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Biomedical subjects

L Marzio

Publications and source records attributed to L Marzio.

At least 91 records · Page 5Linked to original sources
PubMed1987

Study of the cardiovascular effects of clenbuterol in exercise-induced asthma.

The protective effect of clenbuterol on exercise-induced asthma was studied in 14 patients with aspecific bronchial hyperreactivity. The selectivity of clenbuterol for beta 2-receptors was also studied. Patients were selected according to spirometric criteria: reduced dynamic indexes of respiratory function after exercise and, particularly, forced expiratory volume at 1 s (FEV1) decreased by at least 20% compared with initial values. A polycardiographic study was simultaneously carried out for the evaluation of systolic time intervals and polycardiographic indexes (Weissler index, Blumberger index and QT/QS2 index). After the preliminary measurements (C1), oral clenbuterol was started (0.02 mg X 2/day) and measurements were repeated after 30 (CII) and 60 days (CIII) of therapy. During treatment, physical exercise did not significantly influence the indexes of respiratory function (FEV1 decreased by 4.7 +/- 5.8 and 9.8 +/- 10.5% in CII and CIII with respect to initial values). Similarly systolic time intervals and polycardiographic indexes did not change significantly with respect to the initial values. A small increase in heart rate at rest was observed in CII (+ 7%, p less than 0.05): however, no significant changes were recorded in CIII compared with the initial values. Clenbuterol thus seems to offer an effective protection against exercise-induced asthma without the negative effects on the cardiovascular system which may arise from activation of beta 1-adrenergic receptors.

Adolescent↗
PubMed1986

Effect of cisapride on human fasting gallbladder volume: a real-time ultrasonographic study.

The effect of cisapride, a new non-antidopaminergic agent, on human gallbladder volume has been studied in nine normal subjects. In a double-blind crossover fashion, each subject was given a slow i.v. injection of cisapride and placebo after 12-h fasting. Gallbladder volume was monitored every 15 min for 90 min by real-time ultrasonography. After cisapride, gallbladder volume significantly diminished, with a mean reduction of 22.9 +/- 5%, observed 30 min after injection, whereas no significant changes were noted after placebo. A cholinergic mechanism is proposed to explain the effect of cisapride on gallbladder volume.

Adult↗
PubMed1986

Dopamine-induced migrating myoelectrical complex-like activity in human duodenum.

The effect of dopamine on human gastric and small intestinal interdigestive motility was investigated in 12 subjects. Intestinal motility was recorded by means of a four-lumen polyvinyl probe with four open tips located 15 cm apart, continuously perfused with distilled water. In each subject during the same study, after recording two consecutive spontaneous phase III of migrating myoelectrical complexes and when a phase II appeared, dopamine was infused intravenously twice in a dose of 5 micrograms/kg/min for 15 min with an interval of 20 min between each infusion. In six subjects, the second dopamine infusion was preceded by a treatment with sulpiride (10 mg, intravenously, as bolus) or domperidone (10 mg, intravenously, as bolus), each considered a highly selective dopamine antagonist. The results show that dopamine stimulates duodenal motility producing a pattern similar to that observed in phase III of spontaneously occurring migrating myoelectrical complexes. The second dopamine infusion reproduced in all cases the same pattern of motility as observed during the first infusion. Sulpiride and domperidone prevented the effect of dopamine in all cases. It is therefore suggested that dopamine-induced duodenal motility may involve specific dopaminergic receptors.

Adult↗
PubMed1986

Lactate release during the recovery period of pacing-induced angina in assessment of myocardial ischaemia.

Myocardial lactate (L) metabolism was tested in 27 stable angina patients during atrial pacing (AP) and in the recovery period (R) from AP-induced angina pectoris. The recovery period was assessed in order to evaluate the changes in the rate of L release and detect possible relationships with the severity of ischaemic damage. The following variables were assessed: coronary sinus blood flow (CSBF), left ventricular end-diastolic pressure (LVEDP), lactate extraction ratio (L%), lactate extraction or release rate (LR) and myocardial oxygen consumption (MVO2) at the onset of AP (AP1), during angina (AP2), and 30 s, 2 and 4 min (R1, R2 and R3) after AP ceased. At Ap2, negative L% and LR values (-39.37 +/- 43.3, -3.2 +/- 2.9) were found, in spite of a rise in CSBF (+86%, P less than 0.001). Furthermore, LVEDP showed its maximal increase in AP2 (+27%, P less than 0.001). Compared to AP2, L% resulted unchanged in R1, while LR showed a mild decrease (from -3.2 +/- 2.9 to +2.06 +/- 2.93). Lactate production was converted to extraction in R3 only. Since lactate production and release are progressively reduced with increasing severity of ischaemic damage, AP2 coronary sinus lactate release should largely arise from the less damaged areas (i.e. the outer myocardial layers) and the contribution of the more damaged areas (i.e. the inner myocardial layers) should be more limited. After AP ceases, the mild ischaemic areas should recover more rapidly than the severely ischaemic areas, where the damage only declines, leading to a temporary increase in lactate production and release.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Physiology of interdigestive motor activity in man].

Aim of this work has been to investigate the pattern of interdigestive motility from the esophagus to the duodenum. Six human subjects have been studied by means of a manometric probe. The results are very similar to those described elsewhere, and show that a cyclic motor activity spreads down from the esophagus to the duodenum and that a district control of gastrointestinal motility exists.

Adult↗
PubMed1985

Anorectal motility and rectal sensitivity in chronic idiopathic constipation: effect of high-fiber diet.

The rectoanal inhibitory reflex and rectal sensitivity were evaluated in 13 patients with idiopathic chronic constipation and in 13 control subjects. A double balloon probe was used to stimulate and record the rectoanal inhibitory reflex and rectal sensitivity. The results showed a linear relationship between relaxation amplitude and the logarithm of rectal distending volume, and between relaxation duration and the logarithm of rectal distending volume, with a significant reduction of relaxation amplitude in the patient group. The rectal sensitivity thresholds were significantly increased in patients compared with controls. In 10 additional patients with chronic constipation, motility and sensitivity parameters were evaluated before and after 28 days of high-fiber diet. After diet, the values of relaxation amplitude were significantly increased, returning within normal range, but sensitivity parameters did not change. In conclusion, it appears that in adult chronic idiopathic constipation, anorectal motility and rectal sensitivity are altered, and that only motor abnormalities are corrected by a high-fiber diet.

Adolescent↗
PubMed1985

Atropine antagonizes cholecystokinin and cerulein-induced gallbladder evacuation in man: a real-time ultrasonographic study.

Dose-response curves for cholecystokinin (CCK), cerulein (CRL), and the effect of atropine on peptide-induced gallbladder evacuation, were evaluated in 13 normal subjects. Gallbladder volume was monitored by means of real-time ultrasonography. After an overnight fast, CCK was infused in six subjects iv, with increasing doses from 0.002 IDU/kg/min for 15 min, and CRL in seven subjects from 0.5 ng/kg/min for 5 min, until maximum gallbladder evacuation (greater than 70% of the fasting volume) was achieved. Forty-eight hours after the first study, CCK and CRL were readministered at the maximum contracting dose in each subject with and without a pretreatment with atropine (1 mg iv as bolus). The results showed maximum gallbladder evacuation at 0.016 IDU for CCK, and at 4 ng for CRL. Atropine significantly blunted the gallbladder response both to CCK and to CRL. It is therefore suggested that the cholinergic system is involved in the gallbladder response to CCK and to CRL.

Adolescent↗
PubMed1983

Inhibition of postprandial colonic motility by sulpiride in patients with irritable colon.

Sulpiride, a benzamide derivative, selectively antagonizes dopaminergic receptors within and outside the central nervous system. Dopamine has previously been shown to increase colonic motility. In the present investigation the motor response of the pelvic colon to a standard 1000 calorie meal was studied in 12 patients with the irritable bowel syndrome. The meal induced a significant increase in motor activity, lasting for 1 h and greatest in the first 30 min. In 6 cases the administration of sulpiride 100 mg i.m. significantly reduced the postprandial increase in colonic motor activity. Thus dopaminergic receptors may be involved in the colonic motor response to food.

Colonic Diseases, Functional↗
PubMed1983

Some parameters of descending inhibition during colonic propulsion.

Isolated segments of rabbit distal colon were stimulated by distension of intraluminal balloons, with the aim of investigating the electrophysiological pattern of descending inhibition (DI) during the peristaltic reflex. Incidence, duration, and latency of DI were studied by varying the parameters of stimulation. A linear correlation was found between stimulus duration and DI duration for stimuli up to 10 s long. DI duration increased with the distance of the recording site from the stimulus up to 3 cm. A more complex relation was found between balloon volume and DI duration. Propagation velocity decreased with the distance from the stimulus. The relation between ascending excitation and DI was also studied: ascending excitation could always be suppressed by DI. DI was examined after addition of anticholinergics, ganglionic blocking agents, and tetrodotoxin to the organ bath. The results show that DI parameters are partially related to the stimulus characteristics and that propagation of DI is neurally mediated through nonadrenergic inhibitory nerves.

Animals↗
PubMed1982

Hemodynamic and metabolic effects of nitroglycerin ointment in pacing-induced angina pectoris.

Hemodynamic and metabolic effects of nitroglycerin ointment (40 mg nitroglycerin) were tested on 15 patients with clinical evidence of stable angina. Basal value (B) and atrial pacing (AP)-dependent changes were evaluated before and 30 min after ointment administration. After treatment tension time index (TTI) basal value showed a 19% reduction (p less than 0.05). Compared to the control a lesser AP-dependent increase was also noted (27%, compared to 45%; p less than 0.005). According to TTI reduction, MVO2 showed an evident decrease both in basal conditions and during AP (21% and 29.6%, respectively). On the contrary, diastolic pressure time index (DPTI) does not result significantly influenced by the treatment. Consequently, DPTI/TTI ratio increase is largely the result of TTI reduction, which is well correlated to myocardial oxygen demand. Coronary sinus blood flow decrease (16% and 27% under basal conditions and during AP, respectively) confirms that the therapeutic efficacy of the ointment does not result from an increase in myocardial oxygen supply. Finally, during AP nitroglycerin ointment resulted in a significant decrease in myocardial lactate release (L% mean value ranges from-17.5% to 3.4%; p less than 0.001). Such an improvement probably reflects a primary influence of the drug on the extracoronary vascular bed.

Adult↗
PubMed1980

[Motor coordination of the gastro-duodenal junction in the dog].

To record mechanical and electrical activities of the gastro-duodenal junction in dogs, before feeding after feeding and after drugs, four extraluminal strain-gauges and four bipolar electrodes were surgically implanted, one set on the pylorus, one in antrum and one on the duodenum. All the records were analyzed on a Nova 830 minicomputer for the frequency content of signals. The pylorus behaved primarily as an extension of the antrum in the sense that it had electrical and mechanical frequencies mostly in the range of 4-5 c/m, same as antrum. It did not show any relaxation in response to feeding. Both the duodenal electrodes showed a frequency component at antral frequency in both fasted and fed states. After feeding duodenal contractions, usually at a frequency of 18-20 c/m, were either inhibited or reduced and the duodenal mechanical activity showed a dominant frequency component at antral frequency. Pentagastrin (4 ug/kg/hr) induced a pattern similar to that after feedings, but it did not inhibit duodenal contractions at its inherent rate to the same extent as feeding. Antral frequencies were still present in the duodenal electrical records when atropine abolished all mechanical activity. This study shows objectively that during gastric emptying, duodenal contractions are coordinated with antral contractions.

Animal Feed↗
PubMed1978

Motor effect of dopamine on human sigmoid colon. Evidence for specific receptors.

The effect of dopamine on human sigmoid motility has been studied in 26 subjects. To record mechanical activity of the sigmoid colon, two small, air-filled balloons mounted on a probe introduced through a sigmoidoscope were used. The recordings were made at a distance of 25 and 15 cm from the anal edge. Dopamine was infused for 10 min after a 30-min control infusion of physiologic solution. Mean amplitude, mean duration, mean frequency, percentage of motor activity, and motility index of the pressure waves were determined. The motor response to dopamine was characterized by an increased baseline pressure with phasic waves superimposed. Dopamine produced a significant response at the dose of 5 microgram/kg/min. Alpha and beta antagonizing agents failed to oppose the effect of dopamine, while anticholinergic drugs enhanced its motor action. These studies suggest that dopamine may stimulate the motor function of human large bowel through specific receptors.

Atropine↗
PubMed1978

Idiopathic intestinal pseudoobstruction. Report of a case, with intraluminal studies of mechanical and electrical activity, and response to drugs.

Intraulminal recordings of motility were made from a patient with chronic idiopathic intestinal pseudoodstruction. Contractile activity was recorded from esophagus and duodenum with and without cholinergic stimulation. Electrical activity was recorded from duodenum with and without cholinergic stimulation. Contractile and electrical activities were recorded from the sigmoid colon at rest and after morphine. Gastric fundic relaxation was measured during balloon distention. This patient showed abnormalities of esophageal function similar to achalasia, while gastric fundic relation was impared, with a more rapid rise in pressure on distention than is seen in normal persons. Duodenal and colonic electric control and response activities were present on occasion. Duodenal contractions occurred in response to both bethanechol and edrophonium. Therefore, the efferent cholinergic system of the small bowel appears to be functional in this case of idiopathic intestinal pseudoobstruction. The nonardrenergic inhibitory control of esophagus and gastric fundus appears to be functioning abnormally.

Adult↗