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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta neurochirurgica 141 (1999), S. 119-126 
    ISSN: 0942-0940
    Keywords: Keywords: Aged patients; craniovertebral junction; disc hernia; surgical approach.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary  The incidence of high cervical disc lesions is extremely rare, and the mechanism of their development is unclear. We report these three cases, and discuss the possible mechanisms. We also describe surgical strategies for these lesions.  The first and second cases were an 82-year-old male and an 84-year-old male with retro-odontoid disc hernia. The third was an 83-year-old female with a herniated disc at C2/C3. To investigate Aetiological mechanisms of these lesions, we examined the findings on cervical images in extension and flexion, and compared the results in a younger than 80-year-old group and an older than 80-year-old group.  The patients underwent surgery via a posterolateral intradural approach. Wide laminectomy and incision of the dentate ligaments enabled access to the ventral space of the upper cervical spinal canal and sufficient decompression. All patients became ambulatory postoperatively without special fixation of the cervical spine. In the younger group, the level mostly loaded during cervical movement was C5/6, however, the levels in the older group were C2/3 and C3/4.  In elderly patients, less mobilization of the middle and/or lower cervical spine due to spondylotic change causes overloading at higher levels resulting in high cervical disc lesions. Retro-odontoid disc lesions can be caused by a herniated disc at C2/C3, which migrates upward. Regarding surgical strategy, the posterolateral intradural approach is less invasive and more advantageous for these lesions.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0942-0940
    Keywords: Keywords: Down regulation; nitric oxide; protein kinase C; subarachnoid haemorrhage; vasospasm.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary  We previously showed that a canine basilar artery manifested tonic and potent, protein kinase C (PKC)-dependent contractions when nitric oxide (NO) was inhibited. We also reported a linear correlation between chronological changes in the angiographic severity of vasospasm, enhanced PKC, and attenuated guanosine, 13′,15′-cyclic monophosphate (cGMP) activity in a canine subarachnoid haemorrhage model. The activity of cGMP is an indicator of NO-function. Based on this evidence, we have hypothesized that PKC and NO regulate cerebral vascular tone. We particularly focused on the role of NO in a negative feedback mechanism on PKC activity in the maintenance of vascular tone. To further confirm our hypothesis, we investigated the effect of PKC down-regulation on the tonic vascular contraction induced by NO-inhibition.  Canine basilar artery was used in the experiment. Significant down-regulation of PKC activity in vascular smooth muscle cells was obtained by incubation with 10−5 mole/L of phorbol 12-myristate 13-acetate (PMA) for 24 hours. The tonic and potent contraction induced by NO-inhibition was completely suppressed in the PKC down-regulated artery, even though the artery manifested a significant contraction in high-K+ solutions. These results indicate an obligatory role of PKC activity in tonic contraction when NO is inhibited, and support our previous data. Nitric oxide induces vascular relaxation by inhibiting PKC activity. Subarachnoid haemorrhage impairs this inhibition, resulting in PKC-dependent vascular contraction, such as vasospasm.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0942-0940
    Keywords: Keywords: Parkinson's disease; subthalamic nucleus; stereotactic surgery.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary  The neural activity pattern of the subthalmic nucleus (STN) was investigated in five patients with Parkinson's disease who were scheduled for electrode implantation for chronic stimulation of the STN.  The initial target was placed 8 mm or 10 mm lateral to the midline, 3 mm to 4 mm posterior to the midcommissural point, and 5 mm to 6 mm below the intercommissural (AC-PC) line. The STN was identified by semi-microelectrode recordings with a trajectory moving laterally in 2-mm steps. The amplitudes of multi-unit activities were relatively low at depths from 8 mm to 5 mm above and from 1 mm to 4 mm below the target, while those 4 mm to 0 mm above the target were significantly higher than at the other sites (ANOVA, Fisher's test, p〈0.05), with the highest amplitude at 2 mm above the target (91.0±23.3μv, n=15). In the mediolateral direction, amplitudes were relatively higher in the lateral portion, and amplitudes at 14 mm lateral to the midline were significantly higher than at the other sites (ANOVA, Fisher's test, p〈0.05). The target for chronic electrical stimulation was determined to be at the midpoint of the hyperactive STN, i.e., 12 mm lateral to the midline in three patients and 13 mm lateral in two patients. Movement-related neural activity was observed at 5 sites, i.e., 3 sites responded to passive movement of the contralateral wrist and 2 sites to passive knee and/or ankle movement.  In conclusion, our data show that the lateral part of the STN is hyperactive in PD, and recordings of neural activities contributed greatly to identifying the STN and determining the target for chronic stimulation within it.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0942-0940
    Keywords: Keywords: Endothelin-1; protein kinase C; subarachnoid haemorrhage; vasospasm.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary  Endothelium plays a role in the regulation of vascular tone. Endothelin is a family of potent vasoconstrictive peptides, and endothelin-1 (ET-1) produced in the endothelium induces a tonic contraction via specific receptor ETa. ET-1 has been postulated as an important factor in the development of vasospasm after subarachnoid haemorrhage (SAH). We have previously shown that protein kinase C (PKC) of the cerebral artery plays a pivotal role in the pathogenesis of vasospasm. The purpose of this study is to clarify the relationship between ET-1 and PKC in the development and maintenance of vasospasm.  Using a “two-haemorrhage” canine model, chronological changes of angiographic progression of vasospasm, PKC activation, and ET-1 level of the basilar artery were assessed. In an isometric tension study with a control artery, the effects of ETa- and ETa/ETb-antagonists on the tonic contraction induced by ET-1 were examined. The effects of ET-1, ET-1 and an ETa-antagonist, and ET-1 and an ETa/ETb-antagonist on PKC activation were also evaluated.  ET-1 level temporarily increased, then decreased to the control level in a later stage of vasospasm. ET-1 induced a tonic contraction and enhancement of PKC activation, but both were inhibited either by an ETa- or an ETa/ETb-antagonist.  These results indicate that ET-1 initiates the development of vasospasm through PKC activation, but does not contribute to prolonged vasospasm.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0006-291X
    Keywords: [abr] ANP; atrial natriuretic peptide ; [abr] BNP; brain natriuretic peptide ; [abr] Ir-; immunoreactive ; [abr] RIA; radioimmunoassay ; [abr] RP-HPLC; reverse phase high performance liquid chromatography ; [abr] TFA; trifluoroacetic acid
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0006-291X
    Keywords: [abr] ANP; atrial natriuretic peptide ; [abr] BNP; brain natriuretic peptide ; [abr] Ir-; immunoreactive ; [abr] RIA; radioimmunoassay ; [abr] RP-HPLC; reverse phase high performance liquid chromatography ; [abr] TFA; trifluoroacetic acid
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0040-4020
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 8 (1975), S. 202-202 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The stability of the heavily faulted state has been investigated. At temperatures higher than 300°C, remarkable redistributions of peak intensities on diffuse streaks were observed in addition to the decrease in the total diffuse intensity.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 12 (1979), S. 545-550 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Intensity profiles of diffuse streaks along [111] were accurately measured for heavily faulted regions in deformed specimens. They often showed two or three broad peaks and differ remarkably from Paterson's [J. Appl. Phys. (1952). 23, 805–811] profiles (Reichweite s = 1), but are in fairly good agreement with Kakinoki's [Acta Cryst. (1967). 23, 875–885] profile of s = 2 with the sequence probabilities α1 = 0.45–0.85 and α2 = 0–0.1. This means that the deformation (intrinsic) faults are produced more easily on every other (111) plane than on successive planes. A model which shows the distribution of the deformation faults is constructed by a computer simulation. A detailed study using Kakinoki's theory with s = 3 shows a better fit with the experimental profile.
    Type of Medium: Electronic Resource
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