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M Contini

Publications and source records attributed to M Contini.

34 records · Page 2Linked to original sources
PubMed1995

Adenosine activates cardiac sympathetic afferent fibers and potentiates the excitation induced by coronary occlusion.

Adenosine is a possible mediator of cardiac pain during myocardial ischemia; however, little is known about the influence of adenosine on cardiac sympathetic afferent activity and thereby on its algogenic mechanism. In 20 anaesthetized, decerebrated, curarized and artificially ventilated cats, we studied the impulse activity of 20 single afferent sympathetic fibers with a left ventricular receptive field in relation to epicardial applications of adenosine, coronary artery occlusions and arterial pressure rises. All fibers increased their impulse activity (from 1.2 +/- 0.2 to 2.6 +/- 0.5 imp/s; P < 0.001) during slight (20 +/- 8%) rises in aortic pressure, thus exhibiting low-threshold receptor characteristics. In 10 cats, epicardial applications of three different doses of adenosine (0.1, 1 and 10 mg/ml) caused a brief increase in neural activity with dose-related responses. This response was abolished by aminophylline, a P1 purinergic inhibitor. In the other group of 10 cats, four subsequent 30-s occlusions of the coronary arterial vessel supplying the receptive fields of the fibers were performed, in control conditions and 30 s, 3 and 7 min, respectively, after the end of excitation induced by adenosine (1 mg/ml) application. During the control coronary occlusion the impulse activity increased from 1.1 +/- 0.1 to 5.5 +/- 0.7 imp/s (P < 0.0001). A similar activation was present during the second occlusion initiated 30 s after the end of adenosine-induced activation. In contrast, a significant potentiation of the response was observed (8.8 +/- 1.2 vs. 5.3 +/- 0.9 imp/s; P < 0.001) during the occlusion initiated 3 min after the end of excitation by adenosine. This effect was no longer present during the last occlusion performed after 7 min. When the protocol was repeated substituting adenosine with saline (n = 5) or after i.v. administration of aminophylline (n = 5), no potentiation was observed, even though the excitatory response to coronary occlusion was preserved. These data show that adenosine can activate cardiac sympathetic afferent fibers in a dose-related manner, and potentiate their responses to coronary occlusion, while leaving unaffected the responsiveness to a hemodynamic stimulus. The excitatory effects are likely to involve the P1 purinergic receptors. The potentiation phenomenon might play a role in the genesis of an algogenic code.

Adenosine↗
PubMed1994

Morning and Monday: critical periods for the onset of acute myocardial infarction. The GISSI 2 Study experience.

The onset of acute myocardial infarction (AMI) is unevenly distributed over the 24 h and the week. While presence of a morning peak is generally agreed upon, contrasting results had been obtained regarding other periods of the day, probably due to differences of origin, size and composition of the populations. The 24 h and weekly distributions were studied within 6 h from the beginning of the symptoms in a population following a Latin life-style, who were enrolled in the GISSI 2 Study (n = 11472). Subgroups (smokers, the elderly (> 65 years), diabetics, hypertensives) were also considered. Six hour periods starting at midnight were tested for uniformity. Circadian non-uniformity was found. Events increased in the morning hours and reduced during the night regardless of the day of the week. The night and day difference was attenuated in smokers and diabetics. Non-uniformity of the events was also found among the days of the week. AMI significantly increased in non-smokers on Monday. We suggest that there is a night-day gradient (characterized by the short time interval between the two frequency extremes) in the time of onset of AMI. The different distribution in smokers stresses the possible unfavourable and masking effect of a heightened sympathetic tone during the day while the general protective role of the night hours is preserved. Moreover, the increased incidence of events on Monday may suggest the importance of the shift from a period of non-scheduled to scheduled activity.

Aged↗
PubMed1993

Effect of captopril on sympathetic preganglionic efferent activity in cats.

In 13 decerebrate cats, we studied the effects of captopril (10 mg/kg iv bolus) on the background discharge of thoracic preganglionic sympathetic fibers. After drug administration there was an initial reduction in systolic arterial pressure (SAP), which was followed by a later inhibition of sympathetic discharge (from 2.7 +/- 0.5 to 0.79 +/- 0.1 imp/0.1 s; P < 0.01). Captopril significantly reduced the excitatory response of sympathetic fibers to premature ventricular contraction (70 +/- 17 vs. 257 +/- 30%), inferior vena cava obstruction (176 +/- 56 vs. 315 +/- 85%) and asphyxia (143 +/- 20 vs. 245 +/- 51%). Vice versa the sympathetic response to aortic occlusion was unaffected (-58 +/- 8 vs. -62 +/- 6%). A similar reduction in sympathetic discharge was observed after captopril administration in anesthetized cats (n = 3). On the contrary, no changes in background neural discharge were noticed in decerebrate-spinalized cats (n = 5), despite comparable hemodynamic effects. These data indicate that captopril reduces sympathetic efferent activity and its responsiveness to excitatory stimuli. The lack of neural effects in decerebrate-spinalized cats is consistent with a brain stem site of action of captopril.

Animals↗
PubMed1992

Spectral analysis of sympathetic discharge, R-R interval and systolic arterial pressure in decerebrate cats.

In 19 decerebrate and artificially ventilated cats, we analyzed, with a power spectral methodology, the variability simultaneously present in R-R interval and in thoracic preganglionic sympathetic outflow. R-R interval was characterized, as already described in humans and other experimental preparations, by two rhythmic components occurring at a frequency of about 0.1 Hz (low-frequency, LF) and at one corresponding to respiratory rate (high-frequency, HF) which, in these experiments, was set at 0.32 Hz. Two similar rhythmic components were also present in the sympathetic discharge. Arterial pressure changes were produced by aorta or vena cava flow obstruction in order to produce reflex responses in sympathetic activity. Reflex sympathetic excitations induced an increase in the LF component of both R-R interval and sympathetic discharge variabilities, while the HF components were simultaneously reduced. In contrast, reflex sympathetic inhibitions were accompanied by a decrease in LF components of both variability signals, while the HF components were simultaneously increased. A significant and positive correlation was found between changes in impulse activity and the amplitude of LF component of either R-R interval or sympathetic discharge variabilities. These data support the hypothesis that the low-frequency component of R-R variability can be used as a marker of sympathetic modulation.

Animals↗
PubMed1991

[The excitatory effect of adenosine on the discharge activity of the afferent cardiac sympathetic fibers].

Recent clinical observations suggest that adenosine may produce cardiac pain; even though the mechanisms involved still need defining, one of the most convincing hypotheses seems to be a direct adenosine stimulation of the sympathetic nerve endings present in the myocardium. In 10 decerebrate and artificially ventilated cats, single sympathetic afferent fibres innervating the left ventricle were isolated from the third white thoracic ramus communicans of the left sympathetic chain. After locations of the fibre receptor field on the cardiac surface, we evaluated the effects of the local epicardial application of adenosine (0.1, 1 and 10 mg/ml) on the nervous discharge activity. These results were compared with those obtained by application of bradykinin, a potent natural algogenic substance which activates sympathetic afferents, and by a mechanical stimulus such as a slight increase of systolic arterial pressure (46 +/- 6% from 113 +/- 18 mmHg) induced by partial occlusion of the thoracic aorta. In particular, adenosine (1 mg/ml) elicited a significant increase in impulse activity (from 0.11 +/- 0.02 to 0.36 +/- 0.06 imp/0.1 s) with a latency of 16 +/- 2 s. Bradykinin application (20 micrograms/ml), in the same way, produced a significant increase in impulse activity (from 0.11 +/- 0.01 to 0.86 +/- 0.16 imp/0.1 s) with a latency of 8 +/- 1 s. Neither situation showed significant hemodynamic changes. An increased neural discharge (from 0.11 +/- 0.02 to 0.26 +/- 0.04 imp/0.1 s) was also observed during aortic occlusion. After purinergic receptor blockade by aminophylline (5 mg/kg, iv), the response to adenosine was no longer observed, while responses to bradykinin and aortic occlusion were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1989

Restraining effect of captopril on cardiovascular sympathetic efferent neural activity.

In 13 decerebrate cats we studied the effects of captopril (10 mg/kg, intravenous bolus) on the background cardiac preganglionic sympathetic discharge and on its responsiveness to brief baroreceptor deactivations induced by premature ventricular contractions. Captopril caused a significant reduction of 57 +/- 7% (from 2.4 +/- 0.4 impulses/0.1s) in sympathetic discharge, with a mean latency of 35 +/- 3 min from the time of drug administration. In addition, the increase in cardiac sympathetic firing during premature ventricular contractions was markedly reduced, from 257 +/- 30% to 70 +/- 17%, before and after administration of captopril. These data indicate that captopril is not only likely to inhibit sympathetic discharge to the heart, but is also likely to restrain the excitatory sympathetic responses to baroreceptor deactivation.

Animals↗
PubMed1989

Thymomodulin increases the depressed production of superoxide anion by alveolar macrophages in patients with chronic bronchitis.

Thymomodulin is an immunomodulating agent which is derived from calf thymus by partial acid lysis. It promotes T-cell maturation, enhances antibody synthesis and improves the phagocytic response of neutrophils. Clinical trials have revealed the effectiveness of this thymic derivative in the prevention of recurrent respiratory infections (RRI) in children and in adults; 11 patients (8 males and 3 females; age range 18-76 years) with chronic bronchitis dominated by recurrent respiratory infections were studied. They were treated orally for 6 months during the winter season with 120 mg/day of thymomodulin. All the subjects were asked to keep a diary recording the intensity of their symptoms, the number of working days lost (days of illness) and the use of antibiotic and/or mucolytic drugs. At the beginning and at the end of the trial each patient was subjected to a control with a flexible fibreoptic bronchoscope with bronchoalveolar lavage to evaluate the phagocytic response of alveolar macrophages. At the end of therapy a significant improvement of the clinical status, evaluated by the above-mentioned parameters, of the bronchial mucosa aspect and an increase in alveolar macrophage superoxide production was noticed (from 0.1 +/- 0.09 and 0.8 +/- 0.5 nmol to 1.6 +/- 0.8 and 4.1 +/- 2.2 nmol with PMA or zymosan particles respectively; p less than 0.001). During thymomodulin treatment no side-effects were recorded.

Adolescent↗
PubMed1985

Localization of substance P- and enkephalin-like immunoreactivity in the human paravertebral sympathetic ganglia.

The presence of substance P- and enkephalin-like immunoreactive nerve fibers and terminals is demonstrated in the human paravertebral sympathetic ganglia by an indirect immunofluorescence technique. Substance P-positive nerve structures appear in the form of fiber bundles, isolated varicose filaments and dot-like and basket-like nerve terminals around the neuronal cell bodies. Their density shows a remarkable individual variability. Enkephalin-positive nerve structures appear as isolated varicose filaments and dot-like nerve terminals, forming densely innervated patchy areas. No substance P- or enkephalin-containing cell bodies were detected. No overlapping seems to exist among the areas innervated by the two types of neuropeptides.

Aged↗
PubMed1984

Immature Paneth cells in intestinal metaplasia of gastric mucosa.

Various histochemical techniques were performed on paraffin sections of gastric mucosa with intestinal metaplasia to distinguish mature from immature Paneth cells (PC) and to correlate their relative incidence with the degree of differentiation of metaplastic epithelium. The results show a higher incidence of immature PC in the poorly differentiated type of intestinal metaplasia than in the well-differentiated type. The identification of immature PC may be proposed as a further criterion in the evaluation of gastric dysplasia.

Biopsy↗
PubMed1975

[Statistical study of laryngeal frequency. Application to the analysis and synthesis of prosodic features of French].

Some precisions concerning the specification and the instruments developed for the measurement of laryngeal frequency F1 being stated, the authors give statistical results for French. In first approximation, the F1 distribution is gaussian for a given corpus; the standard deviation measured and given in percentage referring to the mean laryngeal frequency F1 is about 16% for male and female speakers. Ceteris partibus, the variations of F1 are relatively low for a given speaker from one record to an other (about +/- 1/2 tone). The means of F1 are given for samples (gaussian) concerning adults (30 males and 30 female): respectively 118 and 207 Hz with standard deviation sigma (F1) of 18 and 20 Hz. The ratio tau 1 of the voiced duration to the total duration of the corpus, dependant on the sex: 0.50 for men and 0.63 for women (the difference is significant at the 0.001 level) allows the specification of the speaking rate. When the speaking rate increases, the length of pauses decreases. These results can be used for an estimation of the precision of the statistical measurement of F1 and sigma (F1), in relation to the number of periods N. To N appears a total duration of the corpus determined by tau 1. A comparison is made between the results of the calculation and the measurement. The F1 specification can be used for determination of the vocal source of synthesizer to improve naturalness of synthetic sounds and for analysis and synthesis of prosodic features using the results of two previous papers which have allowed to specify the position of level 1, 2 and 4 and to show the differences in the perceptual importance of the variations introduced in connection with the three levels.

Acoustics↗
PubMedDate not supplied

Intermittent antegrade warm blood cardioplegia in aortic valve replacement.

BACKGROUND: Intermittent antegrade warm blood cardioplegia (IAWBC) is a well established technique of myocardial protection for coronary artery surgery, with metabolic and experimental basis. METHODS: To evaluate its effectiveness in aortic valve replacement (AVR), we compared 171 consecutive patients who underwent first AVR using IAWBC (group A) with the last 100 consecutive patients who underwent first AVR using intermittent antegrade cold blood cardioplegia (IACBC) (group B). The endpoints considered were myocardial protection related (recovery of spontaneous rhythm, need for mechanical support, incidence of low-output syndrome, perioperative Q wave myocardial infarct, CK-MB levels, ventricular arryhthmias and lidocaine infusion requirement, cardiac-related deaths, and deaths any cause) and temperature perfusion related (bleeding, awaking time, time to extubation, and cerebrovascular accidents). RESULTS: Mortality was similar in both groups, but no patient in group A died for cardiac-related cause (0 vs 4, p < 0.01). More patients in group A recovered a spontaneous rhythm (144 vs 47, p < 0.0001). Incidence of low-output syndrome was higher in group B (16 vs 3, p < 0.0005), as well as ventricular arryhthmias incidence and need for lidocaine infusion (respectively 15 vs 2, p < 0.0001, and 10 vs 1, p < 0.0005). Awaking time was shorter in warm patients (2.5 +/- 2.5 hours vs 4.4 +/- 3.7 hours, p < 0.0005), as the extubation time (9.4 +/- 7.7 hours vs 13.5 +/- 11.7 hours, p < 0.0005) and bleeding (803 +/- 714 mL/24 hours vs 1051 +/- 1375 mL/24 hours, p < 0.05). As a consequence, the intensive care unit and the postoperative hospital stays were shorter in group A (32 +/- 27 hours vs 48 +/- 20 hours, p < 0.0005, and 7.2 +/- 3.1 days vs 11.3 +/- 5.4 days, p < 0.0001, respectively). CONCLUSIONS: IAWBC provides lower cardiac-related mortality and morbidity in patients who undergo AVR in comparison with IACBC.

Aged↗
PubMedDate not supplied

Off-pump myocardial revascularization using arterial conduits without cardiopulmonary bypass.

OBJECTIVE: The feasibility of myocardial revascularization via a median sternotomy with arterial conduits, without and with cardiopulmonary bypass (CPB), was evaluated. MATERIAL AND RESULTS: From May 21, 1997, to November 30, 1999, 721 patients had myocardial revascularization without CPB via median sternotomy using at least two arterial conduits. The procedure was performed without CPB in 322 patients (Group A); the remaining 399 patients (Group B) underwent the same operation with the aid of CPB. Group A patients were older, with a higher ejection fraction and less redo than Group B. There was no early death in Group A versus nine (2.3%) patients in Group B (p < 0.02). Incidence of cerebrovascular accident (CVA) and acute myocardial infarction (AMI) were similar in both groups. Early major events incidences were 1.2% versus 8.0% (p < 0.001) in Groups A and B, respectively. Postoperative angiographic controls showed a cumulative patency rate of 98.4% and a perfect patency rate of 96.7%. After 30 months, Groups A and B showed an actuarial survival of 98.1 +/- 0.7 and 96.5 +/- 2.8 (p = ns) and an event-free survival of 96.6 +/- 1.0 and 96.5 +/- 2.8 (p = ns), respectively. CONCLUSION: Myocardial revascularization without CPB using arterial conduits can be accomplished with the same quality of results obtained with the use of CPB.

Actuarial Analysis↗
PubMedDate not supplied

Macroscopic anatomy of the superficial veins of the lower limb: a systematic review based upon echography.

Saphenous Veins are described in Anatomy textbooks as superficial veins running in the amorphous fatty layer of the lower limbs. Recent papers have demonstrated the complex fascial relationship of Saphenous Veins with the connective framework of the lower limb hypodermis. The aim of the present paper was to systematically review the anatomy of lower limb superficial veins, based upon echographic findings, in a series of normal subject. Our results offer new insight into lower limbs superficial veins anatomy, with important clinical and surgical implications.

Adolescent↗
PubMedDate not supplied

A comparison between the heart of young athletes and of young healthy sedentary subjects: a morphometric and morpho-functional study by echo-color-doppler method.

Morphologic and morpho-functional heart differences between healthy young athletes and healthy young subjects who do not practice agonistic sport have been studied using Color Doppler Echography (CDE). Overall, 68 subjects were enrolled in the study (age range: 19-26 yrs). Of them, 34 subjects (17 men and 17 women) were practicing sport agonistically; the 34 controls (17 men and 17 women) did not practice any sport on a regular basis. In each subject, age, height, weight, body mass index, practiced sport, systolic and diastolic blood pressure were recorded. CDE measures included telediastolic left and right ventricular diameters (LVDd and RVDd, respectively), interventricular septum thickness (IVSd), posterior wall thickness of the left ventricle (PLVWd), left and right atrium diameters during ventricular systole (LAD and RAD respectively), and continence of each heart valve (mitral; tricuspid; aortic; pulmonic). In women, LADd was significantly higher in the athletes than in the controls (35.04+/-4.13 vs 31.81+/-3.34; p<0.02). Physiological regurgitation in at least one heart valve was observed in 15 out of 17 (88.2%) of the athletes; in 12 cases only one valve was involved: the mitral valve presented physiological regurgitation in 8 women, the tricuspid in 4, the aortic in 2 and the pulmonic in 6. In the control female population (17 persons), only 2 women showed evidence of regurgitation. In men, except for RVDd, CDE measurements were all significantly higher in the athletes than in the controls: LVDd (49.4+/-3.13 vs 46.02+/-4.46; p<0.02); IVSd (9.79+/-1.24 vs 8.59+/-0.91; p<0.003); PLVWd (8.63+/-1.29 vs 7.48+/-0.66; p<0.002). Physiological regurgitation through one or more heart valves was demonstrated in all the 17 male athletes studied; in 9 cases (52.9%) only one valve was involved. Mitral regurgitation was ob- served in 8 cases (47%); tricuspid in 6 (35.3%). No physiological regurgitation through the aortic valve was found, while 15 cases (88.2%) presented a pulmonic regurgitation. Among male controls, physiological regurgitation was demonstrated only in 2 persons out of 17 (11.8%), both involving the pulmonic and the aortic valve. In the total population of athletes compared to controls, analyzing men and women jointly, we found that LAD (p<0.001),RAD (p<0.001), LIVD (p<0.01) were significantly larger in cases than in controls, while for RVD, IVSd and PLVWd such a difference did not reach statistical significance. No relationship was fouhd between CDE data and either age, height, weight or blood pressure.

Adult↗
PubMedDate not supplied

Descriptive and morphometric anatomy of the architectural framework of microcirculation: a Videocapillaroscopic study on healthy adult subjects.

Conventional Capillaroscopy allows the observation of a limited number of areas, classically the fingernail-fold. Videocapillaroscopy, on the contrary, can be performed on any part of the skin and of clinically accessible mucosae. The aim of the present paper was to investigate the architectural frameworks of microcirculation in the various regions of the body and their morphometric parameters in healthy adult subjects. Our findings showed four basic architectural patterns plus two special patterns. The calibre of capillary loops ranged from 15 to 20 micrometers, and capillary density ranged from 14 to 30 capillary loops each square millimetre. These findings might be used as normal reference data for future studies.

Adult↗