SummaryIndospicine (L-2-amino-6-amidinohexanoic acid) has been newly characterized as a component of a higher plant, being isolated from the leaves and seeds of Indigofera 8picata. Indospicine was hydrolysed in distilled water at 120°C to 2-aminopimelamic acid and ammonia (1 mole). Mild acid hydrolysis of the latter compound yielded optically pure L-oc-aminopimelic acid. The infrared, nuclear magnetic resonance, and mass spectra of indospicine and of its degradation products supported the proposed structure.When injected subcutaneously into mice (1 mg/g body weight) indospicine produced fat accumulation and cytologioal ohanges in the liver. The fat aocumulation was inhibited by simultaneous injeotion of arginine but not by oanavanine. A substantial part of the hepatotoxioity of extracts of 1. 8picata seed was accounted for in terms of indospicine. The ooncentration of indospicine in the seeds exoeeded that in the leaves and stems of the plant.

Partial hepatectomy 24 h before a single i.p. dose of dimethylnitrosamine, diethylnitrosamine or ethylmethylnitrosamine increased the carcinogenic response in the liver of rats as determined by the number of tumours and the number of "focal proliferations" produced. Secondly, in rats given a single i.p. dose of diethylnitrosamine, 3 partial hepatectomies 5, 10 and 15 weeks after dosing the animals increased the carcinogenic response in the liver. The stimulus of repeated partial hepatectomy therefore appears to act as a "promoting agent" for liver carcinogenesis, that is if the single dose of diethylnitrosamine is regarded as an "initiating agent" in the terms of the two-stage hypothesis. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4

Summary.-A recently introduced assay of cell mediated immunity and humoral inhibitory factors has been evaluated in colorectal cancer patients. Using a perchloric acid extract of adenocarcinoma of the large bowel as antigen, 16/27 patients with colorectal cancer had significant cellular reactivity when their separated peripheral leucocytes were tested in homologous AB serum. In autologous serum only 7/27 had significant reactivity; 6/20 patients with a variety of other malignancies showed sensitization to the colorectal antigen preparation.It is concluded that the leucocyte adherence inhibition test may offer a simple method of assaying for serum blocking factors in sequential studies but will be of little value in the diagnosis of large bowel cancer.In vitro techniques for assessing im-human malignancies (Maluish anld Hallimunological reactivity have facilitated day, 1974). the study of the immune response to The principle of the test is that when human cancer and of factors which specifically sensitized lvmphocytes are modify its expression. Such information incubated with the antigens, a lymphokine is of much more than theoretical impor-is released which decreases the normal tance as it could provide guidelines for tendency of leuocytes to adhere to a planning suitable immunotherapy or moni-glass surface. This is analogous to the toring the post-operative clinical course of macrophage migration system in which a patients.product Isbister, 1974b) and then adapted for resected adenocarcinomiata of large bowel was

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Summary.-Rats were given a single dose of dimethylnitrosamine (DMN, 20 mg/kg body weight) alone or 42 or 60 hours after a non-lethal hepatotoxic dose of carbon tetrachloride (CC14) and killed 12 months later. DMN alone produced no tumours in the kidney and a few in the liver, but when given 42 hours after CC14, tumours formed in the kidneys and the number in the liver was increased. When given after 60 hours, the incidence of kidney tumours was less but that of liver tumours was further increased. A larger dose of DMN (40 mg/kg) was tolerated 42 hours after CC14 and enhanced the number of kidney and liver tumours, the latter apparently due to an increased proportion of cholangiomata. Numerous small focal proliferations of atypical liver cells and of bile duct epithelium were observed after treatment with DMN. The incidence of these lesions in the different experimental treatments varied in a similar manner to the liver tumours.