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Biomedical subjects

A Rizzo

Publications and source records attributed to A Rizzo.

At least 145 records · Page 8Linked to original sources
PubMed1983

[Mexiletine: electrophysiologic effects].

A complete electrophysiological evaluation has been performed before and after the intravenous administration of Mexiletine (M.) (3 mg/Kg/B.W. in 5 minutes) in 28 patients (pts) (6 pts with normal conduction system, 4 pts with sick sinus syndrome, 5 pts with intranodal AV block, 13 pts with bundle branch block, of which 4 with pathological HV and 1 with intrahisian conduction defect). With the exception of a shortening of QTc interval in all the pts, the drug did not significantly affect any other electrophysiological parameters. In the patient with intrahisian conduction defect, M. prolonged the H1 - H2 interval. A statistically significant increase of heart rate has been also observed in a second group of 8 pts with normal sinus function, in whom M. administration was preceded by Atropine (I.V. bolus 0,04 mg/Kg/B.W.). This finding seems to exclude a vagolytic effect of M. The conclusions derived from our experience and pertinent literature are the following: M. is not useful in the treatment of supraventricular arrhythmias because it has negligible effects on atrial and AV nodal conduction; the drug may be safely employed in the treatment of ventricular arrhythmias in pts with atrial and/or AV nodal conduction defects; special caution must be employed when the drug is utilized in pts with sick sinus syndrome and/or with marked intraventricular conduction defects.

Aged↗
PubMed1981

The anaerobically cultured cecal flora of adult fowls that protects chickens from Salmonella infections.

In this work we have analyzed the bacterial composition of anaerobically cultured cecal contents (mixed broth culture) of adult fowls previously shown able to protect 1 day old chickens from oral Salmonella infections. All four cultures studied in this paper gave complete protection against Salmonella infantis when used undiluted or in the 10(-2) dilution and at least some protection in the 10(-4) dilution. The total aerobic as well as anaerobic counts on the nonselective medium used (VLMH) were of the order of 10(8) viable organisms/ml indicating that the mixed broth culture consisted predominantly of facultative organisms. From a total of 239 colonies isolated on the basis of colony morphology 66 were obligate anaerobes and 173 facultative anaerobic or microaerophilic species. Isolates were selected from each medium. They were grouped and tentatively classified on the basis of their ability to grow on selective media, their colony and cell morphology. Gram stain and products formed from glucose fermentation (obligate anaerobes). Further characterization was performed using conventional carbohydrate fermentation and biochemical tests. However only a minor fraction of the anaerobic isolates could be identified as being identical to known species. The most numerous species were E. coli and various Lactobacilli which were still found in the highest dilution (10(-8)) of the broths. Fecal streptococci were the next most frequent, isolated at the 10(-7) dilution. The obligate anaerobes isolated included Gram-positive cocci and Gram-positive and -negative rods tentatively classified as Eubacteria, Propionibacteria, Clostridia, Fusobacteria and Bacteroides. A large number of them were isolated from the 10(-6) dilution and some species of Eubacteria and Clostridia could only be recovered from the 10(-3) or 10(-4) dilutions.

Anaerobiosis↗
PubMed1981

[ATP effects on eccito-conduction and arterial pressure before and after block of the vagus. Haemodynamic and electrophysiologic study (author's transl)].

In order to investigate the cardiovascular effects of ATP (15-30 mg) i.v. administration, 12 normal subjects, aged 27-55 yrs, were studied, during Arterial Pressure Monitoring and His Bundle Electrogram recording, using Sherlag's technique. ATP cardiovascular response was divided in the following four phases: Latency phase, Progressive Bra dyarrhythmic-Hypotensive, Maximal Inhibitor Phase, Tachyarrhytthmic Hypotensive Reflex Phase. Atropine (0.02-0.04 mg/Kg) i.v. injection did not significantly prevent ATP effects. Increasing dosage of atropine (0,06, pointed out a moderate competitive antagonism with ATP. These data suggest a possible direct action of ATP (purinergic receptors or direct membrane effect) but don't exclude an interaction with Parasympathetic system (probable purinergic neuromodulation).

Adenosine Triphosphate↗
PubMed1980

[Role of the vagus nerve in reflex tachycardia evoked by arterial hypotension in the non-anesthetized dog].

The intravenous rapid-injection of nitroglycerin in the resting conscious dog induced arterial hypotension followed by reflex tachycardia. The experiments were performed before and after cold vagal blockade. When vagus nerve was blocked hypotension was more pronounced than in control conditions, but the rise of heart rate was lower and occurred later. This result suggests that, in the conscious dog, hypotension induced reflex tachycardia is due to a decrease in vagal tone, as well as to an increase in sympathetic activity. It is conceivable that the decrease in vagal tone occurs earlier than the sympathetic activity increase. Therefore the short latency reflex inhibition of vagal tone, through early positive inotropic effects, probably plays a relevant role in buffering rapid decreases in arterial pressure.

Animals↗
PubMed1980

Reproducibility of maximum flows in air and He-O2 and of delta Vmax50 in the assessment of the site of airflow limitation.

Maximum expiratory flows at 50% of vital capacity while breathing air and a He-O2 mixture and delta Vmax50 observed during three sittings (morning, noon and morning the day after) in reference subjects and in patients with bronchial hyperreactivity were submitted to statistical analysis by between sittings comparison, looking for correlation coefficients, paired "t" test and variation coefficient. Results of paired "t" test ruled out the influence of fatigue and of training in performing forced expiratory manoeuvres. Correlation coefficients relevant to absolute flows are highly significant in both groups, whereas coefficients of variation are satisfactory in reference subjects and slightly higher although still acceptable in patients with bronchial hyperreactivity. As far as delta Vmax50 is concerned, the results of statistical analysis are positively unacceptable, thus demonstrating that this arithmetic manipulation of absolute flows is the ground for a poor reproducibility of results.

Adult↗
PubMed1978

[Solitary intramedullary tuberculoma: report of a case].

A case of an isolated tuberculoma of the spinal cord is reported. The 22 years old male patient came to the hospital with paraplegia and had a laminetomy performed for a compression of the spinal cord by a tumor mass. The histopathological study showed the presence of the acid-fast bacili in the tissue. After specific treatment the patient recovered partially.

Adult↗