Hokkaido University

About: Hokkaido University is a education organization based out in Sapporo, Hokkaidô, Japan. It is known for research contribution in the topics: Population & Catalysis. The organization has 53925 authors who have published 115403 publications receiving 2651647 citations. The organization is also known as: Hokudai & Hokkaidō daigaku.

Pedicle screw fixation for nontraumatic lesions of the cervical spine

Abstract: Study design This retrospective study was conducted to analyze the clinical results in 45 patients with nontraumatic lesions of the cervical spine treated by pedicle screw fixation. Objectives To evaluate the effectiveness of pedicle screw fixation in reconstructive surgery for nontraumatic cervical spinal disorders. Summary of background data Pedicle screw fixation for hangman's fracture of the axis and traumatic lesions of the middle and lower cervical spine has been reported; however, there have been no reports on pedicle screw fixation for nontraumatic lesions of the cervical spine. Methods Forty-five patients with nontraumatic lesions of the cervical spine underwent reconstructive surgery including pedicle screw fixation and fusion. Five patients underwent occipitocervical fixation for the lesion of the upper cervical spine, and one patient underwent separate occipitocervical fixation and cervicothoracic fixation. Cervical or cervicothoracic fixation was performed in 39 patients. Twenty-six of these patients underwent simultaneous laminectomy or laminoplasty. Supplemental anterior surgery was conducted for 15 patients. Results Solid fusion was obtained in all patients except eight with metastatic vertebral tumors who did not receive bone graft. Correction of kyphosis was adequate. There were no neurovascular complications, except one case of transient radiculopathy caused by screw threads. Conclusions Pedicle screw fixation is a useful procedure for posterior reconstruction of the cervical spine. This procedure does not require the lamina for stabilization, and should be especially valuable for simultaneous posterior decompression and fusion. The risk to neurovascular structures, however, cannot be completely eliminated.

Stability and chemical composition of pargasitic amphibole in MORB pyrolite under upper mantle conditions

Abstract: The stability field of pargasitic amphibole in a model mantle composition (MORB pyrolite) has been experimentally determined for a fixed water content. A solidus for a pargasite-bearing lherzolite has been defined at pressures below the limit of amphibole stability of 30 kbar at T = 925 °C. The maximum temperature for pargasitic amphibole in MORB pyrolite occurs at 1075 °C between P = 18 and 25 kbar. This maximum lies between that determined for a fertile peridotite composition (Hawaiian pyrolite) and a depleted peridotite composition (Tinaquillo lherzolite). A comparison of the new results with those from earlier studies suggests that the stability for a particular bulk H2O content is mostly controlled by alkali content of the lherzolite composition. The systematic compositional variation of pargasitic amphibole as a function of pressure and temperature can be represented as an increase of the richterite component with increase in both pressure and temperature. For a given pressure the tschermakite component increases with increasing temperature. The compositions of coexisting clinopyroxenes also show a systematic variation with pressure and temperature. The phase relationships in MORB pyrolite combined with the modal abundance of coexisting phases show that the breakdown reactions of pargasitic amphibole occur continuously throughout the subsolidus region studied. The temperature stability limit of pargasitic amphibole coincides with the water-undersaturated solidus (amphibole-dehydration solidus) at pressures below 30 kbar. The experimental results are applicable to pargasitic amphibole-bearing natural peridotites. Cooling and decompression paths and heating events observed in natural peridotites can be interpreted from changes in the composition of pargasitic amphibole. The data are also applicable to a model for peridotite melting and hydration process in the subduction environment.

Association of autoantibodies against the phosphatidylserine-prothrombin complex with manifestations of the antiphospholipid syndrome and with the presence of lupus anticoagulant.

Abstract: Objective To clarify the association of autoantibodies against prothrombin with the clinical manifestations of the antiphospholipid syndrome (APS) and with the presence of lupus anticoagulant (LAC). Methods We examined 265 patients who visited our autoimmune disease clinic. IgG and IgM antiprothrombin antibodies were tested by enzyme-linked immunosorbent assay (ELISA) as either antiphosphatidylserine–prothrombin complex (aPS/PT) antibodies or as antibodies against prothrombin coated on irradiated ELISA plates (as antigen) (aPT). IgG, IgM, and IgA anticardiolipin (aCL) antibodies and their β2-glycoprotein I (β2GPI) dependency were also evaluated by ELISA. LAC was tested by 3 different methods. Results The presence of aPS/PT, but not of aPT, significantly correlated with the clinical manifestations of APS (odds ratio [OR] 4.39, 95% confidence interval [95% CI] 2.06–9.38), and aPS/PT antibodies were as specific as β2GPI-dependent aCL for APS (93.1% for both). IgG aPS/PT strongly correlated with the presence of LAC as detected using the dilute Russell viper venom time test (OR 38.2, 95% CI 13.4–109.1). Conclusion Antiprothrombin antibodies are heterogeneous and their clinical relevance depends on the method of detection applied. Positive results on the aPS/PT test can serve as a marker of thrombotic events in patients with autoimmune diseases.