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Biomedical subjects

J Jurkiewicz

Publications and source records attributed to J Jurkiewicz.

At least 19 recordsLinked to original sources
PubMed1996

Effects of the calcium channel blockers Dotarizine and Flunarizine on cerebrovascular reactivity.

Dotarizine and Flunarizine are piperazine derivatives considered to be effective compounds for the treatment of various cerebrovascular disorders. In the present study the influence of these two drugs on changes in cerebral vessel diameter and blood flow velocity were measured and compared utilising transcranial Doppler sonography during hyperventilation in anaesthetized cats. Drugs were administered in 15 min intravenous infusions at a dose of 0.05 mg/kg/min. This investigation revealed that the 15 min intravenous administration of both compounds abolished the cerebral vasoconstrictor effects of hyperventilation and due to vasodilator effects they increased blood flow velocity to initial values. No statistically significant differences were found between the vasodilator effects of Dotarizine and Flunarizine. Results obtained suggest that Dotarizine, a novel piperazine derivative, has similar vasodilator and Ca2+ channel blocking effects on cerebrovascular reactivity compared to the widely clinically applied Flunarizine.

Animals↗
PubMed1995

Effect of dotarizine on CO2-dependent cerebrovascular reactivity.

Dotarizine is chemically related to calcium antagonist cinnarizine and flunarizine. The study presented investigates the influence of the drug on the diameter of cortical arteries and cerebral blood velocity measured in the MCA in two groups of anaesthetized cats. Changes of vessel diameter were measured indirectly using photographs of the cerebral cortex during experiments, and flow velocity was measured using transcranial Doppler sonography. Dotarizine was administrated by 20 minute intravenous infusion in a dose of 0.05 mg/kg/min. In the first group of animals the infusion was started during normoventilation, in the next group the infusion started during 30th minute of hyperventilation. The most conspicuous data were obtained in experiments conducted in hyperventilated animals where dotarizine abolished the vasoconstrictive effect of hyperventilation. The results suggest that dotarizine has a pronounced effect on basal as well as cortical arteries of the brain.

Animals↗
PubMed1995

Evaluation of craniospinal system condition using standardized volume-pressure loadings.

Standardized volume-pressure craniospinal system loadings based on physiological loadings were developed in order to study the CSF outflow route efficiency and to evaluate the intracranial volume-pressure relations. The study was carried out on 10 cats. Standardized abdominal compression was applied in order to produce a central venous pressure increased and subsequently ICP increase to the level of 20 and 30 mmHg for 2 minutes. The abdominal compression test seems to be useful in the CSF outflow route evaluation. The orthostatic changes were studied in control animals and in cats with an epidural balloon. The animal body was evaluated to an angle of 50 degrees and 80 degrees with the head directed upwards and downwards. This test was found suitable for the intracranial volume reserve estimation. Similar application, especially in experimental conditions can be found in the hypercapnia test. PaCO2 concentration was increased by means of respiration with a gas mixture containing 5% CO2. A steady increase of ICP of 9 +/- 1 mmHg was obtained. Vascular dilatation resulted in an intracranial volume loading. The ICP response in subjects with normal CO2 response can be related to the intracranial volume reserve. The studies performed show the usefulness of the standardized volume-pressure loadings. The loadings applied are more physiological than lumbar infusion tests used so far.

Animals↗
PubMed1992

Intracranial volume reserve determination using CT images, numerical analysis and lumbar infusion tests. An experimental study.

The epidural balloon compression model in the cat was used in intracranial volume reserve studies. The evaluation of the intracranial volume-pressure relations was based on the lumbar infusion test data: intracranial pressure, CSF outflow resistance, volume-pressure response and on CT images numerical analysis (CTINA) values. Two methods were applied and compared in the study: lumbar infusion test and CT images numerical analysis. The determinations were performed at the balloon volumes of 0.5 ml, 1.0 ml, and 1.5 ml. First statistically significant changes were found at the balloon volume of 0.5 ml i.e. the increase of CSF outflow resistance and volume-pressure response (data obtained in lumbar infusion test) and the decrease in CTINA values. The rise of intracranial pressure was less informative as it was observed at the balloon volume of 1.5 ml. Therefore CTINA seems to be a very useful noninvasive screening method in clinical studies of intracranial volume reserve.

Animals↗
PubMed1992

[Changes in CSF resorption resistance. Experimental studies].

Lumbar infusion tests (IT) with different infusion rates (0.06 ml/min-1.2 ml/min) were used in order to investigate the intracranial pressure (ICP) and CSF outflow resistance (R) changes. Two groups of animals were studied: control group and animals with an 0.8 ml epidural balloon. In control group (without balloon) significant differences in ICP and R values between the increasing and decreasing IT curve were found. The most pronounced changes were noticed right after the highest infusion rate (40% for ICP value and 49% for R value). The results in the balloon group were very similar and the only difference were delayed ICP and R changes. The results obtained suggest that the determined R values are specific for the applied infusion rate and this phenomenon has to be taken into account in all human studies.

Animals↗
PubMed1990

Application of dynamic computed tomography scan and computed tomography densitometry in the evaluation of brain volume enlargement.

Cats with brain cold injury and epidural balloon compression with sudden decompression were used as models of vasogenic or ischemic edema and vasoparalysis of the brain vessels. Dynamic CT scan and CT densitometric studies were performed to diagnose and differentiate between brain edema and vasoparalytic changes. The CT methods were found to be useful in CBF and edema zone estimation. The correlation of CT scan and CT densitometry enabled us to evaluate the degree of autoregulation disorders and can be also applied in clinical investigations.

Blood-Brain Barrier↗
PubMed1979

[Use of haemodilution in the treatment of cranio-cerebral injuries (author's transl)].

By decreasing blood viscosity and vascular resistance normovolemic haemodilution increases cerebral blood flow and improves microcirculation. This eliminates the symptoms of anoxia of cerebral tissue. The extent of disturbances of the blood brain barrier is decreased. The case presented in this paper illustrates the use of the above-mentioned properties of haemodilution and concerns a patient with chronic subdural haematoma. The patient's status in the pre-operative period was very poor. Craniotomy and avacuation of the haematoma did not result in a visible improvement of the patient's state. He did not regain consciousness and even lost spontaneous respiratory function. Haemodilution /Hct 29%/ was performed using Dextran 60 and 5% human albumin in the proportions 1 : 1. As a result, spontaneous respiration was restored and there was a gradual improvement in the patient's status. 29 days later it was possible to communicate with the patient. The authors are of the opinion that haemodilution could find a much application in neurosurgery than has been the case up to now.

Brain↗
PubMed1978

Effect of haemodilution on experimental cerebral oedema in cats.

The effect of haemodilution with Dextran 60 on experimental cerebral oedema produced by the modified method of Ishii, Hayner, Kelly & Evans (1959) is described. The intracranial pressure was measured from the cisterna magna or epidurally in the parieto-occipital region. In the group of cats subjected to haemodilution, with a haematocrit of 27.20 +/- 1.48%, the intracranial pressure first increased by 500% and, after 1.5 h, began to fall gradually so that at the end of the experiment it was only 160% of initial value. In the other experimental group in which haemodilution with a haematocrit of 27.40 +/- 1.14% was started after 6 h of the experiment, the intracranial pressure gradually fell for the next 6 h from 350% of initial value of 200% of initial value after 12 h. It was concluded that haemodilution slows down the development of cerebral oedema, and can be employed in the treatment of fully developed oedema.

Animals↗
PubMedDate not supplied

[Application of physiological data in evaluation of the intracranial volume-pressure interaction. I. An experimental study].

In experimental studies on cats the pressure and volume loadings corresponding to the physiological situations were used. The following tests were applied: central venous pressure increase, postural changes and increase of CO2 percentage in inspired gas mixture. It was found that the central venous pressure increase test is useful in the evaluation of CSF outflow routes, the postural change test examines the intracranial compensation and the elevation of CO2 level in inspired air tests the intracranial volume reserve.

Animals↗
PubMedDate not supplied

[Usefulness of somatosensory evoked potentials in the diagnosis of low-pressure hydrocephalus].

The study group comprised 35 patients in whom previous computed tomography had demonstrated significant dilatation of the ventricular system. On the basis of analysis of clinical manifestations and tomograms the patients were divided into two groups: 24 cases (group I) low-pressure hydrocephalus, 11 cases (group II) brain atrophy. For establishing of final diagnosis in both groups the resistance of cerebrospinal fluid outflow was determined (using continuous infusion at a rate of 2 ml/min) and somatosensory evoked potentials were produced by stimulation of median nerve. In patients with increased resistance to CSF resorption (low-pressure hydrocephalus) the conduction time in the N14-P15 segment involving brain stem structures was prolonged (in 17 out of 19 cases). In cases with not increased resistance no changes of evoked potentials were noted. It is thought that the so called posterior cranial fossa conduction time (N14-P15) may be a useful indicator for differential diagnosis of low-pressure hydrocephalus from brain atrophy.

Adult↗
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↗