Alterations in splenic natural killer cell activity induced by the Shionogi mouse mammary tumor.

We have previously demonstrated that differential housing conditions alter the growth rate of the Shionogi mouse mammary carcinoma (SC115). The present study was undertaken to determine if natural killer (NK) cells are involved in mediating the effects of differential housing on SC115 tumour growth rate. Splenic NK cell activity was assayed at 24 h, 3 days and 1 week post-injection in both tumour- and vehicle-injected animals. Significant stimulation of splenic NK cell activity occurred 3 days post-injection of SC115 cells. However, no correlation was observed between the level of splenic NK cell activity and tumour growth rate induced by housing condition. We conclude that either splenic NK cell activity does not accurately reflect NK cell activity at the tumour site or that NK cells are not a significant regulator of the differential tumour growth rates seen in this model.

A histological study of the Shionogi adenocarcinoma 115 grown in male and female mice.

We have previously demonstrated that growth rate and morphology differ between androgen-responsive Shionogi mouse mammary tumours maintained in male and female mice. Furthermore, we can modulate the growth rate of these tumours in male mice by exposing the mice to psychosocial stressors. In the present study, we were interested in determining if tumours in male mice with a comparable growth rate to that in females, also had a morphology similar to that in females. SC115 tumours were examined using histochemical and immunohistochemical techniques. Tumours in male mice were easily distinguishable from tumours in female mice regardless of growth rate. Tumours maintained in female mice contained osteoid-like regions which stained positive for sialic acid and sulphate moieties. No such regions were observed in any of the tumours from male mice. In addition, although all tumours contained MSA (muscle specific actin)-positive and S100 protein-positive cells, these regions were more extensive in the tumours of female mice. This study suggests that tumour growth rate and morphology are independently regulated by the host environment.

The histochemical specificity of high iron diamine-alcian blue.

The specificity of the High Iron Diamine-Alcian Blue pH 2.5 (HID-AB 2.5) procedure was examined in tissue sites containing sialogycoproteins alone or differing proportions of sialo- and sulphosialoglycoproteins. Studies with HID in differing final concentrations of hydrochloric acid or sodium chloride confirmed that staining is dependent upon both the pH and the ionic strength of the dye bath and demonstrated a marked heterogeneity in the pKa of the anionic groups of sialosulphoglycoproteins. Use of the sequence High Iron Diamine-Alcian Blue pH 1.0 demonstrated that complete or almost complete staining of O-sulphate esters occurred when HID was prepared in water (final pH 1.3). However, under these conditions HID-AB 2.5 was shown to be non-specific because only black HID staining was observed in sites containing large quantities of sialic acids. This non-specificity was due either to the masking of Alcian Blue staining by HID and/or the black HID staining of anionic groups other than sulphate. These results may account for some of the conflicting data obtained by different groups of investigators who have studied 'transitional mucosa' in human colonic diseases. Caution should be used in drawing conclusions from the use of HID-AB 2.5 without confirmatory evidence from other more specific procedures.