Morphological Parameters Associated with Ruptured Posterior Communicating Aneurysms

The rupture risk of unruptured intracranial aneurysms is known to be dependent on the size of the aneurysm. However, the association of morphological characteristics with ruptured aneurysms has not been established in a systematic and location specific manner for the most common aneurysm locations. We evaluated posterior communicating artery (PCoA) aneurysms for morphological parameters associated with aneurysm rupture in that location. CT angiograms were evaluated to generate 3-D models of the aneurysms and surrounding vasculature. Univariate and multivariate analyses were performed to evaluate morphological parameters including aneurysm volume, aspect ratio, size ratio, distance to ICA bifurcation, aneurysm angle, vessel angles, flow angles, and vessel-to-vessel angles. From 2005–2012, 148 PCoA aneurysms were treated in a single institution. Preoperative CTAs from 63 patients (40 ruptured, 23 unruptured) were available and analyzed. Multivariate logistic regression revealed that smaller volume (p = 0.011), larger aneurysm neck diameter (0.048), and shorter ICA bifurcation to aneurysm distance (p = 0.005) were the most strongly associated with aneurysm rupture after adjusting for all other clinical and morphological variables. Multivariate subgroup analysis for patients with visualized PCoA demonstrated that larger neck diameter (p = 0.018) and shorter ICA bifurcation to aneurysm distance (p = 0.011) were significantly associated with rupture. Intracerebral hemorrhage was associated with smaller volume, larger maximum height, and smaller aneurysm angle, in addition to lateral projection, male sex, and lack of hypertension. We found that shorter ICA bifurcation to aneurysm distance is significantly associated with PCoA aneurysm rupture. This is a new physically intuitive parameter that can be measured easily and therefore be readily applied in clinical practice to aid in the evaluation of patients with PCoA aneurysms.     

Subunit polypeptide composition of rubisco and the origin of allopolyploid Arabidopsis suecica (Brassicaceae)

The polypeptide composition of the large and small subunits of Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) from Arabidopsis thaliana, A. suecica and Cardaminopsis arenosa have been studied by IEF (isoelectric focusing) analysis. The putative recent alopolyploid origin of A. suecica is supported. The chloroplast encoded large subunits served to identify solely A. thaliana as the maternal parent whereas the nuclear encoded small subunits indicate C. arenosa as the paternal species.     

Das pyroelektrische Verhalten und das permanente elektrische Moment von menschlichem und tierischem Sehnengewebe

Zusammenfassung Bei menschlichem und tierischem Sehnengewebe wurde pyroelektrisches Verhalten festgestellt. Pyroelektrisches Verhalten bedeutet, daß eine permanente makroskopische elektrische Polarisation und somit ein permanentes elektrisches Moment in Richtung der pyroelektrischen Achse vorhanden ist.Die pyroelektrische (und daher auch piezoelektrische) Achse verläuft in der Längsrichtung der Sehnenfasern bzw. ihrer Kollagenfibrillen. Sie stimmt überein mit der optischen Faserachse, in deren Verlauf positiv einachsige Doppelbrechung bekannt ist. Sehnen mit leidlicher Parallelausrichtung ihrer Faserbündel zeigen dementsprechend makroskopisch eine pyroelektrische Achse parallel zur physiologischen Sehnenlängsachse. Bei seilartiger Bündelung der Fibrillen oder anderen histologischen Unregelmäßigkeiten im Faserverlauf zeigen sich korrespondierende Unregelmäßigkeiten des pyroelektrischen Achsenverlaufs.In genau korrespondierenden Abschnitten der gleichen Sehne verschiedener Individuen fand sich eine sehr erhebliche biologische Streubreite der pyro- und piezoelektrischen Effekte.In situ hatte das permanente elektrische Moment der untersuchten menschlichen und Rinder-Sehnen, sowie der Schwanzsehnen von Ratten eine festliegende gleichsinnige Vektorrichtung bei allen Individuen. Die Vektorrichtung war bei den untersuchten korrespondierenden Sehnen von Mensch und Rind sowie bei den Rattenschwanz-Sehnen analog.Die Vektorrichtung der permanenten elektrischen Polarisation bei Sehnengewebe, und wahrscheinlich auch bei anderen kollagenhaltigen Strukturen, scheint in Beziehung zur morphogenetischen Entwicklungsrichtung der Tiere zu stehen.

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Summary Tendons are pyroelectric. Pyroelectrical behaviour is identical with a permanent electrical moment in the direction of the pyroelectrical axis. There exists a pyroelectrical (and consequently also piezoelectrical) axis corresponding to the longitudinal axis of the tendon fibres and their collagen fibrils, and also corresponding to their optical axis, in the direction of which a positive birefringence is known.Accordingly in tendons with an approximately parallel alignment of the collagen fibres the pyroelectrical (and piezoelectrical) axis corresponds to the physiological longitudinal tendon axis. In rope-like or any other histological irregular forms of the collagen fibre alignment corresponding irregularities of the electrical axis direction were found.The pyro- and piezoelectric effects show large biological variations in corresponding tendons of different individuals.In situ the permanent electrical moment in the examined tendons of men and ox and of rat-tail respectively is always in the same vector direction in each individual. This vector direction is analogical in all examined corresponding tendons of men, ox, and also in rat-tail. The permanent electrical moment of tendons (as well as of other collagen-containing tissues) seems to correspond to the morphogenetical development axis of animals.The results of this investigation may be understood by the assumption that the rod-like collagen molecule (i.e. tropocollagen) represents an electrical dipole with a permanent electrical moment in the longitudinal direction of the rod.

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Unterstützt durch Sachbeihilfen der Deutschen Forschungsgemeinschaft.