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Biomedical subjects

R Bini

Publications and source records attributed to R Bini.

At least 19 recordsLinked to original sources
PubMed1986

In vitro evaluation of the beta-blocking and electrophysiological properties of mepindolol.

The electrophysiological and beta-blocking effects of mepindolol have been examined in isolated guinea-pig preparations and sheep cardiac Purkinje fibers. Mepindolol did not show selectivity for blocking the chronotropic and inotropic responses to isoprenaline on isolated guinea-pig preparations, and was practically equally potent in blocking the effect of isoprenaline on isolated guinea-pig trachea. Mepindolol 10(-7) M fully antagonized the positive chronotropic effect of isoprenaline (10(-7) M) in Purkinje fibers. However, normal automaticity, action potential characteristics, effective refractory period, membrane responsiveness of Purkinje fibers were unaffected by mepindolol up to 10(-6) M. On the whole, mepindolol appears to be a potent beta-blocker with no cardioselectivity, exerting membrane depressant effect only at concentrations 100-1000 times higher than those exerting effective beta-blockade.

Adrenergic alpha-Antagonists↗
PubMed1986

Effects of dl-methadone on the response to physiological transmitters and on several functional parameters of the isolated guinea-pig heart.

The effects of high concentrations of dl-methadone (1-10 microM) on several parameters of cardiac function were studied in isolated guinea-pig heart preparations. The opioid agonist dose-dependently potentiated the inotropic cardiac response to sympathetic nerve stimulation; this effect was naloxone-insensitive and was antagonized by an increase in extracellular calcium concentration. Moreover, methadone enhanced the dose-inotropic response curve of exogenous noradrenaline. The cardiac response to parasympathetic stimulation was antagonized by the drug through a postsynaptic effect; the responses to histamine and isoprenaline were also antagonized in a noncompetitive way. The spontaneous rate and contractility of atrial preparations were depressed by methadone concentrations above 1 microM; the functional refractory period was increased and the maximal driving rate was reduced at the same range of concentrations. All the above mentioned effects were naloxone-insensitive. In isolated sheep Purkinje fibers methadone, at concentrations of 10 microM and higher, significantly affected the transmembrane action potential parameters, by chiefly decreasing the maximum rate of depolarization and increasing the action potential duration. It was concluded that high concentrations of dl-methadone are able to affect several parameters of cardiac function through an unspecific mechanism different from the stimulation of opiate receptors.

Action Potentials↗
PubMed1982

Modifications in the brush border enzymes of the small intestine after irradiation at different times of the day.

The behaviour of the brush border enzyme activity of the intestinal epithelium after the same sublethal radiation dose to the abdomen at different times of the day was investigated. Three previously observed post-irradiation phases (initial increase of activity, reduction and the return to control values) were confirmed, although with some differences. A later return to normal of lactase was also confirmed. The same dose produced different behaviour of the enzyme activities both during the initial and the recovery phase, depending on the time of the day when irradiation was performed, i.e. on the functional condition of the epithelial cells.

Animals↗
PubMed1978

The straddling mitral valve: morphological observations and clinical implications.

The morphological features of 23 patients with straddling or overriding mitral valve are presented. Levocardia was present in 20 of 23; visceroatrial situs solitisu in 20 of 23, with 3 patients, 2 with asplenia and 1 with polysplenia, having visceral heterotaxia. A concordant D-ventricular loop was present in the 20 patients with visceroatrial situs solitus. Six of these had double outlet right ventricle; 2 had asplenia syndrome; 1 had D-transposition of the great arteries, ventricular defect and pulmonary atresia; 1 with tricuspid atresia and double outlet-outlet chamber; 1 with polysplenia syndrome; and 12 had endocardial cushion defect with marked underdevelopment of the left ventricle, and normally related great arteries. Left ventricular size was related to the amount of mitral valve (or left-sided component of a common atrioventricular valve) connected to it. In those patients in whom little effective mitral orifice was connected to the left ventricle, the left ventricle was diminutive. Endocardial fibroelastosis of the left ventricle was noted in only a single patient. Six of the 7 patients with double outlet right ventricle (including one with double outlet bulbus) had subpulmonary obstruction, and in one of these, this was related in part to the straddling mitral valve. In 1 patient with double outlet right ventricle, there was a double orifice mitral valve, and it was the accessory mitral orifice that straddled. The diagnosis of overriding mitral valve should be suspected in any patient with significant conotruncal anomalies and underdeveloped left ventricle, especially the patient with double outlet right ventricle, and in the patient with endocardial cushion defect, hypoplasia of the left ventricle, and obstructive anomalies of the aortic arch. In certain patients, selective left atriography, left ventriculography, and single and two dimensional echocardiography may be diagnostic of this condition.

Abnormalities, Multiple↗
PubMed1978

[Segmental anatomic diagnosis in congenital cardiac anomalies. I. Anatomic criteria for the identification of the cardiac cavities (author's transl)].

Anatomical features are illustrated for the identification of the cardiac chambers. Essential and accessory morphological structures are recognized. The identification of the atrial cavities is based upon the anatomy of the free walls (crista terminalis, size and shape of the atrial appendages). On the contrary, the identification of the ventricles is founded on the septal morphology (trabecula septo-marginalis on the morphological right side, smooth basal septum on the morphological left side, presence or absence of septal insertions of the atrio-ventricular value apparatus). Finally, no essential feature can be applied to the identification of the great arteries.

Heart↗
PubMed1978

[Segmental anatomic diagnosis in congenital cardiac anomalies. II: Sequential localization of the cardiac chambers (author's transl)].

The approach to the diagnosis of congenital heart disease, based upon the identification of the cardiac chambers, the reconstruction of their sequence and final recognition of the basic circulatory model is discussed. Three cardiac segments are recognizable embriologically, anatomically and functionally: atria, ventricles and great arteries. Connexion is the sequential link of these segments, independently from their spatial relationship. Situs of the atria can be: solitus, inversus or ambiguus, and is determined by the thoracic situs which can be assumed from the bronchial anatomy. Atrio-ventricular connexion can be concordant, absent or double inlet ventricle. Ventricular-arterial connexion can be concordant, discordant, double outlet ventricle or single outlet heart. Since this approach aims to the reconstruction of the connexion among the cardiac segments, heart position and the infundibular anatomy are not relevant to the recognition of the circulatory model.

Heart Atria↗
PubMed1977

[Statistico-mathematical correlation of the B and C isoenzyme ratio of carbonic anhydrase and fetal hemoglobin, and its probable biological significance in the metabolism of zinc].

The AA. performed a study on the Bravais-Galton's correlation coefficient. They applied this coefficient to the HCAB/HCAC ratio and to the fetal haemoglobin often groups of twenty children (one month four years old) values. The result support the assumption that there is a strong biochemical relationship between zinc-carbonic anhydrase and haemoglobin in erithrocytes.

Age Factors↗
PubMed1977

[Subaortic stenosis due to antero-lateral muscular band, associated with ventricular septal defect and underdevelopment of the aortic arch. Anatomical features in three cases (author's transl)].

The pathological findings in three cases with ventricular septal defect and severe coarctation or tubular hypoplasia of the aortic arch are reported. The left ventricular outflow tract was partially obstructed by muscle situated on its antero-lateral wall. The haemodynamic relationship between this type of subaortic stenosis and aortic arch underdevelopment, due to unequal partitioning of the blood flow between the ascending aorta and the pulmonary artery during foetal life, is emphasized. The normal anatomy of the left ventricular infundibulum is described and some embryological hypotheses to explain this antero-lateral muscular band are forwarded.

Aortic Coarctation↗