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Biomedical subjects

R Mauermayer

Publications and source records attributed to R Mauermayer.

6 recordsLinked to original sources

Changes in lung function after working with the shotcrete lining method under compressed air conditions.

Shotcrete techniques under compressed air are increasingly applied in the construction of tunnels. Up to now little is known about the influence of shotcrete dusts on the function of the lung. The lung function of 30 miners working with shotcrete under compressed air (before and after one shift) was measured. They carried personal air samplers to assess the total dust exposure. Long term effects were studied on a second group of 29 individuals exposed to shotcrete dusts and compressed air for two years. A significant increase of airway resistance and a significant decrease of some flow-volume parameters were found after one workshift. These changes partially correlate close to the dust exposure. After two years exposure a significant decrease of mean expiratory flow (MEF)50 and MEF25 was found. These results point to damage in the small airways and emphasise the major role of the lung function test--including the flow-volume manoeuvre for the medical examination of the workers. Additionally, they should carry filter masks.

Adult↗

[The cadmium content of human tissues from biopsies].

The level of cadmium (cd) concentration was determined in organs of 130 men and women. This study was conducted on living human beings who, in their occupation, haven't had extraordinary cd-exposure. Samples of tissues taken during operation were evaluated as well as urine samples (24 hours specimen), blood, an extended patient history including occupation and the postoperative diagnosis. The average cd-concentration was means = 27.3 +/- 29.7 micrograms/g wet weight in kidney cortex, 9.3 +/- 11.7 micrograms/g in kidney medulla, 1.1 +/- 0.5 micrograms/g in liver, 2.9 +/- 2.5 micrograms/l in blood and 2.6 +/- 2.9 micrograms/l in urine. Concentrations in 7 other tissues were measured. The critical cd-level for liver and kidney was not reached in any case. Cd-concentration is related to age and cigarette smoking, not to the sex of the person. It is quite impossible to make a precise estimation on the kidney load from blood or urine level of an individual patient. Differences in cd-load between patients with cancer and those without are discussed. A synopsis of international studies shows that results achieved through various methods, radiological cd-measurement, autopsies and our biopsies were comparatively the same.

Adolescent↗

Inhibition of acetylcholinesterase by diisocyanates and its spontaneous reactivation.

The inhibition of human acetylcholinesterase (AchE) by 4,4'-diphenylmethane diisocyanate (MDI) is determined and compared with the previously described inhibition of this enzyme by two other industrially used diisocyanates: toluene diisocyanate (TDI) and hexamethylene diisocyanate (HDI). The inhibition potency of these three diisocyanates is found to be in the oder HDI greater than TDI greater than MDI. The spontaneous reactivation of inhibited AchE is reanalysed with the help of a computer program designed to fit the reactivation data to the exponential rate equation Vt = Vinf (1 - e-Kobs X (t - to) ). The enzyme inhibited by HDI and MDI undergoes very slow and limited spontaneous reactivation. The rate of delivery of diisocyanates into the respiratory tract of an exposed worker may be faster than the rate of spontaneous reactivation of the inhibited enzyme. These results are discussed in connection with the obstructive lung disease observed in approximately 5% of the workers employed in the isocyanate industry.

Acetylcholinesterase↗