No abstract

Summary. The role of Bacteroides fragilis in the pathogenesis of acute appendicitis was studied in 135 patients in four patient groups: normal (1 7); phlegmonous appendicitis (1 7); gangrenous appendicitis (75); and septic complications of appendicitis (26). Aerobic and anaerobic bacteria were isolated from all groups and members of the 'B. fragilis group' were the most common anaerobic isolates. The rate of isolation of B. fragilis was similar from normal and inflamed appendices but was significantly higher from those with septic complications (p < 0.01). Antibodies against B. fragilis were demonstrated in patients of all groups and occurred with similar frequencies in patients with normal and inflamed appendices but at a significantly higher rate in those with septic complications (p < 0.01). Whereas patients in this latter group showed IgMantibody responses to B. fragilis only, those with acute appendicitis had IgM antibodies against a wide range of organisms of the 'B. fragilis group' which suggests that B. fragilis does not play a significant role in acute appendicitis but may be a major cause of its septic complications.

Summary.-Thirty-two scirrhous cancers of breast have been examined to determine the origin of the collagen stroma in these tumours. Employing two immunohistochemical techniques it has been shown that the malignant epithelial cells in 30 of these tumours contain not only collagen but also prolyl hydroxylase, a key enzyme in collagen biosynthesis. Neither this enzyme nor collagen was detectable in the spindle cells in the stroma of these tumours. Neither the epithelium in normal breast, that in fibrocystic disease and in fibroadenomata, nor the malignant epithelium in two medullary cancers of breast contained either collagen or prolyl hydroxylase. These results strongly suggest that the malignant epithelium of scirrhous breast cancers produces its own collagen stroma and that the scirrhous reaction in these tumours is not a host response to tumour invasion. The production of collagen and prolyl hydroxylase by breast cancer cells (of the scirrhous type) therefore represents another example of inappropriate protein production by a human tumour.

suMMARY Expression of low and high molecular weight cytokeratin proteins was investigated immunohistochemically in a variety of transitional and squamous epithelial lesions of the urinary tract with and without schistosomiasis. The monoclonal antibodies used were CAM 5 2 and NCL5D3 for low, PK 63 and 121 for high, and MAK 6 for a broad range of intermediate molecular weight cytokeratins. On staining with CAM 5 2 and NCL5D3, urothelial hyperplasias (n = 12) and grades 1 (n = 5) and 2 (n = 10) papillary transitional cell carcinomas showed labelling patterns quite distinct from carcinoma in situ (n = 4) and non-papillary grades 2 (n = 6) and 3 tumours (n = 3). Among squamous lesions only focal positivity was obtained in 14 of 22 moderate to poorly differentiated squamous cell carcinomas. By contrast, PK 63 and 121 stained squamous lesions exclusively. MAK 6 stained the whole range ofurothelial and squamous lesions with the exception of squamous metaplasias. Polyclonal antikeratin adequately labelled spindle cell areas of high grade tumours. The distinctive staining patterns given by these or similar antibodies may help in the identification of squamous metaplasia and in diagnosing tumours of the urothelium.