The whitening effect of enzymatic bleaching on tetracycline

OBJECTIVE: Carbamide peroxide and hydrogen peroxide have been used as tooth whitening agents. The aim of this paper was to determine the efficiency of several enzyme-containing whitening systems. A method to determine the rate of 'in vitro' tetracycline whitening was also developed. METHODS: We determined the tetracycline whitening ability of carbamide peroxide and hydrogen peroxide, and the influence of peroxidase and lactoperoxidase on this tetracycline whitening rate. RESULTS: High peroxidase and lactoperoxidase concentrations increased the rate of tetracycline decoloration obtained with carbamide peroxide or hydrogen peroxide. The decoloration rate observed was lower when the glucose/glucose oxidase system was used to generate hydrogen peroxide 'in situ'. The presence of peroxidase increased the decoloration rate of extracted teeth obtained with carbamide. CONCLUSIONS: Enzymes such as peroxidase could be used as whitening catalysts to increase the rate of tetracycline decoloration.     

ERK2, but Not ERK1, Mediates Acquired and “De novo” Resistance to Imatinib Mesylate: Implication for CML Therapy

Resistance to Imatinib Mesylate (IM) is a major problem in Chronic Myelogenous Leukaemia management. Most of the studies about resistance have focused on point mutations on BCR/ABL. However, other types of resistance that do not imply mutations in BCR/ABL have been also described. In the present report we aim to study the role of several MAPK in IM resistance not associate to BCR/ABL mutations. Therefore we used an experimental system of resistant cell lines generated by co-culturing with IM (K562, Lama 84) as well as primary material from resistant and responder patient without BCR/ABL mutations. Here we demonstrate that Erk5 and p38MAPK signaling pathways are not implicated in the acquired resistance phenotype. However, Erk2, but not Erk1, is critical for the acquired resistance to IM. In fact, Bcr/Abl activates preferentially Erk2 in transient transfection in a dose dependent fashion through the c-Abl part of the chimeric protein. Finally, we present evidences demonstrating how constitutive activation of Erk2 is a de novo mechanism of resistance to IM. In summary our data support the use of therapeutic approaches based on Erk2 inhibition, which could be added to the therapeutic armamentarium to fight CML, especially when IM resistance develops secondary to Erk2 activation.     

How well do questionnaires perform compared with physical examination in detecting flexural eczema? Findings from the International Study of Asthma and Allergies in Childhood (ISAAC) Phase Two

Background  Questionnaires are widely used in epidemiological studies to measure eczema symptom prevalence, but there are concerns regarding their accuracy if used as a diagnostic tool.
Objectives  To compare the performance of a validated eczema symptom questionnaire and a standardized skin examination protocol employed in the second phase of the International Study of Asthma and Allergies in Childhood (ISAAC).
Methods  A total of 30 358 schoolchildren aged 8–12 years from 18 countries were examined for flexural eczema. Parents also completed an eczema symptom questionnaire. We compared prevalence estimates at the population level based on the questionnaire vs. physical examination. We also compared the skin examination and the ISAAC questionnaire in making a diagnosis of flexural eczema.
Results  The point prevalences for flexural eczema at centre level based on a single examination were lower than the questionnaire-based 12-month period prevalences (mean centre prevalence 3·9% vs. 9·4%). Correlation between prevalences of both outcome measures was high ( r  =   0·77, P  <   0·001). At the individual level, questionnaire-derived symptoms of 'persistent flexural eczema in the past 12 months' missed < 10% of cases of flexural eczema detected on physical examination. However, between 33% and 100% of questionnaire-based symptoms of 'persistent flexural eczema in the past 12 months' were not confirmed on examination.
Conclusions  ISAAC questionnaire-derived symptom prevalences are sufficiently precise for comparisons between populations. Where diagnostic precision at the individual level is important, questionnaires should be validated and potentially modified in those populations beforehand, or a standardized skin examination protocol should be used.     

Occupational Safety and Health Interventions to Reduce Musculoskeletal Symptoms in the Health Care Sector

Introduction Health care work is dangerous and multiple interventions have been tested to reduce the occupational hazards. Methods A systematic review of the literature used a best evidence synthesis approach to address the general question “Do occupational safety and health interventions in health care settings have an effect on musculoskeletal health status?” This was followed by an evaluation of the effectiveness of specific interventions. Results The initial search identified 8,465 articles, for the period 1980–2006, which were reduced to 16 studies based on content and quality. A moderate level of evidence was observed for the general question. Moderate evidence was observed for: (1) exercise interventions and (2) multi-component patient handling interventions. An updated search for the period 2006–2009 added three studies and a moderate level of evidence now indicates: (1) patient handling training alone and (2) cognitive behavior training alone have no effect on musculoskeletal health. Few high quality studies were found that examined the effects of interventions in health care settings on musculoskeletal health. Conclusions The findings here echo previous systematic reviews supporting exercise as providing positive health benefits and training alone as not being effective. Given the moderate level of evidence, exercise interventions and multi-component patient handling interventions (MCPHI) were recommended as practices to consider. A multi-component intervention includes a policy that defines an organizational commitment to reducing injuries associated with patient handling, purchase of appropriate lift or transfer equipment to reduce biomechanical hazards and a broad-based ergonomics training program that includes safe patient handling and/or equipment usage. The review demonstrates MCPHI can be evaluated if the term multi-component is clearly defined and consistently applied.     

A case of lead poisoning due to snooker chalk

A 3 year, 9 month old child with pica presented with a blood lead concentration of 1.74 micromol/l (360 microg/l). The source of poisoning was snooker chalk (lead content 7200 microg/g). She was treated with intravenous calcium disodium edetate chelation. Thirty months later her blood lead was 0.39 micromol/l (80 microg/l). This case illustrates the need to be vigilant for more unusual causes of lead poisoning in the home.     

胃内肠嗜铬样细胞的分离与培养及功能测定

目的体内研究已提示胃内肠嗜铬样(ECL)细胞在调节胃酸分泌中起到重要的作用.但以往由于缺乏分离、培养ECL细胞的方法,对它的生理调节、病理变化的研究受到了限制.方法采用链霉蛋白酶的消化,淘析法和颗粒梯度离心分离纯化ECL细胞.结果经电镜,组胺含量测定,纯化率达90%～95%.经锥虫蓝染色细胞成活率大于95%.分离纯化后的ECL细胞短期培养24 h后,胃泌素对ECL细胞的作用,经酶标免疫测定组胺分泌的EC50为3×10-10mol/L.经BrdU掺入试验测定DNA增生的EC50为2×10-11mol/L.胃泌素受体拮抗剂L365 266抑制胃泌素释放组胺的作用(IC50 10-8mol/L).结论ECL细胞在培养系统中生长良好,为进一步研究ECL细胞提供了一个可靠的新方法.     

In vitro activity of oral cephalosporins against pediatric isolates of Streptococcus pneumoniae non-susceptible to penicillin, amoxicillin or erythromycin

The aim of this study was to evaluate the effects of penicillin, amoxicillin or erythromycin resistance on the in vitro activity of oral cephalosporins against Streptococcus pneumoniae pediatric isolates. A total of 282 pediatric isolates received during 2005 in the Spanish Reference Pneumococcal Laboratory were tested by agar dilution: 104 strains were penicillin-susceptible, 72 intermediate, and 106 resistant. Serotypes 9 and 14 were the most troublesome with <10% susceptibility to oral cephalosporins. Cefditoren exhibited the highest intrinsic activity against penicillin/amoxicillin-resistant pneumococci, with MIC(90s )of 0.5 microg/ml, followed by cefotaxime (2 microg/ml), cefpodoxime (4 microg/ml), cefuroxime (16 microg/ml), and cefaclor/cefixime (>or= 32 microg/ml), with 0% susceptibility to cefaclor, cefuroxime and cefpodoxime. Cefditoren 0.5 microg/ml inhibited 95.3%, 95.5%, and 98.6% of penicillin-, amoxicillin-, and erythromycin-resistant isolates, respectively. Susceptibility to oral cephalosporins shifted from >90% in penicillin-susceptible isolates to approximately 38% for cefuroxime/cefpodoxime and approximately 7% for cefaclor in penicillin-intermediate, and to 0% in resistant isolates. Despite the different in vitro activity of oral cephalosporins, full resistance to penicillin or amoxicillin implied lack of susceptibility to all oral cephalosporins with defined CLSI breakpoints, rendering them inadequate as empirical treatment in countries with a high prevalence of penicillin resistance.     

Retroperitoneal malignant fibrous histiocytoma with contiguous organs infiltration

Retroperitoneal tumours are extremely rare neoplasms, most of them malignant. We described the case of a 48-year-old man with a large retroperitoneal mass detected during the study of a constitutional syndrome. The mass was treated surgerically and pathological diagnosis was malignant fibrous histiocytoma. Literature is reviewed and clinical features, histological findings, radiological techniques and therapeutic management are analyzed.