[Long association tracts of the human white matter: an analysis of 18 hemisphere dissections and in vivo HARDI-CSD tractography]. / Dlinnye assotsiativnye provodyashie puti belogo veshchestva golovnogo mozga cheloveka: analiz dissektsii 18 polusharii i HARDI-CSD traktografii in vivo.

BACKGROUND: Anatomy of the conduction tracts of the cerebral cortex has been studied for a long time. Invention of diffusion tensor tractography renewed interest in this subject. The objectives of this work were to develop and improve protocols for dissection of the long association tracts of the human brain with studying the features of their segmentation, topography, and variability, compare the obtained data with the MR tractography data, and prepare for further clinical and anatomical studies. MATERIAL AND METHODS: We used 18 cerebral hemispheres (from 10 males and 8 females; 9 left and 9 right hemispheres). The mean age of cadavers was 68 years. Specimen were fixated in accordance with the Klingler technique. Immediately after collection, specimens were placed in a 10% formalin solution for at least 4 weeks. After that, the pia was removed; specimens were frozen at -20 °C for a week and then unfrozen in a 96% ethanol solution for a day. We performed 10 lateral dissections, 2 lateral dissections with isolation of the frontal aslant tract, 2 basal dissections, 1 combined basolateral dissection, 2 frontal dissections, and 1 medial dissection. At the time of dissection and after it, specimens were stored in a 96% ethanol solution. Modified, disposable, therapeutic wooden spatulas were used for manipulations. A microscope (magnification of 6-40x) was used in 2 lateral and 2 basal dissections. MR tractography (HARDI-CSD) was carried out in 5 healthy volunteers using a GE Signa HDxt MRI scanner a field strength of 3.0 T. RESULTS: We clearly identified the following fascicles: the arcuate fascicle (AF) and superior longitudinal fascicle (SLF) in 6/6 hemispheres on the right and in 5/6 hemispheres on the left, the inferior longitudinal fascicle (ILF) in 3/6 hemispheres on the left and in 4/6 hemispheres on the right, the uncinate fascicle (UF) in 4/4 hemispheres on the left and in 4/4 hemispheres on the right, and the inferior fronto-occipital fascicle (IFOF) in 4/4 hemispheres on the left and in 3/4 hemispheres on the right. Identification was less successful in the case of the frontal aslant tract (FAT) in 1/2 hemispheres on the left and in 0/2 hemispheres on the right. The used technique failed to identify the vertical occipital fascicle (VOF) of Wernicke, a segment of the superior longitudinal fascicle SLF I, and the middle longitudinal fascicle (MdLF). The MR tractography HARDI-CSD data were compared with the dissection data. We described in detail segmentation of the superior longitudinal, arcuate, and inferior fronto-occipital fascicles. Contradictory data were obtained for the superior longitudinal fascicle: a two-segment structure (SLFh and SLFv) was found in most (10/12) specimens, while a three-segment structure was revealed in the other (2/12) specimens (identified SLF II and SLF III). In the arcuate fascicle, the ventral and dorsal segments were successfully identified in 2/12 cases (1 left and 1 right), whereas identification failed in the other cases. During dissection of the inferior fronto-occipital fascicle, we could identify its surface layer in 1 of 8 cases (left) and its deep layer in one more case (left). CONCLUSION: Examination of the long association tracts using the Klingler technique has significant limitations in the fiber intersection areas (sagittal striatum). The frontal aslant tract was least studied; we proposed a special anterior dissection technique for its isolation. The superior longitudinal fascicle can have both the two-segment (10/12) and three-segment (2/12) structure. Investigation of the segmental anatomy of the long association tracts will be continued in further dissections. When planning neurosurgical interventions in the projection areas of the long association tracts, both preoperative HARDI-tractography and anatomical dissections ex vivo, based on the proposed protocols, can be recommended for the operating surgeon to master a three-dimensional picture of the tract topography.

Contribution of the actomyosin motor to the temperature-dependent translational diffusion of water by cytoplasmic streaming in Elodea canadensis cells.

The extent to which the actomyosin motor responsible for cytoplasmic streaming contributes to the translational diffusion of water in Elodea canadensis cells was studied by a nuclear magnetic resonance (NMR) spin-echo technique. The relative contribution of the actomyosin motor was determined from the corresponding apparent diffusion coefficient by the Einstein-Smolukhovsky relation. It is equal to the difference between the diffusional displacements of the cytoplasmic and the bulk water (deltaX). The NMR data show that the temperature dependence of deltaX is humpshaped, which is characteristic of enzyme reactions. At the same time, the apparent diffusion coefficient of cytoplasmic water increases with an increase in temperature. The most significant contribution of the actomyosin motor to deltaX is observed at temperatures below 20 degrees C. Within the temperature range of 20 to 33 degrees C, deltaX changes only slightly, and a further increase in temperature reduces deltaX to zero.

Development of neuronal ganglion xenografts from gastropoda in rat brain.

Survival of neuronal ganglia from newborn snail (Helix aspera L.) in the brain of adult rats was studied. Snail ganglion survived in the brain of warm-blooded animals for 6 months without inducing immune conflict. At early stages (5 days) after transplantation, xenografts increased in size and were several times larger than native ganglia from 10-day-old snails, thereafter (on days 28 and 180) they became smaller still surpassing the sizes of ganglia from snail of the corresponding age. Rapid enlargement of the xenograft was due to cell reactive processes in the ganglion. Deep penetration of large vessels from xenografts to rat brain was observed.

[Effect of dopamine enriched ganglion xenografts from the immature CNS of Helix aspersa L. snail on the learning time during acquisition of an operant food-procuring reflex in WAG/RIJ rats]. / Vliianie ksenotransplantatov gangliev, bogatykh dofaminom, iz nezreloi TsNS molliuska Helix aspersa L. na vremia obucheniia pri vyrabotke instrumental'nogo pishchedobyvatel'nogo refleksa u krys linii WAG/RIJ.

Xenografts from the ganglia of a newborn terrestrial snail Helix aspersa L. were implanted into the right parietal area of the brain cortex of WAG/Rij rats with absence epilepsy. Rats with implanted xenografts were trained for reaching a food ball from a tube (reaching test). It was shown that the mean duration of each leaning stage and total time necessary for acquisition of the instrumental conditioning (till the learning criterion) were shorter in animals with xenografts than in control groups of animals.

[Distraction epiphysiolysis for lengthening of the extremities in children with the hip and knee tuberculosis]. / Distraktsionnyi épifizeolitz dlia udlineniia konechnostei u detei s posledstviiami tuberkuleza tazobedreenogo i kolennogo sustavov.

6 cases with the sequelae of bones and joints tuberculosis underwent the distraction epiphysiolysis aimed at the lengthening of these extremities. The maximal lengthening reached 7 cm. The complications and treatment results are described.