Ontogeny of galanin-immunoreactive elements in chicken embryo autonomic nervous system

To elucidate the main ontogenetic steps of galanin immunoreactivity within the extrinsic nerve supply of the alimentary tract, we undertook an immunohistochemical study of chicken embryo specimens. Fluorescence and streptavidin-biotin-peroxidase protocols were combined, using a galanin polyclonal antiserum, on transverse serial sections obtained from chicken embryos from embryonic Day 3 (E3) to hatching, and from 9-day-old newborn chicks. Galanin-immunoreactive cells were first detected at E3.5 within the pharyngeal pouch region, the nodose ganglion, the primary sympathetic chain, primitive splanchnic branches and the caudal portion of the Remak ganglion. At E5.5 galanin-immunoreactive cells and fibers appeared in the secondary (paravertebral) sympathetic chain, splanchnic nerves, peri- and preaortic plexuses, adrenal gland anlage and visceral nerves. Galanin-immunoreactive cells also lay scattered along the vagus nerve, and in the intermediate zone of the thoracolumbar spinal cord. At E18, galanin-immunoreactive cells and fibers were found along the entire Remak ganglion and around the gastrointestinal blood vessels. In post-hatching-9-day old chicks, the para- and prevertebral ganglia, but not the intermediate zone of the spinal cord, contained galanin-immunoreactive cells. Data indicate the presence of a consistent "galaninergic" nerve system supplying the chick embryonal gut wall. Whether this system has growth or differentiating role remains to be demonstrated. Its presence and distribution pattern in the later stages clearly support its well known role as a visceral neuromodulator of gut function.     

Bone Graft Alternatives for Spinal Fusion

Bone grafting to achieve fusion is frequently performed in spinal surgery. Autograft is the gold standard bone graft material. However, due to limitations of supply and morbidity associated with the harvest of autograft, alternatives are being considered. Osteoconductive matrices, such as allograft, calcium or ceramic preparations are one such class of potential bone graft alternatives, but generally they lack osteoinductive properties. Recent attention has focused on osteoinductive materials such as demineralised bone matrix, recombinant bone morphogenetic proteins and bone marrow aspirates or blood product concentrates. These products may be combined with osteoconductive carriers and are clearly finding a place in the clinical arena.     

Human pulmonary alveolar type 2 cells contain an apical membrane glycoprotein common to malignant cells

A monoclonal antibody, Ca1, raised against a detergent extract of Hep 2 cells derived from a human laryngeal carcinoma, was shown in these studies to bind to the apical surface of normal alveolar type 2 cells but not type 1 cells in the human lung. In lung specimens from patients with alveolitis, the antibody also bound to hyperplastic type 2 cells and to transition cells which were in the process of becoming alveolar type 1 cells. Ca1 binds to the apical plasma membrane and to internal membranes of cytoplasmic vesicles thought to be involved in the packaging of pulmonary surfactant. A surfactant-enriched fraction of human lung lavage did not bind the Ca1 antibody suggesting that the antigen was not an integral component of secreted surfactant. In normal human lung parenchyma, Ca1 binds only to type 2 cells, however it also binds to the apical surface of Clara cells in areas of cellular hyperplasia. Solubilized homogenates of whole lung, of a cell membrane fraction and of Hep 2 cells, immunoprecipitated with Ca2, separated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and probed with iodinated lectins, revealed that terminal glycosylation of the type 2 cell antigen differed from that of Hep 2 cells. Ca1 and a 330 kilodalton type 2 cell glycoprotein bind the lectin Maclura pomifera agglutinin. These two glycoproteins represent the first defined membrane markers of the apical surface of the human type 2 cell.     

Thoracolumbar Spine Trauma: II. Principles of Management

The care of patients with thoracolumbar spine trauma with or without neurologic deficits has evolved dramatically over the past 20 years with the emergence of tertiary-care spinal injury centers and the development of more effective spinal instrumentation and anesthesia techniques. Despite these advances, the majority of patients with thoracolumbar injuries are still treated nonoperatively with cast or brace immobilization and early ambulation. More aggressive treatment is guided by the use of classification systems that detail the mechanism of injury, the degree of compromise of spinal structures, and the potential for late mechanical instability or neural injury. The goal of treatment remains attainment of spinal stability with protection or improvement of the patient's neurologic status, allowing rapid and maximal functional recovery.     

Pedicle-Screw Fixation in the Lumbar Spine

This article provides a perspective on the development of pedicle-screw fixation in the lumbar spine, the biomechanics of its application, the possible complications, and the scientific evidence that supports specific applications in selected disorders. The overall goal is to objectify the debate currently surrounding the use of these devices. Lumbar-pedicle fixation devices are currently considered class III med-ical devices. According to the Food and Drug Administration, such devices are investigational or experimental, have not been proved safe and effective, and may potentially pose a risk to patients.     

Efficacy of magnetic resonance imaging in the evaluation of posterior cervical spine fractures

STUDY DESIGN: A retrospective study using two independent, blinded musculoskeletal radiologists to evaluate the sensitivity, specificity, and predictive value of cervical spine magnetic resonance imaging in detecting posterior element fractures of the cervical spine. OBJECTIVE: To evaluate the sensitivity, specificity, and predictive value of magnetic resonance imaging, using computed tomographic scanning as the gold standard, in the diagnosis of posterior element cervical spine fractures. SUMMARY OF BACKGROUND DATA: Few investigators have evaluated the accuracy of magnetic resonance imaging in the determination of cervical spine fractures. METHODS: From January 1994 through June 1996, 75 cervical spine fractures in 32 patients were confirmed by computed tomography. Two musculoskeletal radiologists who were blinded to the clinical history and presence or absence of cervical injury among the study population, independently evaluated each cervical magnetic resonance image recording the presence or absence of soft tissue or bony injury. RESULTS: The overall sensitivity and specificity rates for the diagnosis of a posterior element fracture by magnetic resonance imaging was 11.5% and 97.0%, respectively. The positive predictive value for this group was 83%, and the negative predictive value was 46%. In reference to anterior fractures, the sensitivity was 36.7% and the specificity 98%. Positive and negative predictive values were 91.2% and 64%, respectively. CONCLUSIONS: Magnetic resonance imaging was not effective in recognizing bony injury to the cervical spine and in particular was not as sensitive or as specific as computed tomography in identifying cervical spinal fractures. Computed tomography remains the study of choice for the detection and precise classification of bony injuries to the cervical region, especially when plain radiographs are difficult to evaluate. Magnetic resonance imaging, although not as effective as computed tomography in defining specific bony disorders, remains the gold standard in the evaluation of spinal cord injury, occult vascular injury, and intervertebral disc disruption (hyperextension injury), including herniation and other soft tissue disorders (hematoma, ligament tear).     

Health outcome assessment before and after anterior cervical discectomy and fusion for radiculopathy: a prospective analysis

STUDY DESIGN: A prospective assessment, performed using the Health Status Questionnaire, of the outcomes for 28 patients with cervical radiculopathy treated with one- or two-level anterior cervical discectomy and fusion. OBJECTIVE: To assess patient outcome using the Health Status Questionnaire after one- or two-level anterior cervical discectomy and fusion. SUMMARY OF BACKGROUND DATA: Although outcomes for many types of surgical procedures already have been evaluated, few have focused on the results of cervical surgery. METHODS: Before and after anterior cervical discectomy and fusion for cervical radiculopathy, 28 patients filled out the Health Status Questionnaire. The average follow-up interval was 21.8 months. There were 10 men and 18 women, with an average age of 44 years. All outcome instruments were graded for individual scores of general health, physical function, role limitation because of physical health problems, role limitation because of emotional problems, social function, mental health, bodily pain, and energy. Data were analyzed using the age (< 55 vs. > 55), worker's compensation status, and education status of the patient. Preoperative and postoperative scores were compared for each subscale. RESULTS: Statistically significant improvements were found in postoperative scores for bodily pain (P < 0.001), vitality (P = 0.003), physical function (P = 0.01), role function/physical (P = 0.0003), and social function (P = 0.0004). No significant differences were found before and after surgery for three health scales: general health, mental health, and role function associated with emotional limitations. Age, educational status, and history of compensation litigation did not appear to affect outcome measures. CONCLUSIONS: Although this is a preliminary report involving 28 patients, it would appear, based on the results of the Health Status Questionnaire, that anterior cervical discectomy and fusion performed on appropriately selected patients is a highly reliable surgical procedure for the management of cervical radiculopathy. Additional disease-specific questions may provide more sensitivity in evaluating radiculopathy after surgical and nonsurgical intervention.