Biomineralized diamond-like carbon films with incorporated titanium dioxide nanoparticles improved bioactivity properties and reduced biofilm formation.

Recently, the development of coatings to protect biomedical alloys from oxidation, passivation and to reduce the ability for a bacterial biofilm to form after implantation has emerged. Diamond-like carbon films are commonly used for implanted medical due to their physical and chemical characteristics, showing good interactions with the biological environment. However, these properties can be significantly improved when titanium dioxide nanoparticles are included, especially to enhance the bactericidal properties of the films. So far, the deposition of hydroxyapatite on the film surface has been studied in order to improve biocompatibility and bioactive behavior. Herein, we developed a new route to obtain a homogeneous and crystalline apatite coating on diamond-like carbon films grown on 304 biomedical stainless steel and evaluated its antibacterial effect. For this purpose, films containing two different concentrations of titanium dioxide (0.1 and 0.3g/L) were obtained by chemical vapor deposition. To obtain the apatite layer, the samples were soaked in simulated body fluid solution for up to 21days. The antibacterial activity of the films was evaluated by bacterial eradication tests using Staphylococcus aureus biofilm. Scanning electron microscopy, X-ray diffraction, Raman scattering spectroscopy, and goniometry showed that homogeneous, crystalline, and hydrophilic apatite films were formed independently of the titanium dioxide concentration. Interestingly, the diamond-like films containing titanium dioxide and hydroxyapatite reduced the biofilm formation compared to controls. A synergism between hydroxyapatite and titanium dioxide that provided an antimicrobial effect against opportunistic pathogens was clearly observed.

A new silica-infiltrated Y-TZP obtained by the sol-gel method.

OBJECTIVE: The aim of this study was to evaluate silica infiltration into dental zirconia (VITA In-Ceram 2000 YZ, Vita Zahnfabrik) and its effects on zirconia's surface characteristics, structural homogeneity and bonding to a resin cement. METHODS: Infiltration was performed by immersion of the pre-sintered zirconia specimens in silica sols for five days (ZIn). Negative (pure zirconia specimens, ZCon-) and positive controls (specimens kept in water for 5 days, ZCon+) were also performed. After sintering, the groups were evaluated by X-ray diffraction (XRD), grazing angle X-ray diffraction (DRXR), scanning electron microscopy (SEM), contact angle measurements, optical profilometry, biaxial flexural test and shear bonding test. Weibull analysis was used to determine the Weibull modulus (m) and characteristic strength (σ0) of all groups. RESULTS: There were no major changes in strength for the infiltrated group, and homogeneity (m) was also increased. A layer of ZrSiO4 was formed on the surface. The bond strength to resin cement was improved after zirconia infiltration, acid conditioning and the use of an MDP primer. CONCLUSION: The sol-gel method is an efficient and simple method to increase the homogeneity of zirconia. Infiltration also improved bonding to resin cement. CLINICAL SIGNIFICANCE: The performance of a zirconia infiltrated by silica gel improved in at least two ways: structural homogeneity and bonding to resin cement. The infiltration is simple to perform and can be easily managed in a prosthesis laboratory.

Chondroitin sulfate and glucosamine in the cartilage and subchondral bone repair of dogs - Histological findings / Sulfato de condroitina e glucosamina na reparação da cartilagem e do osso subcondral de cães - Achados histológicos

Chondroitin and glucosamine sulfate nutraceuticals are commonly used in the management of degenerative articular disease in veterinary routine. However, there are controversies on the contribution of these substances to articular cartilage. The purpose of this study was to evaluate the efficiency of a chondroitin and glucosamine sulfate-based veterinary nutraceutical on the repair of an induced osteochondral defect in a dog femoral condyle, by macroscopic, histological and histomorphometric analyses. The nutraceutical was orally administered the day following injury induction, every 24 hours (treated group, TG, n=24), compared with animals that did not receive the product (control group, CG, n=24). Six animals per group were anaesthetized for sample collection at 15, 30, 60 and 90 days after surgery. At 15 days, defects were macroscopically filled with red-pinkish tissue. After 30 days, whitish color tissue was observed, both in TG and CG animals, with firmer consistency to touch at 60 and 90 postoperative days. Histological analysis demonstrated that, in both groups, there was initial blood clot formation, which was subsequently substituted by a fibrin net, with capillary proliferation from the adjacent bone marrow and infiltration of mesenchymal cells in clot periphery. As cellular differentiation developed, repair tissue presented a fibrocartilage aspect most of the time, and new subchondral bone formation occurred in the deepest area corresponding to the defect. Histomorphometry suggested that the nutraceutical did not favor the articular cartilage repair process. It was concluded that nutraceutical did not significantly influence chondrocytes proliferation or hyaline architecture restoration.(AU)

Os nutracêuticos compostos de sulfato de condroitina e glucosamina são comumente utilizados no manejo da doença articular degenerativa na rotina veterinária. Entretanto, existem controvérsias sobre a contribuição dessas substâncias à cartilagem articular. O objetivo deste trabalho foi avaliar a eficácia de um nutracêutico veterinário à base de sulfato de condroitina e glucosamina na reparação de defeitos osteocondrais induzidos no côndilo femoral de cães, através de análises macroscópica, histológica e histomorfométrica. O nutracêutico foi administrado no dia seguinte à indução da lesão, pela via oral, a cada 24 horas (grupo tratado - GT, 24 animais), sendo comparado a animais que não receberam o produto (grupo controle - GC, de igual número de animais). Aos 15, 30, 60 e 90 dias após a cirurgia, seis animais por grupo foram anestesiados para ser realizada a coleta das amostras. Aos 15 dias, os defeitos eram macroscopicamente preenchidos por tecido de coloração rósea a avermelhada. Já a partir dos 30 dias, observou-se preenchimento por tecido de coloração esbranquiçada, tanto nos animais do GT quanto nos do GC, com consistência mais firme ao toque digital aos 60 e 90 dias de pós-operatório. A análise histológica revelou que, em ambos os grupos, houve inicialmente formação de coágulo sanguíneo que, posteriormente, foi substituído por uma rede de fibrina, com proliferação de capilares a partir da medula óssea adjacente e infiltração de células mesenquimais na periferia do coágulo. À medida que se processou a diferenciação celular, o tecido de reparação se apresentou na maioria das vezes com aspecto de fibrocartilagem e, na região mais profunda da área correspondente ao defeito, ocorreu formação de osso novo subcondral. A histomorfometria sugeriu que o nutracêutico não favoreceu o processo de reparação da cartilagem articular. Concluiu-se que o nutracêutico não influenciou consideravelmente na proliferação de condrócitos nem na restauração da arquitetura hialina.(AU)

Quantitative phase analysis from X-ray diffraction in Y-TZP dental ceramics: a critical evaluation.

UNLABELLED: The dentistry literature shows consensus to use the Garvie and Nicholson equation modified by Toraya to quantify the Y-TZP phase transformation. However, this method does not include the possibility of cubic phase transformation and crystallographic texture after artificial ageing, and in this case, it is possible to observe errors of quantification. OBJECTIVES: The aim of this study was to evaluate a dental Y-TZP ageing kinetic of phase transformation under pressure and hydrothermal conditions (130°C, 2bar) and to compare the methods of quantification by the equation of Garvie and Nicholson modified by Toraya and the Rietveld refinement method. METHODS: Discs of Y-TZP (12mm Ø×1.2mm in height) were divided into groups (n=4) according to the ageing times (in the range of 6 and 138h). The superficial characterisation was made using SEM and the XDR for crystallographic analysis. RESULTS: An aggressive superficial degradation process at the beginning of phase transformation in 6-10h of ageing was observed by SEM. The phase transformation quantification showed differences between the methods. It was observed the increase and stabilisation of monoclinic phase until 80% at 40h of ageing by the Garvie and Nicholson modified by Toraya equation, compared to 60% of monoclinic phase and approximately 30% of cubic phase observed by the Rietveld method. CONCLUSION: The Toraya equation showed an overestimated result of monoclinic quantification compared to the Rietveld method. CLINICAL SIGNIFICANCE: The overestimated result of monoclinic phase could lead to different interpretation about the dental Y-TZP ageing process.

Biomimetic calcium phosphate coating on Ti-7.5Mo alloy for dental application.

Titanium and its alloys have been used as bone-replacement implants due to their excellent corrosion resistance and biocompatibility. However, a titanium coating is a bioinert material and cannot bond chemically to bone tissue. The objective of this work was to evaluate the influence of alkaline treatment and heat treatment on the formation of calcium phosphate layer on the surface of a Ti-7.5Mo alloy after soaking in simulated body fluid (SBF). Thirty six titanium alloy plates were assigned into two groups. For group I, samples were immersed in a 5.0-M NaOH aqueous solution at 80°C for 72 h, washed with distilled water and dried at 40°C for 24 h. For group II, after the alkaline treatment, samples were heat-treated at 600°C for 1 h in an electrical furnace in air. Then, all samples were immersed in SBF for 7 or 14 days to allow the formation of a calcium phosphate coating on the surface. The surfaces were characterized using SEM, EDS, AFM and contact angle measurements.

[Natural features of oviposition of Culex (Melanoconion) Group Pilosus (Diptera: Culicidae)]. / Observação sobre característica natural de oviposição de Culex (Melanoconion) Grupo Pilosus (Diptera: Culicidae).

Eggs of Culex (Melanoconion) Grupo Pilosus were found in three oviposition traps set in the toilet of a Bus Station in Joinville city, State of Santa Catarina, Brazil, during a surveillance study of Aedes aegypti. The intrinsic characteristic of group oviposition not directly on the water was confirmed.

Differential effect of thalamic and subthalamic lesions on early and late components of the somatic evoked potentials in man.

The effect of thalamic (Vo), subthalamic (Raprl) and combined (Vo-Raprl) unilateral lesions on early and late components of the somatic evoked potentials (SEPs) was investigated in a group of 16 cases operated on for the treatment of contralateral dyskinetic movements. In these cases, SEPs were independently produced by stimulation of the left and right median nerves and recorded at the corresponding somatosensory scalp regions. In addition, EEG frequencies and reaction time (RT) were independently and bilaterally determined. These tests were performed before and after operation and changes in SEP, EEG and RT were quantitatively evaluated in relation to both ipsilateral preoperative and contralateral postoperative controls. 1. All cases with either thalamic or combined lesions involving Vo nucleus showed an ipsilateral reduction in amplitude of late SEP components and EEG frequency and a contralateral increase RT. A peculiar form of "inattention" to the contralateral hand was also found. Quantitative evaluation of the total group showed significant amplitude reduction in late SEP components in relation to both ipsilateral preoperative and contralateral postoperative controls. Changes in EEG and RT were only significant in relation to their preoperative ipsilateral controls. 2. Two cases with subthalamic lesions and quick postoperative recovery showed no apparent change in SEP, EEG and RT. Three cases with similar lesions and slow postoperative recovery showed bilateral decrease in amplitude of late SEP components, EEG frequency and increase in RT. Clinical inattention to contralateral hand was also found in all these cases. Quantitative evaluation of the total group showed no significant changes in these parameters in relation to preoperative controls. 3. None of these lesions produced changes in early SEP components or somatosensory deficits at the contralateral hand.

Specific and nonspecific multiple unit activities during the onset of pentylentetrazol seizures. I. Intact animals.

A quantitative evaluation of specific and nonspecific multiple unit activity (MUA) before and during pentylenetetrazol-induced EEG tonic-clonic discharges (OTCD) was made at four levels of the CNS: cortical, thalamic, mesencephalic, and pontine. In addition, MUA of sciatic nerve was recorded to detect possible spinal cord efferent discharges. At all levels, sustained increase in specific and nonspecific multiple unit activity preceded EEG and sciatic nerve discharges induced by pentylenetetrazol. Increments in nonspecific MUA occurred sooner and were larger than those of specific MUA, and increments in mesencephalic nonspecific MUA occurred sooner and were larger than those of other cortical, thalamic, and pontine nonspecific MUAs. This sequence of neuronal activation suggests that pentylenetetrazol seizures are initiated in nonspecific structures at the mesencephalic level.

A statisticl outline of the subthalamic target for the arrest of tremor.

In 60 cases operated on for the treatment of tremor, the insertion of an electrode that measured 1 mm in diameter produced complete arrest (40 cases) or significant decrease (20 cases) of the tremor on the contralateral side. The area where such effect was obtained was studied in AP and lateral radiograms. Using a method of standardization of the size of the thalamus and subthalamus, based on a proportional reucction of the length of the AC-PC line, the cases were found to cover a small area in the subthalamus. A statistical analysis of the position of the electrode tips at the moment the tremor was arrested was carried out in order to determine, with a high degree of probability, the area that includes the mean value of the target for the general population. This work allowed us to outline a small zone in the subthalamus as the target to be destroyed in future cases. The practical implications of the method are discussed and the possibility of reducing the size of the lesion is pointed out.