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Biomedical subjects

E Carlsson

Publications and source records attributed to E Carlsson.

At least 127 records · Page 7Linked to original sources
PubMed1977

Acute hypotensive effect of combined beta1-adrenoceptor blockade and beta2-adrenoceptor stimulation in spontaneously hypertensive rats (SHR).

The effect on heart rate (HR) and blood pressure (BP) of metoprolol, propranolol and terbutaline, applied alone or in combinations was studied in spontaneously hypertensive rats. Terbutaline had little effect on BP and HR. Propranolol combined with terbutaline had no effect while metoprolol combined with terbutaline decreased BP by 48 mm Hg without affecting HR. Thus the beta2-mediated increase in peripheral vascular resistance after terbutaline was revealed by a drop in BP after beta1-blockade by metoprolol, but not when both beta1-and beta2-receptors were blocked by propranolol.

Adrenergic beta-Agonists↗
PubMed1977

Differentiation of cardiac chronotropic and inotropic effects of beta-adrenoceptor agonists.

The relative inotropic and chronotropic activity of beta-adrenoceptor agonists was studied in the noradrenaline-depleted, anaesthetized cat. Terbutaline, a selective beta2-adrenoceptor agonist, gave at a certain dose a more pronounced chronotropic than inotropic response, while a new beta1-selective adrenoceptor agonist (-)-H 80/62 produced the same degree of chronotropic and inotropic stimulation. The results indicate that there is some difference between the beta-adrenoceptors in the sinus node mediating chronotropic stimulation and beta-adrenoceptors in the ventricular myocardium mediating stimulation of the contractile force. It has been shown that there are both beta1- and beta2-adrenoceptors in the heart (Carlsson et al., 1972). In the light of this finding it is hypothetized that there are differences in the relative distribution of beta1- and beta2-adrenoceptors in the sinus node and in the myocardium. Athough beta1 is the predominant type of beta-adrenoceptor in both regions, the beta1:beta2 concentration ratio seems to be higher in the myocardium, than in the sinus node.

Adrenergic beta-Agonists↗
PubMed1977

Myocardial stress perfusion scintigraphy with rubidium-81 versus stress electrocardiography.

Fifty-six patients who subsequently underwent selective coronary angiography were studied noninvasively with relative myocardial perfusion scintigraphy with rubidium-81 and graded stress electrocardiography in an attempt to evaluate the ability of these tests to identify the presence of significant ischemia and, indirectly, coronary stenosis. Both the sensitivity (0.91) and specificity (0.91) of perfusion scintigraphy were impressive and better than the sensitivity (0.79) and specificity (0.64) of stress electrocardiography, the specificity of scintigraphy significantly so (P less than 0.05). Additionally, perfusion scintigraphy yielded excellent localizing information and was reliable even in the presence of drug effect, conduction abnormalities and nonspecific electrocardiographic abnormalities. Rare cases of triple vessel disease, prior myocardial infarction or single vessel disease with widespread collateral vessels were causes of scintigraphic misdiagnosis. Although ribidium-81 perfusion scintigraphy with the scintillation camera requires special collimation and significant quality control, it provides well resolved images and may prove particularly useful in facilitating quick successive multiple scintigraphic cardiac studies.

Angina Pectoris↗
PubMed1977

Mode of action of beta blockers in angina pectoris.

The therapeutic effect of beta adrenoceptor blockers in angina pectoris can be ascribed to an inhibition of beta1 receptor mediated stimulation of heart rate and myocardial contractility, resulting in an improved oxygen supply-demand balance in the myocardium. When given in equipotent beta1 blocking doses, the nonselective blocker propranolol and the beta1 selective blocker metoprolol differ markedly as regards inhibition of adrenaline induced beta2 mediated vasodilatation. Only propranolol will inhibit this effect. After propranolol, adrenaline therefore elicits a haemodynamic effect pattern characterized by high peripheral vascular resistance, high arterial blood pressure, low cardiac output and increased cardiac size. In view of these findings it is suggested that a beta1 selective blocker may be a more efficient antianginal agent than a nonselective blocker in those patients in which the anginal attack is associated with a significant release of adrenaline. The clinical relevance of this hypothesis has not been tested.

Adrenergic beta-Antagonists↗
PubMed1977

Lack of acute effect of triiodothyronine on noradrenaline responses of isolated sympathectomized cat hearts.

The effect of 3-5-3'-triiodothyronine (T3) on chronotropic and inotropic responses to noradrenaline (NA) was studied on isolated heart preparations of cats sympathectomized with 6-OH-dopamine. Heart rates, left ventricular isovolumic pressure (P) and dP/dt were recorded, and concentration dose-response curves to NA were constructed. In the test series, T3 (0.01 and 0.1 microng per ml) was added to the perfusion medium. T3 did not affect the form nor the position of these curves. The results indicate that T3 does not have an acute effect on NA responses of symtropic effects of its own in these experimental conditions.

Animals↗
PubMed1976

Some aspects of the pharmacology of beta-adrenorecptor blockers.

The pharmacodynamic properties of a beta-blocker are mainly determined by its affinity to beta1 and beta2-receptors respectively and by its intrinsic activity. It is suggested that there is no absolute organ separation of the two receptor sub-types. Instead both beta1 and beta2-receptors are involved in the mediation of the same effect. The frequency distribution ratio of beta1/beta2-receptors varied markedly among various effector responses. A non-selective and a beta1-selective blocker may have different haemodynamic effects when the levels of circulating adrenaline are high, because of their markedly different potency in inhibiting the beta2-mediated vasodilator effect of adrenaline. Data are presented which suggest the existence of a presynaptic beta1-receptor mediating a positive feedback mechanism on neuronal release of noradrenaline.

Adrenergic beta-Antagonists↗
PubMed1976

Report of the Inter-Society Commission for Heart Disease Resources. Optimal resources for examination of the chest and cardiovascular system. A hospital planning and resource guideline. Radiologic facilities for conventional x-ray examination of the heart and lungs. Catheterization-angiographic Laboratories. Radiologic resources for cardiovascular surgical operating rooms and intensive care units.

This is an updated and expanded planning and oprimal resource guideline for diagnostic examinations of the cardiovascular system. Catheterization-angiographic laboratories are described and detailed specifications given for radiologic and physiologic equipment. Case loads for maintaining safe and effective performance are recommended and complication rates discussed. An optimal location for the laboratory is defined and the status of affiliated laboratories reviewed. Professional staff qualifications, relationships and requirements are enumerated and recommendations are made for organization and administration of the services. There is a protocol for electrical safety and radiation protection and a data base for assessing case loads in hospitals within a community or region. This statement also defines optimal facility and equipment criteria for conventional chest x-rays and radiologic equipment requirements for cardiovascular surgical operating rooms and intensive care units.

Angiocardiography↗