Bacteriological studies of uncontaminated upper jejunal fluid were performed in 85 normal subjects. Fifty-three per cent of the samples were sterile (less than 10(1) CFU/ml). In 10% of the cases the total number of microorganisms exceeded 10(5) CFU/ml. The main groups of microorganisms isolated were Streptococcus sp ('Viridans group'), Lactobacillus sp., Veillonella parvula, Actinomyces sp., Haemophilus sp., Corynebacterium sp., and Candida albicans, each found in more than 10% of the subjects. Only the Streptococcus sp. exceeded 10(5) CFU/ml, and enterobacteria were found in 5% of the subjects, the number not exceeding 10(3) CFU/ml. No other typical members of the lower gastrointestinal tract were isolated. The number of subjects harbouring bacteria and the distribution of bacterial species were the same in both sexes and in different age groups.
Bowman's membrane, seen as a homogeneous layer in light microscopy, is demonstrated by transmission electron microscopy as a layer with fibrils in random distribution, for which reason the term used at present is Bowman's layer. Frozen resin cracking demonstrates that the fibrils of the layer run in certain patterns and lie in 3 or 4 strata in the central areas of the cornea. In the periphery, stratification is scarcely demonstrable. The fibrils consist of collagen inseparable by histochemical methods from the collagen in the stroma, but the diameter is only half or two-thirds of the diameter of the stromal fibrils. The authors discuss the possibility that artifacts are responsible for the findings. However, an explanation of the results may be that Bowman's layer is a condensation of the superficial layers of the stroma resulting from the development of the layer. The fibrils are presumed to break in different ways, but apparently in layers in which the breaking strengths are identical.
When jejunal juice is obtained by means of open pernasal tubes, the risk of the aspirates being contaminated is presumably high. The present study compares jejunal aspirates obtained from an open and from a closed tube system. Ten patients suspected of having abnormal jejunal flora and five healthy human volunteers were investigated. The pH values of aspirates obtained from the open tubes were significantly lower than the values registered in aspirates from the closed tube system, with a median difference of 0.70 (p less than 0.02). No differences between the two types of aspirate were registered with regard to total number of bacteria, number of bacterial species, lipase, total protein, total amylase or its fractions of pancreatic and salivary isoamylases. For the investigation of pH-sensitive substances in jejunal juice, a closed tube system is therefore recommended, whereas the use of such a device does not seem necessary for the study of bacterial microflora and pancreatic enzymes.
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