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Fibrinolytic activity (caused by a plasminogen activator) in the spinal cord was highest in the rat, lowest in the rabbit, and intermediate in the guinea pig. In all species the activity was highest in relation to the pia mater. The central spinal canal was active in the rat and the rabbit, but mostly inactive in the guinea pig. Foci of activity were more numerous in the gray matter than in the white matter corresponding to the greater vascularity of the former. In all species ability to inhibit plasmin was related mainly to the gray matter, with an additional area related to the dura mater. The high fibrinolytic activity of the spinal leptomeninges may play a role in the pathogenesis of hemorrhagic processes related to the spinal cord. Chemicals/CAS: antiplasmin, 9049-68-7; Plasmin, EC 3.4.21.7; Plasminogen Activators, EC 3.4.21.-

Chemicals/CAS: cytarabine, 147-94-4, 69-74-9; methotrexate, 15475-56-6, 59-05-2, 7413-34-5

Values of the relative biological effectiveness (RBE) of fast neutrons for effect on normal tissue depend not only on the neutron energy and the dose, but also on the type of tissue irradiated. Values of the RBE of 15 MeV neutrons are reviewed for rapidly proliferating rodent tissue, such as mouse bone marrow, mouse intestine and rat skin treated with single and fractionated irradiations. In addition, RBE values were obtained for rodent tissue with relatively long cell life times, such as the vascular endothelium, the spinal cord and the lung. In general, the normal tissue data indicate that for doses between 50 and 250 rad the RBE values range up to values of about 2, but depend on the fractionation regimen.

The influence of various neural explants on the morphology and the survival of chick muscle fibers was studied. A method was developed to evaluate the condition of the muscle fibers using the following four morphological parameters: cross striation, thickness, number of fibers and absence of vacuoles. Chick as well as mouse spinal cord explants appeared to have a distinct favorable influence on the muscle fibers. Chick ciliary ganglia and mouse cortex explants had less effect and chick sympathetic ganglia and mouse dorsal root ganglia had no effect. Innervation by spinal cord neurons did not lead to a change in resting membrane potential of the muscle fibers. The amount of cross striation in muscle fibers in the vicinity of mouse spinal cord explants was positively correlated with the frequency of spontaneous end-plate potentials in the muscle fibers. d-Tubocurarine did not interfere with the trophic support of muscle cells by nerve cells, although it reversibly blocked neuromuscular transmission throughout the experiment. This demonstrates that neither the acetylcholine receptor nor the activity induced in the muscle fiber mediate the trophic action. The data suggest that a humoral trophic factor, released at the neuromuscular junction or at a region of close cell-cell contact, is needed for normal development and maintenance of muscle fiber morphology. Chemicals/CAS: acetylcholine, 51-84-3, 60-31-1, 66-23-9; tubocurarine chloride, 57-94-3, 57-95-4, 8006-51-7

We have previously shown that immunization with a mannosylated myelin peptide in complete adjuvant induces tolerance instead of disease in experimental autoimmune encephalomyelitis (EAE), a rodent model for multiple sclerosis. In this report we demonstrate that treatment with a soluble mannosylated epitope of proteolipid protein (M-PLP139-151) significantly inhibits disease mediated by autoreactive myelin-specific T cells during EAE. Treatment with M-PLP139-151, applied in different EAE models, significantly reduced the incidence of disease and the severity of clinical symptoms. Delayed-type hypersensitivity responses were abolished after peptide treatment, emphasizing the impact on peripheral T-cell reactivity. Histological analysis of spinal cord tissue from mice treated with M-PLP 139-151 revealed the presence of only few macrophages and T cells. Moreover, little expression of interferon-γ, interleukin-23, or major histocompatibility complex class II antigen was detected. Immune modulation by M-PLP139-151 was primarily antigen-specific because an irrelevant mannosylated peptide showed no significant effect on delayed-type hypersensitivity responses or on the course of EAE. Therefore, mannosylated antigens may represent a novel therapeutic approach for antigen-specific modulation of autoreactive T cells in vivo. Copyright © American Society for Investigative Pathology.

Chick spinal ganglia, chick muscle cells combined with mouse spinal cord explants, C1300 neuroblastoma cells, Chinese hamster ovary cells and newborn rat cerebral cells were exposed to various concentrations of acrylamide in culture. Four morphological and 1 electrophysiological parameter were applied in order to score toxic effects. It appeared that the neurite formation of rat cerebral neurons was the most sensitive criterion showing an effect at 10-7 M acrylamide. Chemicals/CAS: acrylamide, 79-06-1; Acrylamides

In lifting, the abdominal muscles are thought to be activated to stabilize the spine. As a detrimental effect, they contribute to spinal compression. The existing literature is not conclusive about the biological relevance of this effect. From biological, mechanical and anatomical considerations it was hypothesised that the relative abdominal contribution to compression would be minor in the beginning of the lift, that the relative and absolute abdominal contribution to compression would rise throughout the lift, and that the obliques would contribute to a larger extent than the rectus abdominis. To investigate these hypotheses, 10 subjects lifted 0.5, 10.5 and 22.5 kg. EMG levels obtained from the rectus abdominis and the obliques were converted into force using normalized EMG, muscle potential and area values, and modulating factors for muscle length and contraction velocity. An anatomical model was applied to compute the abdominal effects on spinal compression in three consecutive phases within a lift. If expressed relative to the total spinal compression, the abdominal contribution for the three weight conditions was 7.1% (SD, 1.7), 10.4% (4.7) and 12.5% (4.4) in the begin and 21.0% (5.8), 19.0% (5.3) and 22.2% (6.6) in the end phase. Thus, the relative abdominal contribution to compression was minor in the beginning and increased towards the end. The absolute abdominal contribution was constant throughout the lift. The contributions could be retraced to the obliques rather than the rectus, while during the lift a shift in activation from the obliquus externus to internus was observed.

B&G, PZ.

While myelin-reactive T cells are widely believed to play a pathogenic role in multiple sclerosis (MS), no substantial differences appear to exist in T-cell responses to myelin antigens between MS patients and healthy subjects. As an example, indistinguishable peripheral T-cell responses and serum antibody levels have been found in MS patients and healthy controls to alpha B-crystallin, a dominant antigen in MS-affected brain myelin. This suggests that additional factors are relevant in allowing myelin-reactive T cells to become pathogenic. In this study, we examined whether the inflammatory state of the CNS is relevant to the pathogenicity of alpha B-crystallin-specific T cells in mice. In normal mice, T-cell responses against alpha B-crystallin are limited by robust immunological tolerance. Reactive T cells were therefore generated in alpha B-crystallin-deficient mice, and these T cells were transferred into C57BL/6 recipients. While such a transfer in itself never induced any clinical signs of experimental autoimmune encephalomyelitis (EAE) in healthy recipient mice, acute EAE could be induced in animals that had been infected 7 days before with the avirulent A7(74) strain of Semliki Forest virus (SFV). SFV infection alone did not induce clinical disease, nor did it alter the expression levels of the target antigen. Our findings indicate that at least in mice, alpha B-crystallin-specific T cells can trigger EAE but only when prior viral infection has induced an inflammatory state in the CNS that helps recruit and activate T cells. © 2007 Oxford University Press.

This study investigated the effects of ship motion on peak spinal loading during lifting. All measurements were done on a ship at sea. In 1-min trials, which were repeated over a wide range of sailing conditions, subjects lifted an 18 kg box five times. Ship motion, whole body kinematics, ground reaction forces and electromyography were measured and the effect of ship motion on peak spinal moments and compression forces was investigated. To investigate whether people time their lifts in order to reduce the effect of ship motion on back loading, trials were performed at a free and at a constrained (lifting every 10s) work pace. With increase of the (local) vertical ship acceleration, increased moments and compression forces were found. Furthermore, lifting at a free work pace did not result in smaller effects of ship motion on spinal moments and compression forces than working at a constrained work pace.