DNA damage and repair detected by the comet assay in lymphocytes of african petrol attendants: a pilot study.

Petrol attendants are exposed to petrol volatile organic compounds (VOCs) which may have genotoxic and carcinogenic effects. The single-cell gel electrophoresis assay (comet assay) is a method highly sensitive to DNA damage induced by environmental and occupational exposure to carcinogenic and mutagenic agents. The aim of this study was to evaluate the level of exposure of petrol attendants to petrol VOCs and also to determine their effect on DNA damage and repair in lymphocytes of African petrol attendants. The exposed group consisted of 20 subjects, randomly selected from three petrol stations. A control group of 20 unexposed subjects was also chosen and matched for age and smoking habits with the exposed group. Sorbent tubes were used to assess personal exposure of petrol attendants. The comet assay was used to investigate the basal DNA damage and repair capacity in isolated lymphocytes of petrol attendants and unexposed subjects. Blood samples were taken from the petrol attendants at the end of their 8-h working shift and also from the unexposed subjects. The petrol attendants were found to be exposed to levels of petrol VOCs lower than the South African occupational exposure limit for constituent chemicals. A significant relationship was found between the volume of petrol sold during the shift and the average concentrations of benzene, toluene and the total VOCs measured. However, relative humidity had a negative correlation with the average concentrations of benzene, toluene, xylene and the total VOCs. Significantly higher basal DNA damage was observed with the exposed group compared to the unexposed group. The period of exposure influenced the level of DNA damage and the calculated repair capacity. Smoking and age had a significant influence on the level of DNA damage. DNA repair capacity was delayed in smokers of both exposed and unexposed group.

Dermal exposure sampling methods: an overview

Although a total of 174 and 117 substances have been listed with a skin (Sk) notation in the Regulations for Hazardous Chemical Substances and Regulation 22.9 of the Mine Health and Safety Act respectively; dermal sampling is not used frequently to assess exposure to these substances. A variety of measurement methods and strategies have been developed during the past forty years to assess dermal exposure. These methods include interception methods (also referred to as surrogate skin methods); removal of contaminant (substance) methods and in situ detection methods (also referred to as fluorescent tracer methods). The aim of this paper is to give an overview of the different dermal sampling methods. Furthermore; the applicability of each method for sampling different hazardous chemical substances will be highlighted in order to assist Occupational Hygienists in choosing the correct dermal sampling method

Screening of the venoms of two Parabuthus scorpion species on isolated cardiomyocytes.

Crude, diluted venoms of Parabuthus transvaalicus and P. granulatus were tested on isolated cardiomyocytes. Ventricular myocytes were subjected to hypercontractility tests and whole-cell voltage clamp. Both venoms had a profound influence on the hypercontractility of cardiomyocytes, which was markedly decreased when they were pre-absorbed with commercial antiserum. Whole-cell clamp results showed an increase in the sodium current, and a retardation of the time course of inactivation, implicating the presence of an alpha toxin in both venoms.

The haemodynamic correlations of the cardiopulmonary flow index, a relatively non-invasive technique for diagnosis of myocardial pump insufficiency.

The cardiopulmonary flow index (CPFI) is the ratio of cardiopulmonary blood volume to stroke volume. OBJECTIVE. To compare the CPFI derived from a first-pass radiocardiogram and electrocardiogram with the usual haemodynamic measurements obtained by bedside catheterisation. DESIGN. Sixty-one patients in a coronary care unit who had flow-directed pulmonary artery catheterisation for clinical indications had a CPFI recorded together with the usual haemodynamic measurements and calculations. RESULTS. In patients with myocardial pump failure without significant pulmonary disease, linear regression analysis indicated that the best fit for the CPFI could be obtained with a model that used the inverse of stroke index and pulmonary capillary wedge pressure as independent variables. Ninety-six per cent of the variation in CPFI can be explained by variations in pulmonary capillary wedge pressure and stroke index. The CPFI correlated less well with these variables in patients with concomitant lung disease. CONCLUSION. The CPFI is a potentially useful and relatively non-invasive index of haemodynamic function in acutely ill patients without significant pulmonary disease.

The ratio of cardiopulmonary blood volume to stroke volume as an index of cardiac function in horses.

A method was developed for determining the ratio of cardiopulmonary blood volume to stroke volume, in horses. The radioisotope 99 Tc (technetium 99m pertechnetate) was injected into the jugular vein as a bolus, which was then detected in the right and left ventricles consecutively by a scanning device consisting of a Na I crystal, a collimator, an amplifier and a discriminator. The radiocardiogram (RCG) and the ECG were recorded simultaneously by a two-channel writing device. The ratio of cardiopulmonary blood volume to stroke volume (cardiopulmonary flow index = CPFI) was then determined from the RCG and ECG tracings. Five categories of horses were examined, viz. Thoroughbreds in training, showjumpers in training, horses not in training, horses with cardiovascular disease and horses with chronic lung disease. The mean CPFI of the above categories were respectively 7.0 +/- 0.39, 7.3 +/- 0.45, 6.7 +/- 0.61, 9.8 +/- 1.30 and 6.2 +/- 0.47. The mean CPFI of the subjects with heart disease was significantly greater than the mean values of the other four categories (P less than 0.001). It was concluded that the CPFI was a reproducible physiological parameter in horses and that the value was significantly increased in our series of subjects with heart disease.

Ratio of cardiopulmonary blood volume to stroke volume as an index of cardiac function in animals in man.

A scintillation probe was used to record a radiocardiogram as 99mTc flowed through the heart with the first pass after an intravenous injection. The ratio of cardiopulmonary blood volume to stroke volume, which could be determined indirectly from the simultaneous recording of a radiocardiogram and an electrocardiogram, was found to be a very sensitive and reliable index to describe the efficiency of the pump function of the heart with the different models of heart disease induced in experimental animals. It was found that left ventricular, right ventricular and biventricular failures were reflected by a large increase and pulmonary emboli by a decrease in the value of this index, which was named the cardiopulmonary flow index (CPFI). The technique has also been tested on a number of control and heart patients. The general principles found for animals could also be applied to man. As this is a noninvasive bedside technique it may have an important implication for the diagnosis of heart disease.