Human spine

The human spine is an exquisite and complex structure from both an anatomical and functional standpoint. The spine is composed of approximately 24 boney elements, termed vertebral bodies, which are separated by 23 cartilaginous cushions or shock... 

Passuti, N., Daculsi, G, Rogez, J. M., Martin, S., and Bainvel, J. V., Macroporous calcium phosphate ceramic performance in human spine fusion. Clinical Orthop. 248, 169-176 (1989). 

A cadaveric study comparing the range of motion in the L5-S1 motion segment in five human spines, before and after implantation with the PRODISC, has indicated that implantation of fhis device did not significantly affect the ROM (Lipman et al. 2003). Specimens were tested in an apparatus that applied pure bending moments. The specimens were cycled in torque to a maximum of 10 Nm in flexion-extension, lateral bending, and torsion with 600 N and 1200 N compressive loads. The ROM at 8 Nm after the fifth cycle of loading was documented and used for comparison between intact and implanted specimens. Summary data is shown in Table 10.3. 

Figure 1 False-color scintigram of the human spine and ribs, revealing secondary cancers (metastases) in the vertebrae arising from a primary cancer of the prostate gland. A scintigram (y-camera scan) is a record of radioactive emissions from an isotope (in this case, " Tc) that is selectively absorbed by bone when injected into the body, y-ray scintigraphy is frequently used to screen cancer patients for signs of secondary disease, often after their primary cancer has been treated. Here, the metastases appear as the pink and white hot spots in the thoracic spine. (Reproduced from CNRI/Science Photo Library.)...

Ferrara, L., Shahinpoor, M., Kim, K. J., et al. (1999) Use of Ionic Polymer-Metal Composites (IPMCs) As A Pressure Transducer In the Human Spine, in Electroactive Polymers, SPIE (publication, number 3669-45), 394—401. 

Keywords— Human Spine, Time Dependent, Stress-Relaxation, Spinal Column, Loading. 

Polyalphaolefin Hydraulic Fluids. There is limited information on the potential of polyalphaolefin hydraulic fluids to induce musculoskeletal effects. Kyphosis, a deformity of the spine characterized by extension flexion was observed in rats exposed to 880-5,030 mg/m3 (concentration eliciting response not reported) of a polyalphaolefin hydraulic fluid designated at B85-174 for 4 hours (Kinkead et al. 1987b). It is not known if this effect is related to damage to the musculoskeletal system or to neurological damage. This is the only study that examined musculoskeletal effects. Thus, the likelihood of musculoskeletal effects occurring in humans exposed to polyalphaolefin hydraulic fluids cannot be determined. 

Roberts S et al (1996) Transport properties of the human cartilage endplate in relation to its composition and calcification. Spine (Phila Pa 1976) 21(4) 415 120... 

Roberts S et al (2000) Matrix metalloproteinases and aggrecanase their role in disorders of the human intervertebral disc. Spine (Phila Pa 1976) 25(23) 3005-3013... 

Roughley PJ et al (2006) The structure and degradation of aggrecan in human intervertebral disc. Eur Spine J 15(Suppl 3) S326-S332... 

Johannessen W, Elliott DM (2005) Effects of degeneration on the biphasic material properties of human nucleus pulposus in confined compression. Spine (Phila Pa 1976) 30 (24) E724—E729... 

Bae H, Kanim M, Zhao L (2008) Human fetal chondrocyte transplants for damaged intervertebral disc. Spine J 8(5) 928-938... 

Cloyd JM et al (2007) Material properties in unconfined compression of human nucleus pulposus, injectable hyaluronic acid-based hydrogels and tissue engineering scaffolds. Eur Spine J 16(11) 1892-1898... 

Alini M et al (2008) Are animal models useful for studying human disc disorders/degenera-tion Eur Spine J 17(1) 2—19... 

O Connell GD, Vresilovic EJ, Elliott DM (2007) Comparison of animals used in disc research to human lumbar disc geometry. Spine (Phila Pa 1976) 32(3) 328-333... 

Singh K, Masuda K, An H (2008) Animal models for human disc degeneration. In Yue J, Bertagnoli R, McAfee P, An H (eds) Motion preservation surgery of the spine advanced techniques and controversies. Elsevier, Philadelphia, pp 639-648... 

Smiley, J. F., Levey, A. I., Ciliax, B. J. and Goldman-Rakic, P. S. D1 dopamine receptor immunoreactivity in human and monkey cerebral cortex predominant and extrasynaptic localization in dendritic spines. Proc. Natl Acad. Sci. U.S.A. 91 5720-5724,1994. 

A cross-jS spine model was proposed for the fibril structure of human /]2-microglobulin (h/]2m) (Ivanova et al., 2004). h/I2m is a 99-amino acid serum protein with a 7-stranded /(-sandwich fold (Fig. 10A Saper et al, 1991). In patients on long-term kidney dialysis, the protein is deposited as amyloid fibrils in the joints (Floege and Ehlerding, 1996 Koch, 1992). In vitro-formed fibrils of h/)2m give a cross-/] X-ray diffraction pattern (Ivanova et al., 2004 Smith et al., 200S). Several studies have shown that segments of h/]2m form amyloid-like fibrils on their own (Ivanova et al., 2003 Jones et al., 2003 Kozhukh et al, 2002). 

F. Both the age of the test animal and the application site (saddle of the back versus flank) can markedly alter test outcome. Both of these factors are also operative in humans, of course (Mathias, 1983), but in dermal irritation tests, the objective is to remove all such sources of variability. In general, as an animal ages, sensitivity to irritation decreases. For the dermal test, the skin middle of the back (other than directly over the spine) tends to be thicker (and therefore less sensitive to irritations) than that on the flanks. 

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