Disease relevance of Dalzic

• Six patients who had surgical treatment for sclerosing peritonitis caused by practolol now have a respiratory disorder characterised by dyspnoea, extensive fibrotic pleural thickening, and lesions in the lung parenchyma [1].
• Effects of long-term practolol therapy on plasma-lipids after acute myocardial infarction [2].
• Chronic obstructive lung disease after practolol [3].
• Letter: Pleural effusions after practolol [4].
• Letter: Practolol and migraine [5].

Psychiatry related information on Dalzic

• The duration of treatment before the rash was recognized averaged 10 months, which is about the same latency period as in patients with practolol-induced exanthemas [6].
• The effects of seven beta-receptor blocking drugs differing in lipophilicity by 3.5 orders of magnitude (propranolol, bupranolol, oxprenolol, metoprolol, sotalol, practolol, atenolol) were studied on the circadian rhythm in motor activity of light-dark-synchronized (light (L): 7-19 h, dark (D): 19-7 h) male rats [7].

High impact information on Dalzic

• Neither dose of practolol altered base-line heart rate, forearm vascular resistance, and arterial pressure, Both low and high doses significantly attenuated heart rate responses to exercise [8].
• The results indicate that the phenomenon of selective beta-1 receptor blockade in man is related to the dose and serum concentration of practolol selectively block beta-1 receptors; a high dose and serum concentrations block both beta-1 and beta-2 receptors [8].
• This effect could be blocked by the beta-adrenergic receptor antagonist, propranolol, but not by the specific beta 1-adrenergic receptor antagonist, practolol [9].
• Second, the consistency of the effects observed with respect to pulse, transmural infarction, age and infarct site are in contrast to some previous studies with practolol, propranolol, and alprenolol [10].
• Computer analysis of competition of [125I]iodocyanopindolol binding by betaxolol, practolol, and zinterol in nonmyocyte membranes demonstrates biphasic curves that comprise binding to both beta 1- and beta 2-receptors [11].

Chemical compound and disease context of Dalzic

• In normal subjects, about 30% reduction in exercise-induced tachycardia resulted from single doses of 80 mg propranolol (plasma levels, 50.3, SD, 29.5 to 60.8, SD, 26 ng/ml), 250 mg practolol (plasma levels, 1.05, SD, 0.32 to 1.10, SD, 0.55 mug/ml), 100 mg metoprolol (plasma levels, 137, SD, 111 to 152, SD, 100 ng/ml), and 100 mg tolamolol [12].
• (The treated animals grew less rapidly than the controls; when corrected for body weight these figures were -11.9% and -20.4%, respectively.) In the practolol group, but not the propranolol group, the duration of the atrial intracellular potentials was prolonged [13].
• Also, these findings are not consistent with the Meerson hypothesis, since hypertrophy occurred despite the reduction in myocardial O2 consumption due to practolol [14].
• The effects of dl-propranolol, d-propranolol, butoxamine or practolol on erythropoietin (ESF) production in rabbits exposed to hypoxia (0.42 atmosphere) for 18 hours were investigated [15].
• 1 The degree of beta-adrenoceptor blockade of isoprenaline-induced tachycardia has been determined in three healthy volunteers after the administration of single oral doses of acebutolol, practolol or propranolol [16].

Biological context of Dalzic

• In contrast, beta-adrenergic antagonists such as propranolol (KD = 27,000 nM) and practolol (KD greater than 10(6) nM) did not have high affinity for the binding sites [17].
• Thus, the hydrochloride of (t-butylamino-3-ol-2-propyl)oximino-9 fluorene, a beta-antagonist which has higher affinity at beta 2-sites than at beta 1-sites, was 3 orders of magnitude more potent in inhibiting isoproterenol-stimulated glycogenolysis than either atenolol or practolol, both of which are beta 1-selective antagonists [18].
• Practolol, dextro-propranolol and KO-1313 had no effect on blood pressure in the doses used [19].
• Heart rate decreased in all patients after practolol (avg., --9/min, p less than 0.02) [20].
• In the dosage used in both studies, practolol significantly improved the exercise tolerance and reduced the ischaemic manifestations [21].

Anatomical context of Dalzic

• Differences between the effects of practolol and propranolol on the diastolic properties of the left ventricle [20].
• It was shown in isolated smooth muscle from both man and guinea pig that the order of potency for the three beta-blocking agents studied was: propranolol greater than sotalol greater than practolol [22].
• Practolol was the least effective beta adrenergic-blocking agent in degranulating mast cells [23].
• In order to investigate further the effects of this beta blocking agent, myocardial function and metabolism at rest and during supine exercise were assessed in 12 male patients with coronary artery disease before and after practolol 30 mg, iv [21].
• Neither practolol nor propranolol significantly altered the volume or distribution of blood flow into the normally perfused or ischaemicmyocardial areas, while beta2 stimulation increased blood flow to the normally perfused myocardium from 1.13 +/- 0.12 to 1.28 +/- 1.10 cm3 .min-1 .g-1 (P <0.05) [24].

Associations of Dalzic with other chemical compounds

• Oral doses of pindolol, metoprolol, practolol and oxprenolol had no significant effect on blood pressure in WKY controls [19].
• The effectiveness of cardiac beta-adrenergic blockade was confirmed by absence of an increase in heart rate following intravenous isoproterenol at various times between practolol injections [14].
• 4 Cardioselective beta-blockers (i.e. metoprolol, acebutolol and practolol) were shown to have lower binding site affinities, when compared to other blockers [25].
• 1 Dose-related increases in airways resistance (Raw) and decreases in dynamic lung compliance (Cdyn) were recorded in guinea-pigs and rats following intravenous injection of propranolol and of the cardioselective beta-adrenoceptor blocking drugs, atenolol and practolol [26].
• On the other hand, acebutolol and practolol (0.2-1nM) had no appreciable effects on contractile force or subcellular fractions under similar conditions [27].

Gene context of Dalzic

• In addition, the beta 1-adrenoceptor stimulatory effect of practolol was studied in the right atrium [28].
• The concentration/response relationship for the ganglionic effect of isoprenaline was shifted about ten times to the right by 0.1 microM propranolol (n = 5) and by a beta 2-adrenoceptor-antagonist (0.1 microM ICI 118.551) (n = 8), whereas a beta 1-adrenoceptor-antagonist (10 microM practolol) had no, or only slight, effect [29].
• Competition studies on the binding of DHA and HYP with zinterol and practolol confirmed that the receptor was of the beta 2-subtype for both MN and PMN cells [30].
• The beta 2 identity of these receptors was determined by utilizing the relatively specific beta 1 and beta 2 antagonists practolol and ICI-118,551, respectively [31].
• The Oxt-induced contractile response was not inhibited by pretreatment of aortic strips with phentolamine plus practolol, atropine, diphenhydramine plus cimetidine or indomethacin, but was significantly reduced by verapamil or deamino-ethyl-Oxt [32].

Analytical, diagnostic and therapeutic context of Dalzic

• The purpose of this study was to test the hypothesis that oral administration of a low dose of practolol in man produces selective beta-1 receptor blockade, whereas oral administration of a high dose blocks both beta-1 and beta-2 receptors [8].
• A subsequent group of dogs was studied after vagotomy and practolol administration to block cardiac reflexes [33].
• Intra-arterial infusion of practolol did not influence FBF [34].
• Three hours before each exercise they received placebo or 400 mg practolol administered orally in double-blind fashion in order to complete a cross-over design [21].
• 4 Practolol (0.5 mg/kg) when administered after coronary artery ligation also decreased normal myocardial blood flow but flow in the ischaemic area remained unchanged [35].

References