Autoradiographische Untersuchungen zur Zellneubildungsrate an den Epithelien des oberen Respirations- und Verdauungstraktes

Radioautographic study of human pulmonary tissues

“…The percentage of labelled human bronchiolar epithelium was small and was completely in the range of that of mice and rats as determined in vivo by several independent investigators (Blenkin-sopp, 1967; Edwards and Klein, 1961;Koburg, 1962;Shorter, Titus, andDivertie, 1964, 1966). Because all our adult material was collected from 9 a.m. to 3 p.m. we believe that diurnal variation in the labelling index did not greatly influence our results.…”

“…The life cycle of bronchial epithelium is of critical importance to studies of bronchial carcinogenesis. The range of uptake of tritiated thymidine in vivo 4i varied from 04% to 1.9% in the large bronchi and from 0-2% to 1 -0% in the small bronchi and bronchioles of rats and mice, as determined independently by several investigators (Blenkinsopp, 1967;Edwards and Klein, 1961;Meyer zum Gottesberge and Koburg, 1963;Koburg, 1962;Schultze and Oehlert, 1960;Shorter, Divertie, and Titus, 1964;Shorter, Titus andDivertie, 1964, 1966). The findings of Shorter and co-workers suggested that two cell populations exist in the bronchial epithelium of mice with turnover times less than 2 days or between 5 and 7 days (Shorter, Titus, and Divertie, 1964).…”

Proliferation and differentiation in mammalian airway epithelium

“…The halving by mitotic division occurs after a time equivalent to tS + tG 2 + tM. If the plot of mean grain number against time is extended, the next halving takes place after a time equivalent to tc [87,140,141,210].…”

“…Extrinsic factors may also influence cell division: e) diurnal variation: diurnal variations in mitotic and labelling indices have been well demonstrated in tissues such as epidermis and small bowel [4,49] and also in the respiratory tract. In the latter, a peak of a~ either mitotic or labelling indices has been found in the morning in rats [164,193,205] and the afternoon/ evening in mice and hamsters [57,138,140]. Studies carried out under conditions of constant light by BOREN (36] and BOREN and PARADISE (38] show no significant diurnal variation in LI with time.…”

Cellular Proliferation in Carcinogenesis*

“…This would not appear to be so. As an example for comparison, the tracheobronchial epithelium, with its relatively low cell turnover (Koburg, 1962;Spencer & Shorter, 1962), is, at present, the commonest site of cancer in man. In the gastrointestinal tract the tumour frequency is the greatest where moderate cell turnover occurs, i.e.…”