Study of fifteen respirable aerosol samplers used in occupational hygiene.

European and international standards lay down criteria for the size-selective aerosol sampling in occupational hygiene. Aerosol samplers are supposed to match these target sampling criteria. This study focused on 15 aerosol samplers used to sample the conventional respirable fraction. An aerodynamic particle sizer (APS) method was used to measure the sampling efficiency of the samplers in a low-velocity wind tunnel. Polydisperse coal dust was generated as the test aerosol. The data were fitted by an appropriate mathematical model. For some instruments the results show serious deviations from the conventional target curve, whereas other devices meet the convention quite well. The flow rate of certain cyclone-separator-based instruments was optimized to adjust their sampling efficiency. The mass concentration bias and accuracy of the samplers were calculated for a number of ranges of particle size distributions of aerosols commonly found in industrial workplaces. Finally, the performance of each sampler was evaluated using bias and accuracy maps. Most of these samplers are suitable for sampling the CEN-ISO-ACGIH respirable fraction of aerosols, but several require modification of the flow rate. For real industrial situations, the rough knowledge of the aerosol size distribution can guide the choice of an appropriate sampling technique.

[Abdominal obesity and cardiovascular risk in type 2 diabetics]. / Abdominální obezita a kardiovaskulární rizika diabetiku 2. typu.

A group of 247 middle-aged men and women with diabetes lasting mostly for less than 5 years, treated by diet alone and oral antidiabetics resp. is followed up in the surgeries of nine general practitioners, with special attention to early detection and prevention of macroangiopathies. In the submitted paper the authors focus their attention on the body build of patients and the importance of assessment of abdominal adipose tissue by available anthropometric methods. The patients were obese, mostly with abdominal accumulation of adipose tissue. As to indicators of abdominal obesity in particular the waist circumference and waist/hip ratio proved useful as they correlated significantly with insulin secretion assessed by C peptide, triacylglycerols, HDL-cholesterol, blood pressure, with ECG signs of ischaemia and a reduced blood flow in the lower limbs, evaluated from the ankle indexes (ABP). Determining factors for the waist circumference included the C peptide concentration, ABP index, HDL-cholesterol level and treatment of hypertension. With regard to the relatively high incidence of subclinical signs of vascular injury in these diabetics the authors draw attention to the practical impact of the demonstrated correlations between waist circumference and risk factors of atherosclerosis which is a threat for insulinresistant diabetics already at the time of is onset.

[Serum lysozyme and copper levels in rats after the administration of dust]. / Obsah lyzozýmu a medi v sérech potkanu po podání prachu.

Changes in the content of lysozyme and copper were studied in the blood serum of rats in four time intervals (1, 2, 12, and 24 weeks) after administration of 50 mg TiO2, Sio2 or coal dust and the copper content was also studied 12 weeks after administration of 3 industrial dusts. The obtained results were supplemented by histopathological examinations and in the 12-week interval by the determination of the lung wet weight. The lysozyme content was statistically significantly increased compared to controls practically over the whole time course with differences in the level of the response to SiO2 in comparison with the response to TiO2 and coal. With the exception of the first interval, the serum copper level was statistically significantly increased only after quartz dust administration. The obtained results were compared with literary data and findings reported from clinical practice.

The use of the DENTACRYL rapid (Spofa) resin for preparation of the rat tracheobronchial casts.

We have made tracheobronchial casts of the rat lungs using DENTACRYL Rapid (Spofa)--the synthetic methacrylic resin of Czechoslovak origin. The details of the method are fully described. The differences between preparations of the intact rat tracheobronchial trees and those of the rats after quartz instillation are illustrated. These differences are analogous to the commonly described changes in bronchograms.

Alkaline phosphatase activity in relation to LDH5 (L-lactate: NAD+ - oxidoreductase, E.C.1.1.1.27) in patients with precancerous conditions of the endometrium.

We investigated the serum activity of the fifth fraction of L-lactate: NAD-oxidoreductase (E.C.1.1.1.27) and serum alkaline phosphatase activity prior to diagnostic curettage in patients with abnormal and atypical endomertial hyperplasia. We also determined them in 75 patients with carcinoma of the endometrium, 80 patients with glandular cystic endometrial hyperplasia and a "normal" control group of 70 patients. In the statistical evaluation we found a significantly high incidence of low AP activity and elevated LDH5 in the group of patients with glandular cystic endometrial hyperplasia, as well as in patients with precancerous lesions of the endometrium and carcinoma of the endometrium. The findings raise the question of whether these changes in the serum activity of the given enzymes are only a response to a given hormonal modulation.