WHO guidelines on protecting workers from potential risks of manufactured nanomaterials

The term nanomaterials refers to materials that have at least one dimension (height, width or length) that is smaller than 100 nanometres (10−7 metre), which is about the size of a virus particle. This particular size dimension represents a major characteristic of manufactured nanomaterials (MNMs). The unique properties of MNMs may result in better paints, better drugs and faster electronics. However, for the same reason, MNMs may also present health hazards that differ from those of the substance in bulk form, and may require different test methods for hazard, exposure and risk assessment from their bulk material counterparts. There is currently a paucity of precise information about human exposure pathways for MNMs, their fate in the human body and their ability to induce unwanted biological effects such as generation of oxidative stress. Data from in vitro, animal and human MNM inhalation studies are available for only a few MNMs. So far, no long-term adverse health effects in humans have been observed. This could be due to the recent introduction of MNMs, the precautionary approach to avoid exposure and ethical concerns about conducting studies on humans. Health recommendations must, therefore, be based on extrapolation of the evidence from in vitro, animal or other studies from fields that involve exposure to nanoscale particles, such as air pollution, to the possible effects in humans. Workers in all countries will be at the front line of exposure to these materials, placing them at increased risk for potential adverse health effects. Therefore, WHO proposes these guidelines to policy makers and professionals in the field of occupational health and safety with recommendations on how best to protect workers from the potential risks of MNMs.

Manejo general del intoxicado / General management of intoxicated

Intoxications have become a relevant complaint in the emergency room since the second half of the last century. Toxidromes have been replaced by a more practical combined analysis of vital signs, directed physical examination and selected laboratory tests. Most of the mortality can be prevented by the correct and opportune implementation of general management strategies, including supportive care, prevention of absortion, enhancement of elimination and extracorporeal removal of toxins. Through the following pages we will review many of different diagnostic and therapeutic alternatives...

Molluscicidal and ovicidal activities ofplant extracts of the Piperaceae onBiomphalaria glabrata (Say, 1818)

Schistosomiasis is a tropical disease caused by Schistosoma and occurs in 54countries, mainly in South America, the Caribbean region, Africa and the easternMediterranean. Currently, 5 to 6 million Brazilian people are infected and 30,000are under infection risk. Typical of poor regions, this disease is associated withthe lack of basic sanitation and very frequently to the use of contaminated water in agriculture, housework and leisure. One of the most efficient methods of controlling the disease is application of molluscicides to eliminate or to reduce the population of the intermediate host snail Biomphalaria glabrata. Studies on molluscicidal activity of plant extracts have been stimulated by issues such as environmental preservation, high cost and recurrent resistance of snails tosynthetic molluscicides. The aim of this study was to determine the molluscicideaction of extracts from Piperaceae species on adult and embryonic stages ofB. glabrata. Fifteen extracts from 13 Piperaceae species were obtained from stems, leaves and roots. Toxicity of extracts was evaluated against snails at two different concentrations (500 and 100ppm) and those causing 100% mortality at 100ppm concentration were selected to obtain the LC90 (lethal concentration of 90% mortality). Piper aduncum, P. crassinervium, P. cuyabanum, P. diospyrifolium and P. hostmannianum gave 100% mortality of adult snails at concentrations ranging from 10 to 60 ppm. These extracts were also assayed on embryonic stages of B. glabrata and those from P. cuyabanum and P. hostmannianum showed 100%ovicidal action at 20ppm.

Avaliação da citotoxicidade de mini-implantes ortodônticos / Evaluation of cytotoxicity of orthodontic mini-implants

O objetivo do presente trabalho é avaliar a citotoxicidade de mini-implantes ortodônticos em células de fibroblastos L929. Foram avaliados 6 mini-implantes ortodônticos divididos em 2 grupos, assim denominados Grupo 1 (SIN - Sistema de Implante, São Paulo, SP, Brasil) cor dourada, Grupo 2 (SIN - Sistema de Implante, São Paulo, SP, Brasil) cor prateada. Previamente, os mini-implantes foram esterilizados em luz ultravioleta. Após isso os mesmos foram imersos em meio mínimo essencial de Eagle (MEM) pós 24h, onde então se procedeu a remoção do sobrenadante e colocação em contato com fibroblastos L929. Avaliou-se a citotoxicidade em 4 períodos, 24, 48, 72 e 168h. Após contato com o meio as células foram incubadas por mais 24h onde então foram adicionados 100 µl do corante vermelho neutro a 0,01%. Novamente as células foram incubadas por 3h para que as mesmas incorporassem o corante. Passado esse período as células foram fixadas e realizou-se a contagem de células viáveis em espectrofotômetro. Os resultados demonstraram que em todos os tempos avaliados não foram encontradas diferenças estatísticas entre os mini-implantes dos Grupos 1 e 2. Esses grupos também foram estatisticamente similar ao Grupo C-, em todos os tempos, e ao Grupo CC nos tempos 24 e 48h e 7 dias (p > 0.05). No tempo 72h foram encontradas diferenças estatísticas entre o Grupo 1 e o CC (p < 0.05). Os mini-implantes ortodônticos avaliados não possuem caráter citotóxico no período de até 7 dias de avaliação.

Objective the present study aims to assess the cytotoxic effect of orthodontic mini-implants on L929 fibroblast cells. Six orthodontic mini-implants were divided into 2 groups for evaluation: Group 1 (golden colour, SIN - Sistema de Implante, São Paulo, SP, Brazil) and Group 2 (silver colour, SIN - Sistema de Implante, São Paulo, SP, Brazil). All the mini-implants were previously sterilised using ultraviolet light. Next, the mini-implants were immersed into Eagle’s minimum essential medium (MEM) for 24 hours, where supernatant removal and contact with L929 fibroblasts were performed. Cytotoxicity was evaluated in four different periods of time: 24, 48, 72, and 168 hours. After being in contact with the mini-implants immersed, the cells were incubated for further 24 hours and then 100 µl of 0.01% neutral-red staining solution were added. The cells were incubated again for 3 hours so that they could absorb the stain. After this period of time, they were fixed and a spectrophotometer. The results showed that at all times evaluated were not found statistical differences between the mini-implants of Group 1 and 2. These groups were also statistically similar to Group C, in all times and the CC Group at times 24, 48 and 7 days (p > 0.05). At time 72 hours was found statistical differences between Group 1 with the CC (p < 0.05). The orthodontic mini-implants have not evaluated the cytotoxic character period of up to 7 days of evaluation.

Insecticide resistance in Argentine populations of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)

The tomato leafminer, Tuta absoluta (Meyrick), is one of the key pests of tomato in Argentina. Since its dispersal in the 1970s, chemical control has been the main method of controlling it. However, reduced efficacy of some of the recommended insecticides has been observed since the 1980s. The aim of this work was to study the toxicity of three insecticides widely used in chemical control of T. absoluta (abamectin, deltamethrin and methamidophos) on larvae from a laboratory susceptible population (CASTELAR) and two greenhouse populations (ROSARIO and BELLA VISTA). Insecticides were dissolved in acetone and topically applied to the mid-dorsal abdominal region of two-day old 4th instar larvae. LD50 values were estimated and the Resistance Ratio (RR) for each insecticide was calculated (RR = LD50 value of each greenhouse population/LD50 value of the susceptible population). ROSARIO and BELLA VISTA populations showed the following RRs values: > 68.38 for deltamethrin; 2.48 and 3.49 for abamectin, respectively; and 0.79 and 0.86 for metamidophos, respectively. Deltamethrin resistance observed in ROSARIO could be due to the high selective pressure exerted by pyrethroids in this location. Deltamethrin resistance in BELLA VISTA is more difficult to explain, because pyrethroids were scarcely used in the greenhouse where the insects were sampled. The incipient abamectin resistance detected in the BELLA VISTA population could result from the frequent use of this insecticide in this location, although natural variation can not be discarded.

A traça-do-tomateiro, Tuta absoluta (Meyrick), é uma das pragas chaves no tomateiro na Argentina. O controle químico tem sido o principal método de controle empregado a partir da sua dispersão nos anos 70. Contudo, tem-se observado uma redução na eficácia de alguns dos inseticidas recomendados a partir da década de 80. O objetivo deste trabalho foi estudar a toxicidade de três inseticidas amplamente usados no controle químico de T. absoluta (abamectina, deltametrina e metamidofós) em larvas de uma população susceptível de laboratório (CASTELAR) e duas populações colectadas em casa de vegetação (ROSARIO e BELLA VISTA). Inseticidas foram diluídos em acetona e aplicados topicamente na região dorsal mediana do abdome de larvas no segundo dia do quarto estágio larval. Para cada inseticida estimou-se o LD50 e calculou-se o Nível de Resistência (NR = LD50 de cada população de casa de vegetação/LD50 população de laboratório). As populações de ROSARIO e BELLA VISTA mostraram os seguintes NRs: > 68.38 para deltametrina; 2.48 e 3.49 para abamectina, respetivamente; e 0.79 e 0.86 para metamidofós, respetivamente. A resistência a deltametrina observada em ROSARIO pode ser resultante da alta pressão seletiva exercida pelos piretróides nessa localidade. A resistência incipiente a abamectina detectada em BELLA VISTA pode ter sido causado pelo uso freqüente do inseticida nessa localidade ou pode estar associada à variação natural.