors, frequently are positive for GBV-C/HGV markers. Mother-to-infant transmission could explain this high prevalence, but it has been studied only through small series of GBV-C/HGV-infected mothers co-infected with HCV or HIV. STUDY DESIGN AND METHODS: To determine the rate of mother-to-infant transmission of GBV-C/HGV RNA in women who are HCV- or HIV-negative, a prospective study was performed in a cohort of 288 mothers screened for viral RNA and in the infants born to GBV-C/HGV-infected mothers. RESULTS: Thirteen mothers (4.5%) were found positive for GBV-C/HGV RNA. Of the infants in whom at least one blood sample was collected between the third and the ninth months of life, 89 percent were positive for viral RNA. The majority of these newborns were negative for GBV-C/HGV RNA at birth and positive after the third month. The viral RNA titers of infants born to GBV-C/HGV-infected mothers appeared as elevated as those of their mothers. All the GBV-C/HGV-infected infants remained positive for viral RNA during the entire study period. No clinical events possibly linked to a primary GBV-C/HGV infection were reported in infants. Serum ALT level and blood count remained within normal values throughout the follow-up of all GBV-C/HGV-infected infants. CONCLUSION: The frequency of mother-to-infant GBV-C/HGV transmission is elevated and could explain the high prevalence of GBV-C/HGV markers (viral RNA and E2 antibody) in adults at low risk for blood-borne or sexually transmitted viruses, such as blood donors.

[Retrospective study of exchange transfusion for newborn infants with reconstituted blood. Review of 60 exchanges]. / Etude rétrospective de l'exsanguinotransfusion du nouveau-né au moyen de sang reconstitué. Bilan de 60 échanges.

PURPOSE: The necessity of saving blood products has established the practice of exchange transfusion (ET) with reconstituted blood in newborns. The aim of this retrospective study was to evaluate the indications and the practice of this technique at the Perinatal Hemobiology Centre (Paris, France). METHODS: The records of intervention allowed us to review the etiologic categories for neonates having undergone exchange transfusion with reconstituted blood, the dosages used (bilirubin, hemoglobin), and the other main parameters of ET. RESULTS: Sixty ETs were performed in 48 newborns between the 1st July 1996 and the 1st July 1998. Twenty-seven with Rh hemolytic disease had 39 ETs (19 for hyperbilirubinemia, 12 for anemia, and eight for both), whereas ten out of 12 repeated ETs were indicated for hyperbilirubinemia (six of these cases were in newborns weighing > or = 2500 g and after a volume exchange < or = 1 blood mass [range 0.72-1.0] at the last ET). Twenty-one cases showed other diseases: six of them had anemia, nine had hyperbilirubinemia, and seven showed disseminated coagulopathy. The tolerance of ET was poor in 24% infants in this group. CONCLUSIONS: The volume of 1.3 blood mass for ET is sufficient for the majority of cases with hyperbilirubinemia, allowing transfusional savings in comparison with the previous recommendation of two blood volumes. Exact labeling of the content of units of packed red cells and plasma is essential to fulfill the volume and hematocrit requirements in every case.

[Pseudotumorous presentation of neuro-Behçet: role of the withdrawal of colchicine?]. / Présentation pseudotumorale de neuro-Behçet: rôle de l'arrêt de la colchicine?

BACKGROUND: Neurological involvement occurs in 10 to 28% of patients with Behçet's disease. CASE REPORT: We report a case of neurological pseudotumoral presentation of Behçet's in a patient with a long standing disease treated with low dose of prednisone and colchicine (1 mg/day), 2 months after withdrawal of colchicine. CONCLUSION: Neurological manifestations during Behçet disease can be secondary to direct central nervous system involvement (encephalitis, encephalomyelitis) or vascular angitis (essentially cerebral venous thrombosis and, rarely, intracranial aneurysms). Neurological pseudotumoral presentation is rarely reported.

Different proximal and distal rearrangements of chromosome 7q associated with holoprosencephaly.

Four new cases of holoprosencephaly are described in fetuses exhibiting abnormal karyotypes with different distal and proximal rearrangements of the long arm of chromosome 7. Three of them showed terminal deletions of chromosome 7q, confirming the importance of the 7q36 region in holoprosencephaly. The karyotype of the fourth fetus showed an apparently balanced de novo translocation, t(7;13) (q21.2;q33), without any visible loss of the distal part of chromosome 7q. The involvement of new genes, different from the human Sonic Hedgehog gene (hShh) responsible for holoprosencephaly, or a positional effect are discussed.

[Rationale for a trial of prevention of perinatal transmission of hepatitis C via specific immunoglobulins]. / Bases décisionnelles d'un essai de prophylaxie de la transmission périnatale de l'hépatite C par immunoglobulines spécifiques.

Vertical transmission of the HCV infection is asymptomatic, occurring in 0-25% of infants born to viremic mothers in Europe. Nowadays, the only preventive measure in to advise against breastfeeding. Favourable conditions for a seroprophylaxis trial in neonates at risk are the low viral charge and the absence of former replication or integration. Several impediments to a randomized-controlled trial should be considered: Epidemiological: paucity of recruitment; low risk of transmission; possible antenatal transmission in cases of high maternal viremia; risk for intrafamilial transmission. Methodological: complex randomization of the study groups (genotyping, quantitative PCR, activity of mothers' diseases, modes/durations of delivery and feeding). Ethical: a direct individual benefit is not clearly established; should viremic mothers be allowed to breast feed their babies in the absence of prophylaxis? the risk of the emergence of mutants or quasi-species of the transmitted hepatitis C virus in neonates; the origin and selection of seropositive plasma donors.

[Cardiac involvement in fetal parvovirus B19 infection]. / Les atteintes cardiaques au cours de l'infection foetale à parvovirus B19.

The review of 15 cases of cardiac involvement demonstrate the cardiac tropism of the human parvovirus B19. Ten of these cases were collected from fetuses during second trimester of maternal-fetal infections. In situ hybridisation detects viral DNA sequences in the nucleus of infected myoblasts. Myocarditis is the most frequent histological damage. Cardiac failure, secondary to myocarditis, may occur in the absence of fetal anaemia. When the fetus is deeply anaemic, like usually in cases of hydrops, damages of the cardiac tissues might hamper the reactional increase of cardiac output; therefore, they might account for the poor prognosis of parvovirus B19 fetal hydrops in the second trimester of pregnancy, despite transfusional therapy attempts in the third trimester.

Prenatal identification of an isochromosome for the short arm of the Y i(Yp), by cytogenetic and molecular analyses.

A case of 45,X/46,X,+mar mosaicism was detected in a male fetus (27 weeks' gestation) referred for karyotype analysis following the observation of a short femur at the ultrasound scan. Analysis of 12 Y-chromosome loci by fluorescent in situ hybridization (FISH) and polymerase chain reaction (PCR) demonstrated that the marker chromosome is of Y origin and corresponds to an authentic isochromosome for the short arm of the Y chromosome, i(Yp). The breakpoint on this marker is in YQ11.1 close to the centromere. The present report illustrates the importance of FISH and PCR techniques as a complement to cytogenetic methods for accurate identification and characterization of chromosome rearrangements in prenatal diagnosis.

[Hepatitis C and pregnancy: is it necessary to screen for the risk of vertical transmission?]. / Hépatite C et grossesse: faut-il dépister le risque de transmission verticale?

The diagnosis of the risk for vertical infection with the virus of hepatitis C rests on the finding of specific antibodies in the mother. It is rare to see clinical signs of infection in the newborn. More frequently asymptomatic transmission of the viral genome occurs. As it is important to watch newborn infants at risk it is recommended that pregnant women who have a risk factor should have serum screening.

[The perinatal transmission of the hepatitis B virus in the Paris area]. / Transmission périnatale du virus de l'hépatite B dans la région de Paris.

HBsAg was detected in 152 pregnant women among 6,605 (2.3%) screened in the prenatal clinics of four hospitals representative of the Paris metropolitan area. In 98% of cases, HBsAg positivity indicated chronic HBV carrier status. Among patients born out of continental France (47% of screened women, 79% of positive women) relative risk of chronic infection was 6 in Asians, 5.5 in Africans, and 4 in French women born in non-continental France. No significant difference in medical history was seen between HBsAg-positive and HBsAg-negative patients, in any of the birthplace groups. In women born out of continental France, number of children and crowding in the home were correlated with HBsAg-positivity; these correlations were not found in French women born in continental France. In non-African, non-Asian women, screening on the basis of medical, social and familial criteria (simulated in this study) would not be effective. Routine screening for HBsAg in pregnancy is advocated. The cost of the prevention of each case of perinatally acquired chronic HBV infection by routine screening followed by prophylactic treatment of a risk neonates was estimated at 180,000 French Francs (35,000 dollars). This approach is the only means of preventing the long-term life-threatening complications of chronic HBV infection in the 600 neonates born each year in France to HBsAg-positive mothers.