The ten Berge model, also known as the toxic load model, is an empirical approach in hazard assessment modeling for estimating the relationship between the inhalation toxicity of a chemical and the exposure duration. The toxic load (TL) is normally expressed as a function of vapor concentration (C) and duration (t), with TL equaling C(n) × t being a typical form. Hypothetically, any combination...

Human activities have continuously increased the level of heavy metal ions circulating in the environment. It is important to understand the tolerance of plant species to high concentrations of heavy metals. Very little is known on the response of Eucalyptus species to Zn and Cu toxic concentrations Eucalyptus camaldulensis, E. microtheca, and E. occidentalis seeds were grown in silt and irriga...

Objective High concentration of iron and other trace elements could restrict bacterial growth and modify their metabolic pattern as well. However, this study aimed to find out the influence of iron, chromium, cadmium and synergism or antagonism between these elements on the growth of a gram positive bacterium. Materials and Methods In a series of experiments, Bucillus cereus was cultured in a n...

Biological reactions of individuals of a testing animal to toxic substance are unique and can be used as an indication of the existing of toxic substance. However, to distinguish such phenomenon need a very complicate system and even more complicate to analyze data in 3 dimensional. In this paper, a system to evaluate in vitro biological activities to acute toxicity of stochastic self-affine no...

Two novel crystal protein genes, cry30Ba and cry44Aa, were cloned from Bacillus thuringiensis subsp. entomocidus INA288 and expressed in an acrystalliferous strain. Cry44Aa crystals were highly toxic to second-instar Culex pipiens pallens (50% mortality concentration [LC50] = 6 ng/ml) and Aedes aegypti (LC50 = 12 ng/ml); however, Cry30Ba crystals were not toxic.

was found between digoxin dosage and plasma digoxin concentration. Patients who did not develop symptoms of digitalis intoxication until at high doses showed a slower increase ofplasma levels. At the first appearance of toxic symptoms 'steady state' values of about 6 ng digoxin/ml werefound. Excluding one divergent patient, a close inverse correlation wasfound between plasma digoxin concentrati...

The antibiotic vancomycin was effective in preventing bacterial contamination during studies with psittacosis and trachoma (PT) agents. This antibiotic was not toxic to chick embryos at 80 mg per egg, or to HeLa 229 cells cultivated in a medium containing 3,200 mug/ml of vancomycin; however, it was toxic to LLC-MK2 cells at a concentration of 1,600 mug/ml. Vancomycin did not affect the growth o...

The chemical basis for commercial production and purification of nitrous oxide is outlined and discussed. Nitric oxide is the most likely toxic contaminant but the concentration in the effluent gas from a cylinder diminishes rapidly due to fractionation. Nitric oxide reacts with oxygen but the velocity of the reaction is influenced by concentration and is very slow at concentrations below about...

A wide variety of toxic chemicals cause blebbing of the plasma membrane in isolated hepatocytes. These alterations in surface structure occur well before cell death. The formation of blebs appears to be directly related to changes in the concentration of extramitochondrial calcium ions. These changes probably reduce the ability of the hepatocyte cytoskeleton to maintain normal surface morpholog...

It has been suggested that elevated cytosolic free calcium plays a key role in acetaminophen-induced cell death. The present study has examined the effect of a toxic concentration of acetaminophen on cytosolic free calcium in single mouse hepatocytes, using the dye fura-2 and video imaging fluorescence microscopy. Cytosolic free calcium was calculated from the ratio of emitted fluorescence at g...