[Don't underestimate the information given by midwives about contraception].
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Contraception↗
Biomedical subjects
G Aberg
Publications and source records attributed to G Aberg.
Effects of captopril on atherosclerosis in cynomolgus monkeys.
A study was performed to investigate if oral dosing of captopril could influence the development of atherosclerosis in cholesterol-fed cynomolgus monkeys. Twenty-four monkeys were divided into four groups: (a) a control group given a normal monkey diet and placebo medication; (b) a high cholesterol group given a high cholesterol diet and placebo medication; (c) a low-dose captopril group given the cholesterol diet and 25 mg/kg of captopril twice daily; and (d) a high-dose captopril group given the cholesterol diet and 50 mg/kg of captopril twice daily. The doses of captopril used in this study did not change the levels of total serum cholesterol, high-density lipoprotein (HDL), or triglycerides. The total cholesterol/HDL ratio was also unaffected by captopril. The animals were killed after 6 months of treatment. The progression of atherosclerosis was assessed by gross pathology, histopathology, and biochemical methods. The results showed a significantly reduced progression of arterial lesions in monkeys given captopril; the effects of captopril were most evident in the coronary arteries, which were practically free from atherosclerosis in captopril-treated animals.
Animals↗
Substituted 1,2,3,4-tetrahydroaminonaphthols: antihypertensive agents, calcium channel blockers, and adrenergic receptor blockers with catecholamine-depleting effects.
Substituted 1,2,3,4-tetrahydroaminonaphthols were found to be calcium channel blockers with antihypertensive properties. These compounds also possessed adrenergic beta-receptor blocking activity. From the structure-activity studies, no clear correlation emerged between the in vitro calcium channel blocking activity and the acute anti-hypertensive activity in cannulated spontaneously hypertensive rats. Extensive pharmacological testing of selected compounds indicated that aminonaphthols are antihypertensive agents with many pharmacological properties. The relative contribution of various pharmacological actions toward the observed antihypertensive activity is unclear. Since the clinically useful calcium channel blocker verapamil is structurally related to these compounds, one of the aminonaphthols, trans-3-[(3,3-diphenylpropyl)amino]-1,2,3,4-tetrahydro-6,7 -dimethoxy-2-naphthalenol (12), was compared with verapamil for calcium channel blocking activity, adrenergic blocking activity, and catecholamine-depleting activity. Both compounds were found to be equipotent in these test systems.
Action Potentials↗
Arrhythmogenic assessment of prenalterol in conscious dogs.
Possible arrhythmogenic side-effects of the positive inotropic agent prenalterol were studied in conscious dogs, three to four days after coronary artery ligation. Prenalterol showed a propensity to cause arrhythmias in one out of eight dogs, thereby confirming published data from clinical studies.
Animals↗
Antiarrhythmic effects of tocainide and lidocaine in dogs.
To compare the antiarrhythmic activities of tocainide and lidocaine in dogs, a protocol was designed where the drug plasma levels were increased stepwise. This was achieved by computerizing bolus doses and infusion rates, using pharmacokinetic equations with constants, derived from previous experiments in similar animals. In conscious coronary-ligated dogs with ischaemic arrhythmias both compounds were active, causing a 50% reduction in VPB's at plasma concentrations of 5.0 micrograms/ml (tocainide) and 3.5 micrograms/ml (lidocaine). "Clearing" of catecholamine-induced arrhythmias was not obtained in any of six dogs given tocainide and only in two out of six dogs given lidocaine.
Animals↗
Pharmacological studies on droxicainide, a new antiarrhythmic agent.
The antiarrhythmic, local anesthetic and acute local and systemic toxic effects of DL-N-(2-hydroxyethyl)-pipecolinyl-2,6-dimethylanilide (AL-S-1249, droxicainide) and lidocaine were compared in animals. When given intravenously both substances suppressed ouabain-induced arrhythmias in pentobarbital-anesthetized guinea pigs; they were equipotent in this regard and had the same duration of antiarrhythmic action. Both substances produced generally equivalent sensory anesthesia following intradermal administration in the guinea pig and corneal application in the rabbit and block of motor and sensory function when injected near the sciatic nerve in the rat. In these local anesthetic tests and following intradermal administration to rabbits, droxicainide produced less local tissue irritation than lidocaine. When given intravenously to unanesthetized mice and unanesthetized and pentobarbital-anesthetized rats, the LD50's for droxicainide were consistently higher than those for lidocaine. Since droxicainide has antiarrhythmic and local anesthetic properties that are quantitatively similar to lidocaine but local and systemic toxicity that is relatively weaker, its antiarrhythmic and local anesthetic actions merit further study.
Anesthesia↗
Inotropic, chronotropic and dromotropic effects of prenalterol, a new cardiostimulant drug.
Prenalterol (H 133/22) is an adrenergic beta-receptor stimulator which unlike isoproterenol is both orally active and has a long duration of action. The inotropic, chronotropic and dromotropic effects of prenalterol were investigated in pentobarbital anaesthetized dogs. Prenalterol was found to increase left ventricular maximum dP/dt in a dose-dependent manner up to a dose level of 50 micrograms/kg. Additional doses resulted in only small further increases in cardiac contractility. Electrophysiological studies were done to compare the effects of prenalterol and isoproterenol on sinus node and ventricular pacemaker function. Complete AV block was produced by electrocauterization of the His bundle. Prenalterol accelerated both ventricular and sinus node pacemakers at doses up to 50 micrograms/kg. The increase in ventricular rate was greater than the increase in sinus rate following supramaximal inotropic doses of prenalterol yet no ventricular extrasystoles were ever observed. Similar acceleration of the ventricular and sinus node pacemakers were observed by infusion of isoproterenol. Prenalterol and isoproterenol accelerated AV nodal conduction and ventricular conduction but had little effect upon His-Purkinje conduction. Sinus node reset time was abbreviated as was the functional and effective refractory periods of the atrium and AV nodes.
Animals↗
Studies on the duration of local anesthesia: a possible mechanism for the prolonging effect of "vasoconstrictors" on the duration of infiltration anesthesia.
Attempts have been made to correlate the duration of the local anesthetic effect with the amount of the local anesthetic compound remaining at the injection site at different times after an injection. In addition to delaying the absorption of the local anesthetic, adrenaline but not a vasopressin-derivate decreased the minimal anesthetic concentration of the local anesthetic agent. It is assumed that the pH value of the tissues at the injection site was kept down through the metabolic effects of adrenaline, thereby transforming the local anesthetic agent into cations, which is the form in which the amide-type of local anesthetics mainly exerts their nerve blocking activity.
Absorption↗
Haemodynamic effects of the quaternary ammonium compound QX 572 in anaesthetized cats. I. Cardiac chronotropic effects.
The haemodynamic effects of the antiarrhythmic compound, QX 572, have been studied in anaesthetized cats. It was found that QX 572 increased the heart rate and decreased the blood pressure of the cats during the infusion of the drug. A slight increase in blood pressure was seen after the infusion was terminated. The same results have been obtained in patients. Experiments on cats pretreated with propranolol or reserpine showed that infusions of QX 572 caused an increase in heart rate by increasing the sympathetic activity in the cats. It is also shown that changes in vagal tone may contribute to the effects of QX 572 on the heart rate.
Animals↗
Haemodynamic effects of the quaternary ammonium compound QX 572 in anaesthetized cats. II. Studies on the mechanism for the cardiac chronotropic effects.
The antiarrhythmic compound, QX 572, has been shown to increase heart rate both in patients and experimental animals. In anaesthetized cats the positive cardiac chronotropic effects were mainly due to increased sympathetic activity. The present experiments were designed to localize the active sites within the sympathetic nerve system. It was found that QX 572 caused an increased heart rate in response to electrical stimulation of the cardiac sympathetic nerves, but this was not due to effects on the CNS, the sympathetic ganglia or the cardiac adrenergic beta-receptors. It is concluded that QX 572 by some action increased the amount of noradrenaline released from the cardiac sympathetic nerve endings. The mechanism for this effect has not been clarified.
Adrenalectomy↗
Haemodynamic effects of the quaternary ammonium compound QX 572 in anaesthetized cats. III. Interactions with adrenergic beta-adrenoceptor blockade.
The positive cardiac chronotropic effects of the antiarrhythmic compound, QX 572, in anaesthetized cats has been shown mainly to be due to a release of catecholamines from sympathetic nerve-endings. Furthermore, these undesired effects of QX 572 on heart rate were decreased by adrenergic beta blockade in the animals. In the present study it was found that an adrenergic beta-blockade did not reveal any cardiodepressive effects of QX 572, that in the normal animals might have been masked by the effects of the drug-induced catecholamine-release.
Adrenergic beta-Antagonists↗
Effects of adrenergic beta-blockers and a membrane stabilizing agent on ouabain-induced cardiac arrhythmias in anaesthetized guinea pigs.
The antiarrhythmic effects of dl'propranolol, d-propranolol, metoprolol and lidocaine against ouabain-induced cardiac arrhythmias were studied. It was found that contrary to earlier findings in the dog, the effects of the adrenergic beta-blockers against ouabain-arrhythmias in guinea pigs were due to beta-blocking activity and not the membrane-stabilizing activity of the compounds. The cardioselective beta-blocker, metoprolol, was more or equally effective as dl-propranolol against ouabain-induced arrhythmias in guinea pigs.
Adrenergic beta-Antagonists↗
Inhibition and facilitation of lacrimal flow by beta-adrenergic drugs.
The effects of adrenergic beta-stimulating and beta-blocking compounds on tear flow were studied in conscious rabbits with a modified Schirmer technique. The tear flow was significantly increased by the unselective beta-adrenergic agonist isoprenaline and by the selective beta1-agonist H 80/62 (racemic Prenalterol, Hässle, Sweden). The effects of the agonists were blocked by the unselective beta-adrenergic antagonist propranolol (Inderal) and by the selective beta1-antagonist metoprolol (Seloken, Lopressor). The experimental data favoured the hypothesis that the beta-receptors involved in the regulation of the tear flow were of the beta1-type. The anatomical location of these beta-receptors is at present unclear but in vitro experiments performed on the rabbit lacrimal glands indicated that the receptors were probably not located on cholinergic nerve-endings as the release of acetylcholine was not influenced by isoprenaline.
Acetylcholine↗
[A causerie about the Lion pharmacy in Malmö].
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History of Pharmacy↗
Studies on the duration of local anesthesia. Effects of volume and concentration of a local anesthetic solution on the duration of dental infiltration anesthesia.
In animals and humans the rate of resorption and the duration of the anesthesia have been investigated, using mepivacaine in different concentrations and volumes without addition of a vasoconstrictor. A linear relationship between duration of anesthesia and the logarithm to the concentration of mepivacaine was found.
Adult↗
Studies on the duration of local anaesthesia: a possible mechanism for the prolonging effect of dextran on the duration of infiltration anaesthesia.
The mechanism of the prolonged effect of dextran on the duration of local anaesthesia has been studied. Using radio-active mepivacaine it was found that dextran prolonged the duration of infiltration anaesthesia in guinea-pigs by delaying the absorption of the local anaesthetic agent. Experiments in vitro indicate that molecular complexes between the local anaesthetic and dextran may be formed and it is assumed that the delayed absorption might be due to the formation of such molecular complexes. This hypothesis was strengthened by experiments in which dental infiltration anaesthesias were performed in healthy volunteers.
Adult↗
Pharmacokinetics of clomethiazole in healthy adults.
The systemic availability of clomethiazole was assessed by comparing blood levels after intravenous and oral administration. Clomethiazole was rapidly absorbed after oral administration to volunteers, particularly when administered as syrup. The fraction of the given dose that reached the systemic circulation after 1 capsule of clomethiazole (192 mg clomethiazole) was 0.25 +/- 0.18, after 2 capsules (384 mg clomethiazole) 0.38 +/- 0.18, and after 15 ml syrup (480 mg clomethiazole) 0.42 +/- 0.20. The time-blood concentration profiles were consistent with a two-compartment open model and the mean elimination half-lives of 3.6--5.0 hrs. were found for the different formulations and administration routes. Elimination half-lives showed little variation and a mean systemic clearance of 49 ml/min./kg was found for clomethiazole after intravenous administration. Clomethiazole is bound to human plasma proteins (63.4 +/- 1.6%, 37 degrees), a binding which is not affected by Vacutainer sample tubes. The blood/plasma distribution of clomethiazole was 0.76 +/- 0.02 at 37 degrees. A sensitive mass fragmentographic assay for the determination of clomethiazole in blood/plasma down to levels of 1 ng/ml (6.2 nmol/l) is described.
Administration, Oral↗
Studies on the mechanism of flush induced by nicotinic acid.
Flush is a common side effect of nicotinic acid therapy in patients. The effect is present as long as the level of nicotinic acid increases in the plasma. The mechanism of flush after nicotinic acid has been studied in the ears of guinea-pigs in vivo. The threshold dose of nicotinic acid (1-3 mg/kg) to raise the skin temperature of the ears and to increase the cyclic AMP level of this tissue was similar. Indomethacin and acetylsalicylic acid which inhibit the synthesis of prostaglandins markedly reduce the duration and intensity of the flush. In isolated slices from guinea-pig ears, nicotinic acid increased the level of cyclic AMP; this effect was inhibited by indomethacin. The stimulating action of prostaglandin E1 on the cyclic AMP level of the ear slices was not inhibited by indomethacin. Since administration to man of both cyclic AMP and prostaglandin E1 produces flush it is suggested that nicotinic acid may induce flush by the formation of some prostaglandin which then increases the formation of cyclic AMP.
Animals↗