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A Antona

Publications and source records attributed to A Antona.

17 recordsLinked to original sources
PubMed1996

A new method to measure cardiac inositol levels in intact animals.

Inositol levels have been studied in cellular cultures and recently by perfusion of isolated hearts. The study was aimed to assess inositol turnover in rabbit hearts from intact animals. Thirty rabbits were injected i.v. three times (every 12 hr) with 25 microCi/kg of myo-3H-inositol. The rabbits 12 hr after the last injection were killed and the hearts perfused according to Langerdorff technique. Systolic and diastolic ventricular pressures (SVP, DVP), dp/dt, and coronary flow (CFl) were measured. The hearts (n = 14) were perfused under aerobic conditions and 16 hearts under ischemic conditions for 30 min. In addition, 5 hearts were perfused under aerobic conditions for 10 min, and 6 hearts were perfused under ischemic conditions for 10 min. Samples of myocardial tissue were taken from both groups at the end of 10-min and 30-min period of perfusion, and cAMP and inositol phosphates were assayed. The hearts subjected to ischaemia showed changes of cAMP and 3H-inositol. The cAMP was higher in the ischaemic (10 min and 30 min) than the control hearts, 0.22 +/- 0.09 and 0.21 +/- 0.08 versus 0.41 +/- 0.12 and 0.49 +/- 0.11 pmol 10(6) cells, respectively (p < .05, p < .001. The inositol trisphosphate was higher in control than ischemic hearts (10 min, 30 min), 0.42 +/- 0.02 and 0.39 +/- 0.01 versus 0.31 +/- 0.01 and 0.23 +/- 0.02 (percent of radioactivity) respectively, p < .001. Our data suggest that 3H-inositol may be studied by i.v. administration to intact animals. The ischemia was performed to verify the validity of this new technique.

Animals↗
PubMed1995

Effects of sumatriptan on isolated rabbit heart.

Sumatriptan provokes, in healthy subjects as well as in those who suffer from hemicrania, a slight increase in both systolic and diastolic arterial pressure. It has also been shown to increase the pressure of pulmonary circulation and to reduce the calibre of coronary arteries. The present investigation was undertaken to study the effects of sumatriptan (75 ng/l) on isolated rabbit hearts. Fifteen isolated rabbit hearts, perfused according to Langerdoff's procedure, were divided into two groups: Group I (5 hearts), perfused with Krebs-Henseleit solution, as a control, and Group II (10 hearts), perfused with Krebs-Henseleit mixed with sumatriptan succinate (75 ng/l). After 30 min of perfusion, the basal values of heart rate (HR) dp/dt, systolic ventricular pressure (SVP), diastolic ventricular pressure (DVP) and coronary flow (CF) were measured. The above values in either control or treated hearts were measured 5, 15, 30, 45, 60 min after recording the baseline values. HR, SVP, DVP, dp/dt and CF did not show significant differences in the two groups. The present data suggest that sumatriptan does not exert any action on isolated rabbit hearts.

Animals↗
PubMed1994

Effect of captopril on lymphocytic beta-adrenergic receptors in normal and hypoxic conditions.

BACKGROUND: During heart failure, due to increased level of circulating norepinephrine, the number of beta-adrenergic receptors (beta-AR), both at the cardiac and the lymphocytic level, is reduced (down-regulation). Captopril, an ACE-inhibitor containing an SH group appears capable of resetting beta-AR when used in patients with heart failure. Our study was aimed at checking whether captopril exerts a direct effect upon the beta-AR, possibly through its SH group by disulphur binding with cysteine residues located at the binding sites for catecholamines. METHODS: The study was carried out in vitro on human lymphocytes obtained from healthy volunteers: 10 males (mean age, 34 years; range, 25-45) and 10 females (mean age, 34 years; range 26-48). Lymphocytes were randomly divided in two groups of equal size. Group I were controls; in Group II cells were incubated with three different doses of captopril: 1, 10, and 100 microM. Control lymphocytes and those treated with 10 microM of captopril were exposed to 1 microM isoproterenol. The number of total and surface beta-AR, and the sequestration of beta-AR from isoproterenol under normoxic conditions and after 20 h of hypoxia were checked. Furthermore, the content of cAMP was assayed both in basal conditions and after stimulation with 10 microM and 100 microM isoproterenol and forskolin, respectively. RESULTS: Total beta-AR: 1082 +/- 133 (controls) vs. 1174 +/- 94 (treatment with 1 microM captopril), vs. 1237 +/- 88 (10 microM captopril), vs. 1092 +/- 105 (100 microM captopril). Surface beta-AR: 84 +/- 4.41% (controls) vs. 90.5 +/- 2.1% (10 microM captopril). Basal cAMP: 1.21 +/- 0.4 (controls) vs. 1.23 +/- 0.5 pmol/10 cells (1 microM captopril), 1.05 +/- 0.6 pmol/10 cells (10 microM captopril), 1.15 +/- 0.4 pmol/10 cells (100 microM captopril). After 10 microM isoproterenol: controls 4.10 +/- 0.8 vs. 4.30 +/- 0.9 pmol/10 cells (1 microM captopril), 4.15 +/- 0.7 pmol/10 cells (10 microM captopril), 3.50 +/- 1.0 pmol/10 cells (100 microM captopril). After 100 microM forskolin: controls 13.2 +/- 3.1 vs. 11.2 +/- 3.1 pmol/10 cells (1 microM captopril), 13.1 +/- 4.2 pmol/10 cells (10 microM captopril), 12.6 +/- 2.9 pmol/10 cells (100 microM captopril). Neither of these differences were significant. Lymphocytic beta-AR exposed to hypoxia did not show any significant difference. Exposure to captopril did not cause any further alteration on beta-AR sequestration. CONCLUSIONS: Captopril does not seem to exert any direct action upon lymphocyte beta-AR from healthy volunteers. Moreover, captopril does not modify cAMP storage either in basal conditions or after stimulation with isoproterenol or forskolin. Therefore our data suggest that action of captopril on beta-AR is probably due to the inhibition of both systemic and tissue ACE-system.

Adult↗
PubMed1994

Effects of dopamine on isolated failing rat heart.

Dopamine has been used for many years to treat patients with severe heart failure. It is not clear whether improvements of cardiac function may be due to a direct action on heart. This study was aimed to investigate the direct action of dopamine on failing heart. we chose male Wistar rats which had undergone uninephrectomy under ether anaesthesia to induce hypertension to result in heart failure. After 5 weeks the hearts were excised and perfused according to Langerdoff's technique. Heart rate, systolic and diastolic ventricular pressures, the derivative of the intraventricular pressure time ratio, and coronary flow were measured at baseline, at 2 and 5 min and then every 5 min during a 30-min period. Rat hearts were divided into 4 groups of 5 hearts: group 1, perfused without drug; group 2, perfused with dopamine at 4 micrograms/kg/min; group 3, perfused with dopamine at 8 micrograms/kg/min; group 4, perfused with dopamine at 8 micrograms/kg/min and with 100 nM I.C.I. 118.551 (beta 2-ant: beta-2 receptors antagonist) at the same time. Our results show that dopamine induced a negative inotropic effect and a reduction of coronary flow. Moreover, there was a significant chronotropic action even when dopamine was administered at high concentrations. So we found no positive dopamine effect on isolated failured hearts of rat. This might be explained by both alpha-1-induced vasoconstriction and the stimulation of alpha-1B receptors. We conclude that the favourable effects of dopamine in heart failure could be due to DA1 vasodilation rather than to a direct inotropic action on the heart.

Animals↗
PubMed1992

Effects of captopril on the ACE-tissular system and on models of experimental ischaemia in isolated rabbit hearts.

In this study the authors evaluated the effect of captopril on coronary flow (CBF) dP/dT ratio and on reperfusion ventricular hyperkinetic arrhythmia (VHA) in 15 isolated and perfused (Langendorff's procedure) rabbit hearts following acute experimental ischaemia. The final goal was to determine whether pretreatment with captopril (administered before induced ischaemia or during the perfusion period) could protect the heart from the effects induced by acute ischaemia. Acute ischaemia was produced through 15-min ligation of the anterior descending coronary artery at its origin. After the ischaemic period, the hearts were subjected to a perfusion procedure for 45 min. Isolated hearts were connected to an intraventricular transducer system to evaluate intraventricular pressure curves, associated with a monitoring electrocardiogram system. Renin activity was detected by the RIA method from perfusion fluid samples. The 15 isolated and perfused rabbit hearts were subgrouped into 3 experimental groups as follows: Experiment No. 1: in this model the effects of acute induced ischaemia were evaluated in 5 rabbits without treatment and used as controls. At the end of the ischaemic period a relevant percent decrease in CBF (-36%) and in Dp/dT ratio (-33%) was found; after perfusion period a further percent decrease in CBF (-41%) and in Dp/dT ratio (-41%) was observed. Renin activity increased significantly only during the ischaemic period. In all the rabbits ventricular premature beats (VPB) were found and in 3 rabbits ventricular fibrillation (VF) was also detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Effect of heroin and morphine on cardiac performance in isolated and perfused rabbit heart: evaluation of cardiac haemodynamics, myocardial enzyme activity and ultrastructure features.

In the present study the effects of heroin and morphine administration on cardiac function, myocardial enzyme activity and cardiac ultrastructure features have been evaluated in isolated and perfused rabbit hearts. In 24 male rabbits the hearts were excised and immediately perfused in a retrograde non recirculating Langendorff apparatus. Successively, heroin 1 x 10(-5) or 1 x 10(-4) M or morphine at 1 x 10(-4) M were individually administered in 18 rabbits for 45 min. In 6 rabbits, used as controls, the isolated hearts were perfused with perfusion fluid for the same time. At the end of perfusion period the hearts were removed and histology was studied. During the perfusion period, creatine phosphokinase (CPK), lactic dehydrogenase (LDH) activity, heart rate (HR), derivative of intraventricular pressure time ratio (dP/dt) and changes in systolic ventricular pressure (SVP), diastolic ventricular pressure (DVP) and in coronary blood flow (CBF) were also evaluated. At the end of perfusion period no significant changes in CPK, LDH, HR, dP/dt ratio, SVP, DVP and CBF in comparison with basal values were observed in all groups. Histological specimen were characterized by slight derangements in atrial and ventricular structure both after heroin and after morphine administration. In conclusion our data suggest that alterations following opioids administration might rather be related to a systemic action involving only indirectly the heart.

Animals↗
PubMedDate not supplied

[Endoscopic study in reflux esophagitis. Our experience].

One hundred twenty one cases of oesophagitis by gastroesophageal reflux were observed through a retrospective study of 1250 endoscopies of the upper digestive tract. The oesophagitis was staged according to Savary-Miller classification. The prevalence (93.3%) of cases were in I and II stage. The Authors found that the most frequent associated diseases with oesophagitis by gastroesophageal reflux were: hiatal hernia, gastric and duodenal peptic disorders, gastric resection according Billroth II and biliary disorders. In 86.7% of cases, endoscopic diagnosis was confirmed by histological findings. From these data and from those reported in literature the authors can ascertain that endoscopy, associated with histological findings has an important role in diagnosing oesophagitis and in monitoring medical and surgical treatment used.

Biopsy↗
PubMedDate not supplied

[Effects of prolonged work on "deep-sea" fishermen: influence of blood cortisol, prolactinemia and urinary catecholamines].

Effects of persistent overwork on the deep-sea fishermen: influence on serum cortisol and prolactin, and on urinary catecholamine levels. Variations in serum prolactin and cortisol levels and in urinary catecholamines levels were studied in fishermen exposed to a persistent overwork period of deep-sea fishing. Results indicate that prolactin was rapidly modified. In fact, the serum prolactin levels already increased on the first day and maximum levels were observed on the fifth day. On the contrary, the physiological rise and fall in the serum levels of cortisol were scarcely influenced on the first day while on the fifth day increased in the morning and fell in the evening in a very significant manner. No significant variation in urinary catecholamine levels was observed at the end of fifth day. These results suggest that, unlike for prolactin, the effects of stress on serum levels of cortisol are complex and, under our conditions, could be due, at least in part, to the duration of the stress and to the functional moment of pituitary-adrenal axis.

Adult↗