Mechanoreceptors in intervertebral discs. Morphology, distribution, and neuropeptides.

STUDY DESIGN: The present study investigated the occurrence and morphology of mechanoreceptors in human and bovine intervertebral discs and longitudinal ligaments. OBJECTIVE: To determine the type and frequency of mechanoreceptors present in intervertebral discs and anterior longitudinal ligaments in two patient groups, those with low back pain and those with scoliosis. Bovine coccygeal discs were examined. SUMMARY OF BACKGROUND DATA: Nerves have been described in intervertebral tissues, but there is little information on the endings of these nerves and their receptors, stimulation of which can cause a nerve impulse. METHODS: The presence of mechanoreceptors were investigated by immunolocalization of nerves and neuropeptides. By examining sequential sections, the frequency of receptors was assessed. RESULTS: Immunoreactivity to neural antigens showed mechanoreceptors in the anulus fibrosus and longitudinal ligaments of bovine and human specimens. Their morphology resembled Pacinian corpuscles, Ruffini endings, and, most frequently, Golgi tendon organs. They were found in 50% of discs investigated from patients with low back pain and in 15% of those with scoliosis. CONCLUSIONS: Mechanoreceptors were found in the outer 2-3 lamellae of the human intervertebral disc and anterior longitudinal ligament. Physiologic studies in other tissues indicate that these provide the individual with sensation of posture and movement, and in the case of Golgi tendon organs, of nociception. In addition to providing proprioception, mechanoreceptors are thought to have roles in maintaining muscle tone and reflexes. Their presence in the intervertebral disc and longitudinal ligament can have physiologic and clinical implications.

Density of myosin filaments in the rat anococcygeus muscle, at rest and in contraction. II.

Rat anococcygeus muscles were fixed at rest or in contraction by conventional methods and prepared for electron microscopy. Myosin filaments were counted on cross sections and their density expressed per unit cytoplasmic area. In contracted muscles, the mean density increased from 86 to 168 filaments per micron 2 (1.95 times), while the density of intermediate (10 nm) filaments increased by 1.25 times. Cell cross sections from the same muscles were measured. Contraction produced a shrinkage which explains the apparent increased density of the 10 nm filaments; however an excess of 61 myosin filaments per micron 2 cannot be explained in this way. These findings provide the structural basis which quantitatively explains the birefringence changes observed in living contracted muscle (Godfraind-De Becker & Gillis, 1988). Our optical and electron optical results provide evidence for a reversible formation of myosin filaments during contraction of the rat anococcygeus muscle.

[Morphofunctional changes of coccyx area in posttraumatic coccygodynia]. / Morfofunktsional'ni zminy struktur kuprykovoï dilianky pry posttravmatychnii koktsyhodyniï.

For definition of a pathogenesis ofposttraumatic coccygodynia, a study of morpho-functional changes of the structures of coccyx's area was organized. The preparations of coccyx, removed during operative intervention from 23 different-aged patients with manifestations of disease were analyzed by roentgen, histological technique and a submicroscopy. In a cartilaginous tissue from patients with posttraumatic coccygodynia, dystrophic changes of chondrocytes down to their atrophy, a destruction of the basic material with partial replacement of a fibrillar cartilaginous tissue with a hyaline cartilage were observed with a different degree of manifestation. Vessels and sacrococcygeal nervous plexus were subjected to pathological changes. Increased post-traumatic mobility, alterations in the process of ossification, deceleration of physiological joining of coccyx vertebras and sacrococcygeal joint alter biomechanical properties of coccyx at sitting. These alterations lead to the long-lasting traumatization with degenerative - dystrophic changes, reinforcement of pain syndrome and manifestation of dysfunctions of organs of pelvis.

Extraspinal ependymoma in the sacrococcygeal region. A case report with ultrastructural, immunohistochemical and cytophotometric studies.

We describe on a primary, subcutaneous sacrococcygeal ependymoma presenting in a young female patient. Detailed immunohistochemical and electron microscopic examinations were performed. Out of the 40 similar cases reported in literature this is the first in which the determination of DNA content was also used to predict biological behaviour. The tumour proved to be aneuploid with low proliferative capacity in spite of absent histological signs of malignancy. It is suggested that DNA determination may be helpful in establishing prognosis and that it may contribute to a better understanding of the biological behaviour of this tumour.