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Biomedical subjects

A R Shakhnovich

Publications and source records attributed to A R Shakhnovich.

At least 19 recordsLinked to original sources
PubMed1999

Noninvasive assessment of the elastance and reserve capacity of the craniovertebral contents via flow velocity measurements in the straight sinus by TCD during body tilting test.

Invasive recording of intracranial pressure (ICP) changes during cerebrospinal fluid (CSF) infusion-drainage tests have been used to estimate elastance and reserve capacity of craniovertebral contents. The increase in ICP and its pulse-related oscillations lead to "cuff constriction" of cerebral veins. The purpose of this study is noninvasive assessment of elastance and reserve capacity of craniovertebral contents (RCCC) by measurement of flow velocity (FV) in the straight sinus by transcranial Doppler (TCD) during body tilt tests, which cause changes in ICP. The study was performed in 14 healthy volunteers (age 12-49 y, 6 men) and 32 patients with Intracranial Hypertension (IH) (Benign Intracranial Hypertension, n = 14; Brain Tumors, n = 18). The straight sinus was insonated through the occipital window during body tilt tests (BTT). Tilt table position was changed gradually from head up (+75 degrees) to head down (-45 degrees). It was established that systolic flow velocity and amplitude of FV pulsations (Amp) in horizontal position in patients is usually higher than in healthy volunteers. We found that reserve capacity of craniovertebral contents in patients with IH was usually exhausted. Elastance in patients was usually significantly higher than in healthy volunteers. Evaluation of cerebral venous circulation during body tilt tests clearly differs between the patients with IH and the healthy volunteers. The degree of this difference depends on the localization and character of the pathologic process.

Adolescent↗
PubMed1990

Venous and cerebrospinal fluid outflow in patients with brain swelling and oedema.

67 patients with benign intracranial hypertension (BIH) and 44 with normal pressure hydrocephalus (NPH) were examined by employment of infusion tests. Brain swelling (decrease of ventricular size with normal or increased brain tissue density) was a characteristic feature of BIH. It may result from venous outflow disturbances leading to vascular engorgement. But later, the process appears to be independent from the increase of the dural sinus pressure. This was normal in patients with BIH and NPH. Despite absorption disturbances there was a strong positive correlation in NPH between cerebrospinal fluid- and dural sinus pressure, while in BIH such a correlation was absent. The data confirm a pathogenesis of brain swelling in BIH as an obstacle to venous outflow at the level of the bridging veins and venous lacunae, however, not at the level of the dural sinuses.

Adolescent↗
PubMed1990

[The effect of visual deafferentation on changes in the cerebral blood flow during photic stimulation].

With the aid of transcranial dopplerography, linear velocity of the blood flow was recorded in major cerebral vessels in resting and in photostimulation in 18 healthy subjects and 7 patients with unilateral lesion of visual pathway and exclusion of one half of the field of vision. The photostimulation accelerated the blood flow in middle cerebral arteries by 4.3% and in posterior cerebral arteries by 26.3% in healthy subjects. No acceleration of the blood flow occurred in posterior cerebral artery on the side of unilateral lesion of visual pathways.

Adult↗
PubMed1989

[The interaction of humoral, metabolic and myogenic regulation of the cerebral circulation in unilateral occlusion of the internal carotid artery].

Transcranial dopplerography revealed an asymmetry in middle cerebral arteries in unilateral occlusion of the inner carotid artery. The reactivity of cerebral vessels to carbonic acid diminishes on the side of the occlusion. In absence of the brain tissue infarction, surgical revascularization leads to a partial normalizing of the reactivity. The data obtained suggests a considerable alteration of the interaction among humoral, metabolic and myogenic regulations of cerebral blood flow in unilateral occlusion of the inner carotid artery.

Adolescent↗
PubMed1989

[Surgical treatment of patients with cranio-cerebral trauma and the role of neurological symptoms in the prognosis of its outcomes].

Under examination there were 411 patients with cranio-cerebral traumas. A unified method was used at different medical institutions in order to study questions of prognosis of the outcomes. Surgical treatment was used in 117 of them. The investigations have shown that the state of trance-coma both before operation and in the postoperative period is absolutely unfavourable prognostically. The state of trance-coma and the value of 15 scores and less should be taken into consideration as a contraindication for the solution of the question of operation in patients with cranio-cerebral traumas.

Adult↗
PubMed1988

[Information value of initial clinical signs for the prognosis of outcome in the first 24 hours after craniocerebral injury].

The informativeness of clinical indicators for predicting lethal and favourable outcomes during the first 24 hours after a head trauma has been investigated. A pool of clinical findings about the status of 302 patients examined according to a uniform technique has been analyzed using a packet of the MEDSTAT-85 software. The authors present an optimal set of clinical signs for predicting fatal and favourable outcome within the first 24 hours after the trauma with an 83% probability rate.

Brain Injuries↗
PubMed1987

[Prediction of various categories of recovery in craniocerebral injuries and the informative value of clinical signs].

The authors studied the informative value of clinical signs of craniocerebral trauma (CCT) in relation to the prediction of different categories of recovery. Using a package of applied programmes MEDSTAT-85 a clinical pool of the findings about the status of 302 patients examined by a uniform technique was subjected to clinical analysis. The optimal set of clinical indicators for predicting different categories of recovery in the first 24 hours after the CCT with an average accuracy of 80% is described.

Brain Concussion↗
PubMed1986

[Clinical picture and diagnosis of arteriovenous malformations of the posterior cranial fossa].

An anatomo-surgical classification of arteriovenous malformations of the posterior cranial fossa (PCF) is suggested, based on angiography and computer-aided tomography findings with due consideration for adequate surgical approaches to the defect. Conditions of blood supply and drainage are described with regard to localization of the malformation in the PCF structures. Analysis of the neurologic symptoms in PCF arteriovenous malformations permitted a conclusion on a comparatively rare correlation between the symptoms and the localization of the malformation in a certain PCF structure.

Adolescent↗
PubMed1986

[Evaluation of comatose states].

The most informative neurological symptoms allowing the differentiation of 7 phases of consciousness disorders have been identified on the basis of clinico-physiological correlations and mathematical processing. In the first phase of coma the patient cannot be waken up. Addition of muscle atonia characterizes the transfer to the second phase of coma and of bilateral mydriasis indicates the transfer to the third phase. Eye opening in response to sound or pain points to awakening and transfer to the phase of apallitic syndrome. The performance of simple instructions is characteristic of the phase of deep stupor. Responses to questions characterize stupor, and recovery of orientation in the environment indicates clear consciousness.

Brain↗
PubMed1980

The prognosis of the outcome of comatose states.

Fifty different signs of coma are considered, and the twelve most important have been used to score the degree and progress of patients in coma, together with brain stem evoked responses. The inclusion of brain stem signs and symptoms is considered to be an important new element in this classification.

Coma↗
PubMed1977

Micro-tremor of the eyes of comatose patients.

An electronic method has been used to record the micro-tremor of the eyes of a group of comatose patients. Changes in the micro-tremor waveform patterns have been observed in successive records taken over a period of several days. These changes have been associated with changes in the depth of coma.

Action Potentials↗
PubMed1975

An investigation of the correlation between abnormal patterns of ocular microtremor and an abnormal pupil reflex in neurological patients.

Twenty-two patients and 7 normal subjects at the Burdenko Institute of Neurosurgery, Moscow, have taken part in an investigation in which the direct light reflex to a brief flash, and the high-frequency microtremor of the eyes, have been recorded. The direct pupil reflex recordings obtained with a flash of 20 msec duration and 100 lux intensity at the plane of the pupil were registered from the right eye of each patient. Ocular microtremor recordings were obtained simultaneously from both eyes of 20 of the patients. A set of criteria of abnormality of ocular microtremor, as judged by visual examination of the records, is proposed by the authors. Abnormality of the pupil reflex is assessed in terms of the amplitude, latent period, and time course of the contraction and relaxation phases of the reflex. A strong correlation has been found between the occurrence of an abnormal ocular tremor record and an abnormal pupil reflex. On the basis of this correlation, the authors propose that ocular tremor recordings may be used in diagnosis as sensitive indicators of brain-stem dysfunction.

Brain Diseases↗