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Biomedical subjects

Z Czernicki

Publications and source records attributed to Z Czernicki.

At least 37 records · Page 2Linked to original sources
PubMed1997

The effect of Dotarizine (Ca2+ channel blocker) on cerebral vessel reactivity in animals subjected to hyperventilation and anoxia.

Dotarizine--a novel piperazine derivative--belongs to wide spectrum Ca+ channel antagonists. It was reported to have strong vasodilatory and antiserotoninergic activities. Unlike other Ca+ channel blockers Dotarizine was found to have lower oral toxicity. In the presented study the influence of the oral administration of the novel compound on the blood flow velocity changes in different cerebral arteries--in basilar artery (BA) and middle cerebral artery (MCA)--was investigated under hyperventilation and hypoxic conditions of rabbits. In the first experimental group 25 mg/kg of Dotarizine dissolved in 0.25% agar was administered orally three times at the 10 hours' intervals. The sham group of animals was fed with agar of the same concentration. The results revealed that oral administration of Dotarizine diminished the vasoconstrictive effect of hyperventilation and this was more pronounced in MCA than in BA. During anoxic conditions stronger vasodilatory effects were observed in both groups of vessels and the low value of pulsatility index (PI) reflected pronounced decrease of the peripheral resistance, in comparison to the control group. Thus, the oral administration of Dotarizine decreases the peripheral resistance of cerebral vessels and therefore seems to have influence on the minute arteries of cerebrovascular system of the brain.

Animals↗
PubMed1997

The anatomical aspects of a surgical approach through the floor of the fourth ventricle.

In 1993 Kyoshima et al. introduced safe entry zones in the region of the 4th ventricle floor: infrafacial triangle and suprafacial triangle. Is it possible to demarcate these zones precisely in every case intra-operatively? A postmortem study of 40 brainstems of patients who had died of non-brain disease was performed to evaluate the degree of individual morphological and morphometrical variability of the 4th ventricle floor. The purpose of this study was to find constant landmarks and distances within the rhomboid fossa region which would help a neurosurgeon to determine safe approach zones through the 4th ventricle floor to brainstem lesions. Several anatomical landmarks-median sulcus, obex, vestibular area, vagal triangle, hypoglossal triangle-were found to be sufficiently visible in all examined brainstems. However, the facial colliculus which is a border structure between the infrafacial and suprafacial safe approach zone was poorly visible in about 37% of the analyzed material. The striae medullares were not found to be good orientation structures as they were not visible in 30% of the material and exhibited individual variability of a high degree in relation to their number and arrangement. In the morphometrical study analyzed measurements were taken by utilizing the digital image analyzer MULTISCAN. Based on the results obtained the authors suggest new borders of the infrafacial safe approach zone and morphometrical directions to determine the suprafacial safe approach zone in cases when the facial colliculus is not clearly visible or invisible intra-operatively.

Adult↗
PubMed1997

Digital-image analysis of the rhomboid fossa surface.

Forty brainstems were investigated in order to evaluate morphological and morphometrical variability of the 4th ventricle floor. Visibility evaluation of the following rhomboid fossa structures: striae medullares, facial colliculus, superior fovea, vestibular area, sulcus limitans, incisure, medial eminence, median sulcus, vagal triangle, hypoglossal triangle and obex was performed. Obex, median sulcus, vestibular area, vagal and hypoglossal triangles were found to be sufficiently visible in all specimens. Facial colliculus was poorly visible in 37% of the examined brainstems. Striae medullares were invisible in 30% of the analysed material and exhibited individual variability of a high degree in relation to their number and arrangement. Morphometrical study showed measured distances to be individually variable with a relatively low coefficient of variation of approximately 10%.

Adult↗
PubMed1996

Acetazolamide produced blood flow velocity changes measured by laser Doppler in gerbils with reduced CBF.

The effect of acetazolamide on the cerebral blood flow was studied in gerbils with unilateral carotid ligation. According to the effect of ligation the animals were divided into three groups: first group-the reduction more than 70%, second-CBF reduction 30-70% and the third group-CBF reduction less than 30%. The effect of acetazolamide administration was closely related to the effect of carotid ligation. More reduction of CBF was produced by carotid ligation, less increase of CBF after acetazolamide injection was noticed. The acetazolamide vascular reserve test was found a sensitive and useful method for detecting even modest reduction of vascular reserve in animals with slight - less than 30% CBF decrease following carotid ligation.

Acetazolamide↗
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

Transcranial Doppler sonography in experimental Cushing response.

Searching for the early warning symptoms of brain ischaemia, transcranial Doppler sonography (TCD) was used in cats during the Cushing response. The study was performed on seven cats. The intracranial pressure was increased by means of different rate lumbar infusions. The TCD changes of middle cerebral artery (MCA) and basilar artery (BA) flows were analyzed at the stage of the slightest but significant systemic blood pressure increase. The first symptoms of Cushing phenomenon were accompanied by BA flow pattern alternations while the MCA flow remained unchanged. The study suggests the necessity of BA TCD monitoring in cases at risk from brain stem ischaemia. It was shown also that in such cases the MCA TCD study can be misleading.

Adrenergic Fibers↗
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↗
PubMed1994

The endogenous ouabain-like sodium pump inhibitor in cold injury-induced brain edema.

An endogenous ouabain-like factor (EOLF) was measured in brain tissue of cats 12 and 24 hrs after cold injury-induced edema. EOLF was assayed via its inhibition of 86Rb+ uptake in human red blood cells in a fraction which was obtained from brain tissue by methanol extraction, chloroform treatment and purification of the water phase by C-18 HPLC. As compared to the contralateral hemispheres with an EOLF concentration of 605 +/- 71 pmol ouabain equivalents per g wet weight, the edematous hemisphere had significantly higher concentrations: 12 hours after cold injury it was 2600 +/- 1762 pmol (p < 0.03) and fell to 857 +/- 160 pmol ouabain equivalents/g wet weight after 24 hrs. Similar kinetics were evident for the EOLF concentrations in cerebrospinal fluid. It is suggested that the increase of EOLF in the edematous brain hemisphere may participate as a mediator in the development of vasogenic brain edema in the disturbance of the sodium metabolism.

Animals↗
PubMed1994

Effect of acetazolamide on early ischemic cerebral edema in gerbils.

Acetazolamide was given in the early stage of ischemic cerebral edema produced by unilateral permanent carotid occlusion in gerbils. The animals were studied 1, 4, and 6 hours after ischemia. The tissues were examined for water and electrolyte concentrations and ischemic areas were visualized by 2,3,5-triphenyltetrazolium chloride (TTC) and H-E staining. Acetazolamide injected just after occlusion showed a positive effect in reducing edematous changes. Later administration of the drug had neither positive nor harmful effect on the ischemic brains. Thus, acetazolamide seems to be useful for cerebrovascular response studies in the early stage of a brain lesion.

Acetazolamide↗
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

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↗
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↗
PubMed1992

[Evaluation of the usefulness of cerebral perfusion pressure in threatened cerebral ischemia].

The Cushing response was produced using the lumbar infusions in cats. The following parameters were recorded and computed: arterial blood pressure (ABP), central venous pressure (CVP), intracranial pressure (ICP), heart rate and ECG. The lactate concentration was studied in brain stem and brain cortex. The analysis of ABP and ICP recordings showed in some cases that the Cushing response was obtained at CPP over 60 mmHg. The role of adrenergic reaction in Cushing phenomenon was confirmed by the increase in blood catecholamine concentration and typical adrenergic changes in ECG pattern.

Animals↗
PubMed1990

Evaluation of oedema spreading and intracranial volume reserve using CT image numerical analysis.

Using the cold lesion model vasogenic oedema was produced in 8 cats. The intracranial volume reserve was evaluated applying CT image numerical analysis (CTINA). Summarizing all voxels corresponding to CSF and brain tissue in 8 CT slices, the brain/CSF ratio was computed. The animals were studied at different time intervals after the lesion (2 h, 4 h, 6 h) then sacrificed and the spreading of oedema was estimated based on the BBB disturbances. The brain/CSF ratios varied from mean value of 0.043 in control animals to mean values of 0.022 in animals 6 hours after the lesion. The CTINA method was found very useful as a noninvasive screening method to study brain oedema development with a promising application in clinical practice.

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↗
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↗