Biomedical subjects
Publications and source records attributed to B V Gaĭdar.
The specifics of local blood flow (LBF) was studied in the areas of electrical stimulation. The occurring changes are determined primarily by the functional state of neural tissue in the stimulation area as well as in the whole brain. The cortex develops an insrement of the LBF after stimulation by the 4th-5th day whereas no such tendency was found in the white matter.
The authors analyze possibilities of early diagnosis of cauda equina tumors based on examining 105 patients. Note the lack of pathognomonic symptoms. Distinguish, however, a considerable group of patients with a progressive disease course destined to a mandatory goal-oriented examination at specialized hospitals. Lay emphasis on the necessity of a mandatory analysis of the cerebrospinal fluid (CSF) and CSF samples over time. Validate the necessity of carrying out positive myelography primarily with water-soluble contrast substances and computer-aided tomography with a purpose of differential diagnosis between spinal lesions associated with the radicular syndrome.
Clinico-physiological studies of 426 healthy subjects revealed normal parameters of the blood flow linear velocity along the extra- and intracranial portions of major cerebral vessels as determined by means of transcranial dopplerography. Normal parameters of the systolic-diastolic coefficient, the reactivity of major vessels and their pial draining network were studied in respect to their responses to functional loads of physical and chemical character which enabled one to determine functional possibilities of the cerebral circulation system. The ability of the dopplerographic technique was assessed in respect to studying of separate control mechanisms of the brain circulation system.
The effect of mildronate (25 mg/kg, i.v.) administration during 14 days on the restoration of cerebral blood flow and vascular reactivity after local lesions and ischemia, was studied in rabbits. The effect involved an improvement of restorative processes due to a faster normalizing of reactivity of cerebral vessels. The latter seems to be more important for optimization of cerebral blood flow after extreme effects than the absolute level of the cerebral blood flow.
Presented is the clinical experience with vision restitution by direct electrostimulation (ES) of lesioned visual nerves in 128 operated patients with chiasmal-sellar diseases (chiasmal-sellar tumors and optico-chiasmatic arachnoiditis). Comparative analysis of ES-treated and control group was performed. Indications for this technique were determined in different forms of the disease depending on its severity and duration. ES showed positive results increasing the reliability and speed of vision restitution in operated patients.
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The local cerebral blood flow (LCBF) and cerebrovascular reactivity to CO2 inhalation test were studied in rabbits after experimental local brain lesions. A decrease of the LCBF and cerebrovascular reactivity was observed in the grey and white matter surrounding the traumatic focus at the distance of about 15 mm, being minimal on the 3rd-5th days followed by normalizing by the 10th-14th days after lesions. The cerebrovascular reactivity was found to be a valuable prognostic parameter to assess the functional restoration of the brain.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The article generalizes experience in the restoration of vision by direct stimulation of damaged optic nerves after operations for pathological conditions of the chiasmal-sellar region (tumors of the chiasmal-sellar region, optochiasmic arachnoiditis, damage of the optic nerve in the bone canal) in 111 patients. The therapeutic effect was favourable in two thirds of the patients. Indications are determined for the use of the method in various types, duration, and severity of the disease. The use of the method with due regard for the determined indications increases the reliability, degree, and rate of restoration of vision in patients who underwent operation.
The specific features of immunological responses and enzymatic activity of cerebrospinal fluid in the development of intracranial infectious complications were outlined in 16 neurosurgical patients after surgical interventions. On days 1-3-5 days after surgery, the immunobiochemical spectrum of cerebrospinal fluid showed substantial changes associated with the impaired permeability of the blood-brain barrier and the stress-induced transition of biochemical functional systems on the minimum functioning during anaerobic energy supply. Increasing lipid peroxidation processes reflect the result of catabolic reactions and energy deficiency, followed by intensive cytolysis of leukocytes and nerve cells. With this, antibody synthesis and great rises in the formation of circulating immune complexes is the essence of sanogenetic mechanisms basically aimed at eliminating the released and bound antigen in the given time interval.
Cerebral bloodflow and central hemodynamics were studied during general anesthesia in patients with tumors of the posterior cranial fossa operated on in a sitting posture. A sitting posture during general anesthesia is conductive to a marked reduction of the stroke volume and linear velocity of the cerebral bloodflow, this creating a risk of cerebral tissue ischemia under conditions of intracranial hypertension and a hardly adequate short-term compensatory increase of the total vascular resistance and "paradoxical" increase of cerebrovascular tone. Since the neurogenous mechanisms of cerebral bloodflow autoregulation are disordered during anesthesia, one should admit that stabilization of central hemodynamics at all stages of anesthesia is a most important condition for optimizing brain tissue perfusion.
The outcomes of multimodality treatment were assessed in 42 patients with glial tumors of cerebral hemispheres. Radical surgery turned out to be feasible only in 52.4% of patients with high-grade tumor histological variants and 66.7% of patients with low-grade tumors. Five-year survival rates did not improve when a cumulative radiation dose was increased from 33 to 70 Gy and amount to 21.4 and 73.8% in high- and low-grade tumours, respectively.
The incidence of vascular abnormalities in the pattern of central nervous diseases is steadily increasing. Arterioventricular malformations (AVM) are of great significance among cerebrovascular diseases to be surgically treated. A comprehensive examination of 57 patients with AVM, which involved cerebral angiography, transcranial Doppler at the stages of surgical treatment led to the conclusion that the application of AVM morphological characteristics alone did not allow the development of specific complications, hyperemic ones in particular, to be accurately predicted in the early postoperative period after elimination of malformation. It was suggested that due to the naturally significant relationship of Doppler indices of blood flow in the nutrient arteries having structural malformations and showing cerebral circulatory disorders, the use of values of the linear velocity of blood flow in and the reactivity and resistance in the nutrient arteries enables one to predict a risk for hyperemic complications after AVM elimination to a high precision and to define a preferable surgical intervention. The priority employment of transcranial Doppler in the diagnostic examination of patients with AVM will optimize an instrumental preliminary study, make a correct treatment policy, improve the outcomes of surgical intervention, and reduce the length of hospital stay.
Analysing the body's responses in 32 patients operated on for cerebral vascular aneurysms has shown that preoperatively there is activation of the peripheral blood antiprotease system, which appears to be associated with the impaired permeability of the vascular wall and with the activation of the hemostatic system and that their liquores contain sensitizing substances which are products of hemorrhages and cerebral detritus. On the whole, the immune responses of this group of patients are common to those of other groups of neurosurgical patients: acute-phase blood reaction, synthesizing-antibody binding of antigens, sanitating and brain tissue-transient neurosensitization. The use of mildronate contributes to the activation of the humoral link of the immune system on post-operative days 5-7, increases the serum antiprotease potential, by intensifying the body's responses, levels stress immunodeficiency and prolongs the time of neurosensitization.
The potentialities of current Neuroimaging methods were established to allow one to make an early minimally invasive diagnosis of arteriovenous [correction of arterioventricular] malformations. The most promising method is a combined use of X-ray computer and magnetic resonance tomography with transcranial Doppler echography, which is in conformity with the unity principle of morphological and functional non-invasive diagnostic methods. At present, cerebral angiography should be used only in combination with preoperative examination of these patients.