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Biomedical subjects

L Hess

Publications and source records attributed to L Hess.

At least 37 records · Page 2Linked 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↗
PubMed1991

[Anesthesia in dogs with the combination preparation Tilest 500].

Tilest 500 contains tiletamine and the water-soluble benzodiazepine zolazepam in the ratio 1:1. The drug was administered intramuscularly in ten dogs at a dosage of 10 mg/kg bwt of tiletamine and 10 mg/kg bwt of zolazepam and tested for its effects on hemodynamics, respiration, and the antagonistic effect of flumazenil. Initial effects occurred quickly, analgesia and muscle relaxation were excellent 10 minutes after administration. There was a highly significant increase in heart rate and a slight decrease in both mean arterial blood pressure and arterial pO2. In a second group of ten dogs the interventricular paraconal branch of the left coronary artery was ligated which induced local myocardial ischemia. Here Tilest 500 showed electrostabilizing and antifibrillatory properties even in the presence of severe arrhythmias. The benzodiazepine compound of this drug combination can be antagonized by flumazenil. To avoid excitatory reactions flumazenil should not be injected earlier than 45 to 60 minutes after administration of Tilest 500.

Analgesia↗
PubMed1990

Phalloidin reduces the release of inorganic phosphate during actin polymerization.

Phalloidin, an actin-filament stabilizing peptide from Amanita phalloides, did not inhibit ATP hydrolysis during actin polymerization but strongly retarded the release of the hydrolysis product Pi. Thus, the lifetime of the intermediate F-actin-ADP-Pi is significantly increased by phalloidin. The results suggest a close correlation between filament stability and F-actin-ADP-Pi intermediates.

Actins↗
PubMed1990

Expanding community health nursing roles to meet health-care needs of frail elderly. An adult learning model.

The increased training needs for community health nurses (CHNs) working with frail elderly offer a variety of challenges in staff development. Santa Clara County addressed these challenges with an innovative model, and geriatric assessment skills building program presented to 40 CHNs. The model uses a team teaching approach, a preceptorship and adult learning theory, making it readily adaptable to a variety of community health settings.

Aged↗
PubMed1989

The antifibrillatory effect of fentanyl, sufentanil and carfentanil in the acute phase of local myocardial ischaemia in the dog.

To determine the effect of strong analgesics on electrical instability (vulnerability to ventricular fibrillation), we examined the action of fentanyl (60 micrograms/kg), sufentanil (10 micrograms/kg) and carfentanil (3 micrograms/kg) on the ventricular fibrillation threshold (VFT) in a dog model of coronary artery occlusion. The effect of strong analgesics was compared with that of the first-generation beta-blocker propranolol (1.2 mg/kg) and the third-generation beta-blocker celiprolol (3 mg/kg). In the 5th minute of ischaemia, VFT declines in all groups of dogs. VFT values rise significantly from the 23rd to the 60th minute of ischaemia after opiate analgesic administration. The mean increase in VFT after opiate analgesics is less pronounced than after beta-blockers. Administration of opioid analgesics is followed by strong prevalence of vagal drive to the heart. Sympathetic drive to the heart after propranolol administration disappears and is depressed after the administration of celiprolol only. Blockers of the beta-receptors apparently intervene directly in the ischaemic focus and affect the "substrate" of electrical instability. The opioid analgesics probably exert their effect through a change in "substrate" modulation. There is an ongoing search for drugs that would stabilize the heart electrically in acute myocardial infarction, thus preventing sudden death. Our experimental results favour a combination of strong analgesics with other electrostabilizing drugs.

Adrenergic beta-Antagonists↗
PubMed1989

The electrostabilizing effect of a combination of midazolam and fentanyl: an experimental study in the dog.

Using a model of local myocardial ischaemia in the dog, the authors studied the electrostabilizing effect of a combination of the benzodiazepine midazolam (Dormicum Hoffman--La Roche) and the strong narcotic analgesic drug Fentanyl (Richter). The electrostabilizing effect was assessed using the method of ventricular fibrillation threshold (VFT) measurement. The same increase in the fibrillation threshold as that induced by the administration of midazolam or fentanyl alone was achieved by a combination of both drugs given, however, in reduced doses. The electrostabilizing effect of benzodiazepines and potent analgesics is enhanced by their simultaneous administration. At the same time, the adverse side effects observed on the administration of fentanyl alone (bradycardias, hypotension, cardiac blockade) due to the prevalence of parasympathetic drive, are reduced. Simultaneous administration of a benzodiazepine and an analgesic has become a modern technique, in anaesthesiology, so-called analgosedation. Experiments have shown the technique, in addition to the generally recognized analgesia, sedation and anxiolysis, exerts electrostabilizing effects on the myocardium damaged by ischaemia. The authors therefore recommend analgosedation in the drug treatment of acute myocardial infarction.

Animals↗
PubMed1987

A comparison of the antifibrillatory effect of midazolam and flunitrazepam in acute myocardial ischaemia in the dog.

A study was carried out using a model of myocardial ischaemia in the dog after ligation of the left coronary artery to determine the effects of the benzodiazepines, flunitrazepam and midazolam, on the ventricular fibrillation threshold. The fibrillation threshold was measured twice within 15 min and 8 min after ligation. Fifteen minutes after the onset of ischaemic heart attack, 1.2 mg midazolam/kg or 0.25 mg of ischaemia. Their effects on haemodynamics were negligible. It is suggested that both benzodiazepines can be used for increasing electrical stability of the heart in patients with acute myocardial infarction and to inhibit the psychic stress response. Because of its short biological half-life and water solubility, allowing painless intravenous administration, midazolam offers a more flexible approach to pharmacotherapy immediately after acute heart attack according to the patient's current clinical status.

Animals↗
PubMed1987

An experimental contribution to the treatment of acute myocardial infarction.

1. Benzodiazepines and strong analgesics raise considerably the ventricular fibrillation threshold and thus electrically stabilize the heart in the early stage of myocardial ischaemia. 2. Benzodiazepines markedly potentiate the electrostabilizing effect of the beta-blocker metipranolol. 3. Trimecaine per se does not electrically stabilize the heart in the first hour of ischaemia. When combined with a benzodiazepine, trimecaine stabilizes the heart also in this early stage of myocardial ischaemia. 4. Infusion of a benzodiazepine (midazolam) combined with fractionated administration of a potent analgesic (fentanyl) does not produce pronounced changes in the haemodynamics and ventilation of healthy subjects. 5. Benzodiazepines and strong analgesics exert a favourable effect on the neurovegetative stress response in the early stage of acute myocardial ischaemia. They can be therefore recommended as a component in the treatment of patients with acute myocardial infarction.

Adult↗
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↗