Characterization of oxidative stress biomarkers in a freshwater anomuran crab / Caracterização de biomarcadores de estresse oxidativo em caranguejos anomuros de água doce

Abstract In general, environmental responses at level of populations or communities are preceded by alterations at lower biological levels which can be efficiently detected by the analysis of biomarkers. We analyzed the oxidative biomarkers TBARS and Catalase in Aegla singularis, a freshwater crustacean highly sensitive to environmental changes. The objective was to address if are differences in these biomarkers related to the gender as well if they are influenced by seasonal or water physicochemical variables. The results showed differences in biomarkers profile related to the gender. In female crabs were not sensitive to seasonal variations throughout the study period. However, in males the biomarkers evaluated were higher in the winter as compared to remaining seasons and showed tendency of negative correlation with water temperature and pH. This study highlights that gender, seasonal variations and physicochemical variables can influence oxidative stress biomarkers in A. singularis. Female crabs probably are better suited as a model for biomarker application in environmental studies, because their insensibility to seasonal variations can facilitate the observations of responses related specifically to environmental disturbances.

Resumo Em geral, as respostas ambientais ao nível de populações ou comunidades são precedidas pelas alterações nos níveis biológicos inferiores que podem ser eficientemente detectados pela análise de biomarcadores. Neste trabalho, foram analisados os biomarcadores oxidativos TBARS e Catalase em Aegla singularis, um crustáceo de água doce altamente sensível às mudanças ambientais. O objetivo foi investigar se há diferenças nestes biomarcadores relacionados com o gênero, bem como se eles são influenciados por parâmetros sazonais ou físico-químicos. Os resultados mostraram diferenças no perfil de biomarcadores relacionados com o gênero. Caranguejos fêmeas não foram sensíveis a variações sazonais ao longo do período de estudo. Nos machos, os biomarcadores avaliadas apresentaram níveis mais altos no inverno, em comparação com as demais estações e mostraram uma tendência de correlação negativa com a temperatura e pH da água. Este estudo destaca que o sexo, variações sazonais e variáveis físico-químicas podem influenciar os biomarcadores de estresse oxidativo em A. singularis. As fêmeas de A. singularis provavelmente são mais adequadas como um modelo para aplicação destes biomarcadores em estudos ambientais, uma vez que sua insensibilidade às variações sazonais podem facilitar as observações das respostas relacionadas especificamente com perturbações ambientais.

Characterization of oxidative stress biomarkers in a freshwater anomuran crab.

In general, environmental responses at level of populations or communities are preceded by alterations at lower biological levels which can be efficiently detected by the analysis of biomarkers. We analyzed the oxidative biomarkers TBARS and Catalase in Aegla singularis, a freshwater crustacean highly sensitive to environmental changes. The objective was to address if are differences in these biomarkers related to the gender as well if they are influenced by seasonal or water physicochemical variables. The results showed differences in biomarkers profile related to the gender. In female crabs were not sensitive to seasonal variations throughout the study period. However, in males the biomarkers evaluated were higher in the winter as compared to remaining seasons and showed tendency of negative correlation with water temperature and pH. This study highlights that gender, seasonal variations and physicochemical variables can influence oxidative stress biomarkers in A. singularis. Female crabs probably are better suited as a model for biomarker application in environmental studies, because their insensibility to seasonal variations can facilitate the observations of responses related specifically to environmental disturbances.

Oral medicine in Europe: past, present and future.

Oral medicine (OM) is a relatively young dental specialty usually dealing with the oral healthcare of patients suffering from chronic recurrent and medically-related disorders of the mouth and maxillofacial region and with their diagnosis and mostly non-surgical management. The beginning of OM goes back to 1925 in the USA and 1950s in Europe. However, official specialty recognition is more recent and within Europe, it is only in the UK, Croatia and Israel where OM is recognised by local registering authorities, although in several other European countries it is viewed as a distinct field of study. Despite a broad agreement in OM syllabi and clinical practice, there are still some important differences in its definition and scopes within Europe. It is crucial that European countries agree a consensus definition of OM and clarify competencies and limits, so they may move from institution and region-specific approaches to an international framework. According to the European Directives, it is timely to recognise a minimum three year standard curriculum at a post-graduate level which will lead to uniformity of training for OM residencies in European country members and will eventually provide guidelines for a broader OM specialty recognition.

Characterization of oxidative stress biomarkers in a freshwater anomuran crab

Abstract In general, environmental responses at level of populations or communities are preceded by alterations at lower biological levels which can be efficiently detected by the analysis of biomarkers. We analyzed the oxidative biomarkers TBARS and Catalase in Aegla singularis, a freshwater crustacean highly sensitive to environmental changes. The objective was to address if are differences in these biomarkers related to the gender as well if they are influenced by seasonal or water physicochemical variables. The results showed differences in biomarkers profile related to the gender. In female crabs were not sensitive to seasonal variations throughout the study period. However, in males the biomarkers evaluated were higher in the winter as compared to remaining seasons and showed tendency of negative correlation with water temperature and pH. This study highlights that gender, seasonal variations and physicochemical variables can influence oxidative stress biomarkers in A. singularis. Female crabs probably are better suited as a model for biomarker application in environmental studies, because their insensibility to seasonal variations can facilitate the observations of responses related specifically to environmental disturbances.

Resumo Em geral, as respostas ambientais ao nível de populações ou comunidades são precedidas pelas alterações nos níveis biológicos inferiores que podem ser eficientemente detectados pela análise de biomarcadores. Neste trabalho, foram analisados os biomarcadores oxidativos TBARS e Catalase em Aegla singularis, um crustáceo de água doce altamente sensível às mudanças ambientais. O objetivo foi investigar se há diferenças nestes biomarcadores relacionados com o gênero, bem como se eles são influenciados por parâmetros sazonais ou físico-químicos. Os resultados mostraram diferenças no perfil de biomarcadores relacionados com o gênero. Caranguejos fêmeas não foram sensíveis a variações sazonais ao longo do período de estudo. Nos machos, os biomarcadores avaliadas apresentaram níveis mais altos no inverno, em comparação com as demais estações e mostraram uma tendência de correlação negativa com a temperatura e pH da água. Este estudo destaca que o sexo, variações sazonais e variáveis físico-químicas podem influenciar os biomarcadores de estresse oxidativo em A. singularis. As fêmeas de A. singularis provavelmente são mais adequadas como um modelo para aplicação destes biomarcadores em estudos ambientais, uma vez que sua insensibilidade às variações sazonais podem facilitar as observações das respostas relacionadas especificamente com perturbações ambientais.

An international survey of oral medicine practice: proceedings from the 5th World Workshop in Oral Medicine.

OBJECTIVES: (i) To define the current state of oral medicine clinical practice internationally, and (ii) to make recommendations for future modeling of the practice of oral medicine. MATERIALS AND METHODS: A survey was designed by an international panel of oral medicine experts to assess the current state of oral medicine practice internationally. The survey was sent to oral medicine experts across the world, and responses were electronically stored and analyzed using descriptive statistics. RESULTS: Two hundred respondents completed the survey representing 40 countries from six continents. The two most common settings for an oral medicine practice were in a hospital and a dental school. More than 88% of respondents considered management of oral mucosal disease, salivary dysfunction, oral manifestations of systemic diseases, and facial pain in the definition of oral medicine. CONCLUSIONS: (i) Oral medicine clinicians diagnose and manage a wide variety of orofacial conditions; (ii) There are significant differences in the definition of oral medicine clinical practice from country to country; (iii) India has the largest expansion of oral medicine services as defined by escalating numbers of clinicians within the specialty as compared with other countries; (iv) oral medicine practitioners have a wide range of professional responsibilities.

Detection of survivin mRNA in healthy oral mucosa, oral leucoplakia and oral cancer.

BACKGROUND: Survivin is involved in modulation of cell death and cell division processes. Survivin expression in normal adult tissues has not been fully understood, although it is markedly lower than in cancer, where it is over-expressed. OBJECTIVE: To investigate survivin expression in normal, potentially malignant and cancerous oral mucosa. METHODS: We measured survivin mRNA levels by real-time RT-PCR in specimens of oral mucosa (15 from normal mucosa, 17 from potentially malignant lesions, 17 from neoplasms). Scores were compared using Kruskal-Wallis test and post hoc according to Conover. Chi-squared test was used for dichotomous data. RESULTS: The median relative levels of survivin mRNA resulted six for normal mucosa, eight for potentially malignant lesions, 13 for cancers: differences among these three groups were statistically significant, as between cancer and potentially malignant lesions. Expression in normal mucosa and potentially lesions group showed no significant difference. Low, but not marginal expression of survivin in normal mucosa is a new finding, and it could be explained with the higher sensibility of our methods. CONCLUSIONS: Survivin expression in oral potentially malignant lesions might indicate a progressive deregulation of expression paralleling oncogenesis, particularly during the first stages of process, suggesting a putative predictive role for survivin.

Interventions for treating oral leukoplakia.

BACKGROUND: Oral leukoplakia is a relatively common oral lesion that in a small but significant proportion of cases changes into cancer. Since most leukoplakias are asymptomatic, the primary objective of treatment should be to prevent such malignant transformation. OBJECTIVES: To assess effectiveness, safety and acceptability of treatments for leukoplakia. SEARCH STRATEGY: The following databases were searched for relevant trials: Cochrane Oral Health Group's Trials Register (to April 2006), CENTRAL (TheCochrane Library 2006, Issue 1), MEDLINE (from 1966 to December 2005), and EMBASE (from 1980 to December 2005). Handsearching was performed for the main oral medicine journals. References of included studies and reviews were checked. Oral medicine experts were contacted through an European mailing list (EURORALMED). SELECTION CRITERIA: Randomised controlled trials (RCTs), enrolling patients with a diagnosis of oral leukoplakia, were included. Any surgical or medical (topical and systemic) treatment was included. The primary outcome considered was malignant transformation of leukoplakia. Other outcomes considered were clinical resolution, histological modification and frequency of adverse effects. DATA COLLECTION AND ANALYSIS: Data were collected using a specific extraction form. Malignant transformation of leukoplakia, demonstrated by histopathological examination, was the main outcome considered. Secondary outcomes included clinical resolution of the lesion and variation in dysplasia severity. The validity of included studies was assessed by two review authors, on the basis of the method of allocation concealment, blindness of the study and loss of participants. Data were analysed by calculating risk ratio. When valid and relevant data were collected, a meta-analysis of the data was undertaken. MAIN RESULTS: The possible effectiveness of surgical interventions, including laser therapy and cryotherapy, has never been studied by means of a RCT with a no treatment/placebo arm. Twenty-five eligible RCTs of non-surgical interventions were identified: 11 were excluded for different reasons, five were ongoing studies, leaving nine studies to be included in the review (501 patients). Two studies resulted at low risk of bias, six at moderate risk of bias and one at high risk of bias. Vitamin A and retinoids were tested by five RCTs, two studies investigated beta carotene or carotenoids, the other drugs tested were bleomycin (one study), mixed tea (one study) and ketorolac (one study). One study tested two treatments. Malignant transformation was recorded in just two studies: none of the treatments tested showed a benefit when compared with the placebo. Treatment with beta carotene, lycopene and vitamin A or retinoids, was associated with significant rates of clinical resolution, compared with placebo or absence of treatment. Whenever reported, a high rate of relapse was a common finding. Side effects of variable severity were often described; however, interventions were well accepted by patients, since drop-out rates were similar between treatment and control groups. AUTHORS' CONCLUSIONS: To date there is no evidence of effective treatment in preventing malignant transformation of leukoplakia. Treatments may be effective in the resolution of lesion, however relapses and adverse effects are common.

Effectiveness of budesonide nebulising suspension compared to disodium cromoglycate in early childhood asthma.

OBJECTIVE: The optimal treatment for early childhood asthma remains controversial. Budesonide (BUD) has shown superiority over placebo in infants, and over disodium cromoglycate (DSCG) in children aged > 2 years. The aim of this double-blind, randomised, parallel-group study was to compare the effectiveness of nebulised BUD and DSCG in asthmatic children aged < 36 months. RESEARCH DESIGN AND METHODS: 82 infants (mean age 18.0 months [range, 11.6-31.2 months]) with suspected asthma (three exacerbations of dyspnoea and wheezing during the past 12 months, with one or more exacerbations in the past 3 months) were treated for 3 months with nebulised BUD (Pulmicort Respules) 0.5 mg/2 mL bid or DSCG 20 mg/2 mL tid. Follow-up was at 6 months. MAIN OUTCOME MEASURES AND RESULTS: Patients treated with BUD had a lower exacerbation rate than DSCG-treated patients after 3 months of treatment (5.4% vs. 31.7%; p = 0.003) and towards the end of follow-up (30% vs. 49%; p = 0.062). During treatment, days without cough were 80% and 65% for BUD and DSCG, respectively (p = 0.014), and nights without cough were 89% and 78%, respectively (p = 0.016). Side-effects were mild and of similar frequency in both groups. CONCLUSIONS: Inhaled nebulised BUD was well tolerated and more effective than nebulised DSCG in reducing the incidence of asthma exacerbations and days with symptoms. These beneficial effects of BUD were maintained throughout the 6-month follow-up.

Burning mouth syndrome: a retrospective study investigating spontaneous remission and response to treatments.

OBJECTIVE: The aim of this investigation was to evaluate the spontaneous remission rate of burning mouth syndrome (BMS) in a group of subjects suffering from this syndrome. SUBJECTS AND METHODS: The medical records of BMS patients attending the Unit of Oral Medicine (1995-2002) were reviewed. The patients with a follow-up period of at least 18 months were then contacted over phone and interviewed using a structured ad hoc questionnaire to record their current symptoms and data about their treatment responses to the therapies. RESULTS: Forty-eight women and five men with a mean age of 67.7 years (range 33-82 years) were included in the study (mean duration of BMS 5.5 years, s.d. +/-1.9 years, mean follow-up period of 56 months). As a consequence of different treatments, 26 patients (49.0%) reported no change in oral symptoms, 15 (28.3%) moderate improvement and 10 (18.9%) a worsening of oral complaints. Only two patients (3.7%) reported a complete spontaneous remission of oral symptoms without any treatment. CONCLUSIONS: In this study, a complete spontaneous remission was observed in 3% of the patients within 5 years after the onset of BMS. A moderate improvement was obtained in <30% of the subjects.

Spline-based image-to-volume registration for three-dimensional electron microscopy.

This paper presents an algorithm based on a continuous framework for a posteriori angular and translational assignment in three-dimensional electron microscopy (3DEM) of single particles. Our algorithm can be used advantageously to refine the assignment of standard quantized-parameter methods by registering the images to a reference 3D particle model. We achieve the registration by employing a gradient-based iterative minimization of a least-squares measure of dissimilarity between an image and a projection of the volume in the Fourier transform (FT) domain. We compute the FT of the projection using the central-slice theorem (CST). To compute the gradient accurately, we take advantage of a cubic B-spline model of the data in the frequency domain. To improve the robustness of the algorithm, we weight the cost function in the FT domain and apply a "mixed" strategy for the assignment based on the minimum value of the cost function at registration for several different initializations. We validate our algorithm in a fully controlled simulation environment. We show that the mixed strategy improves the assignment accuracy; on our data, the quality of the angular and translational assignment was better than 2 voxel (i.e., 6.54 angstroms). We also test the performance of our algorithm on real EM data. We conclude that our algorithm outperforms a standard projection-matching refinement in terms of both consistency of 3D reconstructions and speed.

Spectral signal-to-noise ratio and resolution assessment of 3D reconstructions.

Measuring the quality of three-dimensional (3D) reconstructed biological macromolecules by transmission electron microscopy is still an open problem. In this article, we extend the applicability of the spectral signal-to-noise ratio (SSNR) to the evaluation of 3D volumes reconstructed with any reconstruction algorithm. The basis of the method is to measure the consistency between the data and a corresponding set of reprojections computed for the reconstructed 3D map. The idiosyncrasies of the reconstruction algorithm are taken explicitly into account by performing a noise-only reconstruction. This results in the definition of a 3D SSNR which provides an objective indicator of the quality of the 3D reconstruction. Furthermore, the information to build the SSNR can be used to produce a volumetric SSNR (VSSNR). Our method overcomes the need to divide the data set in two. It also provides a direct measure of the performance of the reconstruction algorithm itself; this latter information is typically not available with the standard resolution methods which are primarily focused on reproducibility alone.

Lichen planus and hepatitis C virus: a multicentre study of patients with oral lesions and a systematic review.

BACKGROUND: An association between hepatitis C virus (HCV) infection and lichen planus (LP) has been investigated, but results have been inconsistent. OBJECTIVES: To investigate the relationship between LP and HCV seropositivity. Methods In a cross-sectional study we tested the sera of 303 consecutive newly diagnosed patients with histologically proven LP referred to three Italian centres for the presence of anti-HCV IgG. A comparable control group was also tested. Next, in a systematic review, studies were identified by searching different databases in April 2004. Inclusion criteria were: (i) analytical study design; (ii) clinical and histological diagnosis of LP; and (iii) serological test for anti-HCV antibodies as main outcome. The risk of bias was assessed on the basis of characteristics of the study group, appropriateness of the control group and study design. Pooled data were analysed by calculating odds ratios (ORs), using a random effects model. RESULTS: In the cross-sectional study, nearly one in five (19.1%) of the LP group was HCV positive, while a much lower prevalence of infection was found in the control group (3.2%) [OR 7.08; 95% confidence interval (CI) 3.43-14.58]. The systematic review yielded 25 relevant studies, six of which had a low risk of bias. There was a statistically significant difference in the proportion of HCV-seropositive subjects among patients with LP, compared with controls (OR 4.80; 95% CI 3.25-7.09). Following subgroup analyses, the variability of HCV prevalence in patients with LP seemed to depend on geographical area, but not on age. CONCLUSIONS: Anti-HCV circulating antibodies are more common in patients with LP than in controls, although such an association may not be significant in some geographical areas.

Interventions for treating oral leukoplakia.

BACKGROUND: Oral leukoplakia is a relatively common oral lesion that in a small but significant proportion of cases changes into cancer. Since most leukoplakias are asymptomatic, the primary objective of treatment should be to prevent such malignant transformation. OBJECTIVES: To assess effectiveness, safety and acceptability of treatments for leukoplakia. SEARCH STRATEGY: The following databases were searched for relevant trials: Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE, EMBASE. Handsearching was performed for the main oral medicine journals. References of included studies and reviews were checked. Oral medicine experts were contacted through an European mailing list (EURORALMED). SELECTION CRITERIA: Randomised controlled trials (RCTs), enrolling patients with a diagnosis of oral leukoplakia, were included. Any surgical or medical (topical and systemic) treatment was included. The primary outcome considered was malignant transformation of leukoplakia. Other outcomes considered were clinical resolution, histological modification and frequency of adverse effects. DATA COLLECTION AND ANALYSIS: Data were collected using a specific extraction form. Malignant transformation of leukoplakia, demonstrated by histopathological examination, was the main outcome considered. Secondary outcomes included clinical resolution of the lesion and variation in dysplasia severity. The validity of included studies was assessed by two reviewers, on the basis of the method of allocation concealment, blindness of the study and loss of participants. Data were analysed by calculating relative risk. When valid and relevant data were collected, a meta-analysis of the data was undertaken. MAIN RESULTS: The possible effectiveness of surgical interventions, including laser therapy and cryotherapy, has never been studied by means of a RCT. Nineteen potentially eligible RCTs of non-surgical interventions were identified: eight were excluded for different reasons, four were ongoing studies, leaving seven studies to be included in the review. Two studies resulted at low risk of bias, four at moderate risk of bias and one at high risk of bias. Vitamin A and retinoids were tested by five RCTs (245 patients), the other drugs tested were bleomycin (one study), mixed tea (one study) and beta carotene (one study). Malignant transformation was recorded in just two studies: none of the treatments tested showed a benefit when compared with the placebo. Treatment with beta carotene and vitamin A or retinoids, was associated with significant rates of clinical resolution, compared with placebo or absence of treatment. Whenever reported, a high rate of relapse was a common finding. Side effects of variable severity were often described; however, interventions were well accepted by patients, since drop-out rates were similar between treatment and control groups. REVIEWERS' CONCLUSIONS: To date there is no evidence of effective treatment in preventing malignant transformation of leukoplakia. Treatments may be effective in the resolution of lesion, however relapses and adverse effects are common.

Effect of anti-immunoglobulin E on nasal inflammation in patients with seasonal allergic rhinoconjunctivitis.

BACKGROUND: Binding of allergens to IgE on mast cells and basophils causes release of inflammatory mediators in nasal secretions. OBJECTIVE: The combined effect of specific immunotherapy (SIT) and omalizumab, a humanized monoclonal anti-IgE antibody, on release of eosinophilic cationic protein (ECP), tryptase, IL-6, and IL-8 in nasal secretion was evaluated. METHODS: Two hundred and twenty five children (aged 6-17 years) with a history of seasonal allergic rhinoconjunctivitis induced by birch and grass pollen were randomized into four groups: either birch- or grass-pollen SIT in combination with either anti-IgE or placebo. Complete sets of nasal secretion samples before treatment Visit 1 (V1), during birch- (V2) and grass (V3)-pollen season and after the pollen season (V4) were collected from 53 patients. RESULTS: A significant reduction in tryptase only was seen in the anti-IgE-treated group at V2 (P<0.05) and V4 (P<0.05) compared with the placebo group. During the pollen season, patients with placebo showed an increase of ECP compared with baseline (V2: +30.3 microg/L; V3: +134.2 microg/L, P< 0.005; V4: +79.0 microg/L, P< 0.05), and stable levels of tryptase, IL-6 and IL-8. Treatment with anti-IgE resulted in stable ECP values and a significant decrease of tryptase compared with V1 (baseline): V2: -80.0 microg/L (P< 0.05); V3: -56.3 microg/L, which persisted after the pollen season with V4: -71.6 microg/L (P< 0.05). After the pollen season, a decrease of IL-6 was observed in both groups (V4 placebo group: -37.5 ng/L; V4 anti-IgE group: -42.9 ng/L, P< 0.01). CONCLUSION: The combination of SIT and anti-IgE is associated with prevention of nasal ECP increase and decreased tryptase levels in nasal secretions.

A multiresolution approach to orientation assignment in 3D electron microscopy of single particles.

Three-dimensional (3D) electron microscopy (3DEM) aims at the determination of the spatial distribution of the Coulomb potential of macromolecular complexes. The 3D reconstruction of a macromolecule using single-particle techniques involves thousands of 2D projections. One of the key parameters required to perform such a 3D reconstruction is the orientation of each projection image as well as its in-plane orientation. This information is unknown experimentally and must be determined using image-processing techniques. We propose the use of wavelets to match the experimental projections with those obtained from a reference 3D model. The wavelet decomposition of the projection images provides a framework for a multiscale matching algorithm in which speed and robustness to noise are gained. Furthermore, this multiresolution approach is combined with a novel orientation selection strategy. Results obtained from computer simulations as well as experimental data encourage the use of this approach.

Safety and tolerability of methacholine challenge in infants with recurrent wheeze.

Bronchial hyperreactivity (BHR) is a key feature of asthma, but measurement can usually not be achieved in infants with standard lung function tests. We investigated the safety and tolerability of methacholine challenge in infants with recurrent wheezing episodes. 78 methacholine challenges in 51 sedated infants aged 12-36 months with recurrent wheezing episodes were performed. Methacholine challenge was stopped when clinical signs (coughing, wheezing, or cyanosis) or a drop of oxygen saturation (SPO2) of at least 5% or a drop of transcutaneous oxygen tension (PtcO2) of at least 0.8 kPa or an increase of resistance (RrsSO), of 50% by single occlusion technique were observed. Prior to methacholine challenge, all children were symptom-free with a mean SPO2 of 97.4% (SD 1.80%). In 48 cases (61.5%), no clinical sign was observed, 17 (21.8%) coughed, and 13 (16.7%) wheezed. A mean reduction of SPO2 of 5.0% (SD 3.89%) for the entire population was observed. In 15 of 78 cases, a decrease of SPO2 <90% occurred. This SPO2 drop was short-lasting and resolved spontaneously or after bronchodilator inhalation. Infants whose SPO2 dropped <90% showed a greater increase of RrsSO compared to infants who did not drop <90% (133% vs. 65% RrsSO increase, p<0.001). Methacholine challenge, using a combination of clinical observation, monitoring of SPO2 and PtcO2, and airway resistance using the single-occlusion technique, is a safe and tolerable tool to measure the BHR in infants with recurrent wheezing episodes.

Cryo-negative staining reduces electron-beam sensitivity of vitrified biological particles.

Beam damage is the main resolution-limiting factor when biological particles are observed by cryoelectron microscopy in a thin vitrified solution film. Furthermore, the low contrast of the specimen frequently makes observation difficult and limits the possibility of image processing. Cryo-negative staining, in which the particles are vitrified in a thin layer of concentrated ammonium molybdate solution, makes it possible to visualize the particles with a much better signal-to-noise ratio (SNR) while keeping the specimen in a good state of preservation. We have observed the Escherichia coli GroEL chaperonin, prepared in a native vitrified solution and by cryo-negative staining after electron exposure from 1000 to 3000e(-)/nm(2). We have compared the resulting three-dimensional models obtained from these different conditions and have tested their fit with the atomic model of the protein subunit obtained from X-ray crystallography. It is found that, down to 1.5-nm resolution, the particles appear to be faithfully represented in the cryo-negatively stained preparation, but there is an approximately 10-fold increase of SNR compared with the native vitrified preparation. Furthermore, for the same range of irradiation and down to the same resolution, the particles seem unaffected by beam damage, whereas the damage is severe in the native vitrified particles.

Prevention and treatment of chemo- and radiotherapy-induced oral mucositis.

The administration of many chemo-radiotherapy regimens in patients with cancer may be complicated by toxicities that limit the clinicians' abilities to deliver the most effective doses of active agents. Oral mucositis is a major dose-limiting toxic effect and the most important cause of morbidity in patients undergoing chemo-radiotherapy for head and neck cancers, in patients undergoing bone marrow transplantation and those receiving certain chemotherapeutic agents for a variety of human malignancies. The intent of this paper is to review preventive strategies and treatment approaches for patients with established oral mucositis. Many agents of differing mechanisms of action have been used in the prevention and treatment of oral mucositis induced by anticancer therapies. Currently, no intervention is completely successful at preventing or treating oral mucositis. The several solutions, drugs and methods used and studied in the prophylaxis and therapy of chemotherapy or radiotherapy-induced oral mucositis reflects the need of new, more efficient tools in the management of this complication. Current studies and our increasing understanding of the etiology and pathogenesis of oral mucositis will lead to new approaches to the management and improved quality of life for these patients.

Interventions for treating oral leukoplakia.

BACKGROUND: Oral leukoplakia is a relatively common oral lesion that in a varying proportion of cases undergoes malignant transformation. Since most leukoplakias are asymptomatic, the need for treatment is primarily based on the precancerous nature of the lesion. OBJECTIVES: To assess effectiveness, safety and acceptability of treatments for leukoplakia. SEARCH STRATEGY: The following data bases were searched for relevant trials: MEDLINE, EMBASE, CancerLit, Biological Abstracts, Cochrane library. Hand searching was performed for the main oral medicine journals. Oral medicine experts were contacted through an European mailing list (EURORALMED). SELECTION CRITERIA: Randomised controlled trials (RCTs), enrolling patients with a diagnosis of oral leukoplakia, were included. DATA COLLECTION AND ANALYSIS: Data were collected using a specific abstraction form. Malignant transformation of leukoplakia, demonstrated by histopathological examination, was the main outcome considered. Secondary outcomes included clinical resolution of the lesion and variation in dysplasia severity. The validity of included studies was assessed on the basis of the method of allocation concealment, blindness of the study and loss of participants. Data were analysed by calculating relative risk. MAIN RESULTS: The possible effectiveness of surgical interventions, including laser therapy and cryotherapy, has apparently never been studied by means of a RCT. Fourteen potentially eligible RCTs of nonsurgical intervention were identified: five were excluded for different reasons, three were ongoing studies, leaving six studies to be included in the review. Vitamin A and retinoids were tested by four RCTs (224 patients), the other drugs tested were bleomycin (one study), mixed tea (one study) and beta carotene (one study). Malignant transformation was recorded in just two studies: none of the treatments tested showed a benefit when compared with the placebo. Treatment with beta carotene and vitamin A or retinoids, was associated with better rates of clinical remission, compared with placebo or absence of treatment. Whenever reported, a high rate of relapse was a common finding. Side effects of variable severity were often described; however, interventions were well accepted by patients, since drop-out rates were similar between treatment and control groups. REVIEWER'S CONCLUSIONS: To date there is no evidence of effective treatment in preventing malignant transformation of leukoplakia. Treatments may be effective in the resolution of lesion, however relapses and adverse effects are common.

Self-preventive oral behavior in an Italian university student population.

BACKGROUND/AIM: The aim of this study was to assess the oral hygiene attitude and the professional preventive examination compliance in Italian university students. METHOD: A sample of 202 students attending the University of Bologna was randomly selected and interviewed about their preventive oral health attitude and compliance. All students reported using toothpaste and most of them (92.1%) brushed their teeth at least 2x a day using artificial, medium stiffness bristles. The toothbrush was generally (81.6%) replaced within 3 months. Few subjects (14.9%) said they used dental floss daily or utilized other devices. A majority of subjects (59.9%) had a dental examination within the year previous to the interview. Cluster analysis was performed. RESULTS: 4 groups were identified with homogeneous oral hygiene behavior and compliance toward professional preventive examination. Only one cluster, representing 33.6% of the sample, showed consistent frequency and modalities of oral hygiene habits. The other clusters seemed to be defective with interproximal cleaning procedures and compliance toward professional preventive care. Since the sample was characterized by a young, urbanized, homogeneous group with a high educational level and frequently from an upper middle class social status, the analysis probably gives a supra-estimation of the positive behavior. CONCLUSION: It is rational to suppose that strategies to promote dental service utilization, patients' compliance and a professional style oriented toward prevention may be useful to improve the oral health condition in the young adult Italian population.