Nasal dermoids: the significance of a midline punctum

Nasal dermoids are rare and their diagnosis is often delayed until complications occur. Signs such as a midline nasal punctum may be noted at birth but the significance of this finding frequently passes unrecognised. The cases are reported of two patients which illustrate the typical presentation of these lesions and their subsequent management is discussed.     

A locus that influences susceptibility to 1, 2-dimethylhydrazine-induced colon tumors maps to the distal end of mouse chromosome 3

While inheritance of mutated alleles of highly penetrant tumor suppressor genes such as retinoblastoma or p53 predisposes individuals to a greatly increased risk of developing cancer, epidemiological data indicate that the majority of sporadic tumors in humans result from interactions of environmental and host genetic factors. The host genetic factors are poorly penetrant tumor susceptibility genes that determine the likelihood that a cancer will arise from carcinogen exposure. The majority of colon tumors in humans are sporadic in nature. 1,2-dimethylhydrazine (DMH)-induced colon tumors in mice provide a useful animal model to identify genes that influence susceptibility to carcinogen-induced colon tumors in humans. A genome-wide scan of genetic crosses of relatively sensitive C57BL/6J with relatively resistant CBA mice treated with DMH revealed a linkage of DMH susceptibility with the distal end of mouse chromosome 3, suggesting that one or more tumor susceptibility genes may map to this region.     

Cyclophosphamide-induced apoptosis of murine lymphosarcoma cells in vivo

The antitumor action of combination chemotherapy (cyclophosphamide + adriamycin + vincristin + prednisolone) for transplantable nitrosomethylurea-induced lymphosarcoma was studied in male CBA mice. Single injections of the mixture were followed by complete regression of tumors of up to 2 cm in diameter. The effect was shown to be caused by cyclophosphamide (CP) alone, by inducing apoptosis. The other components failed to potentiate the CD effect. Being useless, they are likely to cause harm by contributing to the overall toxic effect of therapy. The nature and duration of CP-induced remission appeared dose-dependent: on day 50 of the administration of 50, 100 and 150 mg/kg body, tumors were detected in 100, 55 and 0% of the animals, respectively. Such means of apoptosis induction as glycocorticoid treatment and ionizing radiation did not cause complete regression.