Endovascular treatments for ischemic stroke: Present status and prospects

Endovascular treatments for ischemic stroke (IS) are coming into clinical practice and, as shown by recent investigations, have good prospects. These treatments for IS make it possible to expand indications for revascularization and to create prerequisite for improving the outcomes of treatment.Interventional treatments for IS should not be set off against intravenous thrombolytic therapy (ITT); it is necessary to seek their reasonable sharing. The promising directions in the development of ITT and endovascular revascularization (EVR) for IS are to upgrade tools and to choose the safest and most effective constructions, as well as to identify target patient groups needing these treatment options based on the prediction of the efficacy of these techniques with consideration for clinical findings, the pattern of a lesion, and radiological data (including estimates of perfusion, ischemic core-penumbra relationships, and collateral blood supply intensity).The paper discusses the present status and prospects of EVR of cerebrovascular arteries, its indications, and basic procedures

ВЛИЯНИЕ ГЛУБОКОЙ АНЕСТЕЗИИ НА ВОЗНИКНОВЕНИЕ ПОСЛЕОПЕРАЦИОННОЙ КОГНИТИВНОЙ ДИСФУНКЦИИ

The profound deepening of medicamentous sleep down to the burst-suppression electroencephalography pattern is used to provide medication-based protection of brain during preventive temporary clipping of the major arteries when performing surgery due to cerebral aneurysms. There is no consensus about the effect of profound suppression of electrobiological activity on the development of post-operative cognitive dysfunction. The goal: to evaluate the impact of anesthesia with the burst-suppression electroencephalography pattern on the post-operative cognitive status of the patients with no cerebral disorders. Subjects and methods. 30 patients were enrolled into the prospective randomized study, they all had surgeries due to degenerative spinal diseases. All patients were divided into two groups. Anesthesia in the main group (Group 1) differed from the one in the control group (Group 2); it included administration of propofol till achieving suppression of the electrobiological activity of burst-suppression electroencephalography pattern during 15 minutes. Prior to the surgery and in 4 days after it, all patients had neuro-psychological tests using Montreal Cognitive Assessment (MoCA), Frontal Assessment Battery (FAB) and numbers memorization techniques (NMT). Results. When testing in 4 days after surgery, results in the patients from Group 1 did not differ from pre-operative results of MoCA (Mebefore = 28, Meafter= 28, Z = 0.714, p = 0.476), FAB (Mebefore = 18, Meafter = 18, Z = 0.592, p = 0.554), memorization of numbers in the direct order (Mebefore = 18, Meafter = 18, Z = 0.178, p = 0.859) and in the reverse order (Mebefore = 18, Meafter = 18, Z = 0.548, p = 0.583). The results of the post-operative testing in Group 2 were compatible with pre-operative results of (Mebefore = 18, Meafter = 18, Z = 0.459, p = 0.646), FAB (Mebefore = 18, Meafter = 18, Z = 1.348, p = 0.178), memorization of numbers in the direct order (Mebefore = 18, Meafter = 18, Z = 0.21, p = 0.843) and in the reverse order (Mebefore = 18, Meafter = 18, Z = 0.809, p = 0.418). None of the tests detected significant differences between the Groups (U = 88, p = 0.319, Z = 0.995 for MoCA; U = 102.5, p = 0.644, Z = 0.394 for FAB; U = 92.0, p = 0.407, Z = -0.829 for memorization of numbers in the direct order, and U = 33.5, p = 0.62, Z = 0.572 for memorization of numbers in the reverse order). Conclusion. Anesthesia with burst-suppression electroencephalography pattern as a model of medication-based cerebral protection during temporary clipping of the major arteries does not cause the deterioration of cognitive status in the patients who had no cerebral pathology initially. Для медикаментозной защиты головного мозга в период превентивного временного клипирования магистральных артерий при операциях по поводу церебральных аневризм применяют значительное углубление медикаментозного сна до появления на электроэнцефалограмме паттерна «вспышка ‒ подавление». Нет единого мнения в отношении влияния выраженного угнетения биоэлектрической активности на возникновение послеоперационной когнитивной дисфункции. Цель: оценить влияние анестезии с электроэнцефалографическим паттерном «вспышка ‒ подавление» на послеоперационный когнитивный статус пациентов без патологии головного мозга. Материалы и методы. В проспективном рандомизированном исследовании участвовали 30 пациентов, которым выполнили хирургическое лечение по поводу дегенеративных заболеваний позвоночника. Все пациенты были разделены на две группы. Анестезия в основной группе (1-я группа) отличалась от контрольной (2-я группа) введением пропофола до появления в биоэлектрической активности головного мозга паттерна «вспышка ‒ подавление» в течение 15 мин. Перед операцией и на 4-е сут после вмешательства всем пациентам проводили нейропсихологическое тестирование с использованием Монреальской шкалы оценки психических функций (MoCA), батареи тестов для оценки лобной дисфункции (FAB) и методики запоминания цифр. Результаты. При обследовании на 4-е сут после операции в 1-й группе пациентов не отличались от предоперационных показателей результаты тестов MoCA (Meдо = 28, Meпосле = 28, Z = 0,714, p = 0,476), FAB (Meдо = 18, Meпосле = 18, Z = 0,592, p = 0,554), запоминания цифр в прямом (Meдо = 18, Meпосле = 18, Z = 0,178, p = 0,859) и обратном порядке (Meдо = 18, Meпосле = 18, Z = 0,548, p = 0,583). Во 2-й группе пациентов результаты послеоперационного обследования были сопоставимы с предоперационными данными тестов MoCA (Meдо = 18, Meпосле = 18, Z = 0,459, p = 0,646), FAB (Meдо = 18, Meпосле = 18, Z = 1,348, p = 0,178), запоминания цифр в прямом (Meдо = 18, Meпосле = 18, Z = 0,21, p = 0,843) и обратном порядке (Meдо = 18, Meпосле = 18, Z = 0,809, p = 0,418). Между 1-й и 2-й группами значимых отличий не выявлено ни по одной из методик (U = 88, p = 0,319, Z = 0,995 для MoCA; U = 102,5, p = 0,644, Z = 0,394 для FAB; U = 92,0, p = 0,407, Z = -0,829 для запоминания в прямом и U = 33,5, p = 0,62, Z = 0,572 для запоминания в обратном порядке). Вывод. Проведение анестезии с электроэнцефалографическим паттерном «вспышка ‒ подавление» как модели медикаментозной защиты мозга на период временного клипирования магистральных артерий не приводит к ухудшению когнитивного статуса пациентов без исходной патологии головного мозга.

High-field magnetic structure of the triangular antiferromagnet RbFe(MoO4)2

The magnetic H − T phase diagram of a quasi-two-dimensional antiferromagnet RbFe(MoO4 )2 (S = 5/2) with an equilateral triangular lattice structure is studied with 87Rb NMR and neutron-diffraction techniques. This combination of experimental techniques allows us to determine the ordered components of the magnetic moments on the Fe3+ ions within various high-field phases—the Y, UUD, V, and fan structures, stabilized in the compound by the in-plane magnetic field. It is also established that the transition from the V to the fan phase is of first order, whereas the transition from the fan phase to the polarized paramagnetic phase is continuous. An analysis of the NMR spectra shows that the high-field fan phase of RbFe(MoO4 )2 can be successfully described by a periodic commensurate oscillation of the magnetic moments around the field direction in each Fe3+ layer combined with an incommensurate modulation of the magnetic structure perpendicular to the layers

New high magnetic field phase of the frustrated S=1/2S=1/2 chain compound LiCuVO4_4

Magnetization of the frustrated $S=1/2$ chain compound LiCuVO$_4$, focusing on high magnetic field phases, is reported. Besides a spin-flop transition and the transition from a planar spiral to a spin modulated structure observed recently, an additional transition was observed just below the saturation field. This newly observed magnetic phase is considered as a spin nematic phase, which was predicted theoretically but was not observed experimentally. The critical fields of this phase and its dM/dH curve are in good agreement with calculations performed in a microscopic model (M. E. Zhitomirsky and H. Tsunetsugu, preprint, arXiv:1003.4096v2).Comment: 5 pages, 4 figure

Magnetic properties and revisited exchange integrals of the frustrated chain cuprate PbCuSO4_4(OH)2_2 - linarite

We present a detailed study in the paramagnetic regime of the frustrated $s$ = 1/2 spin-compound linarite, PbCuSO$_4$(OH)$_2$, with competing ferromagnetic nearest-neighbor and antiferromagnetic next-nearest-neighbor exchange interactions. Our data reveal highly anisotropic values for the saturation field along the crystallographic main directions, with $\sim$ 7.6, $\sim$ 10.5 and $\sim$ 8.5\,T for the $a$, $b$, and $c$ axes, respectively. In the paramagnetic regime, this behavior is explained mainly by the anisotropy of the \textit{g}-factor but leaving room for an easy-axis exchange anisotropy. Within the isotropic $J_1$-$J_2$ spin model our experimental data are described by various theoretical approaches yielding values for the exchange interactions $J_1$ $\sim$ -100\,K and $J_2$ $\sim$ 36\,K. These main intrachain exchange integrals are significantly larger as compared to the values derived in two previous studies in the literature and shift the frustration ratio $\alpha = J_2/|J_1|$ $\approx$ 0.36 of linarite closer to the 1D critical point at 0.25. Electron spin resonance (ESR) and nuclear magnetic resonance (NMR) measurements further prove that the static susceptibility is dominated by the intrinsic spin susceptibility. The Knight shift as well as the broadening of the linewidth in ESR and NMR at elevated temperatures indicate a highly frustrated system with the onset of magnetic correlations far above the magnetic ordering temperature $T_\mathrm{N}$ = 2.75(5)\,K, in agreement with the calculated exchange constants.Comment: 18 pages, 18 figure

Рефрактерный эпилептический статус после клипирования аневризмы средней мозговой артерии (клиническое наблюдение)

We present the management features for the refractory epileptic status in a patient after surgical treatment of unruptured cerebral aneurysm and no epileptic prehistory. The role of continuous electroencephalographic monitoring in adjusting the rate of drugs administration for general anesthesia in the treatment of this condition is also described.Приведена демонстрация и обсуждение особенностей ведения пациентки с рефрактерным эпилептическим статусом после хирургического лечения неразорвавшейся аневризмы головного мозга без эпилептического анамнеза. Показана роль непрерывного электроэнцефалографического мониторинга для подбора скорости введения препаратов для общей анестезии при лечении данного состояния