Influence of tooth bleaching on dental enamel microhardness: a systematic review and meta-analysis.

Several studies have investigated the effect of bleaching on dental tissues. The evaluation of the effect of home bleaching with 10% carbamide peroxide is important for assessing alterations in enamel microhardness that may affect dental health in terms of resistance to masticatory forces. This meta-analysis was performed in order to determine scientific evidence regarding the effects of home vital bleaching with 10% carbamide peroxide gel on the microhardness of human dental enamel. A systematic electronic literature search was conducted in the PubMed and Web of Science databases using search terms. Two independent researchers evaluated the information and methodological quality of the studies. Inclusion and exclusion criteria were established for article selection; further, only studies published in English were selected. Thirteen studies that met all of the inclusion and exclusion criteria were selected and underwent statistical analysis. The results of this meta-analysis showed no significant changes in enamel microhardness when using the 10% carbamide peroxide bleaching gel over periods of 7, 14 and 21 days.

A wearable, highly stable, strain and bending sensor based on high aspect ratio graphite nanobelts.

A simple and scalable method was developed for the fabrication of wearable strain and bending sensors, based on high aspect ratio (length/thickness ∼10(3)) graphite nanobelt thin films deposited by a modified Langmuir-Blodgett technique onto flexible polymer substrates. The sensing mechanism is based on the changes in contact resistance between individual nanobelts upon substrate deformation. Very high sensor response stability for more than 5000 strain-release cycles and a device power consumption as low as 1 nW were achieved. The device maximum stretchability is limited by the metal electrodes and the polymer substrate; the maximum strain that could be applied to the polymer used in this work was 40%. Bending tests carried out for various radii of curvature demonstrated distinct sensor responses for positive and negative curvatures. The graphite nanobelt thin flexible films were successfully tested for acoustic vibration and heartbeat sensing.

Development of a risk-based prioritisation methodology to inform public health emergency planning and preparedness in case of accidental spill at sea of hazardous and noxious substances (HNS).

Hazardous and noxious chemicals are increasingly being transported by sea. Current estimates indicate some 2000 hazardous and noxious substances (HNS) are carried regularly by sea with bulk trade of 165milliontonnes per year worldwide. Over 100 incidents involving HNS have been reported in EU waters. Incidents occurring in a port or coastal area can have potential and actual public health implications. A methodology has been developed for prioritisation of HNS, based upon potential public health risks. The work, undertaken for the Atlantic Region Pollution Response programme (ARCOPOL), aims to provide information for incident planning and preparedness. HNS were assessed using conventional methodology based upon acute toxicity, behaviour and reactivity. Tonnage was used as a proxy for likelihood, although other factors such as shipping frequency and local navigation may also contribute. Analysis of 350 individual HNS identified the highest priority HNS as being those that present an inhalation risk. Limitations were identified around obtaining accurate data on HNS handled on a local and regional level due to a lack of port records and also political and commercial confidentiality issues. To account for this the project also developed a software tool capable of combining chemical data from the study with user defined shipping data to be used by operators to produce area-specific prioritisations. In conclusion a risk prioritisation matrix has been developed to assess the acute risks to public health from the transportation of HNS. Its potential use in emergency planning and preparedness is discussed.

The impact of industrial anthropization on mosquito (Diptera, Culicidae) communities in mangrove areas of Guanabara Bay (Rio de Janeiro, Brazil).

The effects of industrial anthropization on species composition and community diversity of Culicidae (Diptera) were studied in a mangrove area impacted by industrial activities as compared to a preserved area, both around Guanabara Bay in the state of Rio de Janeiro, Brazil. Diversity, equitability, and species richness in Culicidae community differed between the studied areas. Indicator species analysis and correspondence analysis were carried out and indicated that the Sabethini, especially Wyeomyia (Phoniomyia) theobaldi Lane, Wyeomyia (Phoniomyia) fuscipes (Edwards), and a non-identified species of Wyeomyia sp. were associated to the preserved area, whereas Aedes taeniorhynchus Wiedemann and Aedes scapularis (Rondani) to the impacted area.

Behavioral and physiological methods for early quantitative assessment of spinal cord injury and prognosis in rats.

Methods for reliable evaluation of spinal cord (SC) injury in rats at short periods (2 and 24 h) after lesion were tested to characterize the mechanisms implicated in primary SC damage. We measured the physiological changes occurring after several procedures for producing SC injury, with particular emphasis on sensorimotor functions. Segmental and suprasegmental reflexes were tested in 39 male Wistar rats weighing 250-300 g divided into three control groups that were subjected to a) anesthesia, b) dissection of soft prevertebral tissue, and c) laminectomy of the vertebral segments between T10 and L1. In the lesion group the SC was completely transected, hemisected or subjected to vertebral compression. All animals were evaluated 2 and 24 h after the experimental procedure by the hind limb motility index, Bohlman motor score, open-field, hot-plate, tail flick, and paw compression tests. The locomotion scale proved to be less sensitive than the sensorimotor tests. A reduction in exploratory movements was detected in the animals 24 h after the procedures. The hot-plate was the most sensitive test for detecting sensorimotor deficiencies following light, moderate or severe SC injury. The most sensitive and simplest test of reflex function was the hot-plate. The hemisection model promoted reproducible moderate SC injury which allowed us to quantify the resulting behavior and analyze the evolution of the lesion and its consequences during the first 24 h after injury. We conclude that hemisection permitted the quantitation of behavioral responses for evaluation of the development of deficits after lesions. Hind limb evaluation scores and spontaneous exploration events provided a sensitive index of immediate injury effects after SC lesion at 2 and 24 h. Taken together, locomotion scales, open-field, and hot-plate tests represent reproducible, quantitatively sensitive methods for detecting functional deficiencies within short periods of time, indicating their potential for the study of cellular mechanisms of primary injury and repair after traumatic SC injury.

Behavioral and physiological methods for early quantitative assessment of spinal cord injury and prognosis in rats

Methods for reliable evaluation of spinal cord (SC) injury in rats at short periods (2 and 24 h) after lesion were tested to characterize the mechanisms implicated in primary SC damage. We measured the physiological changes occurring after several procedures for producing SC injury, with particular emphasis on sensorimotor functions. Segmental and suprasegmental reflexes were tested in 39 male Wistar rats weighing 250-300 g divided into three control groups that were subjected to a) anesthesia, b) dissection of soft prevertebral tissue, and c) laminectomy of the vertebral segments between T10 and L1. In the lesion group the SC was completely transected, hemisected or subjected to vertebral compression. All animals were evaluated 2 and 24 h after the experimental procedure by the hind limb motility index, Bohlman motor score, open-field, hot-plate, tail flick, and paw compression tests. The locomotion scale proved to be less sensitive than the sensorimotor tests. A reduction in exploratory movements was detected in the animals 24 h after the procedures. The hot-plate was the most sensitive test for detecting sensorimotor deficiencies following light, moderate or severe SC injury. The most sensitive and simplest test of reflex function was the hot-plate. The hemisection model promoted reproducible moderate SC injury which allowed us to quantify the resulting behavior and analyze the evolution of the lesion and its consequences during the first 24 h after injury. We conclude that hemisection permitted the quantitation of behavioral responses for evaluation of the development of deficits after lesions. Hind limb evaluation scores and spontaneous exploration events provided a sensitive index of immediate injury effects after SC lesion at 2 and 24 h. Taken together, locomotion scales, open-field, and hot-plate tests represent reproducible, quantitatively sensitive methods for detecting functional deficiencies within short periods of time, indicating their potential...

Anxiogenic-like effect of glycine and D-serine microinjected into dorsal periaqueductal gray matter of rats.

The glutamatergic system of the dorsal periaqueductal gray matter (DPAG) has been implicated in anxiety. This study shows that microinjections of glycine (GLY) or D-serine (D-SER), into the DPAG of rats, dose-dependently reduced the number of entries and the time spent on open arms of an elevated plus-maze (EPM), an established animal model for measuring anxiety-related behavior. This anxiogenic-like effect was greatest following DPAG application of either 80 nmol GLY or 160 and 320 nmol D-SER. Microinjections of these same amino acid doses outside the DPAG, or of L-serine (320 nmol) inside the DPAG, produced neither of these pro-anxiety effects. The current results suggest that, in vivo, the GLY modulatory site of N-methyl-D-aspartate receptors is not fully saturated, and further substantiate a role for the DPAG excitatory amino acid system in anxiety.

Phospholipids associated with vitamin C in experimental atherosclerosis.

The favourable action of phospholipids and of Vitamin C in reverting the process of atherogenesis, already repeatedly described in the literature, was explored by the authors in applying an association of these two substances in experimental atherosclerosis. The obtained results not only confirm, once again, the prophylactic and therapeutic activity of phospholipids and vitamin C, but also demonstrate that these components, when associated, lead to much better results in the prevention and resolution of atheromatous plaques provoked in rabbits by cholesterol-feeding.

An infallible method for producing ascitic fluid from solid tumours.

Notwithstanding all precautions, the methods usually applied for the transformation of solid tumours into the ascitic form, frequently fail. This must certainly be ascribed to the still existing, considerably high intercellular adhesion forces despite the fact that cancer cells generally show lack of adhesiveness due to their higher electrical charge in comparison with normal cells. Hagmar recently stipulated that particularly anionic detergents increase the negative surface charge of tumour cells, while cationic detergents drastically reduce or even reverse this charge. A series of comparative experiments were undertaken by us in order to study the influence of anionic, nonionic and amphoteric detergents on the production of ascitic fluid from macerates of Yoshida sarcoma and fibrosarcoma BUSP. This latter tumour was produced and maintained in our laboratory and resisted to all our attempts to produce the ascitic form. Heparin, in concentrations of 0,2, 0,4 and 1,0 mg/ml, was used as an example of an anionic detergent; Pluronic F-68 and phosphatidylcholine, both in concentrations of 1, 2, and 5 mg/ml, represent a nonionic and an amphoteric detergent, respectively. The obtained results clearly show a most favourable action of the applied surfactants: whereas the controls, in which the detergents were not applied, failed to produce ascitic fluid in, sometimes, considerable percentages (up to 100% in the case of BUSP) of the treated animals, not a single animal remained free of ascite when the injected macerate was pre-treated with the emulsifier. It should here be mentioned, however, that heparin in the highest concentration applied (1 mg/ml) caused lysis of the tumour cells impeding, thus, whatever formations of ascitic fluid.