Regeneration in vitro of axolotl peripheral and central axons

Peripheral nerves and spinal cords of axolotls were maintained in organ culture for periods of up to 2 weeks. Sensory axons in peripheral nerves and the dorsal funiculus of the spinal cord showed regeneration through the crush site within about 2 days. Axonal regeneration also occurred in peripheral nerves after cutting but was dependent on close contact between proximal and distal stumps of nerve. When cells in the distal stump of nerve were killed by freezing, axonal regeneration was inhibited.     

Osteosarcomatosis

A review of the 690 cases of osteosarcoma in the radiographic file of the Armed Forces Institute of Pathology revealed 29 cases of "osteosarcomatosis" (multiple skeletal sites of osteosarcoma). Fifteen of these patients were 18 years old and under and manifested rapidly appearing, usually symmetric, sclerotic metaphyseal lesions. The remaining 14 patients were more than 18 years old and had fewer, asymmetric sclerotic lesions. In most patients (28 of 29), a radiographically dominant skeletal tumor was seen. Pulmonary metastases occurred in the majority of patients and were detected at the same time as the bone lesions. These 29 patients were studied with regard to demographic data and skeletal distribution and radiographic appearance of their lesions. As a result of the findings, a metastatic origin from a primary dominant osteosarcoma is favored over a multifocal origin as the basis for osteosarcomatosis. Osteosarcomatosis is more commonly encountered in the mature skeleton than has been previously recognized.     

S-laminin and N-acetylgalactosamine located at the synaptic basal lamina of skeletal muscle are involved in synaptic recognition by growing neurites

Summary The purpose of the work reported here is to identify molecular components of the synaptic basal lamina of skeletal muscle fibres which allow recognition of original synaptic sites by regenerating motor axons. We focused on s-larninin and components recognized by the lectinDolichos biflorus agglutinin previously shown to be specifically located at the synaptic basal lamina. We used a cryoculture bioassay in which chick ciliary ganglion neurons grow on rat skeletal muscle cryostat sections. In control cultures, neurites extended over the muscle sections in close association with the muscle cell surface. It was observed that most of the neurites that extended towards the endplate zone and reached an area of 40 m around the neuromuscular junction ceased to grow when they contacted the synaptic site. Masking either lectin receptors or some s-laminin molecule epitopes prior to the culture of neurons alters the behaviour of growing neurites. On sections treated either withDolichos biflorus agglutinin or anti s-laminin monoclonal antibodies (D5 and C4) most of the neurites did not stop their growth at the synaptic regions. Moreover, treating muscle sections withDolichos biflorus agglutinin removed the gradient of substratum affinity around the endplate. These results indicate that the s-laminin andDolichos biflorus agglutinin receptors present on muscle cell surfaces may play a functional role in the interaction of growing neurites with original synaptic sites in the process of neuromuscular regeneration.