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Biomedical subjects

Z Blazek

Publications and source records attributed to Z Blazek.

At least 19 recordsLinked to original sources
PubMed1992

Analgosedation raises baroreflex sensitivity in acute myocardial ischaemia.

Acute local myocardial ischaemia is associated with a decrease in baroreflex sensitivity while electrical instability (vulnerability) of ventricles increases. Co-administration of a benzodiazepine and a potent analgesic (analgosedation) has been found to raise both baroreflex sensitivity and ventricular fibrillation threshold. Pharmacological modulation of neurovegetative ionization of the heart in the early phase of ischaemia is a promising method for preventing sudden coronary death.

Animals↗
PubMed1991

Prevention of sudden coronary death.

The following results were obtained in an experimental study in the dogs in general pentobarbital anaesthesia: Lidocaine type antiarrhythmics (lidocaine, Xylocaine ASTRA, Ethmozin USSR) administered shortly before artery ligation have a pro-fibrillation effect. This effect is indirectly proportional to the ischaemic focus development. A 3rd-generation beta blocker with intrinsic sympathetic activity (celiprolol, Selectol Chemie-Linz) had the same electrostabilizing effect on the ventricles in the acute phase of ischaemia as a 1st-generation beta blocker (metipranolol, Trimepranol SPOFA). The 3rd-generation blocker, however, stopped short of provoking a drop in the heart rate invariably associated with the 1st-generation beta blocker. The analgesic fentanyl (G. Richter) in combination with benzodiazepine (m,idazolam, Dormicum Hoffmann-La Roche) inducs analgosedation. In this way the dose of the analgetic can be reduced and yet the analgesia and electrostability of the heart remain the same. Due to the lower dose of the analgesic there is a lesser decrease in the heart rate and blood pressure. Analgosedation can be discontinued by administering an antagonist-agonist of benzodiazepines (flumazenil, Anexate Hoffmann-La Roche) or an antagonist of potent analgesics (butorphanol, Beforal SPOFA) without the risk of eliminating, at the same time, the electrostabilizing effect of analgosedation on the ischaemically damaged ventricles of the heart. For the prevention of sudden coronary death due to ventricular fibrillation in the acute phase of local myocardial ischaemia we can, on the basis of our experimental results, recommend analgosedation and the use of beta blockers with intristic sympathetic action. The use of lidocaine antiarrhythmics may lead to a reduction in the electric stability of the heart ventricles the ischaemic focus is developing under a certain "critical" blood level of the antiarrhythmics.

Adrenergic beta-Antagonists↗
PubMed1991

Analgosedation-enhanced baroreflex sensitivity in acute local myocardial ischaemia.

In acute local myocardial ischaemia produced in mongrel dogs, the sensitivity of baroreflex decreased as electrical instability (vulnerability) of cardiac ventricles increased. Simultaneous administration of a benzodiazepine and a powerful analgesic (analgosedation) augmented both baroreflex sensitivity and ventricular fibrillation threshold. Modulation of neurovegetative activation of the heart by drugs in the early stage of ischaemia holds promise as a potential technique of sudden coronary death prevention.

Animals↗
PubMed1989

[Extraction magnets in ophthalmology].

Magnetic extraction of foreign bodies has been used in the ophthalmologic practice more than one hundred years. The magnetic field of the extractive magnet causes the magnetization of the material present in the foreign intraocular body. Magnetization could be induced only in the ferromagnetic bodies and enables surgeons to perform the extractions. At this time the hand-manipulated and the based magnets are used, without adequate adaptability for the needs of now prevailing ocular microsurgery. Authors explain the use of the new generation of the extraction performed by means of the permanent magnet ORMEX which is based on Czechoslovak invention of the magnetic system ORMAKON characterized by significantly increased effectivity.

Eye Foreign Bodies↗
PubMed1989

[Permanent Ormex magnets in clinical practice].

Permanent magnets ORMEX have been successfully used in 14 extractions of the foreign intraocular nodies localized in the anterior and posterior segments of the eye. These magnets proved to be more advantageous than the usually used electromagnets, with respect to their size, weight, easier manipulation and usual mode of sterilization. The ORMEX magnets do not need source of the electric energy and their energetic performance is greater than of the routinely used magnets of the Hirschberg's type. Authors recommend to equip all ophthalmic stationaries with these permanent ORMEX magnets.

Adolescent↗
PubMed1988

The importance of the electrode system for the success of intracardiac defibrillation.

An experimental study was designed to assess the effect of intracardiac defibrillation in 15 dogs, in whom a total of 25 episodes of ventricular fibrillation were induced. Defibrillation using a Medtronic electrode catheter (model 6880), with the discharge passing between the right ventricle and atrium turned out to be of little effect even though energy discharges of 25 J were used. Discharges between an electrode placed in the right ventricle and another one placed on the thoracic left wall, with the discharge passing through the left ventricle, were more successful. While this arrangement terminated half of ventricular fibrillation episodes, its results are not sufficiently convincing for widespread clinical use. Histology documented significant myocardial damage even when intracardiac energy discharges with energy not exceeding 25 J were used.

Animals↗
PubMed1986

Electrical instability of the heart in acute local myocardial ischaemia: pathogenesis and experimental prevention.

The pathogenesis of electrical instability of tissue in the earliest phase of ischaemia is well known. Convincing results in the prevention of ventricular fibrillation at this stage have been obtained only by agents inhibiting sympathetic activation of the heart, or by agents significantly prolonging the refractory period of heart cells. On the other hand, it was documented that sodium channel inhibitors are not suitable for prevention of electrical instability in the early phase of ischaemia and can, on the contrary, aggravate it. A question which is still unresolved and deserves further research is the effect of calcium channel inhibitors and of agents acting directly on the metabolism of ischaemic tissue.

Animals↗
PubMed1986

Comparative study of rat-paw oedema tests for assessing reactivity of B. pertussis-containing combined vaccines.

Two volumetric (electrocapacity plethysmography and mercury volumetry) and two linear methods (a new type of scale and a calliper rule) for rat-paw oedema measurement used in local reactivity of combined vaccines containing a B. pertussis component were compared. The reproducibility and sensitivity of the methods was tested on a diphtheria-tetanus-pertussis vaccine and a toxic pertussis suspension. The linear methods proved more adequate for measuring small and chiefly unidirectionally (vertically) progressing oedemas.

Animals↗
PubMed1979

Antiarrhythmic effect of cardiac sympathectomy.

The authors studied the effect of sympathetic denervation of the heart (removal of the stellate ganglion together with the sympathetic trunk up to the level of the 5th thoracic ganglion) on the ventricular fibrillation threshold (VFT) in dog. The acute experiments were performed under general anaesthesia with pentobarbital. Unilateral left sympathetic denervation raised the VFT to 144% of the initial value (14 measurements) and unilateral right sympathectomy to 214% (9 measurements). Immediately after bilateral denervation the VFT increased to 242% (23 observations). Atropine blockade of the vagus nerve (0.1 mg/kg b.w.) displayed no effect on the VFT increase. The observed increase in VFT corresponded with the finding that bilateral sympathetic denervation of the heart protected the dogs from spontaneous ventricular fibrillation after ligating the intraventricular branch of the left coronary artery. The authors compared their own results with those reported in the literature and discuss the possible clinical use of sympathetic denervation of the heart in the treatment of tachyarrhythmia.

Animals↗
PubMed1977

[A modified guaiac test for the early detection of tumors of the intestinal tract (author's transl)].

Of 1400 patients who were submitted to the Haemoccult test, 46 showed a postive result. Among other things there were 29 polyps, of which 3 already showed a focal carcinoma, and 5 carcinomata of the large intestine and 3 gastric carcinomata were also diagnosed. Over 70% of the tumor hosts had observed bleeding per anum at some time. In order to detect the number of false nagative results, patients were investigated in the same way even when the Haemoccult test had been negative three times. In this way 55 polyps were found as well as 7 partly advanced carcinomata of the large intestine. 35% of the Haemoccult-negative patients stated bleeding per anum in their history. The number of false negative findings must be considerably higher than previously estimated.

Colonic Neoplasms↗
PubMed1977

Efficacy of monophasic electrical impulses with steep leading and trailing edges in cardiac defibrillation.

Experiments on dogs were performed to investigate the efficacy of various defibrillation impulse waveforms. The results showed that the decisive factors for the effectiveness of the defibrillation impulse of certain shape are its relationship to the carciac tissue accomodation and the duration of the suprathreshold current flow. For cardiac defibrillation the most convenient impulse is therefore the impulse with the highest rate of rise of the leading edge as well as the trailing edge. The amplitude of the rear trailing edge of the defibrillation impulse should be either equal or higher than the amplitude of the front leading edge. That means that rectangular or trapezoidal impulses with an ascending slope may be most conveniently used for cardiac defibrillation. The biologically optimal duration of the trapezoidal impulse with an ascending slope proved to range from 7 to 14 msec. The authors emphasize the inevitability of additional characteristics of the defibrillation impulse by its peak current and total energy contents.

Animals↗
PubMed1977

Prevention of ventricular fibrillation in experimental myocardial infarction.

The fall in the ventricular fibrillation threshold during the first half an hour following ligation of the descending branch of the left coronary artery in dog was not influenced by the i.v. injection of trimecain (Mesokain Spofa). On the other hand, an i.v. injection of methypranol (Trimepranol Spofa) given prior to ligation increased the level of ventricular fibrillation threshold 3 to 4 times compared to control value before occlusion in all 10 studied dogs. Depression of the beta-blocking adrenergic activity may thus prevent the occurrence of ventricular fibrillation in acute myocardial ischaemia.

Animals↗