[Features of the ultrastructure of the brain tissue of Meriones unguiculatus after cerebral ischemia and postischemic recirculation]. / Osobennosti ul'trastruktury tkani mozga mongol'skikh peschanok v usloviiakh ishemii mozga i postishemicheskoi retirkuliatsii.

The authors studied the ultrastructure of the brain tissue in "symptom negative" clawed jirds (M. unguiculatus) in the presence of permanent and transient circulatory ischemia caused by ligation of the right common carotid artery and by a 3-minute occlusion of the left common carotid artery which was unattended by any clinical manifestations signifying cerebral ischemia. The formation of oedema and dystrophic changes in the right hemisphere differed from that in the left one. Permanent ischemia was associated with the typical picture of hypoxic damage to the neural tissue with the development of cytotoxic oedema. Transient ischemia was predominantly characterized by an impairment of the blood-brain barrier with the development of marked vasogenic oedema. The study made it possible to closely follow the differences in the formation of an early stage of brain damage in permanent and transient ischemia and to establish the possibility of the damaging effect of blood recirculation in the hemisphere previously affected with ischemia.

[Possible significance of the gastrointestinal "steal" syndrome in experimental cerebral ischemia]. / O vozmozhnom znachenii sindroma "obkradyvaniia" zheludochno-kishechnym traktom pri ishemii mozga v éksperimente.

The authors studied the clinical manifestations of cerebral ischemia induced by the ligation of the right common carotid artery and by a 3-minute ligation of the left carotid artery in two groups of clawed jirds: 28 animals on the usual diet and 34 animals which were given the usual meal 2-3 hours prior to the operation after 24 hours of fasting. The clinical manifestations of cerebral ischemia were more significantly pronounced in the second group. This group was also characterized by a more marked hyperemia of the gastrointestinal tract as shown both macro- and microscopically. It is suggested that a more severe course of ischemia in this group of animals is induced by the redistribution of the blood into the bed of the gastrointestinal arteries, which leads to a decrease in the cerebral blood content and aggravated conditions of the collateral blood supply in cases of brain ischemization.

[Analysis of the causes of the predominant localization of macular cerebral vessel and tissue lesions following an acute rise in arterial pressure]. / K analizu prichin preimushchestvennoi lokalizatsii piatnistogo povrezhdeniia sosudov i tkani mozga pri ostrom pod'eme arterial'nogo davleniia

In acute experiment on rabbits a rise in arterial pressure was induced by intravenous administration of noradrenaline with simultaneous recording of the changes in the vessel diameter on the surface of the brain in arterial bordering zones and in the basin of the middle cerebral artery and permeability of the hematoencephalic barrier to Evans blue. Autoregulation disorder manifesting itself in dilatation of the arteries and spreading out of their enternal elastic membrane developed first of all in arterial bordering zones, appeared earlier and was marked mainly in the anastomoses of the major type and small arteries lying at an acute angle which are more often detected in the occipital regions of the blood supply area. Similar results were obtained with an analysis of 3-section cases of hypertensive encephalopathy.

[Sequelae of diathermocoagulation of cerebellar arteries and veins in normal rabbits and rabbits sensitized to brain antigen]. / Posledstviia diatermokoaguliatsii arterii i ven mozzhechka u normal'nykh i sensibilizirovannykh mozgovym antigenom krolikov

Electrocauterization of an artery or a vein on the surface of the posterior lobe of the cerebellum may cause no focal changes in the bed of the occluded vessel, or result in varying severity and extension of lesion of the posterior cerebellar lobe. In occluding an artery a focus of complete necrosis or oedema is formed in its bed, while in occluding avein a focus of oedema is formed that may be accompanied by erythrocytic extravasation. In the group of animals sensitized with brain antigens a tendency towards oedema enhancement, and a vascular permeability increase is noted, neuronal changes are more frequent at a distance from the occluded vessel's basin. However, the importance of sensitization is, as a rule, masked by individual peculiarities of the collateral supply or venous return in the bed of the occluded vessel.

[Changes in local cerebral blood flow during increased general arterial pressure in animals]. / Ob osobennostiakh izmeneniia lokal'nogo mozgovogo krovotoka pri povyshenii obshchego arterial'nogo davleniia u zhivotnykh

General blood pressure was increased in normal rabbits and in the animals with experimental renal hypertension by intravenous injection of noradrenaline; local cerebral circulation was recorded in two areas of the cortex the white matter of the large hemispheres by the method of hydrogen clearance and also by EEG. A number of successive changes of the local cerebral circulation was observed; these changes could be unitypical or different by duration and character on different electrodes. The appearance of pathological forms of electrical activity was noted on the EEG.