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Biomedical subjects

G Pawłowski

Publications and source records attributed to G Pawłowski.

At least 19 recordsLinked to original sources
PubMed1992

ICP dependent changes of CSF outflow resistance.

CSF outflow resistance was studied in cats using the lumbar infusion tests. Different infusion rates were applied from 0.012 to 1.8 ml/min. ICP level obtained during infusions varied from 8.9 +/- 3.0 to 144.0 +/- 25.7 mmHg. The calculated resistance (R) values were within 75.2 +/- 14.4 to 255.6 +/- 71.2. mm Hg/ml/min. The relation between ICP and R are characterized by a curve which can be divided into three parts. First R rises until an ICP level of about 20 mmHg is reached, then R decreases fast until the ICP value is about 50 mmHg, a further drop is much slower and the ICP/R curve becomes almost parallel to the ICP axis. The possible reasons for the ICP dependent changes of R as well as the clinical importance of the results obtained are discussed.

Animals↗
PubMed1990

Early pathomorphological changes and intracranial volume-pressure: relations following the experimental sagittal sinus occlusion.

Saggital sinus occlusion was produced in cats. The intracranial volume-pressure relations were studied using the lumbar infusion tests. Right after occlusion ICP rised from 7.1 +/- 1.8 to 12.4 +/- 4.1 mmHg. The values of outflow resistance and volume-pressure response increased also and remained significantly unchanged with only slight decrease of the volume-pressure response. The morphometric study of the surface veins showed the dilatation of the veins draining to the occluded saggital sinus for about 10-20%. No signs of the blood-brain barrier disruption were observed.

Animals↗
PubMed1986

Analysis of CSF dynamics by computerized pressure-elastance resorption test in hydrocephalic children. Indications for surgery.

Since 1982, 23 hydrocephalic children have been studied for compensatory mechanisms of the cerebrospinal fluid system. The authors describe the method and results of a computerized pressure-elastance resorption test (CPERT), a spinal steady-state infusion test, in hydrocephalic children. Computerized analysis of the P/V and AMP/P curve provides valuable data that precisely describe the degree of disturbances of CSF dynamics. The following parameters were quantitatively determined: out-flow resistance, opening pressure, elastance, elasticity, reference pressure and optimum (break-point) pressure. It is concluded that the described test allows the differential diagnosis of chronic hydrocephalus in children. The value of optimum pressure (analysis of AMP-P relation) gives precise indications for surgery and the selection of a valve system with adequate opening pressure. In some cases, the CPERT test can be used instead of continuous ICP monitoring.

Adolescent↗
PubMed1982

CSF absorptive capacity in patients without intracranial pathology.

The role of changes in CSF inflow in patients without intracranial pathology has been studied. The CSF outflow resistance has been calculated, by dividing the CSF pressure rise by the speed of intrathecal saline infusion. The average CSF pressure rise produced during infusion test (infusion 2 ml/min) amounted to 11.15 mmHg. The calculated CSF outflow resistance equaled to 5.58 +/- 1.1 mm Hg/ml/min. On-line computer assisted analysis during infusion test helps to shorten the procedure and makes it more precise.

Adult↗
PubMed1980

The effect of medial amygdalotomy and anterior hippocampotomy on behavior and seizures in epileptic patients.

In 70 patients with epilepsy and severe behavioural disturbances with EEG changes in the temporal regions, we performed EEG investigations of deep temporal structures, temporal cortex and scalp, using Talairach's stereotactic apparatus. Taking into account the recorded changes we performed 115 stereotactic lesions on the medial amygdala (both unilaterally and bilaterally) and on the anterior hippocampus (cornu Ammonis). The results in epileptic processes were: total recovery in 11.4%, evident clinical improvement in 74.3% and no improvement in 14.3%. Similar results were obtained in behavioural disturbances. Bilateral amygdalotomy and unilateral hippocampotomy in selected cases may produce recovery or amelioration and make possible return to normal social life for epileptic patients with severe behavioural changes.

Adolescent↗
PubMedDate not supplied

[Changes of visual evoked potentials in experimental occlusion of superior sagittal sinus in the cat].

In the model of experimental occlusion of superior sagittal sinus (SSS) in 6 cats, the authors examined cerebral cortex activity by means of visual evoked potentials (VEP). They found shortening of latency of P2 wave potential in relation to the control by 5.5-13.3 msec, appearing after 4-6 hours following occlusion. Simultaneous cerebrospinal fluid pressure measurement indicated an increase in pressure following SSS occlusion from the control medium value 6.8 mmHg to 12-13 mmHg. Visual cortex in cat (area 17) is situated along the posterior portion of SSS. The occlusion of this vessel results in local haemostasis, which is likely to affect the physico-chemical properties of visual cortex cells, especially in the slow conducting system X (X cells can be found exclusively in area 17). The partial disappearance of this system activity results in reducing the signal and noticeable shortening of latency to peak P2 wave of VEP.

Animals↗
PubMedDate not supplied

[Relation between resorption resistance of cerebrospinal fluid and the degree of intracranial pressure].

Changes in the CSF resorption resistance in relation to the value of the intracranial pressure have been assessed in 44 cats. Changes in the intracranial pressure have been produced with fluid infusions. Between 1 to 5 infusion tests with the rate 0.012-1.8 ml/min have been performed in each animal. A relationship between CSF resorption resistance and intracranial pressure has been found. With an increase in the intracranial pressure CSF resorption resistance increased to maximum value of 34 kPa/ml per minute (255.6 mm Hg/ml per minute) at pressure 2.96 +/- 0.69 kPa (22.2 +/- 5.2 mm Hg). At the intracranial pressure about 6.7 kPa (50 mm Hg) CSF resorption resistance rapidly decreased to the value of 13.9 kPa/ml per minute (104 mm Hg/ml per minute). Later, changes have been rather slight. It is possible, that the breaking point at 6.7 kPa corresponds to the mobilisation of all ways of CSF evacuation.

Absorption↗
PubMedDate not supplied

[Analysis of the correlations of volume-pressure parameters and visual evoked potentials during disturbances of intracranial volume compensation].

The experiment was carried out on 19 cats with changed intracranial volume-pressure relations by means of an epidural balloon which was inflated to 1.0 ml volume over 60 minutes. The intracranial pressure, the resistance to cerebrospinal fluid resorption, the volume-pressure responses and visual evoked potentials were determined at balloon volumes of 0.3 ml, 0.5 ml, 0.8 ml, 1.0 ml, 1.3 ml, 1.5 ml, 1.8 ml, 2.0 ml and 2.3 ml. It was demonstrated that intracranial pressure is of important informative value only after exhaustion of 63% of the intracranial volume reserve. This value of the volume-pressure responses and resistance to CSF resorption appeared after exhaustion of 28% of this reserve, and the visual evoked potentials were changed after exhaustion of 43% of the reserve. The correlation coefficient between these parameters was high during decompensation. At the time of compensation of the volume the correlation coefficient between the intracranial pressure and the remaining determined parameters was only 0.6.

Animals↗
PubMedDate not supplied

[Changes in the intracranial volume-pressure relations and visual evoked potentials produced by stabilized and compensated additional volume].

The experiment was carried out on 17 cats with intracranial volume-pressure relations changed by means of an epidural balloon of 1.0 ml volume (group I--12 cats) and 0.5 ml (group II--5 cats). The duration of compression exerted by the balloon was 360 min. The intracranial pressure, volume-pressure responses, resistance to cerebrospinal pressure resorption and visual evoked potentials were determined at intervals of 60 minutes. In group I pressure exerted by 1 ml balloon was followed by changes of volume-pressure relations and visual evoked potentials which increased with duration of the experiment. In group II the changes were noted only in the volume-pressure responses and resistance to CSF resorption at the time of balloon volume rise from 0 to 0.5 ml. Maintenance of this balloon volume in the cranial cavity caused no further changes of volume-pressure parameters or visual evoked potentials during 360 minutes of the experiment.

Animals↗
PubMedDate not supplied

[Methods of evaluation of disorders of the cerebrospinal fluid outflow resistance].

Diagnostic methods for estimating the disturbances of the intracranial fluid resorption process were presented. The following tests are described: constant rate infusion test, boluses, perfusion test, constant pressure infusion test. The methods were compared in the face of the concept of nonlinear outflow resistance--pressure relationship. The author presents his concept of the test for complex examination of outflow resistance--pressure relationship.

Cerebrospinal Fluid↗
PubMedDate not supplied

[The process of learning verbal material in patients with various damaged cerebral structures].

The results are described of a study of the process of verbal material learning and its recall after distraction in 20 patients with involuntary movements treated by thalamotomy, and in 20 epileptic patients treated by amygdalotomy and hippocampotomy. In both groups learning difficulties had been noted already before the operation. In postoperative tests these difficulties were found to have increased immediately after the surgical intervention in patients with lesions in the left cerebral hemisphere. On the other hand, late after the operation they were particularly pronounced after lesions placed in the right thalamus. Disturbances of material recall after distraction were shown in both groups independently of the side of the lesion.

Adult↗
PubMedDate not supplied

[The complementation test with feedback. Preliminary assessment of the test and comparison with a test using a continuous infusion rate].

The complementation test with feedback is described as a method for the assessment of disturbances of volume-pressure compensation. The method is characterized by changing infusion rate and the value of this rate depends on the value of cerebrospinal fluid pressure rise in the test. The infusion is stopped when the relative pressure rise reaches 10 mm Hg. Computer-assisted control of infusion and pressure measurement makes possible achieving of greater accuracy of determination of parameters. The test with feedback was compared with the test with stable infusion rate with regard to the indices characterizing the invasiveness of the method. A statistically significant reduction of this invasiveness was noted.

Cerebrospinal Fluid Pressure↗
PubMedDate not supplied

[Characteristics of intracranial volume-pressure relationship in hydrocephalic children with reference to age].

The purpose of the study was establishing of the effect of child's age, and thus the biomechanical properties of cranial coverings, on the parameters characterizing the intracranial space in the infusion test. The results of the infusion tests performed as a supplementary diagnostic examination in 59 cases of infantile hydrocephalus were subjected to statistical analysis. The studied material and the methods used for its processing no significant differences were found in the mean values of the biomechanical parameters of intracranial space were found between the group of younger children (aged up to 2 years) and older children (over 2 years). This finding may be important in the interpretation of the results of the infusion test, since it was not found that the biomechanical properties of the cranial coverings had any significant effect on the results of this test.

Age Factors↗
PubMedDate not supplied

[The sinusoidal infusion test--an additional filling test for evaluating the mechanisms of the volume-pressure compensation in the intracranial cerebrospinal fluid space].

A diagnostic additional filling test is described which is used for the assessment of the mechanisms of volume-pressure compensation. In the test infusion is used of "physiological" sinusoidal relationship between the infused volume and time. The duration of the test is 10 minutes and it does not require pressure stabilization. On the basis of 23 clinical tests the values were determined of four indices of method "invasiveness" which were compared with analogous indices obtained in the group of tests with stable infusion rate. The obtained results indicate that the sinusoidal test is less invasive and is better tolerated by the patients.

Brain Injuries↗
PubMedDate not supplied

[Effect of dehydrobenzperidol (DHB) on cortical and thalamic somatosensory evoked potentials in patients with muscle dystonia].

Investigations of somatosensory evoked potentials in patients with muscular dystonia meet with difficulties due to abnormal muscle tone and dyskinesia producing myogenic artifacts deforming potentials recorded after their evoking. For obtaining better conditions for recording of somatosensory evoked potentials single dose of DHB was used. Somatosensory evoked potentials were recorded before and after operations and during stereotactic thalamotomy of the complex of the VL nucleus in the thalamus. The authors report the results of investigations in the above mentioned three periods of treatment in hospital. The results suggest the hypothesis that DHB affects the cerebellofugal transmission organizing the proper muscle tone.

Adult↗