Evaluation of the cytotoxicity, oral toxicity, genotoxicity, and mutagenicity of the latex extracted from Himatanthus drasticus (Mart.) Plumel (Apocynaceae).

ETHNOPHARMACOLOGICAL RELEVANCE: Himatanthus drasticus is a tree popularly known as janaguba. Endemic to Brazil, it is found in the Cerrado and Caatinga biomes, rock fields, and rainforests. Janaguba latex has been used in folk medicine for its antineoplastic, anti-inflammatory, analgesic, and antiallergic activities. However, studies investigating the safety of its use for medicinal purposes are limited. AIM OF THE STUDY: This study aimed to evaluate the toxicity of the latex extracted from H. drasticus. MATERIALS AND METHODS: The latex was extracted from H. drasticus specimens by removing a small area of bark (5 × 30 cm) and then dissolving the exudate in water and lyophilizing it. Phytochemical screening was performed by TLC and GC-MS, protein, and carbohydrate levels. Cell viability was performed by the MTT method. Acute oral toxicity, genotoxicity, and mutagenicity assays were performed in mice. RESULTS: TLC showed the presence of saponins and reducing sugars, as well as steroids and terpenes. The GC-MS analysis of the nonpolar fraction identified lupeol acetate, betulin, and α/ß-amyrin derivatives as the major compounds. The latex was toxic to S-180 cells at 50 and 100 µg/mL. No signals of toxicity or mutagenicity was found in mice treated with 2000 mg/kg of the latex, but genotoxicity was observed in the Comet assay. CONCLUSIONS: H. drasticus latex showed toxicity signals at high doses (2000 mg/kg). Although the latex was not mutagenic to mice, it was genotoxic in the Comet assay in our experimental conditions. Even testing a limit dose of 2000 mg/kg, which is between 10 to 35-fold the amount used in folk medicine, caution must be taken since there is no safe level for genotoxic compounds exposure. Further studies on the toxicological aspects of H. drasticus latex are necessary to elucidate its possible mechanisms of genotoxicity.

Toxicity of Milkweed Leaves and Latex: Chromatographic Quantification Versus Biological Activity of Cardenolides in 16 Asclepias Species.

Cardenolides are classically studied steroidal defenses in chemical ecology and plant-herbivore coevolution. Although milkweed plants (Asclepias spp.) produce up to 200 structurally different cardenolides, all compounds seemingly share the same well-characterized mode of action, inhibition of the ubiquitous Na+/K+ ATPase in animal cells. Over their evolutionary radiation, milkweeds show a quantitative decline of cardenolide production and diversity. This reduction is contrary to coevolutionary predictions and could represent a cost-saving strategy, i.e. production of fewer but more toxic cardenolides. Here we test this hypothesis by tandem cardenolide quantification using HPLC (UV absorption of the unsaturated lactone) and a pharmacological assay (in vitro inhibition of a sensitive Na+/K+ ATPase) in a comparative study of 16 species of Asclepias. We contrast cardenolide concentrations in leaf tissue to the subset of cardenolides present in exuding latex. Results from the two quantification methods were strongly correlated, but the enzymatic assay revealed that milkweed cardenolide mixtures often cause stronger inhibition than equal amounts of a non-milkweed reference cardenolide, ouabain. Cardenolide concentrations in latex and leaves were positively correlated across species, yet latex caused 27% stronger enzyme inhibition than equimolar amounts of leaf cardenolides. Using a novel multiple regression approach, we found three highly potent cardenolides (identified as calactin, calotropin, and voruscharin) to be primarily responsible for the increased pharmacological activity of milkweed cardenolide mixtures. However, contrary to an expected trade-off between concentration and toxicity, later-diverging milkweeds had the lowest amounts of these potent cardenolides, perhaps indicating an evolutionary response to milkweed's diverse community of specialist cardenolide-sequestering insect herbivores.

Toxicity of Jatropha curcas L. latex in Allium cepa test / Toxicidade do látex de Jatropha curcas L. no modelo de Allium cepa

The latex obtained from Jatropha curcas (physic nut) is used in traditional medicine to treat a variety of disturbs, including burns, hemorrhoids, ringworm and ulcers. Phytochemical analyses have shown that J. curcas latex contains natural compounds with therapeutic potential. In this study, the toxicity, cytotoxicity and genotoxicity effects of J. curcas latex on the root cells of Allium cepa were examined. Onion seeds and bulbs were exposed to seven different concentrations of latex and then the roots were submitted to macro and microscopic analyses. Water and sodium azide were used as negative and positive controls, respectively. The analysis of root growth showed that J. curcas crude latex or 50% diluted is highly toxic. Cytogenetic results showed that the mitotic index of the onion roots submitted to latex treatment decreased significantly compared to the negative control, which suggests that the latex is cytotoxic. High incidence of chromosome aberrations in the cells treated with J. curcas latex was observed too, indicating that the latex also presents genotoxic effect. The analyses presented in this report suggest the toxic, cytotoxic and genotoxic effects of J. curcas latex. Then, the indiscriminate use of J. curcas latex in folk medicine could bring risk to human health.

O látex obtido de Jatropha curcas (pinhão manso) é usado na medicina tradicional para tratamento de diversos distúrbios, como queimaduras, hemorroida, micose e úlcera. Análises fitoquímicas apontaram que o látex de J. curcas contém compostos naturais com potencial terapêutico. Este estudo avaliou a toxicidade, citotoxicidade e genotoxicidade do látex de J. curcas em células da raiz de Allium cepa. Sementes e bulbos de cebola foram expostos á sete diferentes concentrações de látex e, então, as raízes foram submetidas a análises macro e microscópica. Água e azida sódica foram utilizadas como controle negativo e positivo, respectivamente. A análise do comprimento das raízes mostrou que o látex de J. curcas puro e diluído a 50% é altamente tóxico. O índice mitótico das raízes de cebola submetidas ao tratamento com o látex diminuiu significativamente comparado com o controle negativo, o que sugere que o látex é citotóxico. Uma alta incidência de aberrações cromossômicas em células tratadas com o látex de J. curcas também foi observada, indicando que o látex apresenta efeito genotóxico. Essa análise sugere que o látex de J. curcas possui efeitos tóxico, citotóxico e genotóxico, sendo que o uso indiscriminado do látex de J. curcas na medicina popular pode trazer risco à saúde humana.

Globos de látex de caucho natural: objetos peligros a desterrar de las instituciones de salud / Natural rubber latex balloons: dangerous objects to be banned from health institutions

Los globos de látex de caucho natural y los guantes de examinación del mismo material inflados como globos, que se entregan a los pacientes para aliviar el estrés de la atención sanitaria en las instituciones de salud tanto públicas como privadas, pueden provocar reacciones de hipersensibilidad de tipo I y son una de las causas más comunes de aspiración fatal. La suelta de globos contaminan el ambiente y agravan la extinción de la fauna y de la vida marina. Los pacientes sensibilizados o alérgicos al látex que participan en los festejos donde se utilizan globos de látex corren el riesgo de una reacción anafiláctica, potencialmente fatal. Aconsejarles no concurrir a dichos eventos, implica impedirles el disfrute de las actividades recreativas que es un derecho de la infancia manifestado en la Declaración de los Derechos del Niño. Muchos hospitales de países desarrollados ya cuentan con una política de prohibición de los globos de látex en sus instituciones, que podría replicarse en nuestro medio por las ventajas que conlleva y su muy bajo costo de implementación (AU)

Natural rubber latex balloons and examining gloves of the same material blown up as balloons to entertain patients to alleviate the stress of care at public and private health institutions, may cause reactions of type-1 hypersensitivity and are the most common cause of fatal asphyxia. Balloons that are released up into the air contaminate the environment and aggravate the extinction of fauna and marine life. Patients who are sensitized or allergic to latex and participate in celebrations in which latex balloons are used are at risk of a potentially fatal anaphylactic reaction. To advise them not to participate in these events means to stop them from enjoying recreational activities which is a right manifested in the Declaration of the Rights of the Child. In many hospitals in developed countries a policy of prohibition of latex gloves is already in place. This prohibition may be replicated in our environment considering its advantages and very low cost of implementation (AU)

Evaluation of cytotoxicity and genotoxicity of Hancornia speciosa latex in Allium cepa root model / Avaliação da citotoxicidade e genotoxicidade do látex de Hancornia speciosa usando o modelo da raiz de Allium cepa

Abstract The latex obtained from Hancornia speciosa Gomes (Mangabeira tree) is widely used in traditional medicine to treat a variety of diseases, including diarrhea, ulcer, gastritis, tuberculosis, acne and warts. In this study, the cytotoxicity and genotoxicity effects of H. speciosa latex on the root meristem cells of Allium cepa were examined. Onion bulbs were exposed to different concentrations of latex and then submitted to microscopic analysis using Giemsa stain. Water was used as a negative control and sodium azide as a positive control. The results showed that, under the testing conditions, the mitotic index (MI) of the onion roots submitted to latex treatment did not differ significantly from the negative control, which suggests that the latex is not cytotoxic. Low incidence of chromosome aberrations in the cells treated with H. speciosa latex was also observed, indicating that the latex does not have genotoxic effect either. The MI and the chromosome aberration frequency responded to the latex concentration, requiring more studies to evaluate the dosage effect on genotoxicity. The results indicate that in tested concentrations H. speciosa latex is probably not harmful to human health and may be potentially used in medicine.

Resumo O látex obtido de Hancornia speciosa é amplamente utilizado na medicina popular para tratar uma variedade de doenças, tais como: diarreia, úlcera, gastrite, tuberculose, acne e verrugas. Nesse estudo, foram avaliados os efeitos citotóxicos e genotóxicos do látex de H. speciosa sobre as células meristemáticas das raízes de Allium cepa. Os bulbos das cebolas foram expostos a diferentes concentrações de látex e depois submetidos à analise microscópica usando o corante Giemsa. A água foi usada como controle negativo e a ázida sódica como controle positivo. Os resultados mostraram que o índice mitótico (IM) das raízes de cebola submetidas ao tratamento com látex, nas condições testadas, não diferiram significativamente do controle negativo, e sugerem que o látex não é citotóxico. Também foi observada uma baixa incidência de aberrações cromossômicas nas células tratadas com látex de H. speciosa, o que sugere que o látex também não possui efeito genotóxico. O IM e a frequência de aberrações cromossômicas foram dependentes da concentração de látex. Outros estudos devem ser realizados para avaliar o efeito da dose na genotoxidade. Os resultados indicam que o látex de mangabeira, nas concentrações testadas, provavelmente não é danoso para saúde humana e pode ter potencial para ser usado na medicina.

Latex of Euphorbia antiquorum-induced S-phase arrest via active ATM kinase and MAPK pathways in human cervical cancer HeLa cells.

Latex of Euphorbia antiquorum (EA) has demonstrated great chemotherapeutic potential for cancer. However, the mechanisms of anti-proliferation of EA on cancer cell remain to be further investigated. The purpose of this study was to explore the influence of EA in human cervical cancer cells. Here, the cell cycle distribution by flow cytometry was examined and the protein expression by the western blotting methods was analyzed. From the cytometric results it was shown that EA-induced S-phase arrest in a concentration manner both in human cervical cancer HeLa and CaSki cells. According the western blot results it was illustrated that EA could downregulate early cyclin E1-Cdk2; and cyclin A-Cdc2 provides a significant additional quantity of S-phase promotion, that in turn promoted the expression of p21(waf1/cip1) and p27(kip1) which were the inhibitors in the complex of cyclin A and Cdc2 that led to cell cycle arrest. Moreover, EA promoted the activation of ataxia telangiectasia mutated (ATM) and check-point kinase-2 (Chk2); however, it negatively regulated the expression of Topoisomerases I and II, Cdc25A, and Cdc25C signaling. Caffeine, an ATM/ATR inhibitor significantly reversed EA downregulation in the levels of Cdc25A. Furthermore, JNK inhibitor SP600125 and p38 MAPK inhibitor SB203580 both could reverse the EA upregulation of the protein of Chk2 level, significantly. This study, therefore, revealed that EA could downregulate topoisomerase, and activate ATM kinase, which then induce parallel Chk 1/2 and MAPK signaling pathways to promote the degradation of Cdc25A to induced S-phase arrest in human cervical cancer HeLa cells.

The latex story.

The milky sap of the rubber tree Hevea brasiliensis is the source of the commercial production of natural rubber latex (NRL) devices, and also represents a source of potent allergenic proteins. NRL materials were introduced in the health care field in about 1840 with the advent of technical abilities to produce suitable and flexible NRL materials for medical products, especially gloves. In the late 1980s, with the increase of transmittable diseases, particularly HIV infection, the use of NRL gloves increased dramatically. During the 1990s, NRL emerged as a major cause of clinically relevant allergy in health care workers using NRL gloves and spina bifida patients with operation on the first day. The increased recognition of NRL allergies, the enhanced research on allergen characterization and sensitization mechanisms, and education about this allergy in health care facilities combined with the introduction of powder-free gloves with reduced protein levels are all factors associated with a decline in the number of suspected cases of NRL allergies in the late 1990s. NRL allergy is a very good example of a 'new allergy' that suddenly arises with tremendous health and economic implications, and also of an allergy which becomes history in a relatively short period of time based on successful primary prevention strategies by strict allergen avoidance.

Anti-proliferation effect of Hevea brasiliensis latex B-serum on human breast epithelial cells.

The rubber tree (Hevea brasiliensis) extracts are becoming increasingly visible in pharmaceutical and therapeutical research. The present study is aimed at examining the specific anti-proliferation property of H. brasiliensis latex B-serum sub-fractions against human breast cancer epithelial cell lines MCF-7 and MDA-MB231. The results showed that the latex whole B-serum and DBP sub-fraction exerted a specific anti-proliferation activity against cancer-origin cells MDA-MB231 but had little effect on non-cancer-origin cells. On the other hand, the anti-proliferative activity was diminished in the pre-heated B-serum fractions. With the low toxicity that the B-serum demonstrated previously in Brine Shrimp Lethality Test (BSLT), the present results suggest the potential use of the B-serum sub-fractions in cancer treatment.

Larvicidal activity of silver nanoparticles synthesized using Plumeria rubra plant latex against Aedes aegypti and Anopheles stephensi.

In the present study activity of silver nanoparticles (AgNPs) synthesized using Plumeria rubra plant latex against second and fourth larval instar of Aedes aegypti and Anopheles stephensi was determined. Range of concentrations of synthesized AgNps (10, 5, 2.5, 1.25, 0.625, 0.3125 ppm) and aqueous crude latex (1,000, 500, 250, 125, 62.50, 31.25 ppm) were tested against larvae of A. aegypti and A. Stephensi. The synthesized AgNps from P. rubra latex were highly toxic than crude latex extract in both mosquito species. The LC(50) values for second and fourth larval instars after 24 h of crude latex exposure were 1.49, 1.82 ppm against A. aegypti and 1.10, 1.74 ppm against A. stephensi respectively. These figures were 181.67, 287.49 ppm against A. aegypti and 143.69, 170.58 ppm against A. stephensi respectively for crude latex extract. The mortality rates were positively correlated with the concentration of AgNPs. The characterization studies of synthesized AgNPs by UV-Vis spectrophotometry, transmission electron microscopy (TEM), Particle size analysis (PSA) and zeta potential confirmed the spherical shape and size (32-200 nm) of silver nanoparticles along with stability. Toxicity studies carried out against non-target fish species Poecilia reticulata, the most common organism in the habitats of A. aegypti and A. stephensi showed no toxicity at LC(50) and LC(90) doses of the AgNPs. This is the first report on mosquito larvicidal activity of latex synthesized nanoparticles.

Anti-Candida albicans activity and brine shrimp lethality test of Hevea brasiliensis latex B-serum.

BACKGROUND AND OBJECTIVES: Hevea brasiliensis extracts could potentially be employed as a relatively low cost resource for various anti-fungal activities due to the simplicity of the extract preparation and its abundance especially in the tropical region. Latex B-serum was reported to have anti-cancer property and its specificity in anti-fungal property has not been elucidated. The present study was conducted to determine the anti-fungal activity of Hevea latex B-serum against Candida (C.) albicans (a rounded cell fungus) and Aspergillus (A.) niger (a filamentous fungus). METHODS AND RESULTS: The results showed that the anti-fungal activity of latex B-serum was specific to C. albicans but not to A. niger. The MIC value of latex B-serum for C. albicans was found to be 2.5 mg/ml. The time-killing profile showed that the growth of C. albicans was inhibited and the inhibition was prolonged throughout the tested time period. Brine shrimp toxicity test showed an LC50 of 461.0 mg/ml with latex B-serum, indicating the non-toxicity of the serum. CONCLUSION: Further purification and identification of the crude extract should point the way to bioactive compound(s) responsible for anti-Candida activity.

Anti-fungal effect of Hevea brasiliensis latex C-serum on Aspergillus niger.

OBJECTIVES: Hevea brasiliensis extract could potentially be employed as a relatively low cost resource for various anti-fungal activities due to the simplicity of latex preparation and the abundance of latex that can be obtained in rubber producing regions. The present study was aimed at examining the species specific anti-fungal property of H. brasilensis latex C-serum against Aspergillus niger. RESULTS: The results showed that the latex C-serum exerted a specific antifungal activity against Aspergillus niger, but not Candida albicans. Low toxicity of the C-serum was demonstrated in Brine Shrimp Lethality Test (BSLT) with an LC50 value of 98.4 mg/ml. CONCLUSIONS: Pending further more elaborated investigations, H. brasiliensis latex C-serum, with its species specific anti-fungal and cancer-origin cell line specific anti-proliferation properties, would probably contribute in healthcare in addition to its traditional role in polymer industry.

Rabbit rubeosis iridis induced by intravitreal latex-derived angiogenic fraction.

PURPOSE: To describe the presence of iris neovascularization in a rabbit-model of retinal neovascularization induced by the intravitreal injection of latex-derived angiogenic fraction microspheres (LAF). MATERIALS AND METHODS: Eight New Zealand rabbits received one intravitreal injection of PLGA (L-lactide-co-glycolide) microspheres with 50 ug of LAF in the right eye (Group A). Microspheres without the LAF (0.1 ml) were injected in controls (Group B; n = 8). Follow-up with clinical evaluation and iris fluorescein angiography was performed after 4 weeks when eyes were processed for light microscopy. RESULTS: All eyes from Group A showed significant vascular dilation, conjunctival hyperemia and neovascularization on the iris surface, after LAF injection. No vascular changes were observed in Group B. CONCLUSIONS: The intravitreal injection of microspheres containing the LAF can induce rubeosis iridis in rabbits and could be used as a simple experimental model for iris neovascularization.

Potato disc bioassay and cytotoxic effect of Leptadenia pyrotechnica: comparative study of diverse extracts.

Comparative acute toxicity studies of the latex and sequential extracts of Leptadenia pyrotechnica (Forsk.) Decne (Asclepiadaceae) were recorded using brine shrimp. The higher toxicities were exhibited in latex; methanol, methanol/dichloromethane (1:1), defatted methanol/dichloromethane (1:1), defatted methanol and dichloromethane extracts. The other extracts; aqueous, alkaloids, ethyl acetate and n-butanol exhibited less toxicities compared with the other extracts. The estimated LC50 and its 95% confidence limits for these extracts expressed in ppm were: methanol, latex 18.84 (11.22-31.61), methanol/dichloromethane 19.95 (7.76-53.70), defatted methanol/dichloromethane 21.38 (7.24-63.10), defatted methanol 28.19 (16.27-48.81) and dichloromethane 30.90 (11.75-79.43). The anti-tumor activities; potato disc assays of methanol, ethyl acetate and alkaloids extracts showed good activities as anti-tumor agent which represented-49.30,-43.20 an -33.60%, respectively. While latex and aqueous extract represented-30.80 and-28.17%, respectively.

Citotoxicidade de luvas de procedimentos em látexSupermax® / Cytotoxic of the procedures gloves in latex Supermax®

O objetivo foi avaliar a citotoxicidade de luvas de procedimento em látex. Foram avaliados três diferentestipos de luvas de procedimento divididos em três grupos assim denominados: 1 (Supermax®),2 (Supermax -Powder Free®) e 3 (Supermax-Microtexturizado®). Utilizou-se 3 grupos controle: positivo(C+) detergente celular Tween 80, negativo (C-) PBS, e controle de célula (CC) cujas não foramexpostas a nenhum material. Após confecção dos corpos de prova, os mesmos foram imersos em meiomínimo essencial Eagle (MEM) por 24 hrs. Passado esse período procedeu-se a remoção do sobrenadantee colocação em contato com os fibroblastos L929. Após contato com o meio, as células foramincubadas por mais 15, 30 e 60 minutos, então foram adicionados 100μl do corante vermelho neutro a0,01%. Uma vez coradas, as mesmas foram fixadas com formoaldeido e então realizada contagem decélulas viáveis em espectrofotômetro (BioTek, Winooski, Vermont, USA). Os valores da quantidade decélulas viáveis, foram submetidos à análise de variância (ANOVA) para determinar se havia diferençasestatísticas entre os grupos, e posteriormente ao teste de Tukey (p<0.05). Nos tempos de 15, 30 e 60minutos os grupos 1 e 3 foram os que demonstraram maior quantidade de células viáveis respectivamente.Com 1 hora de contato todos os grupos demonstraram alta toxicidade celular quando comparadoaos C- e CC. Todas as luvas foram citotóxicas nos tempos avaliados. A toxicidade aumentou como aumento de contato das células.

The objective was to evaluate the cytotoxicity of procedure latex gloves. Three different types ofgloves procedure divided into three groups so called: 1 (Supermax®), 2 (Supermax -- Powder Free®)and 3 (Supermax-Microtexturizado®). We used 3 control groups: positive (C +) cell detergent Tween80, negative (C-) PBS, and control of cell (CC) whose cells were not exposed to any material. Aftermaking the bodies of evidence, they were immersed in Eagle minimum essential medium (MEM) for24 hrs. After this period there has been the removal of supernatant and placed in contact with thefibroblasts L929. After contact with the medium, the cells were incubated for another 15, 30 and 60minutes, which were then added 100 the dye neutral red to 0.01%. Once stained, they were fixedwith formoaldeido and then performed counting of viable cells in spectrophotometer (BioTek, Winooski,Vermont, USA). The values of the quantity of viable cells were subjected to analysis of variance(ANOVA) to determine whether there were statistical differences between groups, and then the Tukeytest (p <0.05). In times of 15, 30 and 60 minutes the groups were 1 and 3 showed that the greatestamount of viable cells respectively. 1 hour of contact with all groups showed high cellular toxicity whencompared to the C-and CC. All gloves were cytotoxic in the time evaluated. The toxicity increased withthe increase of cell contact.

Cytotoxicity of orthodontic elastics: in vitro investigation with on L929 mouse fibroblasts

Aim: To test the hypothesis that there is no difference in the cytotoxicity among natural latex elastics of different manufacturers using a L929 cell line culture. Methods: Different latex intra oral elastics (I.D. = 5/16", 4.5 oz.) were tested. The sample was divided into 7 groups of 15 elastic seach: Group AO (American Orthodontics), Group GAC (GAC International), Group TP (TP Orthodontics), Group AD (Aditek), Group AB (Abzil), Group MO (Morelli) and Group UN (Uniden).Cytotoxicity assays were performed by using cell culture medium containing L-929 line cells(mouse fibroblast). The cytotoxicity was evaluated by using the “dye-uptake” test, which wasemployed at two different moments (1 and 24 h). Data were compared by ANOVA and Tukey’s test(P < 0.05). Results: The results showed a significant difference (P < 0.05) between all groups and the group CC (cell control) at 1 and 24 h. Groups AD, AB, MO and UN were noticeably more cytotoxic than the groups AO, GAC and TP at 1 h. After 24 h, a significant decrease in cell viability was observed in all groups. Conclusions: Intraoral elastics from American Orthodontics, GACand TP Orthodontics trademarks induced less cell lysis than Aditek, Abzil, Morelli and Uniden trademarks.

Acute Toxicity Of Euphorbia Royleana Boiss (Euphorbiaceae) latex on freshwater catfish, Heteropneustes Fossilis (Siluriformes, Heteropneustidae) / Toxicidad aguda del látex de Euphorbia royleana Boiss (Euphorbiaceae) en el bagre de agua dulce, Heteropneutes fossilis (Siluriformes, Heteropneustidae)

An acute toxicity test was performed by using a four-day static renewal test to determine the LC50 value of aqueous extract of Euphorbia royleana latex for the freshwater fsh, Heteropneustes fossilis. The LC50 values, their upper and lower confdence limits and slope functions were calculated. The LC50 values for aqueous extract of Euphorbia royleana latex at various exposure periods were 7.758 mg/L for 24 h, 5.847 mg/L for 48 h, 4.474 mg/L for 72 h and 3.090 mg/L for 96 h. The regression coeffcient showed that there was signifcant negative correlation between exposure time and different LC values. Hence, it is concluded that the concentration to produce toxicity of latex of Euphorbia royleana is comparable and close to the concentration to produce toxicity of synthetic organophosphates pesticides for the fsh H. fossilis. Therefore, adequate precautions must be taken when Euphorbia royleana latex is being used near fsh- inhabited areas.

La prueba de la toxicidad aguda fue realizada utilizando un test estático con renovación, de cuatro días de duración, para determinar el valor de la CL50 de un extracto acuoso del látex de Euphorbia royleana, en el pez de agua dulce Heteropneustes fossilis. Se calcularon el valor de la CL50, los límites de confanza máximo y mínimo y la pendiente. Los valores de la CL50 para el extracto acuoso del látex en varios períodos de exposición fueron 7,758 mg/L para 24 h, 5,847 mg/L para 48 h, 4,474 mg/L para 72 h y 3,090 mg/L para 96 h. El coefciente de regresión mostró una correlación negativa signifcativa entre el tiempo de exposición y diferentes valores de la CL50. Se concluye que la concentración del látex de E. royleana que produce toxicidad es comparable y cercana a la de los plaguicidas sintéticos organofosforados para el pez H. fossilis. Por lo tanto, se deben tomar precauciones adecuadas cuando el látex de E. royleana es utilizado cerca de áreas donde habita el pez H. fossilis.

In vitro cytotoxicity of latex orthodonticelastics / Citotoxicidad de los elásticos ortodònticos de látex

Natural latex does not fall into the category of materials known to be entirely inoffensive. The objective of the present in vitro study is to test the hypothesis that there is no difference in the cytotoxicity between natural latex elastics of different colours. The present article compared different latex intra-oral elastics (5/16 = 7.9 mm). The sample was divided into four groups according to their manufacturer: Group N (Natural latex elastic, Morelli), Group R (Red colour elastic, Morelli) Group Y (Yellow colour elastic, Morelli) and Group G (Green colour elastic, Morelli). Cytotoxicity assays were performed by using cell culture medium containing L-929 line cells (mouse fibroblast). The cytotoxicity was evaluated by using the “dyeuptake” test, which was employed at two different moments (1 and 24 h). Data were compared by analysis of variance (ANOVA) and Tukey’s test (p<0.05). The results showed a significant difference (p<0.05) between the groups N, R, Y, G and the negative cytotoxicity control at 1 and 24 h (p<0.05), it did not have presented significant difference between the groups N, R, Y, G tested (p>0.05) at 1 and 24 h. Morelli intra-oral elastics were found to be highly cytotoxic, regardless of their colour and immersion time.

El látex natural no entra en la categoría de materiales que se sabe del todo inofensivo. El objetivo del presente estudio in vitro es poner a prueba la hipótesis de que no hay diferencia en la citotoxicidad entre elásticos de látex natural de diferentes colores. El presente artículo compara diferentes elásticos intraorales de látex (5/16 =7,9 mm). La muestra se dividió en cuatro grupos según su fabricante: Grupo N (elástico látex, Morelli), Grupo I (elástico de color rojo, Morelli) Grupo Y (elástico de color amarillo, Morelli) y el Grupo G (elástico color verde, Morelli). Pruebas de citotoxicidad se realizaron mediante el uso de medio de cultivo celular que contiene líneas celulares L-929 (fibroblastos de ratón). La citotoxicidad se evaluó mediante el test “dye-uptake”, que se empleó en dos momentos diferentes (1 y 24 h). Los datos se compararon mediante análisis de varianza (ANOVA) y test de Tukey (p<0,05). Los resultados mostraron una diferencia significativa (p<0,05) entre los grupos N, R, Y, G y la negativa citotoxicidad del control en 1 y 24 h (p<0,05), no han presentado diferencias significativas entre los grupos N, R , Y, G probado (p>0,05) en 1 y 24 h. Elásticos intraorales Morelli resultaron ser altamente citotóxicos, independientemente de su color y tiempo de inmersión.

Skin exposure to micro- and nano-particles can cause haemostasis in zebrafish larvae.

Low mass ambient exposure to airborne particles is associated with atherothrombotic events that may be a consequence of the combustion-derived nanoparticle content. There is concern also over the potential cardiovascular impact of manufactured nanoparticles. To better understand the mechanism by which toxic airborne particles can affect cardiovascular function we utilised zebrafish as a genetically tractable model. Using light and confocal fluorescence video-microscopy, we measured heart-rate and blood flow in the dorsal aorta and caudal artery of zebrafish larvae that had been exposed to a number of toxic and non-toxic microparticles and nanoparticles. Diesel exhaust particles (DEP), carboxy-charged Latex beads (carboxy-beads) and toxic alumina (Taimicron TM300), but not non-toxic alumina (Baikalox A125), were found to promote both skin and gut cell damage, increased leukocyte invasion into the epidermis, tail muscle ischaemia and haemostasis within the caudal artery of free swimming zebrafish larvae. The presence of sodium sulfite, a reducing agent, or warfarin, an anticoagulant, within the system water abrogated the effects of both toxic alumina and carboxy-beads but not DEP. Genetic manipulation of skin barrier function augmented skin damage and haemostasis, even for the non-toxic alumina. The toxic effects of carboxy-beads were still apparent after leukocyte numbers were depleted with anti-Pu.1 morpholino. We conclude that particle uptake across skin epithelium and gut mucosal barriers, or the presence of leukocytes, is not required for particle-induced haemostasis while a compromised skin barrier function accentuated tissue injury and haemostasis.

Evaluation of the cytotoxicity of latex and non-latex orthodontic separating elastics.

OBJECTIVE: To test the hypothesis that a difference in cytotoxicity exists between latex and non-latex orthodontic separating elastics. MATERIAL AND METHODS: Five intra-oral separating elastics from different manufactures (four latex and one non-latex) were divided into five groups of 15 elastics each: Group MA (non-latex elastics, Masel), Group MO (natural latex, Morelli), Group DE (natural latex, Dentaurum), Group TP (natural latex, TP Orthodontics) and Group UN (natural latex, Unitek). The cytotoxicity assay was performed using cell cultures (epithelial HEp-2 cells originating from human laryngeal carcinoma) that were submitted to the cell viability test with neutral red (dye-uptake) at 24, 48, 72 and 168 h. Analysis of variance (anova) with multiple comparisons and Tukey's test were employed (p < 0.05). RESULTS: The results showed no statistically significant differences between groups MA, DE, TP and UN in relation to Group CC (cell control) for experimental times of 24, 48 and 168 h (p > 0.05). Morelli, Dentaurum, TP Orthodontics and Unitek elastics induced a great amount of cell lyses at 72 h. CONCLUSION: One can demonstrate that the Masel elastic induced less cell lysis compared with other elastics, but all trademarks were found to be clinically biocompatible. CLINICAL RELEVANCE: Separating orthodontic elastics are used in the interdental subgingival region with the aim to separate the teeth for placement of orthodontic bands. However, latex has been known to cause allergy. As these materials are widely used in clinical orthodontics, care regarding the cytotoxicity of orthodontic elastics should be taken. Thus, clinically proven biocompatible materials should be acquired whenever possible.

Rabbit retinal neovascularization induced by latex angiogenic-derived fraction: an experimental model.

PURPOSE: To create a retinal neovascularization experimental model using intravitreal injection of microspheres loaded with latex-derived angiogenic fraction. METHODS: Thirty-two albino New Zealand rabbits, divided in 4 groups of 8 animals, were enrolled in this study. Rabbits in groups I, II, and III received one intravitreal injection of PLGA (L-lactide-co-glycolide) microspheres with 10, 30, and 50 microg of latex-derived angiogenic fraction into their right eyes, respectively, and group IV received 0.1 ml of microspheres without the angiogenic fraction. Weekly follow-up with ophthalmoscopy and fluorescein angiography was performed; the rabbits were sacrificed in the 4th week and their eyes processed for light microscopy. RESULTS: All eyes from group I demonstrated increased retinal vascular tortuosity, observed from 14 days after injection and maintained for 28 days, otherwise without new vessels detection. All group II eyes showed vascular changes similar to group I. Fifty percent of the eyes from group II rabbits developed retinal neovascularization 21 days after injection. All eyes from group III demonstrated significant vascular tortuosity and retinal new vessels 2 weeks after injection, progressing to fibrovascular proliferation and tractional retinal detachment. No vascular changes or retinal new vessels were observed in group IV eyes. Light microscopy confirmed the existence of new vessels previously seen on fluorescein angiography, in retinal sections adjacent to the optic disc, not observed in sections at the same area in the control group. CONCLUSION: Thirty- and 50-microg microspheres containing latex-derived angiogenic fraction injected into the vitreous cavity induced retinal neovascularization in rabbits.