Electrochemical and cytocompatibility assessment of NiTiNOL memory shape alloy for orthodontic use.

Orthodontic arcs and wires are mostly realised from alloys and constitute the motor of dental shifting. Ti-base alloys rapidly replaced the formerly used stainless steel wires due to their excellent corrosion resistance, their high mechanical characteristics and their increased biocompatibility. NiTiNOL shape memory alloys add to these advantages their ability of deforming force. NiTiNOL, highly pure Nickel (hp-Ni) and commercially pure titanium (cp-Ti) were tested by electrochemical assays in artificial saliva and in vitro biological tests with L132 cells and HEPM cells. All tests gave concordant results: the electrochemical assays, the proliferation test, the colony forming method, and the inflammatory test clearly show, that nickel is a corrosive and a cytotoxic material. Ti and NiTiNOL are cytocompatible and in particular corrosion resistant. No significant differences are observed for both materials on the electrochemical and the biological level as well. The NiTiNOL shape memory alloy is a master trump for dental practitioners to repair occlusal defects by shifting teeth under optimal biological conditions. In spite of its high Ni-content, it is biocompatible. It considerably reduces the tune of therapeutic treatment, facilitate the occlusal concept and leads to a result of high clinical quality.

Competitive inhibition of specific steroid-protein binding: practical use of relative competition ratios for the derivation of equilibrium inhibition constants.

The relative competition ratio (RCR) is widely used to express the relative affinities of inhibitor(s) and agonist for a binding protein. The RCR is not a constant; it depends on the concentrations of binding sites and of radioactive hormone, and on the presence of nonsaturable binding component(s). According to the assay conditions used, equating the RCR value to the ratio Ka/Ki of the equilibrium association constants of agonist and inhibitor can lead to large errors. In the case of homogeneous non-interacting binding sites, simple correction factors permit one to calculate the ratio Ka/Ki from the measured RCR value. Calculations are given for the eventual contribution of nonsaturable binding components. Corrections can be unnecessary under well defined experimental conditions, where the bound fraction of hormone in absence of competitor is reduced by using a large dilution of binding protein and/or an increased concentration of radioactive hormone.

[Post-radiation duodenal ulceration treated with hyperbaric oxygen]. / Ulcération duodénale post-radique traitée par oxygène hyperbare.

Radiation enteric disorders are rare and difficult to treat. A case of radiation duodenitis treated by hyperbaric oxygen is reported. A sixty-year-old man underwent right nephroureterectomy, chemotherapy (platin and 5 fluorouracil) and radiation therapy (54 Gy) for excretory urinary carcinoma. Six months later, even though he was under omeprazole therapy for reflux oesophagitis, he experienced antroduodenitis, duodenal ulceration, and duodenal telangiectasia. Symptoms and duodenal ulcer disappeared 2 months later with hyperbaric oxygen (10 one hour sessions at 2 ATA). Most likely, hyperbaric oxygen can reduce the consequences of obliterative endarteritis due to irradiation, responsible for ischaemia and fibrosis later on.

[Anisometropia and presbyopia: prescription of progressive lenses, a new approach]. / Anisométropie et presbytie: équipements en verres progressifs, nouvelle approche.

OBJECTIVE OF THE STUDY: To show that anisometropia does not absolutely preclude the prescription of progressive lenses. MATERIALS AND METHODS: Forty-one anisometropes and presbyopes were selected for a prolonged trial of visual correction using progressive lenses. The congenital or acquired type of their anisometropia and its particular form were also studied. Each patient was submitted to a protocol comprising of a series of ophthalmologic and orthoptic tests so as to evaluate the patient's subjective far and near refraction, with measurement of phorias and of horizontal and vertical ductions, visual acuity, and the quality of binocular vision while looking in different directions. A preliminary trial of correction in actual situation was done in order to check fusion in near vision. The entire range of tests was repeated two months after the patient was provided with the lenses. The tolerance for progressive lenses during the different activities of daily life was evaluated after the second and the sixth months. RESULTS: Seven patients presenting an associated strabismus were not provided with the lenses because the initial pre-lens trial revealed a total inability to read within the near-vision zone. Among the 34 patients provided with the lenses, 21 constantly wore their progressive lenses and said that they were satisfied, 6 wore their progressive lenses during daily activities but preferred to use their unifocal lenses for prolonged reading, and 7 abandoned their progressive lenses because they could not tolerate them. Association with a strabismus is not synonymous with an initial impossibility or with abandonment because of the 27 patients who constantly wore their progressive lenses 9 were strabismic. The best results were obtained in the age range of 45 to 52 years old, for visual acuity for > 20/40, and in cases of congenital anisometropia with intermittent or permanent unilateral neutralization. On the other hand, patients presenting an acquired anisometropia, particularly postoperative, proved to be poor candidates. CONCLUSION: Weak and strong anisometropia does not absolutely preclude the prescription of progressive lenses except for certain strabismic subjects with an abnormal lateral-oriented posture.

[Contribution and role of the scanner in the preoperative evaluation of chronic otitis. Radiosurgical correlation apropos of 85 cases]. / Apport et place du scanner dans le bilan pré-opératoire de l'otite chronique. Corrélation radio-chirurgicale à propos de 85 cas.

High resolution computed tomography (CT) is today the best imaging to study chronic middle ear diseases. In a retrospective analysis of 85 chronic otitis media (cholesteatoma or not), the authors emphazise the diagnostic value of CT scan, its preoperative's role and the radiologic imaging of cholesteatoma. In our study, the radiosurgical correlation rate is 0.6 regarding positive diagnosis in chronic otitis or cholesteatoma. The malleus and incus analysis is correct, but stapes is not observed in 40% of cholesteatoma. The correlation of surgical and radiographic findings is excellent regarding the scutum, the horizontal semicircular canal (> 0.7), the tegmen (= 0.6), bad for the canal of facial nerve (< 0.5). The actual extent of chronic otitis media lesions is overestimated by CT scan in 70% of cases. The correlation's rate is reliable for epitympanum and aditus. To conclude, the preoperative CT is necessary in those cases: closed eardrum cholesteatoma, single functional ear, clinical complications and doubtful diagnosis.

[Kikuchi's disease. Apropos of a case. Review of the literature]. / Maladie de Kikuchi. A propos d'un cas, revue de la littérature.

Kikuchi's disease is rare necrotic histiocytosis of the lymph nodes. Since the first description in Japan in 1972 by Kikuchi, several cases have been reported. The disease occurs most frequently in young women. Manifestations include enlargement of the cervical lymph nodes, sometimes with fever, and often associated with other non-specific clinical signs. Blood chemistry, including immunologic tests, are often normal but neutropenia and raised erythrocyte sedimentation rate have been reported. Diagnosis relies on the histological examination of lymph node biopsies. Generally the clinical course is favourable in 3-4 months. Secondary systemic lupus erythomatosus may develop and require regular follow-up. The aetiology of this rare disease is still unclear although certain observations would favour an immunological process. Very rare in France, we report a case of Kikuchi's disease in a pregnant woman and present a review of the literature.

[Osteoid osteoma of the middle ear. Review of the literature apropos of the first described case]. / Ostéome ostéoïde de la caisse du tympan. Revue de la littérature à propos du premier cas décrit.

The case of an osteoid osteoma of the middle ear in a 42 year old man is reported. No former case has now been reported in the literature for this localization. The suspected diagnosis of osteoid osteoma was based on the pain and the findings of bone computerize tomography. In our case, the osteoid osteoma was totally painless and the diagnosis was made after surgical findings by histological studies. Some clinical and imaging points, pathologic findings and differential diagnosis are also discussed.

[Herpetic pseudotumor laryngitis]. / Laringitis herpética pseudotumoral.

The goal of this paper is to report an interesting case of laryngeal involvement by herpes virus, showing a morphological aspect very alike to an extense neoplasm of this region. Laryngeal involvement of herpes virus is a clinical infrequent entity, but as its wide onset forms range from a banal laryngitis until a severe airway obstruction, hoarseness or dysphagia, it seems mandatory an accurate differential diagnose to settle a treatment and the effective follow-up.

[Risks and regulations related to materials used in implantology and maxillofacial surgery]. / Risques et réglementations relatifs aux matériaux utilisés en implantologie et chirurgie maxillo-faciale.

In the present paper, the authors call in mind the definitions of biocompatibility and the essential qualities required for biomaterials. The materials mostly used in implantology and maxillofacial surgery are numerous alloys, bioceramics, resorbable and non-resorbable polymers, and finally osseous substitutes of human or animal origin. As to synthetic and non-living materials, the risks in patients are generated by the degradation products. These may induce tissular reactions of inflammatory or immune origin owing to toxic effects. Concerning osseous substitutes, rejections are mostly of immune origin, for allografts and in particular for xenografts. Infections may be another major risk and in spite of all precautionary measures viral infections by hepatitis B, HIV and transmissible spongiform encephalopathy are not yet got under total control. It is just in these domains that one can state juristic lacks which national and european organisation of standardisation and homologation have to cover during the next few years.

[Characterization of the "4 S-trypsin" form of the cytosoluble estradiol receptor of calf uterus in a nondenaturing system]. / Caractérisation par électrophorèse en système non dénaturant de la forme "4 S-trypsine" du récepteur cytosoluble de l'oestradiol d'utérus de Veau

The characterisation of the "4 S-trypsin" form of the estradiol-receptor from calf uterus cytosol was carried out by polyacrylamide gel electrophoresis under non-denaturing conditions. In a multiphasic buffer system (upper buffer Tris-glycine pH25degrees C = 8,6, lower buffer Tris HCl pH25degrees C = 7,4), three radioactive estradiol peaks were observed. The first was free estradiol, the second estradiol initially complexed with a macromolecule and dissociated during electrophoresis, and the third the hormone-receptor complex. The sedimentation coefficient (4 S) of this complex was the same before and after electrophoresis. Its mean geometric radius is R = 2.53 + 0.08 nm and its molecular weight was estimated to be 55,000.

[In vitro and in vivo biocompatibility of stainless steel as a function of surface treatments: roughness and surfacing with hydroxyapatite]. / Biocompatibilité in vitro et in vivo de l'acier inoxydable en fonction du traitement de surface: rugosité et revêtement avec hydroxyapatite.

The in vitro tests on cell viability reveal a favorable position for steel and hydroxyapatite (HA)? However, the roughness induces a negative effect on cell proliferation. Sandblasting of the stainless steel considerably decreased cell number compared with the polished substrate. HA showed a better percentage of proliferation in spite of the surface effect compared with controls. For in vivo biocompatibility, intramuscular implants revealed localized inflammatory reactions for the HA treated stainless steel but nor for the untreated alloy.

Osteoid osteoma of the petrous bone.

We present a case of osteoid osteoma of the petrous bone presenting with progressive sensorineural hearing loss. CT showed a dense homogeneous mass at the promontory surrounded by a thin bony border. On MRI this lesion gave intermediate signal intensity on T1- and T2-weighted spin-echo images and enhanced intensely with gadolinium. Surgical removal and pathological study proved the diagnosis.

Isotonic mechanics of a pharyngeal dilator muscle and diaphragm in the rat before and after fatigue.

Pharyngeal and diaphragm muscles contract and relax in synergy, which is why it was decided to compare their mechanical performance throughout the overall load continuum. The effects of fatigue were also studied. The isotonic mechanics of rat sternohyoid (SH; n=10) and diaphragm (D; n=10) were investigated in vitro. Force and length were measured in muscles contracting from zero load up to isometry. Maximum isometric tension (Pmax), peak mechanical work (Wmax), maximum unloaded shortening velocity (vzL) and mechanical efficiency (eff(max)) were recorded. Data were obtained both at baseline and after fatigue. SH muscles had a lower Pmax (96.0+/-13.7 versus 119.5+/-22.7 mN x mm(-2); p<0.05), a lower Wmax (5.5+/-1.2 versus 8.0+/-2.1 mJ x g(-1); p<0.01), a lower eff(max) (56.0+/-6.9 versus 62.6+/-5.8%; p<0.05) and a higher vzL (4.8+/-0.4 versus 3.4+/-0.4 initial length (L0) x s(-1); p<0.001) than D muscles. Wmax occurred at a higher relative load in SH (40% Pmax) than in D (30% Pmax). Fatigue did not modify eff(max) in SH muscles, whereas it significantly improved eff(max) in D muscles. These findings suggest that under control conditions, economy of force generation was less efficient in sternohyoid than in diaphragm muscles. Fatigue in sternohyoid muscles induced unfavourable mechanical behaviour. This may partly explain pharyngeal dilator muscle failure in the presence of increased loads. Whether these findings are relevant to human sleep apnoea syndrome has yet to be determined.