Association of cytogenetic abnormalities in a neuroblastoma and fragile sites expression.

A 15 month old boy with a stage IV right suprarenal gland neuroblastoma showed a number of raised biochemical parameters, whilst catecholamines and skeletal survey were normal. Treatment with peptichemio failed to give a clinical response. Histological evidence of neuroblastoma infiltration in the bone marrow aspirate was absent. Immunofluorescence on sedimented cells was negative using antibody UJ223.8, PI153/3 and H11; only UJ308 and to a lesser extent UJ13A gave positive results. After 21 days, however, the same cells in culture showed highly differentiated dendritic processes. Thirty-seven percent metaphases from bone marrow aspirate showed the following karyotype 45XY, del (1) (p32), and two markers. Mar1 = der (2) t (2; 2) (2qter----2q14::2p24----2qter). Mar2 = der (15) t (15; 2) (15qter----15p11::2p11----2pter). Treatment with methotrexate reduced the aberrant mitoses rate to 2%. N-myc in situ hybridisation showed significant signal on both markers confirming the cytogenetic interpretation. Peripheral blood lymphocytes at 72 h showed a higher level of breaks per cell than control. After treatment with aphidicolin (APC) or methotrexate (MTX) for the last 24 h, to induce fragile sites, the incidence of breaks per cells was increased. Moreover 11.4% of APC-induced breaks were in 1p31-32 (mean of normal controls = 2.3%). The mother presented an increased sensitivity to the inducibility of fragile sites, while the father's lymphocytes showed values within the control range. The genetic changes produced by the abnormalities on chromosomes 1 and 2 might be related to tumour progression. Furthermore this is the first description of correlation between a high frequency of fragile site 1p31-32 induced by APC in the patient's lymphocytes and deletion of 1p32 in tumour cells. The interpretation of these findings and of other similar correlations needs further study

Fluoration de l’émail in vitro par laser à rayons ultraviolets

28 samples of human enamel have been studied in order to measure fluoride absorption after treatment with ultraviolet radiations.Samples treated with topical application only presented limited fluoride absorption in enamel surface (up to 0,5 µm deep). The absorption rate was higher, using an U.V. lamp. In samples treated with «excimer» laser, fluoride absorption was much higher in the surface layer and occurred also deeper (3 µm).28 échantillons d’émail dentaire humain ont été analysés afin de quantifier l’absorption du fluor après traitement aux rayons ultraviolets.Les analyses ont montré que les échantillons soumis à une simple application topique présentent une absorption de fluor modeste, uniquement dans les couches superficielles de l’émail (jusqu’à 0,5 µm de profondeur). L’absorption est plus importante en utilisant une lampe à vapeur de mercure. Avec le laser «excimer», comparé aux deux autres méthodes, la fixation du fluor dans le réseau de l’émail est très supérieure en surface et se produit également en profondeur (3 µm)

L’emploi de la stabilométrie assistée par ordinateur dans le diagnostic des troubles crânio-mandibulaires (TCM)

The aim of this study was to evaluate the influence of the cervical region and the stomatognatic system on the balance control. We examined 35 healthy subjects and 201 balance disorder patients; of the 201 patients 60 suffered also from craniomandibular disorders (CMD) and 40 from cervical rachis disease. All cases were tested by computerized stabilometry executed in Romberg position: with closed eyes, retroflexed head and two cotton roles between the dental archs. The results show that cervical rachis disease and stomatognatic dysfunction have a significative influence on the balance control; however, this influence is smaller than that of vestibular disease; moreover, the computer stabilometry allows to measure the degree of ascending or descending correlation between the posture and stomatognatic system.Le but de cette étude a été d’évaluer l’influence de la région cervicale et de l’appareil stomatognatique sur le contrôle postural. On a examiné 35 sujets normaux et 201 patients avec troubles de l’équilibre, dont 60 présentaient aussi des troubles cranio-mandibulaires (TCM) et 40 une pathologie du rachis cervical. Tous les patients ont été soumis à un examen stabilométrique assisté par ordinateur, effectué en position de Romberg: les yeux fermés, la tête en rétroflexion, en occlusion modifiée par rouleaux interdentaires. Les résultats indiquent que les pathologies du rachis cervical et celles de l’appareil stomatognatique ont une influence significative sur le contrôle postural; toutefois, cette influence est nettement inférieure à celle des pathologies vestibulaires. Ils montrent également que la stabilométrie permet de mesurer le degré de corrélation ascendant ou descendant entre la posture et l’appareil stomatognatique

Rôle de la stabilométrie dans l’évaluation des corrélations entre les troubles crânio-mandibulaires (TCM) et les troubles de l’équilibre (TE)

We examined three groups:- 29 patients suffering from balance disorders and craniomandibular disorders but not from vestibular disease;- 21 patients suffering from balance disorders, craniomandibular disorders and vestibular disease;- 26 patients suffering from craniomandibular disorders but not from vestibular disease or balance sorders.All cases were examined by the odontologist and otoneurologist and tested by computerized stabilometry; they were reexamined after six months of therapy by an occlusal stabilization splint. The static analysis of the results shows a significative reduction of the postural oscillations in all patients.Trois groupes de patients ont été examinés :- 29 sujets présentant des TE et des TCM sans vestibulopathie;- 21 sujets présentant des TE et des TCM associés à une vestibulopathie;- 26 sujets avec TCM sans TE ni vestibulopathie.Après une visite odontologique et otoneurologique complétée par une stabilométrie assistée par ordinaeur, les 3 groupes ont tous été recontrôlés après 6 mois de thérapie avec plaque de stabilisation. L’analyse les données a permis de constater une réduction significative des oscillations posturales chez tous les patients

Etude biochimique de la pulpe dentaire de veau

A biochemical study of dental pulp of calves has been performed concerning:a) peroxydabilityb) A, E, C vitamins contentc) glutation (GSH) contentd) presence of paramagnetic compoundse) phosphorylation ratioThe dental pulp from incisives of 5 months old calves has been preserved. Immediately after decapitation the pulp was immersed in liquid nitrogen. Chromatographie (HPLC) and spectroscopic (NMR-ESR) techniques have been used.GSH in dental pulp are present and dosable (4.56 +/-0.08 n moles/mg prot.) and GSSG (1.05 +/-0.01 n moles/mg prot.).Because of blood traces in the extracted pulps, the AA. have determined the hemoglobin (Hb) dosage and GSH of erythrocytary derivation (Fig. 1).After deduction of GSH of erythrocytary derivation, the GSH really present in the pulp was 4.41 n moles/mg prot. and the GSSG was 0.90 n moles/mg prot.Peroxydability of the dental pulp has been evaluated with Lowry method with dental pulp homogenate and rat liver homogenate (see Table 1).The ESR spectre shows 4 resonances with the following values: g. 2.24 - 2.04 - 2.00 - 1.97; there are some free intermediary radicals (gr. - 2.00) (Fig.2).The NMR spectre shows the presence of ATP (0.22 n moles/g) of inorganic phosphate (16.58 n moles g) (Fig.3).The pulp seems to have a lot of antioxydant factors. The next researches will be to study E, A and C vitamins concentrations. This high presence of GSH and GSSG may be an embryonary peculiarity.Une étude biochimique de la pulpe dentaire a été entreprise pour étudier les propriétés antioxydantes et leurs interactions avec le métabolisme énergétique et les équilibres redox de la pulpe dentaire de veau. Le GSH réduit et oxydé (GSSG) a été mesuré et la spectroscopie avec ESR (Electron Spin Résonance) a été utilisée pour la recherche des substances paramagnétiques et la résonance magnétique nucléaire (NMR) pour la détermination des métabolites phosphorylés de petit poids moléculaire. Après la soustraction de la quantité de GSH érythrocytaire, le GSH présent dans la pulpe est resté identique 4,41 n moles/mg prot. (GSH) et 0.90 n moles/mg n moles/mg prot. (GSSG). La péroxydation lipidique de la pulpe dentaire a été étudiée. Le spectre ESR montre 4 résonances, respectivement de valeurs de G de 2.24, 2.04, 2.00, 1.97.L’analyse des résultats montre l’existence d’une petite quantité de radicaux libres intermédiaires (g-2.00) dépendant du métabolisme tissulaire. Le spectre NMR a montré la présence d’ATP (0.22 n moles/g) et de phosphate inorganique (16.50 n moles/g)

PARP-1 modulates amyloid beta peptide-induced neuronal damage.

Amyloid beta peptide (A beta) causes neurodegeneration by several mechanisms including oxidative stress, which is known to induce DNA damage with the consequent activation of poly (ADP-ribose) polymerase (PARP-1). To elucidate the role of PARP-1 in the neurodegenerative process, SH-SY5Y neuroblastoma cells were treated with A beta(25-35) fragment in the presence or absence of MC2050, a new PARP-1 inhibitor. A beta(25-35) induces an enhancement of PARP activity which is prevented by cell pre-treatment with MC2050. These data were confirmed by measuring PARP-1 activity in CHO cells transfected with amylod precursor protein and in vivo in brains specimens of TgCRND8 transgenic mice overproducing the amyloid peptide. Following A beta(25-35) exposure a significant increase in intracellular ROS was observed. These data were supported by the finding that A beta(25-35) induces DNA damage which in turn activates PARP-1. Challenge with A beta(25-35) is also able to activate NF-kB via PARP-1, as demonstrated by NF-kB impairment upon MC2050 treatment. Moreover, A beta(25-35) via PARP-1 induces a significant increase in the p53 protein level and a parallel decrease in the anti-apoptotic Bcl-2 protein. These overall data support the hypothesis of PARP-1 involvment in cellular responses induced by A beta and hence a possible rationale for the implication of PARP-1 in neurodegeneration is discussed

Fragile site induction by aphidicolin may be increased in parents of neuroblastoma patients

We recently demonstrated an increased expression of fragile sites, induced by aphidicolin, in lymphocytes of neuroblastoma patients. We have now extended our studies to parents of affected children with neuroblastoma to verify if this characteristic may be genetically transmitted. We have examined 20 families. In most of them, the hypersensitivity to aphidicolin was found in the affected child and in at least one parent. Moreover, some of the parents showed an increase in the expression of the fragile sites 1p32, 1p13, or both that are preferentially expressed in neuroblastoma patients. The possible relations between the hypersensitivity to aphidicolin and the inheritance of predisposition to neuroblastoma must be clarified