Monitoring of titanium base alloys-biofluids interface.

Monitoring of the titanium, Ti-5Al-4V, Ti-6Al-4Fe implant materials--Ringer 1 and Ringer 2 solutions (of different pH values) interface for long term was studied in this work. In Ringer 1 solution (with high chloride ion content) all biomaterials present self-passivation. On Ti-6Al-4Fe alloy, the breakdown of the passive film was registered but at high pitting potential; pitting protection potential is very noble and can not be reached in human fluids. In Ringer 2 solution was obtained more electropositive corrosion potential values than in Ringer 1 solution; pitting corrosion of Ti-6Al-4Fe alloy is characterised by nobler breakdown and pitting protection potential values, therefore a better pitting corrosion resistance and tendency. Ion release increases in time, for the first 400-600 immersion hours and then tend to a constant level with very low values, non-dangerous for human body. All open circuit potentials oscillate around some electropositive values. The potential gradients calculated for extreme pH values have low values during 20,000 exposure hours and can not accelerate the corrosion. Atomic Force Microscopy images obtained after different exposure periods in Ringer 1 solution revealed that the roughness increased in time, suggesting a dynamic process at biomaterial-biofluid interface. X-ray Photoelectron spectra obtained after 2880 immersion hours in Ringer 2 solution show the existence of protective titanium dioxide TiO(2) and TiO and Ti(2)O(3) oxides both for titanium and Ti-5Al-4V alloy. Also, Al(2)O(3) oxide was detected.

Microstructure, surface characterization and long-term stability of new quaternary Ti-Zr-Ta-Ag alloy for implant use.

The novel Ti-20Zr-5Ta-2Ag alloy was characterised concerning its microstructure, morphology, mechanical properties, its passive film composition and thickness, its long-term electrochemical stability, corrosion resistance, ion release rate in Ringer solution of acid, neutral and alkaline pH values and antibacterial activity. The new alloy has a crystalline α microstructure (by XRD). Long-term XPS and SEM analyses show the thickening of the passive film and the deposition of hydroxyapatite in neutral and alkaline Ringer solution. The values of the electrochemical parameters confirm the over time stability of the new alloy passive film. All corrosion parameters have very favourable values in time which attest a high resistance to corrosion. Impedance spectra evinced a bi-layered passive film formed by the barrier, insulating layer and the porous layer. The monitoring of the open circuit potentials indicated the stability of the protective layers and their thickening in time. The new alloy releases (by ICP-MS measurements) very low quantities of Ti, Zr, Ag ions and no Ta ions. The new alloy exhibits a low antibacterial activity.

[Cancer of the head of pancreas--resection vs. palliative surgery]. / Cancerul de cap de pancreas--rezectie vs. paleatie.

Pancreatic cancer remains a disease with high mortality. The unspecific symptoms for a long time make the diagnostic difficult. Between 1995-2004, only 85 from 465 patients with this diagnosis, had pancreatic resection. To them, we performed Whipple pancreaticoduodenectomy (60), pylorus preserving pancreaticoduodenectomy (15), pancreatico-duodenectomy with preserving of duodenum (2), pancreaticoduodenectomy with associated resections (5), subtotal pancreatico-duodenectomy (30). The reconstruction after pancreatic resection was pancreatico-jejuno anastomosis (26) and pancreatico-gastro-anastomosis (59). Morbidity was about 34% and the mortality was about 9%.

Optimal timing for burned hands in children.

Hand burns in children are frequent, severe, and require adequate treatment. A fundamental, though problematic aspect of this treatment is the assessment of the burn depth as this determines the surgical strategy. From a retrospective study of 369 hand burns admitted to our clinic, we were able to identify some patterns. A total of 14.91% required surgery, with varying etiology among these patients. Differences were also noticed in the number of days post-burn prior to surgical intervention. The patterns revealed by our results are reviewed in order to improve therapeutic strategy.

Les brûlures à la main chez les enfants sont fréquentes et graves, et nécessitent un traitement adéquat. Un aspect fondamental de ce traitement est l'évaluation de la profondeur de la brûlure, car cela détermine la stratégie chirurgicale. D'une étude rétrospective de 369 brûlures à la main admis à notre clinique, nous avons pu identifier certaines tendances. Un total de 14,91% de ces cas, avec des étiologies varies, ont nécessité une chirurgie. On a remarqué également des différences dans le nombre de jours aprés la brûlure avant l'intervention chirurgicale. Ces résultats sont revus afin d'améliorer la stratégie thérapeutique.

Changing bioperformance of TiO2 amorphous nanotubes as an effect of inducing crystallinity.

Controlled-diameter TiO(2) nanotubes were obtained by electrochemical anodizing of two different substrates (Ti and Ti6Al7Nb) in an aqueous electrolyte. As-formed TiO(2) nanotubes are amorphous and by subjecting to thermal treatments, the structure becomes crystalline. An optimal thermal treatment with a specific anatase/rutile ratio was chosen, determined from X-ray diffraction (XRD). The electrochemical behaviour of annealed and as-formed samples was followed with Tafel plots and Electrochemical impedance spectroscopy (EIS), while surface analysis involved scanning electron microscopy (SEM) and contact angle measurements (CA). Annealed samples have a more hydrophilic character than as-formed as well as a better stability in bioliquids. Such behaviour of annealed samples is connected with a better biocompatibility expressed in terms of cell morphology and gene expression of bone specific markers obtained from Reverse Transcription Polymerase Chain Reaction (RT-PCR).

An alternative for local treatment of superficial burns.

There is a wide variety of local therapeutical methods for partial superficial burns. Burns require meticulous local treatment as part of the complex therapeutic protocol. Local treatment for burns is essential, influencing the patient's evolution and future. All local burn treatment methods are adapted in relation to the particular aspects of the burn lesion (patient's age, aetiology, localization, associated pathologies). Immerci H3 was clinically tested for partial superficial burns treatment and the results were favourable. Healing was more rapid and there was a decrease in mean hospital stay and treatment costs.

Long-term assessment of the implant titanium material--artificial saliva interface.

This paper studies the long-term (20,000 exposure hours) behavior of titanium and Ti-5Al-4V alloy-Carter-Brugirard saliva interface and the short-term (500 exposure hours) resistance of titanium and Ti-5Al-4V alloy-Tani&Zucchi saliva interface. Potentiodynamic polarization method was applied for the determination of the main electrochemical parameters. Linear polarization measurements for to obtain the corrosion rates were used. Monitoring of the open circuit potentials (E(oc)) for long-term have permitted to calculate the potential gradients due to the pH, DeltaE(oc)(pH) and to the saliva composition DeltaE(oc)(c) changes which can appear "in vivo" conditions and can generate local corrosion. Atomic force microscopy (AFM) has analyzed the surface roughness. Ion release was studied by atomic absorption spectroscopy (AAS). In Carter-Brugirard saliva both titanium and Ti-5Al-4V alloy present very stable passive films, long-term stability, "very good" resistance, low values of the open circuit potential gradients, which cannot generate local corrosion. In Tani&Zucchi artificial saliva, pitting corrosion and noble pitting protection potentials (which cannot be reached in oral cavity) were registered; titanium ion release is very low; surface roughness increase in time and in the presence of the fluoride ions, denoting some increase in the anodic activity.