Stage-dependent genetically-based deformities of the regenerating newt limb from 4-nitroquinoline-N-oxide mutagenesis: potential embryonic regulation of cancer.

The effect of the mutagenic carcinogen 4-nitroquinoline-N-oxide (4NQO) on limb regeneration was studied in adult Triturus cristatus newts. Delayed limb regeneration was observed when a 10- to 15-micrograms crystal of 4NQO was implanted at the late dedifferentiation or late bud stage. Additionally, 4NQO administration at these stages caused developmental deformities in skeletal elements of the subsequent regenerates. In contrast, 4NQO implanted at the wound healing stage did not affect skeletal morphogenesis. These critical stages of limb regeneration affected by carcinogen exposure (but not other manipulations) represent mechanisms distinct from disruption of basement membrane deposition. Secondary regeneration, initiated by reamputation of the 4NQO-treated abnormal regenerates 4-5 mm proximal to the site of carcinogen implantation, produced normal regenerates, setting a limit on the diffusion distance of 4NQO in the limb. Distal reamputation through regenerates at the level of the abnormality resulted in regeneration of the original bone deformity, suggesting that the teratogenic effect of 4NQO is mediated via heritable mutational events in blastema cells. These results extend a previously published conclusion that 4-NQO is mutagenic in non-regenerative tissue to include regenerative tissue as well. However, in spite of mutagenic activity, squamous carcinomas were not induced by 4NQO exposure at any stage of regeneration. Therefore, the resistance of regenerative tissue to 4'-NQO carcinogenesis is not due to resistance to mutations, but rather to other mechanisms perhaps similar to those which regulate malignant cells in murine embryos.

A continuum of rehabilitative care. A day hospital extends patients' lifeline to the medical center.

Alexian Brothers Medical Center in Elk Grove Village, IL, carries out its commitment to a continuum of care through the Alexian Brothers Rehabilitation Center and its Physical Rehabilitation Day Hospital. The day hospital treats patients who need rehabilitation but do not need around-the-clock hospitalization. The day hospital individualizes its intensive comprehensive, pulmonary, and arthritis programs. An important component of these outpatient programs is education and preventive techniques to reduce the need for repeat treatment. Only medically stable patients are transferred to the rehabilitation center, where an interdisciplinary team helps them achieve the maximum function possible within the limits imposed by their disabilities. The rehabilitation center sponsors a community support group for young adults who have sustained head injuries and a group for alumni of the center. Through its home healthcare program and its adult day care program, the medical center offers a variety of treatment delivery methods that enhance the center's continuum of care.