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Toxicology Jan 2018According to the new EU Medical Devices (MDR) legislation coming into effect in 2017, manufactures will have to comply with higher standards of quality and safety for...
According to the new EU Medical Devices (MDR) legislation coming into effect in 2017, manufactures will have to comply with higher standards of quality and safety for medical devices in order to meet common safety concerns regarding such products. Metal alloys are extensively used in dentistry and medicine (e.g. orthopedic surgery and cardiology) even though clinical experience suggests that many metals are sensitizers. The aim of this study was to further test the applicability domain of the in vitro reconstructed human epidermis (RhE) IL-18 assay developed to identify contact allergens and in doing so: i) determine whether different metal salts, representing leachables from metal alloys used in medical devices, could be correctly labelled and classified; and ii) assess the ability of different salts for the same metal to penetrate the skin stratum corneum. Twenty eight chemicals including 15 metal salts were topically exposed to RhE. Nickel, chrome, gold, palladium were each tested in two different salt forms, and titanium in 4 different salt forms. Metal salts were labelled (YES/NO) as sensitizer if a threshold of more than 5 fold IL18 release was reached. The in vitro estimation of expected sensitization induction level (potency) was assessed by interpolating in vitro EC50 and IL-18 SI2 with LLNA EC3 and human NOEL values from standard reference curves generated using DNCB (extreme) and benzocaine (weak). Metal salts, in contrast to other chemical sensitizers and with the exception of potassium dichromate (VI) and cobalt (II) chloride, were not identified as contact allergens since they only induced a small or no increase in IL-18 production. This finding was not related to a lack of stratum corneum skin penetration since EC50 values (decrease in metabolic activity; MTT assay) were obtained after topical RhE exposure to 8 of the 15 metal salts. For nickel, gold and palladium salts, differences in EC50 values between two salts for the same metal could not be attributed to differences in molarity or valency. For chrome salts the difference in EC50 values may be explained by different valencies (VI vs. III), but not by molarity. In general, metal salts were classified as weaker sensitizers than was indicated from in vivo LLNA EC3 and NOEL data. Our in vitro results show that metals are problematic chemicals to test, in line with the limited number of standardized human and animal studies, which are not currently considered adequate to predict systemic hypersensitivity or autoimmunity, and despite clinical experience, which clearly shows that many metals are indeed a risk to human health.
Topics: Allergens; Animal Testing Alternatives; Epidermis; Haptens; Humans; Infant, Newborn; Interleukin-18; Local Lymph Node Assay; Male; Metals; No-Observed-Adverse-Effect Level; Toxicity Tests
PubMed: 29079364
DOI: 10.1016/j.tox.2017.10.014 -
Sisli Etfal Hastanesi Tip Bulteni 2020Sensitization of allergens varies among societies and also it is influenced by various factors, such as age and gender. It may even change over the years. In this study,...
OBJECTIVES
Sensitization of allergens varies among societies and also it is influenced by various factors, such as age and gender. It may even change over the years. In this study, we aimed to evaluate the patch test results in patients with contact dermatitis (CD) in our center.
METHODS
European standard series patch test results of patients with CD between 2017 and 2018 were evaluated retrospectively.
RESULTS
Of the 135 patients, 65 (48.1%) were males, 70 (51.9%) were females. The mean age of patients was 41.43±14.26 (11-78) years. In 78 (57.8%) patients, a positive reaction against at least one allergen was detected. The most common allergens were nickel sulfate (27.4%), potassium dichromate (14.8%), cobalt chloride (11.9%), textile dye mix (8.1%), fragrance mix i, ii (6.7%) and balsam of Peru (4.4%). The sensitization of nickel sulfate was higher in females and sensitization of cobalt chloride and potassium dichromate in males (p=0.03, 0.05, 0.03, respectively). In the multivariate logistic regression analysis, age was independently related to a positive reaction against at least one allergen.
CONCLUSION
Nickel sulfate, potassium dichromate, cobalt chloride and textile dye mix were the most common allergens. Legal regulations should be made to decrease exposure to allergens.
PubMed: 32617060
DOI: 10.14744/SEMB.2020.02703 -
Veterinary Medicine and Science Jul 2022Intestinal infection, caused by various protozoans and helminths, represents one of the significant health concerns in pigeons around the world.
BACKGROUND
Intestinal infection, caused by various protozoans and helminths, represents one of the significant health concerns in pigeons around the world.
OBJECTIVES
The present study aimed to determine the diversity and prevalence of the intestinal parasites in pigeons found in Ratnanagar Municipality, Chitwan, in central Nepal.
METHODS
The fresh faecal samples (n = 155) were non-invasively collected from different households and temples pigeons The individual samples were immediately preserved in the 2.5% potassium dichromate solution and transported to the research laboratory. Following direct wet mount and concentration methods, the samples were observed under a compound microscope.
RESULTS
The results showed 87.1% prevalence rate with 16 parasite species that included 8 protozoan and 8 helminth faunae. The faecal samples of temple pigeons contained a higher prevalence rate with higher parasitic richness (95.6%; 16 species) than household pigeons (75.4%; 12 species). Mixed infection up to four different species was recorded in both types of sampling populations.
CONCLUSIONS
Pigeons harbour a greater prevalence and wider diversity of intestinal parasites and the parasitism varies based on the habitats. Proper management and effective deworming practices are recommended to control intestinal parasitic infection in these avian hosts.
Topics: Animals; Bird Diseases; Columbidae; Intestinal Diseases, Parasitic; Nepal; Parasites; Prevalence
PubMed: 35352510
DOI: 10.1002/vms3.792 -
Bioengineering (Basel, Switzerland) Jul 2023Converting more CO absorbed by plant photosynthesis into biomass-activated carbon effectively reduces carbon emissions. In this study, we used a one-step preparation of...
Converting more CO absorbed by plant photosynthesis into biomass-activated carbon effectively reduces carbon emissions. In this study, we used a one-step preparation of biomass-activated carbon loaded with MgO nanoparticles to investigate the effect of Mg loading on the catalytic pyrolysis process. The influences of magnesium loading on biochar yield and fixed carbon production were assessed. The addition of 1% Mg weakened the carbonyl C=O, inhibited the dehydroxylation reaction, enhanced the C-H signal strength, and the formation of MgO inhibited the weaker- bound substituent breakage. Additionally, the addition of magnesium altered the morphological features and chemical composition of the biochar material. It also increased the activated carbon mesoporosity by 3.94%, biochar yield by 5.55%, and fixed carbon yield by 12.14%. The addition of 1% Mg increased the adsorption capacity of the activated carbon to potassium dichromate, acid magenta, methylene blue, and tetracycline effluents by 8.71 mg, 37.15 mg, 117.68 mg, and 3.53 mg, respectively. The results showed that MgCl played a significant role in promoting the thermal degradation of biomass and improving the solid yield and adsorption performance of activated carbon.
PubMed: 37508863
DOI: 10.3390/bioengineering10070836 -
Veterinary Sciences Nov 2022Coccidiosis is one of the most common infectious diseases that causes digestive problems in rabbits, leading to global economic losses. This study was conducted to...
Coccidiosis is one of the most common infectious diseases that causes digestive problems in rabbits, leading to global economic losses. This study was conducted to evaluate the effects of bile obtained from sheep gallbladder on the sporulation and morphology of oocysts and sporozoites affecting rabbit liver cells and to determine the best concentration for sporulation inhibition. Sporulation inhibition per milliliter was measured in samples exposed to five concentrations of sheep bile (SB) in a 2.5% potassium dichromate solution: 12.5%, 25%, 50%, 75%, and 100% concentrations for oocysticidal activity and 125, 250, 500, 750, and 1000 μg/mL concentrations for antisporozoidal activity. A bioassay was performed to assess the in vitro anticoccidial activity of sheep bile against oocysts and sporozoite sporulation. In this assay, six-well plates with 5 mL of bile containing 1000 oocysts showed unsporulated oocysticidal activity after 48, 72, and 96 h and antisporozoidal activity after 12 and 24 h. A chemical assay was performed via infrared spectroscopy to investigate the presence of several anticipated active chemical compounds in sheep bile. Sheep bile was able to inhibit oocysts at 100% and 75% concentrations by about 91% and 81%, respectively. In addition, SB had the highest inhibition of sporozoite viability (92%) at a concentration of 1000 μg/mL and had the lowest inhibition of 8% at a concentration of 125 μg/mL. An increase in the incubation time and a higher dose generally increased the inhibition rate. The results showed that sheep gallbladder bile is effective due to its inhibitory potential and effect on the coccidian oocyst sporulation of . Further studies are needed to determine the precise active chemicals present in SB and their modes of action and application in vivo.
PubMed: 36548819
DOI: 10.3390/vetsci9120658 -
Microbiology Spectrum Dec 2021Soil-transmitted helminths (STH) are important and widespread intestinal pathogens of humans and animals. It is presently unknown which inactivating procedures may be...
Soil-transmitted helminths (STH) are important and widespread intestinal pathogens of humans and animals. It is presently unknown which inactivating procedures may be universally effective for safe transport, preservation, and disinfection of STH-contaminated specimens, and this lack of knowledge may expose laboratory staff to higher risk of laboratory-acquired infections (LAI's). There are limited data on the efficacy of commonly used disinfectants and fecal fixatives for inactivating the eggs of STH. This work tested five disinfectants for surface cleanup, four storage temperature conditions, and six transport/storage fixatives, to inactivate eggs of three species of STH of animal origin ( "roundworm," "whipworm" and Ancylostoma caninum "hookworm") as surrogates for human STH. Among disinfectants, exposure to 10% povidone-iodine for ≥5 min inactivated 100% of the three species tested, while 5 min exposure to 95% ethanol inactivated and A. caninum eggs. All of the fixatives tested had inactivation effects on A. caninum hookworm eggs within 24 h of exposure, except potassium dichromate, which required 48 h. 95% ethanol for ≥48 h inactivated eggs from all three STH species. Freezing at ≤-20°C for ≥24 h inactivated eggs of and A. caninum, but only freezing at -80°C for ≥24 h inactivated >99% eggs, including . This work provides an evidence base for health and safety guidelines and mitigation strategies for the handling, storage, and disposal of stool samples containing STH eggs in laboratory, health care, childcare, or veterinary settings. This study systematically evaluates common laboratory disinfectants and storage conditions for their effectiveness in inactivating the infective stages of soil-transmitted helminths (STH). Animal-infecting proxy species were chosen to represent three major groups of STH that infect humans: roundworms, whipworms, and hookworms. Previously published work in this area typically focuses on a particular inactivation method, either for a single STH species, or on a subset of closely related species. Because prediagnostic fecal specimens must be regarded as potentially infectious with a mix of species, such information may be of limited utility in a working laboratory. We provide a straightforward summary of storage and disinfection methods that can achieve complete inactivation across a range of STH species, which represents a significant advance for clinical, veterinary and research laboratory biosafety.
Topics: Ancylostoma; Ancylostomatoidea; Animals; Anti-Infective Agents, Local; Ascaris suum; Containment of Biohazards; Disinfectants; Disinfection; Ethanol; Feces; Helminths; Hookworm Infections; Humans; Ovum; Povidone-Iodine; Soil; Specimen Handling; Trichuris
PubMed: 34908464
DOI: 10.1128/Spectrum.01828-21 -
British Journal of Cancer Aug 1981Cr(III) and Cr(VI) compounds of varying solubilities have been tested in vitro for their ability to inhibit cell growth and nucleic acid and protein syntheses in BHK... (Comparative Study)
Comparative Study
Cr(III) and Cr(VI) compounds of varying solubilities have been tested in vitro for their ability to inhibit cell growth and nucleic acid and protein syntheses in BHK cells, to induce alterations in the mitotic cycle in HEp cells, and to increase the frequency of chromosomal aberrations and sister chromatid exchanges (SCE) in CHO cells. All Cr(VI) compounds, and particularly those containing soluble Cr(VI), such as potassium dichromate and zinc yellow, differentially inhibit macromolecular syntheses in BKH cells, that of DNA being always the most affected. Among Cr(III) compounds, which generally have very low cytotoxicity, chromite is particularly active, and inhibits cell growth and DNA synthesis even more than the poorly soluble Cr(VI) compounds. Preincubation in growth medium, with or without metabolizing cell cultures, solubilizes considerable amounts of Cr(VI) from zinc yellow and chromite, but significant amounts are also obtained from the most insoluble Cr(VI) pigments. When BHK cells are treated with such preincubated solutions, reduction of soluble Cr(VI) to Cr(III) by cell metabolites is seen with all Cr(VI) compounds, accompanied by decreased cytotoxicity. The same differences between Cr(VI) and Cr(III) compounds apply to the cytotoxic effects on mitosis of HEp cells and the clastogenic effects on CHO cells. The activity of chromite, the only Cr(III) pigment capable of significantly increasing the frequency of SCE, is due to contamination with soluble Cr(VI). In contrast to the very low cytotoxicity of Cr(III), much higher chromium levels are detected in the cells incubated with soluble Cr(III) than with the same concentrations of soluble Cr(VI). 50% and 75% of chromium accumulated in the cells during treatments with Cr(VI) and Cr(III) respectively remains firmly bound to the cells, even when they are incubated for up to 48 h in normal growth medium. Chromium accumulated in the cells after treatment with Cr(III) is most probably bound to the cell membrane, whereas some of the Cr(VI) is transported through the cell membrane and reduced in the cell nucleus. The results of the present investigation are in agreement with those obtained with the same Cr(VI) and Cr(III) compounds in mutagenicity assays in bacteria and carcinogenicity tests in rodents. A re-evaluation of the mechanisms of chromium carcinogenisis is proposed.
Topics: Animals; Cell Division; Cell Line; Cell Survival; Chromium; Chromosome Aberrations; Cricetinae; Cricetulus; Crossing Over, Genetic; Epithelial Cells; Humans; Kidney; Mesocricetus; Mitosis; Sister Chromatid Exchange; Solubility; Structure-Activity Relationship
PubMed: 7272188
DOI: 10.1038/bjc.1981.173 -
PloS One 2017Pseudokirchneriella subcapitata is a sickle-shaped freshwater green microalga that is normally found in unicellular form. Currently, it is the best known and most...
Cell reproductive patterns in the green alga Pseudokirchneriella subcapitata (=Selenastrum capricornutum) and their variations under exposure to the typical toxicants potassium dichromate and 3,5-DCP.
Pseudokirchneriella subcapitata is a sickle-shaped freshwater green microalga that is normally found in unicellular form. Currently, it is the best known and most frequently used species of ecotoxicological bioindicator because of its high growth rate and sensitivity to toxicants. However, despite this organism's, our knowledge of its cell biology-for example, the patterns of nuclear and cytoplasmic division in the mitotic stage-is limited. Although it has been reported that P. subcapitata proliferates by popularity forming four daughter cells (autospores) through multiple fission after two nuclear divisions, here, we report two additional reproductive patterns by which two autospores are formed by binary fission ("two-autospore type") and eight autospores are formed by multiple fission ("eight-autospore type"). Moreover, we found that cell reproductive patterns differed markedly with the culture conditions or with exposure to either of two typical toxicants, potassium dichromate (K2Cr2O7) and 3,5-dichlorophenol (3,5-DCP). The eight-autospore type occurred at the highest frequency in the early phase of culture, but it disappeared under 3,5-DCP at 2.0 mg/L. Under 0.3 mg/L K2CrO7 (Cr(VI)) the eight-autospore type took substantially longer to appear than in control culture. The two-autospore type occurred only in the late phase of culture. To our knowledge, this is the first detailed evaluation of the reproductive patterns of P. subcapitata, which changed dramatically in the presence of toxicants. These findings suggest that observation of the reproductive patterns of P. subcapitata will help to elucidate different cell reactions to toxicants.
Topics: Cell Division; Cell Nucleus; Chlorophenols; Chlorophyta; Microscopy, Fluorescence; Phylogeny; Plastids; Potassium Dichromate; Reproduction
PubMed: 28152022
DOI: 10.1371/journal.pone.0171259 -
The Korean Journal of Parasitology Dec 2003The present study was undertaken to determine the viability and infectivity of oocysts of Cryptosporidium baileyi that had been stored from 1 to 40 months at 4 degrees C...
The present study was undertaken to determine the viability and infectivity of oocysts of Cryptosporidium baileyi that had been stored from 1 to 40 months at 4 degrees C preserved in 2.5% potassium dichromate solution. Oocysts of C. baileyi were purified from the feces of experimentally infected chickens using discontinuous sucrose gradients. Subsequently, the purified oocysts were suspended in 2.5% potassium dichromate solution at a concentration of 1 x 10(7) organism/ml, and their viabilities were assessed by nucleic acid staining, histologic examination, and infectivity to 2-day-old chickens. All chickens inoculated with oocysts that had been stored for 1-18 months developed patent infections, while chickens infected with older oocysts remained uninfected. Between 5.8% and 82.2% of the oocysts, stored at 4 degrees C in 2.5% potassium dichromate solution, were found to be viable, as determined by nucleic acid staining. Parasite colonization in the bursa of Fabricius was detected in the microvillus border of bursal epithelium. The finding that C. baileyi oocysts remain infective to chickens for at least 18 months offers important time-saving advantages to investigators who frequently require large numbers of oocysts.
Topics: Animals; Bursa of Fabricius; Chickens; Coloring Agents; Cryptosporidiosis; Cryptosporidium; Feces; Oocysts; Organic Chemicals; Potassium Dichromate; Poultry Diseases; Preservation, Biological; Staining and Labeling
PubMed: 14699260
DOI: 10.3347/kjp.2003.41.4.197 -
Acta Dermato-venereologica May 2001There is still some doubt about the reproducibility of patch tests. A sound assessment needs optimized and unbiased studies. This study analysed the results of a... (Clinical Trial)
Clinical Trial Randomized Controlled Trial
There is still some doubt about the reproducibility of patch tests. A sound assessment needs optimized and unbiased studies. This study analysed the results of a double-blind multicentre study with nickel sulfate and potassium dichromate patch tests attached synchronously to both sides of the back of patients with a history of nickel allergy, conducted with a highly standardized randomized test system (TRUE-test). Out of 589 patients tested, a total of 388 had responded with allergic reactions to nickel sulfate and 130 to potassium dichromate. The reproducibility of positive nickel (dichromate) patch tests was 99.2% (90.8%). The reaction index was also calculated, which relates the number of allergic reactions obtained with a test preparation to the number of questionable and irritant reactions; the reaction index can range from -1 (questionable and irritant reactions only occur) to 1 (allergic reactions only occur). For nickel sulfate the reaction index was 0.91, but it was only 0.23 for potassium dichromate, as a result of considerably more questionable reactions. In conclusion, a highly synchronous reproducibility of results can be achieved by using a well-standardized patch-test system, especially with nickel sulfate. However, distinct allergens and test systems need to be evaluated separately.
Topics: Adult; Coloring Agents; Double-Blind Method; Female; Humans; Hypersensitivity; Irritants; Male; Middle Aged; Nickel; Patch Tests; Potassium Dichromate; Reproducibility of Results
PubMed: 11501649
DOI: 10.1080/00015550152384263