Collaborative Study of Thresholds for Mutagens: Hormetic Responses in Cell Proliferation Tests Using Human and Murine Lymphoid Cells

Background: We previously showed that hormetic responses can be established in cell activity tests using human and murine adherent cells. This time, we examined whether hormetic responses can be established in cell proliferation tests using suspended human and murine lymphoid cells. Methods: Human lymphoblastoid cells (TK6) and mouse lymphoma cells (L5178Y) were cultured in multi-well culture plates and treated with mitomycin C, ethyl methansulfonate, hygromycin B, aclarubicin or colchicine at various dose levels and the number of cells was measured at varied times using a flow cytometer. Results: When the ratio of the number of cells treated with a test chemical to those in the negative control was plotted, the dose-response relationship typically showed a reverse U-shaped curve, indicating the occurrence of hormesis and existence of thresholds in cell toxicity. The hormetic responses depended largely on the test chemical, dose level and exposure time. When examining responses over the course of time, a J-shaped or fallen S-shaped curve was also observed. Conclusions: The dose-response relationship showed a reverse U-shaped curve, a hallmark of hormesis, at least some time points for all chemicals tested here, indicating that chemical hormesis can be established in in vitro cell proliferation tests.

Rheological Modification for Asphaltic Materials Using a Mixture (Poly carbonate: Poly Methyl Methacrylate) and Microwave Radiation

Obtaining asphalt that suits the nature of the countries it is used in, is of great importance. Asphalt constitutes an important component in the paving of roads, mastic and flattening substance. This study was included the modification of the asphaltic material by the use of a mixture of polycarbonate and polymethyl methacrylate after crushed to obtain low molecular weight. The study included two paths: In the first asphaltic materials was treated with different percentages of a mixture in the presence of anhydrous aluminium chloride (0.06%of weight) as a catalyst for this reaction. The mixture was heated at 150° for 30 minutes. In the second path, the process of mixing was performed with the existence of a 360 watt microwave radiation for 15 minutes. The process of mixing was repeated in the presence of sulphur (1% of weight) instead of anhydrous aluminium chloride and under the same conditions. Properties of the original and modified asphalts were determined, and this included the measurement of ductility, penetration, softening point, penetration index and calculating the percentage of separated asphaltenes. Additionally, Marshal test, chemical Immersion test and aging were measured for some of the samples. Good samples that can suit Iraq's climate were obtained from this study.

Residues of antibiotics in milk: persistence and quality interference

The objective of this study was (i) to analyze antibiotic residues, two which were beta-lactam antibiotics, one tetracycline, and one quinolone in the milk of lactating animals; (ii) to evaluate the interference of the drug ceftiofur which is considered as discard-zero. The SNAPduo™ ST Plus kit was used to evaluate the presence of beta-lactam antibiotics and tetracyclines in natural milk. Medications based on penicillin, ceftiofur, enrofloxacin, and oxytetracycline were used. As expected, the milk from control animals and animals administered with enrofloxacin did not present antibiotic residue because it is not one of the classes detected by the SNAPduo™ ST Plus kit, and thus it was used to prove the efficiency of the test. Ceftiofur, known as a “discard-zero” antibiotic, tested positive for the SNAPduo™ ST Plus kit and the BetaStar Combo® “S” test. Chemical residues were detected in cow’s milk treated with different groups of antibiotics after the withdrawal time indicated in the package inserts of the medicines used.

Development of bacteriophage agent for soyean bacterial blight control

There is a description for the method for development of bacteriophage agent to control bacterial blight of soybean caused by Pseudomonas savastanoi pv. glycinea. Biological effectiveness of bacteriophage application was about 75% that was approximately the same as for test chemical bactericides.

Statistical treatment of cytotoxicity in Ames bacterial reverse mutation assays can provide additional structure–activity relationship information

The bacterial reverse mutation assay, that is, the Ames test, measures mutations that reverse the inactivation of a gene involved in the synthesis of either histidine in Salmonella bacteria or tryptophan in Escherichia coli. The classic dose–response curve of an Ames assay plots number of reverse mutations (“revertants”) on the y-axis versus dose of the test chemical on the x-axis. Frequently, the dose–response curve resembles a parabola with a linear initial slope resulting from the accumulation of mutations, which transitions to a downward curvature resulting from cell killing (cytotoxicity) at increasingly higher doses of the test chemical. For regulatory purposes, a positive Ames test is usually considered as induction of twice the number of reverse mutations above background levels. For research purposes, the potency of the mutagenic response can be calculated from measuring the initial slope of the mutagenic response. This initial slope can be calculated in a manner that disentangles the downward pull on the initial slope value provided by the initiation of cytotoxicity. For a dose–response curve resembling a parabola, both the initial positive slope representing mutagenicity and the secondary negative slope representing cytotoxicity can be calculated from the same dose–response curve. The Ames test is the most commonly conducted genotoxicity assay. When a series of molecular congeners are assayed in the Ames test for mutagenicity, additional consideration of the cytotoxicity can provide important structure–activity relationship information.

Statistical approach for …a test chemical is considered to be positive… in regulatory toxicology: Trend and pairwise tests

In regulatory toxicology an outcome is claimed positive when both a trend is significant and any pairwise test against control. Two statistical approaches are proposed: a joint Dunnett and Williams test (assuming the dose as a qualitative factor) and a joint test of the Tukey regression test and Dunnett test (assuming the dose as a quantitative covariate). Related R software is available.

KARAKTERISTIK KIMIA DAN ORGANOLEPTIK PRODUK STIK DENGAN SUBSTITUSI DAGING IKAN GABUS (Channa striata)

ABSTRACT The aim of this study was to determine the effect of fish meat substitution on organoleptic and chemical compound of stick product. This study used a Randomized Complete Design (RCD) consist of four treatments such as P0 as control (0% fish meat : 100% wheat flour); P1 (30% fish meat : 70% wheat flour); P2 (40% fish meat : 60% wheat flour); P3 (50% fish meat : 50% wheat flour). Result showed that the highest value on sensory analysis was P3 with rather good category. The highest value of sensory analysis was P3, including colour (yellow-brownish), aroma (fishy), chrunciness (crunchy) and juiciness (very juicy). The highest value of protein and carbohydrate compound was P3 39.13% and 71.56% respectively. Keywords: Crackers, mackerel scad fish (Decapterus spp.), seaweed (E. cottoni), organoleptic test, chemical testABSTRAKPenelitian ini bertujuan untuk mempelajari pengaruh substitusi daging ikan terhadap nilai organoleptik dan komposisi kimia produk stik. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) yang terdiri dari empat perlakuan yaitu P0 (kontrol) (0% daging ikan: tepung terigu 100%), P1 (daging ikan 30% : tepung terigu 70%), P2 (daging ikan 40% : tepung terigu 60%) dan P3 (daging ikan 50% : tepung terigu 50%). Berdasarkan hasil penelitian produk stik yang disubstitusikan dengan daging ikan gabus diperoleh perlakuan tertinggi uji sensorik diperoleh pada perlakuan P3 dengan penilain panelis yang cukup baik. Rerata uji sensorik tertinggi terdapat pada perlakuan P3 meliputi warna (kuning kecoklatan), aroma (beraroma ikan), rasa (terasa ikan), kerenyahan (renyah), dan rasa gurih (sangat gurih). Komposisi kimia protein dan karbohidrat tertinggi pada produk stik ditemukan pada perlakuan P3 masing-masing sebesar 39,13 dan 71,56%.Kata kunci: Eucheuma cottonii, Ikan layang (Decapterus spp), Kerupuk, uji organoleptik, uji kimia