Chemical and physical mutagenesis has been used to increase genetic variability in crop plants. More than 430 new varieties have been derived as mutants of rice (Oryza sativa L.) via the application of different mutag...Chemical and physical mutagenesis has been used to increase genetic variability in crop plants. More than 430 new varieties have been derived as mutants of rice (Oryza sativa L.) via the application of different mutagenic agents. Chemical mutagens such as ethyl methane sulphonate (EMS), diepoxybutane-derived (DEB), sodium azide and irradiation (Gamma rays, X-rays and fast neutrons) have been widely used to induce a large number of functional variations in rice and others crops. Among chemical mutagens, the alkylating agent, ethyl methane sulfonate (EMS) is the most commonly used in plants as it causes a high frequency of nucleotide substitutions, as detected in different genomes. In this study, seeds of potential genotype of the popular variety, (Oryza sativa L. spp. Indica cv. MR219) were treated with EMS at concentrations of 0.25%, 0.50%, 0.75%, 1%, 1.25%, 1.5% and 2%. Sensitivity to EMS was determined by various measurements on the M1 generation. As concentration of applied EMS increased, will decrease in germination, seedling height, root length and emergence under field conditions was observed in M1 generation as compared to the non-treatment control. Plant height and root length also decreased with increases in EMS mutagenesis in an approximately linear fashion. The LD25 and LD50 values were observed based on growth reduction of seedlings after EMS treatment with 0.25% and 0.50% on the rice variety (Oryza sativa L. spp. Indica cv. MR219).展开更多
Fascioliasis is a parasitic disease of worldwide distribution affecting mainly cattle and sheep. Its importance lies in the economic losses it produces in the livestock industry. Its control is carried out by using a ...Fascioliasis is a parasitic disease of worldwide distribution affecting mainly cattle and sheep. Its importance lies in the economic losses it produces in the livestock industry. Its control is carried out by using a chemical fasciolicide showing resistance problems and environmental contamination. Looking for an alternative control for this disease the present study was aimed at determining the hexane anti-Fasciola hepatica in the in vitro effect of some plant extracts and the minimum lethal dose of the mentioned extracts. All selected plants were tested in vitro at concentrations of 500, 250, 125 and 50 mg/L):Achilleamillefolium (plumajillo), Artemisiaabsinthium (wormwood), Artemisia mexicana (estafiate), Castelatortuousa (chaparroamargo), Chenopodiumgraveolens (epazote de zorrillo), Gymnospermaglutinosum (popote) Justicia spicigera (muicle), Limpia critridora (cedron), Lippiagraveolens (oregano), Menthapiperita (Mint), Populus alba (alamo) and Thymusvulgaris (thyme). Subsequently proceeded to perform a toxicity study with these fractions in CD1 male mice 10-13 weeks of age, forming groups of 3-5 animals they were administered a single oral dose being (5 mg/kg, 50 mg/kg, 500 mg/kg, 2500 mg/kg and 5000 mg/kg) and were kept under observation 20 days, later were sacrificed and a kidney and liver histology was performed, finding the safety of the extracts. To perform the toxicity study with these fractions, groups of five CD1 male-mice were formed, they were treated with oral doses of 5, 50, 500, 2500 and 5000 mg/kg, administered with a cannule. All mice were kept under observation for 20 days. Finally they were sacrificed to perform histology of the kidney and liver in search of possible side effects. Results show that none of the extracts exhibited that fasciolocide activity for mice CD1 even at the highest dose thereforefinding the safety of the extracts.展开更多
Somina (herbal preparation) prepared by Hamdard Laboratories (Waqf) Pakistan is a mixture of five different medicinal plants, widely prescribed for the treatment of mental illness. For acute toxicity, the Karber arith...Somina (herbal preparation) prepared by Hamdard Laboratories (Waqf) Pakistan is a mixture of five different medicinal plants, widely prescribed for the treatment of mental illness. For acute toxicity, the Karber arithmetic method for the calculation of LD50 and Hodge and Sterner toxicity scale was used. In this study, different doses (10, 100, 285, 500, 1000, 5000 and 10,000 mg/kg) of the extract was administered orally to the different groups of rats and mice. Signs of toxicity and possible death of animals were monitored for 24 hrs to calculate the median lethal dose (LD50) of somina. At the end of the study, all the animals in all the dose groups were sacrificed and the internal organ-body was compared with values from the control group. The LD50 was found to be >10,000 mg/kg body weight upon oral administration in mice and rats as no mortality was observed after single dose administration. According to Hodge and Sterner toxicity scale, the obtained value of LD 50 > 10,000 mg/kg classified the Somina as Practically non-toxic herbal medicine.展开更多
The lethal dose LD<sub>50</sub> represents the most important experimental value for acute toxicity. The simple logarithmic calculation of -log<sub>10</sub> LD<sub>50</sub> = value ...The lethal dose LD<sub>50</sub> represents the most important experimental value for acute toxicity. The simple logarithmic calculation of -log<sub>10</sub> LD<sub>50</sub> = value leads to the possible poison power pLD. As with the pH or pK value, respectively, for acid or the scale of earthquake intensities the logarithm helps making large differences of orders of magnitude easier to understand since they are more comparable. The higher the pLD value, the higher is the power of poison. An increase of the pLD value by 1 stands for a tenfold increase in toxicity. The lethal acute dose for water, one of the most important and at the same time non-toxic substances of all, is about one tenth of the body weight. This leads to a possible pLD value for water of 1, an ideal starting value for a logarithmic poison scale.展开更多
In order to prevent severe pollution by de-icing salt on greenery along urban roads, a half lethal dose （LD_50）for a plant population was confirmed through stress simulation of chloride de-icing salt on Euonymus jap...In order to prevent severe pollution by de-icing salt on greenery along urban roads, a half lethal dose （LD_50）for a plant population was confirmed through stress simulation of chloride de-icing salt on Euonymus japonicus, with an ianalysis of physiological changes, statistics on mortality rate on plant populations and mathematic modeling during a 30- day subacute toxicity test. The results indicate that a significant positive correlation in the early stages and a significant negative correlation in the later stages were observed between the amount of chlorophyll a and b in plants and a cumulative dose of de-icing salt. The amounts of free proline in plants and the dose of de-icing salt were positively correlated Over the entire period. No significant correlation in the initial stage, but a significant negative correlation in later stages was observed between the soluble protein and the dose of de-icing salt. LDs0 of this chloride agent on E. japonicus is 5 kg.（L·m2）-1 over 30 days.展开更多
Dose-response studies in arthropod research usually involve observing and collecting successive information at different times on the same group of insects exposed to different concentrations of stimulus. When the sam...Dose-response studies in arthropod research usually involve observing and collecting successive information at different times on the same group of insects exposed to different concentrations of stimulus. When the same measure is collected repeatedly over time, the data become correlated and Probit Analysis technique which is the standard method in analyzing bioassay experiments data cannot be used. Lethal time is estimated when the speed of kill is of interest since mortality varies over time. We evaluate a complementary approach, repeated measures logistic regression using Generalized Estimating Equations (GEE), for lethal time determination in mosquito dose response. Mortality data from anopheles larva exposed to 3 botanical extracts (B,C,E) at 4 concentration levels: 500 mg/ml, 250 mg/ml, 50 mg/ml and 12.5 mg/ml were used. The result shows the estimated LT50 values with concentration 500 mg/ml being the most virulent chemical for extract B (LT50 = 10.3 hrs), C (LT50 = 7.2 hrs) and E (LT50 = 10.3 hrs). The least virulent chemical was concentration 12.5 mg/ml for extract B (LT50 = 52.1 hrs), C (LT50 = 70.7 hrs) and E (LT50 = 55.0 hrs). We conclude that repeated measures of logistic regression via GEE can be used as a tool to estimate LT50 more effectively in repeated measures of arthropod data.展开更多
The Gompertz model is the long-time well-known mathematical model of exponential expression among mortality models in the literature that are used to describe mortality and survival data of a population. The death rat...The Gompertz model is the long-time well-known mathematical model of exponential expression among mortality models in the literature that are used to describe mortality and survival data of a population. The death rate of the “probacent” model developed by the author based on animal experiments, clinical applications and mathematical reasoning was applied to predict age-specific death rates in the US elderly population, 2001, and to express a relationship among dose rate, duration of exposure and mortality probability in total body irradiation in humans. The results of both studies revealed a remarkable agreement between “probacent”-formula-predicted and published-reported values of death rates in the US elderly population or mortality probabilities in total body irradiation in humans (p - value > 0.995 in χ2 test in each study). In this study, both the Gompertz and “probacent” models are applied to the Sacher’s comprehensive experimental data on survival times of mice daily exposed to various doses of total body irradiation until death occurs with an assumption that each of both models is applicable to the data. The purpose of this study is to construct general formulas expressing relationship between dose rate and survival time in total body irradiation in mice. In addition, it is attempted to test which model better fits the reported data. The results of the comparative study revealed that the “probacent” model not only fit the Sacher’s reported data but also remarkably better fit the reported data than the Gompertz model. The “probacent” model might be hopefully helpful in research in human tolerance to low dose rates for long durations of exposure in total body irradiation, and further in research in a variety of biomedical phenomena.展开更多
文摘Chemical and physical mutagenesis has been used to increase genetic variability in crop plants. More than 430 new varieties have been derived as mutants of rice (Oryza sativa L.) via the application of different mutagenic agents. Chemical mutagens such as ethyl methane sulphonate (EMS), diepoxybutane-derived (DEB), sodium azide and irradiation (Gamma rays, X-rays and fast neutrons) have been widely used to induce a large number of functional variations in rice and others crops. Among chemical mutagens, the alkylating agent, ethyl methane sulfonate (EMS) is the most commonly used in plants as it causes a high frequency of nucleotide substitutions, as detected in different genomes. In this study, seeds of potential genotype of the popular variety, (Oryza sativa L. spp. Indica cv. MR219) were treated with EMS at concentrations of 0.25%, 0.50%, 0.75%, 1%, 1.25%, 1.5% and 2%. Sensitivity to EMS was determined by various measurements on the M1 generation. As concentration of applied EMS increased, will decrease in germination, seedling height, root length and emergence under field conditions was observed in M1 generation as compared to the non-treatment control. Plant height and root length also decreased with increases in EMS mutagenesis in an approximately linear fashion. The LD25 and LD50 values were observed based on growth reduction of seedlings after EMS treatment with 0.25% and 0.50% on the rice variety (Oryza sativa L. spp. Indica cv. MR219).
文摘Fascioliasis is a parasitic disease of worldwide distribution affecting mainly cattle and sheep. Its importance lies in the economic losses it produces in the livestock industry. Its control is carried out by using a chemical fasciolicide showing resistance problems and environmental contamination. Looking for an alternative control for this disease the present study was aimed at determining the hexane anti-Fasciola hepatica in the in vitro effect of some plant extracts and the minimum lethal dose of the mentioned extracts. All selected plants were tested in vitro at concentrations of 500, 250, 125 and 50 mg/L):Achilleamillefolium (plumajillo), Artemisiaabsinthium (wormwood), Artemisia mexicana (estafiate), Castelatortuousa (chaparroamargo), Chenopodiumgraveolens (epazote de zorrillo), Gymnospermaglutinosum (popote) Justicia spicigera (muicle), Limpia critridora (cedron), Lippiagraveolens (oregano), Menthapiperita (Mint), Populus alba (alamo) and Thymusvulgaris (thyme). Subsequently proceeded to perform a toxicity study with these fractions in CD1 male mice 10-13 weeks of age, forming groups of 3-5 animals they were administered a single oral dose being (5 mg/kg, 50 mg/kg, 500 mg/kg, 2500 mg/kg and 5000 mg/kg) and were kept under observation 20 days, later were sacrificed and a kidney and liver histology was performed, finding the safety of the extracts. To perform the toxicity study with these fractions, groups of five CD1 male-mice were formed, they were treated with oral doses of 5, 50, 500, 2500 and 5000 mg/kg, administered with a cannule. All mice were kept under observation for 20 days. Finally they were sacrificed to perform histology of the kidney and liver in search of possible side effects. Results show that none of the extracts exhibited that fasciolocide activity for mice CD1 even at the highest dose thereforefinding the safety of the extracts.
文摘Somina (herbal preparation) prepared by Hamdard Laboratories (Waqf) Pakistan is a mixture of five different medicinal plants, widely prescribed for the treatment of mental illness. For acute toxicity, the Karber arithmetic method for the calculation of LD50 and Hodge and Sterner toxicity scale was used. In this study, different doses (10, 100, 285, 500, 1000, 5000 and 10,000 mg/kg) of the extract was administered orally to the different groups of rats and mice. Signs of toxicity and possible death of animals were monitored for 24 hrs to calculate the median lethal dose (LD50) of somina. At the end of the study, all the animals in all the dose groups were sacrificed and the internal organ-body was compared with values from the control group. The LD50 was found to be >10,000 mg/kg body weight upon oral administration in mice and rats as no mortality was observed after single dose administration. According to Hodge and Sterner toxicity scale, the obtained value of LD 50 > 10,000 mg/kg classified the Somina as Practically non-toxic herbal medicine.
文摘The lethal dose LD<sub>50</sub> represents the most important experimental value for acute toxicity. The simple logarithmic calculation of -log<sub>10</sub> LD<sub>50</sub> = value leads to the possible poison power pLD. As with the pH or pK value, respectively, for acid or the scale of earthquake intensities the logarithm helps making large differences of orders of magnitude easier to understand since they are more comparable. The higher the pLD value, the higher is the power of poison. An increase of the pLD value by 1 stands for a tenfold increase in toxicity. The lethal acute dose for water, one of the most important and at the same time non-toxic substances of all, is about one tenth of the body weight. This leads to a possible pLD value for water of 1, an ideal starting value for a logarithmic poison scale.
基金financially supported by the Science Innovation Project of Beijing Forestry University (No. 101305)the 985 Innovation Platform, China
文摘In order to prevent severe pollution by de-icing salt on greenery along urban roads, a half lethal dose （LD_50）for a plant population was confirmed through stress simulation of chloride de-icing salt on Euonymus japonicus, with an ianalysis of physiological changes, statistics on mortality rate on plant populations and mathematic modeling during a 30- day subacute toxicity test. The results indicate that a significant positive correlation in the early stages and a significant negative correlation in the later stages were observed between the amount of chlorophyll a and b in plants and a cumulative dose of de-icing salt. The amounts of free proline in plants and the dose of de-icing salt were positively correlated Over the entire period. No significant correlation in the initial stage, but a significant negative correlation in later stages was observed between the soluble protein and the dose of de-icing salt. LDs0 of this chloride agent on E. japonicus is 5 kg.（L·m2）-1 over 30 days.
文摘Dose-response studies in arthropod research usually involve observing and collecting successive information at different times on the same group of insects exposed to different concentrations of stimulus. When the same measure is collected repeatedly over time, the data become correlated and Probit Analysis technique which is the standard method in analyzing bioassay experiments data cannot be used. Lethal time is estimated when the speed of kill is of interest since mortality varies over time. We evaluate a complementary approach, repeated measures logistic regression using Generalized Estimating Equations (GEE), for lethal time determination in mosquito dose response. Mortality data from anopheles larva exposed to 3 botanical extracts (B,C,E) at 4 concentration levels: 500 mg/ml, 250 mg/ml, 50 mg/ml and 12.5 mg/ml were used. The result shows the estimated LT50 values with concentration 500 mg/ml being the most virulent chemical for extract B (LT50 = 10.3 hrs), C (LT50 = 7.2 hrs) and E (LT50 = 10.3 hrs). The least virulent chemical was concentration 12.5 mg/ml for extract B (LT50 = 52.1 hrs), C (LT50 = 70.7 hrs) and E (LT50 = 55.0 hrs). We conclude that repeated measures of logistic regression via GEE can be used as a tool to estimate LT50 more effectively in repeated measures of arthropod data.
文摘The Gompertz model is the long-time well-known mathematical model of exponential expression among mortality models in the literature that are used to describe mortality and survival data of a population. The death rate of the “probacent” model developed by the author based on animal experiments, clinical applications and mathematical reasoning was applied to predict age-specific death rates in the US elderly population, 2001, and to express a relationship among dose rate, duration of exposure and mortality probability in total body irradiation in humans. The results of both studies revealed a remarkable agreement between “probacent”-formula-predicted and published-reported values of death rates in the US elderly population or mortality probabilities in total body irradiation in humans (p - value > 0.995 in χ2 test in each study). In this study, both the Gompertz and “probacent” models are applied to the Sacher’s comprehensive experimental data on survival times of mice daily exposed to various doses of total body irradiation until death occurs with an assumption that each of both models is applicable to the data. The purpose of this study is to construct general formulas expressing relationship between dose rate and survival time in total body irradiation in mice. In addition, it is attempted to test which model better fits the reported data. The results of the comparative study revealed that the “probacent” model not only fit the Sacher’s reported data but also remarkably better fit the reported data than the Gompertz model. The “probacent” model might be hopefully helpful in research in human tolerance to low dose rates for long durations of exposure in total body irradiation, and further in research in a variety of biomedical phenomena.
