[en] A study of the effects of dehydration, atropine, terbutaline and N-acetylcysteine on canine tracheobronchial mucus is presented. Mucociliary clearance rates, mucus secretion volumes and mucus rheologic properties were studied. Clearance rates were studied by a radioisotope technique mucus collected by a canine Tracheal pouch method and rheologic studies performed on a microrheometer. Clearance rate was unaffected by dehydration and terbutaline, increased by N-acetylcysteine and decreased by atropine. Secretion volume was increased by terbutaline while dehydration and atropine were without effect. Rheologic factors were increased by dehydration and atropine while terbutaline was without an effect. The effects of N-acetylcysteine on secretion volume and rheologic properties could not be studied because of the nature of the techniques employed

[en] Tracheal mucociliary clearance studies, mucus collections, and rheologic studies were performed on a weekly basis in 7 adult purebred beagles in an attempt to correlate clearance rate with rheology of mucus. Clearance rates were determined by a percutaneous transtracheal, radioisotope injection technique. Mucus was collected from dogs equipped with a tracheal pouch, and rheologic determinations were performed on a dynamic microrheometer. Individual analysis of data for each dog failed to reveal any significant relationship between clearance rate and any parameter of elasticity or viscosity. However, when data from all 7 dogs were pooled, covering a much wider range of the measured variables, it was seen that as the elastic modulus increased, the rate of clearance decreased. The mucociliary clearance rate was halved by an approximate ten-fold increase in elastic modulus of mucus

[en] Brief item

[en] The authors used in situ hybridization of repeat-sequence DNA probes, specific to the paracentromeric locus 1q12 and telomeric locus 1p36, to fluorescently stain regions that flank human chromosome 1p. This procedure was used for fast detection of structural aberrations involving human chromosome 1p in two separate experiments: 1) human lymphocytes were irradiated with 0, 0.8, 1.6, 2.4 and 3.2 Gy of ¹³⁷Cs γ-rays; 2) human lymphocytes were irradiated with 0, 0.09, 0.18, 2.0, 3.1 and 4.1 Gy of ⁶⁰Co γ-rays. Frequencies of translocations and dicentrics increased with dose, D, in a linear-quadratic manner. The δ, α and β coefficients resulting from a fit of the equation f(D)=δ+αD+βD² to the translocation frequency dose-response data were 0.0025, 0.0027 and 0.0037 for ¹³⁷Cs γ-rays, and 0.0010, 0.0041, and 0.0057 for ⁶⁰Co ''gamma-rays. The δ, α and β coefficients resulting from a fit to dicentric frequency dose-response data were 0.0005, 0.0010 and 0.0028 for ¹³⁷Cs γ-rays and 0.0001, 0.0002 and 0.0035, for ⁶⁰Co γ-rays. Approximately 32,000 metaphase spreads were scored. Average analysis rate was over two metaphase spreads per minute. (author)