OBJECTIVETo evaluate the feature of experimental endplate fracture in lumbar spine and its related factors.

METHODSNineteen cadaveric lumbar motion segments aged 48 - 77 years were compressed by overload to fracture the endplate and dissected into isolated vertebrae to evaluate feature of their endplate failure. Before and after failure of endplate, radiographic tests were taken on every motion segment. The bone mineral density (BMD), bone mineral content (BMC) of the vertebral body and endplate were tested respectively before endplate fracture.

RESULTSAmong 19 motion segments, 16 were fractured and accounted for 84.2% of all and fracture featured as stellate, step, depression and intrusion. Fracture concentrated on the center or anterior of superior endplate of the inferior vertebrae in one motion segment. Failure load of endplate was positively correlated with BMD, BMC of vertebral endplate. Within one vertebral body, the BMD and BMC of its superior endplate was markedly less than that of inferior endplate, on the other hand, the difference of BMD and BMC of endplate around one disc was opposite.

CONCLUSIONSFractures usually concentrate on the center or anterior part of superior endplate of one vertebrae and are hard to be identified by conventional radiographic examination. Failure load of endplate is positively correlated with BMD, BMC of vertebral body and endplate. There might be certain relationship between feature of fracture and severity of disc degeneration.

Aged ; Bone Density ; Cadaver ; Female ; Fractures, Stress ; diagnostic imaging ; pathology ; Humans ; Intervertebral Disc ; diagnostic imaging ; pathology ; Lumbar Vertebrae ; diagnostic imaging ; injuries ; pathology ; Male ; Middle Aged ; Radiography ; Spinal Fractures ; diagnostic imaging ; pathology

Butylated hydroxytoluene (BHT) can inhibit experimental atherosclerosis in animals. Although the agent is an antioxidant, the exact mechanism of the reaction in atherosclerosis is still unknown. To investigate the effects of BHT on expression of P-selectin (PADGEM, GMP-140), intercellular adhesion molecule-1 (ICAM-1) and class II MHC (Ia) antigen, we proposed an experiment on rats. Male rats (n=18 per group) were fed either a normal cholesterol control diet, a normal cholesterol diet containing 0.5% BHT (BD), a high cholesterol diet containing 1.5% cholesterol and 0.1% sodium cholate (CD), or the CD diet containing 0.5% BHT (BCD). Rats were sacrificed after 3 days, and after 1, 2, 4, 10, and 17 weeks of dietary treatment. Although there was no gross or light microscopic atherosclerotic lesions, scanning electron microscopy revealed monocytic adhesion to aortic endothelium and mild endothelial injuries in CD and BCD groups. Immunohistochemically, the addition of BHT to a high cholesterol diet inhibited P-selectin expression but not in ICAM-1 and Ia antigen. These findings suggest that in rats, high cholesterol diets induce expression of ICAM-1, P-selectin and Ia antigen. In addition, the antiatherogenic effect of BHT may play a role in the inhibition of P-selectin.
Animal ; Antioxidants/pharmacology ; Antioxidants/metabolism* ; Aorta, Abdominal/ultrastructure ; Aorta, Abdominal/pathology ; Aorta, Thoracic/ultrastructure ; Aorta, Thoracic/pathology ; Butylated Hydroxytoluene/pharmacology ; Butylated Hydroxytoluene/metabolism* ; Cholesterol/metabolism ; Cholesterol, Dietary/metabolism* ; Male ; Microscopy, Electron, Scanning ; P-Selectin/biosynthesis* ; Rats ; Rats, Sprague-Dawley

Cell clusters are a histological hallmark feature of intervertebral disc degeneration. Clusters arise from cell proliferation, are associated with replicative senescence, and remain metabolically, but their precise role in various stages of disc degeneration remain obscure. The aim of this study was therefore to investigate small, medium, and large size cell-clusters. For this purpose, human disc samples were collected from 55 subjects, aged 37–72 years, 21 patients had disc herniation, 10 had degenerated non-herniated discs, and 9 had degenerative scoliosis with spinal curvature <45°.15 non-degenerated control discs were from cadavers. Clusters and matrix changes were investigated with histology, immunohistochemistry, and Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Data obtained were analyzed with spearman rank correlation and ANOVA. Results revealed, small and medium-sized clusters were positive for cell proliferation markers Ki-67 and proliferating cell nuclear antigen (PCNA) in control and slightly degenerated human discs, while large cell clusters were typically more abundant in severely degenerated and herniated discs. Large clusters associated with matrix fissures, proteoglycan loss, matrix metalloproteinase-1 (MMP-1), and Caspase-3. Spatial association findings were reconfirmed with SDS-PAGE that showed presence to these target markers based on its molecular weight.Controls, slightly degenerated discs showed smaller clusters, less proteoglycan loss, MMP-1, and Caspase-3. In conclusion, cell clusters in the early stages of degeneration could be indicative of repair, however sustained loading increases large cell clusters especially around microscopic fissures that accelerates inflammatory catabolism and alters cellular metabolism, thus attempted repair process initiated by cell clusters fails and is aborted at least in part via apoptosis.

Air flow and particle-particle/wall impacts are considered as two primary dispersion mechanisms for dry powder inhalers (DPIs). Hence, an understanding of these mechanisms is critical for the development of DPIs. In this study, a coupled DEM-CFD (discrete element method-computational fluid dynamics) is employed to investigate the influence of air flow on the dispersion performance of the carrier-based DPI formulations. A carrier-based agglomerate is initially formed and then dispersed in a uniformed air flow. It is found that air flow can drag API particles away from the carrier and those in the downstream air flow regions are prone to be dispersed. Furthermore, the influence of the air velocity and work of adhesion are also examined. It is shown that the dispersion number (i.e., the number of API particles detached from the carrier) increases with increasing air velocity, and decreases with increasing the work of adhesion, indicating that the DPI performance is controlled by the balance of the removal and adhesive forces. It is also shown that the cumulative Weibull distribution function can be used to describe the DPI performance, which is governed by the ratio of the fluid drag force to the pull-off force.