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Biomedical subjects

A G Rebuzzi

Publications and source records attributed to A G Rebuzzi.

At least 19 recordsLinked to original sources
PubMed1992

Importance of reperfusion on thromboxane A2 metabolite excretion after thrombolysis.

Fibrinolytic therapy is a major advance in the treatment of coronary artery disease. A marked elevation in plasma and urinary metabolites of thromboxane A2 (TXA2) after administration of thrombolytic therapy has been observed and has been related to a direct effect of thrombolytic drugs on platelets. To test this hypothesis we evaluated the 11-dehydro-thromboxane B2 (11-d-TXB2) level, as an index of platelet activation, in 20 healthy subjects and in 30 patients with acute myocardial infarction (AMI). Patients with infarction received streptokinase (n = 8), recombinant tissue-type plasminogen activator (rt-PA) (n = 8), or thrombolytic therapy preceded by acetylsalicylic acid (n = 7) or were treated without thrombolytic therapy (n = 7). The urinary 11-d-TXB2 level in healthy control subjects was 327 +/- 126 pg/mg creatinine. A significant increase was observed in patients with AMI with no difference between those who received no thrombolytic therapy (673 +/- 283 pg/mg creatinine in the first 12 hours) and those who received streptokinase (833 +/- 613 pg/mg creatinine) or rt-PA (836 +/- 653 pg/mg creatinine). Patients pretreated with acetylsalicylic acid had urinary 11-d-TXB2 values ranging between 361 and 155 pg/mg creatinine. A significant difference in 11-d-TXB2 values was observed only when patients who were reperfused were separated from those who remained occluded according to angiographic criteria (1085 +/- 498 vs 391 +/- 227 pg/mg creatinine in the first 12 hours, p less than 0.001). We conclude that reperfusion and not thrombolytic agents per se appears to be the factor that induces platelet activation and consequently facilitates reocclusion.

Aspirin↗
PubMed1990

Reproducibility in circadian rhythm of ventricular premature complexes.

To evaluate the existence and reproducibility of a circadian rhythm of ventricular premature complexes (VPCs), 38 patients (mean age 57 +/- 17 years) with greater than or equal to VPCs/hour were studied with 24-hour electrocardiogram Holter monitoring. Nineteen patients had coronary artery disease and 19 had structurally normal hearts. A second Holter electrocardiogram was recorded in all patients from 2 to 47 days (mean 11) after the first. Chronobiologic analysis was made by single and mean cosinor methods. A significant and similar circadian rhythm of VPCs was found in the total sample both on the first (mesor 399, acrophase at 15:08, p less than 0.01) and the second day (mesor 306, acrophase at 14:47, p less than 0.05), with 2 main peaks, the first in the late morning and the second in the afternoon. However, only 18 patients (47%, group A) had a significant individual circadian rhythm of VPCs on both days, whereas 20 (53%, group B) did not have a significant rhythm in greater than or equal to 1 day. A high reproducibility of the circadian rhythm of VPCs was found in group A patients, with a difference of 2.1 +/- 1.8 hours between the acrophases of the 2 days, whereas the difference was 4.4 +/- 3.3 hours in group B patients (p less than 0.01). Among group A patients, 14 (78%) had a VPC rhythm with acrophase occurring during waking hours, whereas the acrophase of 4 (22%) occurred during the night. The reproducibility of the circadian rhythm of VPCs was not influenced by gender, presence of coronary disease, medical therapy, basal VPC number, or day-to-day variability of VPCs, although group A patients were older than group B patients (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Accuracy in clinical arrhythmia detection of a real-time Holter system (Oxford Medilog 4500).

The accuracy of a real-time analysis Holter system (Oxford Medilog 4500) in detecting ventricular and supraventricular arrhythmias was evaluated. Hand-counted data from randomly selected hours of 152 ECG monitorings of 152 patients were used as the control standard. Accuracy of the system was evaluated on 606 hours for premature ventricular complexes (PVC), PVC couplets and supraventricular extrasystoles (SVE), and on 1,789 hours for ventricular tachycardia (VT), accelerated idioventricular rhythm (AIVR), and supraventricular tachycardia (SVT). Sensitivity and positive predictive accuracy for the Oxford system were (1) 92.9% and 94.9% for PVC; (2) 90.1% and 87.8% for PVC couplets; (3) 98.1% and 56% for AIVR; (4) 80% and 82.3% for VT; (5) 88.6% and 56.5% for SVE, and (6) 43.7% and 60.2% for SVT. Furthermore, negative predictive accuracy, the ability to predict the total absence of an arrhythmic event in an hour, was determined. It was 91.7% for PVC, 99.5% for PVC couplets, 99.9% for AIVR, 99.7% for VT, 95% for SVE, and 98% for SVT. ventricular arrhythmias, whereas significant inaccuracies appear to exist in the analysis of supraventricular arrhythmias.

Algorithms↗
PubMed1990

[rTPA and streptokinase in acute myocardial infarct. Clinical instrumental evaluation of the 2 treatments].

Fifty-four patients with acute myocardial infarction were treated with thrombolytic therapy (27 with rTPA and 27 with streptokinase). In all the subjects CK was monitored (every 3 hours) and ergometric test, echocardiogram, and 24 hours holter ecg were performed in the pre-discharge period. In 22 of the patients, coronary angiography was also performed. No differences were shown between the two groups of patients as regards CK values and ejection fraction. Repetitive ventricular premature beats were registered without difference between the two groups (23% in patients treated with SK and 18% in the patients treated with rTPA). No bleeding events were shown in the patients treated with rTPA without calciparin. On the other hand no difference there was between patients treated with rTPA + calciparin and patients treated with SK with or without calciparin.

Aged↗
PubMed1989

[Characteristics of non-sustained ventricular tachycardia found during dynamic ECG in patients with recent myocardial infarction].

The characteristics of ventricular tachycardia found during Holter ECG monitoring before discharge in patients hospitalized because of acute myocardial infarction were analyzed. One or more ventricular tachycardia episodes were found in 29 of 251 patients (11.5%). On the whole, there were 233 episodes of ventricular tachycardia: 18 patients (62%) had only one episode of ventricular tachycardia, 9 (31%) 2-5 episodes and 2, respectively, 68 and 118 episodes. Episodes of ventricular tachycardia were more numerous in patients with frequent or polymorphic premature ventricular complexes than in patients with sporadic or monomorphic premature ventricular complexes. Fifty-seven ventricular tachycardia episodes were analyzed: 30 of 3 beats, 25 of 4-9 beats and 2 of 15 beats. Forty-seven episodes were monomorphic and 10 (17.5%) were polymorphic. The ventricular tachycardia rate was 136.4 +/- 25 b/m' (range 104-200). The RR'/QT ratio (where RR' = coupling interval of the first beat of ventricular tachycardia) was 1.67 +/- 0.42 and was not correlated either with the rate or the number of beats of ventricular tachycardia. Heart rate at the moment of ventricular tachycardia was 82 +/- 15 b/m' and QT interval 0.36 +/- 0.05 sec; there was no difference when compared to their values of 1 and 5 minutes before ventricular tachycardia. Furthermore, the heart rate showed no difference when compared to the mean value of the hours in which ventricular tachycardia episodes occurred. In addition, heart rate was not correlated with ventricular tachycardia rate, whereas a good correlation was found between the last RR interval preceding ventricular tachycardia and RR' interval (r = 0.61, P less than 0.01).

Aged↗
PubMed1989

[Bidirectional tachycardia during therapy with lorajmine].

We report a case of bidirectional tachycardia (BT) found on Holter recording (H-ECG), likely due to antiarrhythmic therapy with lorajmine. The patient, who was not on digitalis therapy and had good myocardial function, was investigated for presyncope. H-ECG revealed frequent premature ventricular complexes (PVC). Disopyramide, lorajmine and amiodarone (in succession) were ineffective in controlling the arrhythmias. During therapy with lorajmine (600 mg/die) H-ECG showed numerous symptomless episodes of BT. Two forms of BT were found. In the first one the PVC had a right bundle branch block (BBB) pattern in lead CM1 and alternating polarity (Rs-rS) in lead CM5, whereas in the second one an alternating right and left BBB pattern in CM1 was found. PVC were subsequently controlled with flecainide. In a 4-year follow-up period the patient underwent several H-ECGs, both with and without antiarrhythmic drugs; however, BT episodes were found only during lorajmine therapy. Thus, this drug was likely responsible for the appearance of BT episodes.

Aged↗
PubMed1989

Rhythm of carnitine levels in serum and urine of normal subjects.

A study of the diurnal serum and urine levels of L-carnitine and acetylcarnitine was carried out in eleven healthy volunteers. No significant difference was found between the levels in the morning and in the afternoon, although a higher carnitinaemia was shown in the waking hours when the energy demands were higher.

Acetylcarnitine↗
PubMed1986

Ventricular parasystole: a chronobiologic study.

Previous works have reported circadian rhythms for several cardiovascular parameters. A chronobiologic rhythm is characterized by: mesor (a rhythm-determined average), amplitude (half difference between the highest and lowest values), and acrophase (timing of high point in degrees and/or in hours) along with 95% confidence limits. We performed 24-hour ECG Holter monitoring in seven patients (mean age, 50.6 years) with ventricular parasystole (VP) in order to determine whether the chronotropic activity of parasystolic foci has a circadian rhythm similar to that of the sinus node. For each Holter recording parasystolic rates (PRs) and heart rates (HRs) were calculated every hour. Furthermore, a mean hourly PR and a mean hourly HR were calculated from the hourly PRs and HRs of the patients. The statistic chronobiologic analysis was done by single and mean cosinor methods. Correlation between mean hourly PR and HR was evaluated by Pearson's 'r' coefficient. A statistically significant rhythm (P less than 0.05) was found for the single and mean rhythms both of HR and PR. In our patients, HR had acrophase at 1.27 P.M., mesor at 73.28 beats/min, and amplitude at 9.53 beats/min, whereas PR had acrophase at 1.42 P.M., mesor at 38.31 beats/min, and amplitude at 3.64 beats/min. Chronobiological data and the high direct correlation between mean hourly HRs and mean hourly PRs (r = 0.96, P less than 0.001) indicate a similar circadian variability of the chronotropic activity of sinus nodes and parasystolic foci. Although several hypotheses can be made, responsiveness of parasystolic foci to circadian variations of the autonomic nervous system tone (sympathetic and/or vagal) and/or circulating substances (particularly catecholamines) seems the more probable one for explaining our findings.

Adolescent↗
PubMed1985

[Blood catecholamines in liver cirrhosis].

Haematic concentrations of catecholamines were found to be higher in cirrhotic patients with ascites, than cirrhotic patients without ascites and controls. In compensated and decompensated cirrhosis, different forms of sympathetic nervous activity were observed. The high catecholamine values in cirrhotic patients and the activation of the renin angiotensin-aldosterone system suggest the use of beta-blockers to reduce sodium-water retention.

Adrenergic beta-Antagonists↗
PubMed1979

Altered urinary excretion of human kininase activity in acute myocardial infarction.

This study concerns the determination of levels of human urinary kininase excretion in acute myocardial infarction (AMI). The results obtained by a biological method show that there is a significant reduction of the enzymatic activity in patients affected by AMI in comparison with normals (6.4 +/- 0.4 ng of destroyed bradykinin/min. versus 164.4 +/- 31.4 ng; P less than 0.001), while urinary kallikrein excretion was close to normal values.

Humans↗
PubMed1979

Glucose, insulin and somatostatin infusion for the determination of insulin resistance in liver cirrhosis.

Twelve patients with liver cirrhosis and ten normal subjects were studied. Using a constant intravneous infusion of glucose, insulin and somatostatin over 2 1/2 hours we determined the stteady state plasma glucose level (SSPG) in order to measure insulin resistance. The results demonstrated that the cirrhotic patients were insulin resistant compared to normals and that plasma glucagon does not account for the insulin resistance in these patients.

Adult↗
PubMed1979

Early insulin and glucagon response to subsequent pulses of arginine, glucose, and tolbutamide in normal man.

To determine the dynamics of insulin and of glucagon secretion in response to several sequential stimuli administered shortly after an arginine pulse (5 g), 20 nonobese, apparently healthy volunteers were given arginine (5 g), glucose (5 g), and tolbutamide (1 g) by rapid intravenous injection. The early insulin and glucagon area 0-8 min was studied. At the intervals and with the dosages used in this study, different stimuli with and without prestimulation with arginine did not lead to changes in early secretion of insulin. There was no exhaustion of the pool of insulin released after multiple sequential pulses. These results suggest a pattern in which stimulation induces a rapid release of insulin and activates the interchange between the stored and labile insulin pool; the 8-min interval is sufficient for the rapid return of the two compartments to a state of equilibrium. Also for glucagon, subsequent different stimuli did not exhaust glucagon release; nevertheless, glucagon is immediately suppressed by a submaximal glucose pulse.

Adolescent↗
PubMed1979

GH secretion in open-angle glaucoma.

Open-angle glaucoma is frequently observed in patients with acromegaly suggesting that the somatotropic hormone might facilitate a condition of glaucoma. The open-angle glaucoma patients studied, displayed higher plasma human growth hormone (HGH) levels than control subjects 60 min (30.3 +/- 1.7 against 16.8 +/- 2.7 ng/ml; p less than 0.001) and 90 min (19.0 +/- 1.9 against 9.3 +/- 1.2 ng/ml; p less than 0.001) after intravenous administration of arginine (25 g in 30 min). The authors support the hypothesis that the increased plasma HGH level may interfere with the regulation of ocular pressure by modifying the flow of aqueous humor from the eyeball via changes in the sclero-corneal trabecular meshwork; these changes are also found in diabetic subjects. The interplay between HGH and changes of carbohydrate metabolism (frequently occurring in glaucomatous patients) may be at the root of the variations of intraocular pressure in open-angle glaucoma.

Arginine↗
PubMed1979

Gastrin response to insulin in patients with cirrhosis of the liver.

Fasting gastrinemia in cirrhotics (48.35 +/- 2.77 pg/ml) was higher than in normal controls (32.93 +/- 0.75 pg/ml; P less than 0.001). After insulin-induced hypoglycemia, the mean increase of gastrin above basal level was 42.29 +/- 1.92 pg/ml in controls and 10.85 +/- 5.05 pg/ml in cirrhosis (P less than 0.001). BAO was 2.53 +/- 0.36 mEq/h in controls and 0.42 +/- 0.004 mEq/h in cirrhotics (P less than 0.001). After i.v. insulin, TAO was 8.42 +/- 0.72 mEq/h in controls and 3.06 +/- 0.26 mEq/h in cirrhotics (P less than 0.001). The authors suggest that the lack of an adequate gastrin and acid response to the hypoglycemic stimulus in cirrhotics might be accounted for by a decreased insulin sensitivity.

Adult↗