PubMed Health⌕ Search

Biomedical subjects

E Musso

Publications and source records attributed to E Musso.

At least 37 records · Page 2Linked to original sources
PubMed1988

Newer data on the configuration and variability ranges of body surface maps in a sample of normal subjects.

Quantitative data on the normal variability of body surface maps (BSM) are scarce in the literature. This is one of the reasons why BSM are not yet widely used in clinical practice despite their superior information contents. In this study we determined the average value and variability of a number of parameters derived from BSM in a group of 36 normal adult males, ages 22 to 60. Forty to 60 homogeneous beats were averaged for each subject. This enabled us to extend our study to the low voltage intervals (P,PQ,ST,U) which encompass more than 60% of the entire P-U duration and to contribute new data to controversial issues, such as the presence of two simultaneous maxima during atrial excitation. The following parameters were measured: a) the coordinates of the absolute potential maximum and minimum on the chest surface during the entire cardiac cycle; b) the time course of four voltage-related functions, namely: highest instantaneous potential value on the chest surface, lowest (most negative) potential, highest potential difference, and surface integral of the absolute value of the potential function. In recent studies these parameters were shown to be of considerable value in discriminating normal subjects from different categories of cardiac patients.

Adult↗
PubMed1987

Body surface maps in left bundle branch block uncomplicated or complicated by myocardial infarction, left ventricular hypertrophy or myocardial ischemia.

We provided a topographic and quantitative description of body surface maps (BSM) during the entire QRST interval in seven uncomplicated LBBBs and 31 LBBBs complicated by: myocardial infarction (MI, seven cases), left ventricular hypertrophy (LVH, eight cases), myocardial ischemia (IS, seven cases), MI + LVH (six cases) and LVH + IS (three cases). In all patients we observed abnormal map configurations attributable to the LBBB. We were unable to identify consistent effects of the complicating heart condition(s) on the general pattern of chest potentials. Conversely, the surface voltages were generally decreased by MI and IS and increased by LVH. By considering the 38 patients as a preliminary learning set we applied a stepwise discriminant analysis to 77 voltage-related variables derived from BSM to produce a model for discriminating between LBBBs with and without MI. We properly allocated more than 90% of the patients. We also attempted to classify the patients into four groups: pure LBBB, LBBB + MI, LBBB + LVH and LBBB + IS, with a percentage of correct classification of about 80%. The two classifying procedures were applied to ten new LBBB patients with results similar to those obtained in the 38 of the study group.

Adult↗
PubMed1986

Body surface potential mapping in ischemic patients with normal resting ECG.

Patients with ischemic heart disease frequently have a normal 12-lead electrocardiogram. We recorded body surface maps from 14 ischemic patients with normal (group A) and 5 with abnormal (group B) resting electrocardiograms. ST-T map data were compared with those of 36 normal subjects. In ischemic patients the following abnormalities were found: an anomalous location and/or trajectory of the potential minimum (lowest potential) on the chest in some; in others the instantaneous values of the time functions: Mxi (highest potential on the chest), delta Vi (highest potential difference) and integral of s/Vi/dS (integral of the absolute value of the potential function extended to the entire chest surface) were lower. In some ischemic patients, both abnormalities were observed. All changes were detectable during the first 200 msec of ST-T. The anomalous potential patterns were similar in group A and B patients, suggesting an ischemic origin of group A abnormalities. By submitting 10 properly selected variables, obtained from body surface maps, to Fisher's discriminant analysis, we succeeded in correctly classifying more than 90% of the cases. The efficacy of the method was validated by using one third of the cases as a test set, with correct allocation in 80.9% of the cases. We conclude that body surface maps at rest can reveal an altered cardiac electrogenesis induced by myocardial ischemia, not apparent in the 12-lead electrocardiogram.

Action Potentials↗
PubMed1983

[Ceftriaxone, a long-acting cephalosporin. Microbiological, kinetic and clinical study].

Ceftriaxone effectively inhibited 332 out of 452 (73.45%) bacterial strains in vitro tests. 291 out of 365 (79.69%) gram negative and 41 out of 87 (47.12%) gram positive strains were inhibited. The tests showed ceftriaxone to be more effective than cephalothin, cephotaxime, cephuroxime, cephamandol and cephoxitin. Kinetic tests showed that cephtriaxone has a plasmatic half life of 7.25 hrs. 24 hours after administration of a 1000 mg venous bolus the drug was still present in the blood. Urinary elimination over a 24 hr. period amounted to means 486.8 mg (48.68%). The drug has liquor transfer capacity. 37 of the 38 patients treated showed complete clinical or clinicobacteriological cure. Improvement was noted in the 38th.

Adolescent↗
PubMed1983

[Piperacillin: microbiological and clinical studies].

A microbiological and clinical study of the action of piperacillin is presented. The drug showed an excellent in vitro antibacterial action on gram positive and gram negative microorganisms. Its in vitro action on Ps. aeruginosa (70.8% of strains inhibited) was also extremely interesting, making it the second most effective of the antibiotics tested after polymyxin B and colistin, polypeptides unsuitable for clinical use. In vivo, the administration of piperacillin achieved a clinical and bacteriological cure in 35 out of 40 patients and a clinical cure in 2 out of 40. It was only therapeutically unsuccessful in 3 cases. It is concluded that its microbiological, kinetic and tolerance features make piperacillin suitable for a wide range of therapeutic purposes.

Acinetobacter↗
PubMed1983

[Microbiological, kinetic and clinical study on a new cephamycin: cefotetan].

Microbiological, kinetic and clinical studies were conducted on a new cephamycin, cephotetan. In vitro the antibiotic was found to be very effective against all strains tested. It had a particularly strong action against Gram negative bacteria too. Kinetically speaking, an intravenous bolus produced a high plasmatic concentration with a half life of about 4 hours. Elimination via the kidneys was fastest in the first 3 hours after administration (49.82%) and the slowed down. 82.76% of the dose administered was excreted within 24 hours. This antibiotics is particularly indicated in cases of urinary, respiratory and biliary infections.

Adolescent↗
PubMed1982

[Kinetic and clinical studies on a new cephalosporin: Cefotiam].

Kinetic and clinical evaluation of cefotiam, a new cephalosporin, is reported. It was found that the drug is rapidly distributed to the tissues. Equilibrium between tissues and plasma is reached in about an hour. Some 90-91% of the dose administered is excreted in the urine, and accumulation does not occur. A clinical cure was obtained in 27 of a series of 35 patients (77.1%). Improvement was observed in 7 cases (20%). The antibiotic proved ineffective in the remaining cases (2.8%). Tolerance was excellent and there were no side-effects worthy of note.

Adult↗
PubMed1982

The role of calcium in overdrive suppression of canine cardiac Purkinje fibers.

The role of calcium in the electrical and mechanical changes induced by overdrive was studied in canine cardiac Purkinje fibers. The following results were obtained: (1) hyperpolarization and pause induced by a "short" (1-minute) overdrive are smaller in a low and larger in a high calcium solution; (2) overdriving at a constant ratio of overdrive to spontaneous rate only reduces the difference in pause duration in different calcium concentrations; (3) after overdrive, the initial diastolic depolarization is flatter and the late diastolic depolarization is steeper the control in low calcium and the opposite changes occur in high calcium; (4) the threshold for the first beat after overdrive is more negative in low than high calcium; (5) with "long" (2-minute or more) overdrives, hyperpolarization of comparable magnitude is seen during overdrive in low and high calcium; (6) the decline of hyperpolarization after overdrive is faster in high calcium unless the fiber is driven at slow rate ("postdrive"); (7) the contractile force after overdrive is greater than before overdrive in low and normal calcium and smaller than before overdrive in high calcium, and this difference is less during postdrive; (8) hyperpolarization and pause are reduced in a low sodium solution. It is concluded that calcium modifies overdrive suppression in several respects (hyperpolarization, slope of diastolic depolarization, duration of the pause and threshold), but is only one of the several factors involved in determining overdrive hyperpolarization and suppression.

Animals↗
PubMed1982

[Experimental studies on the diffusion of excitation on the right ventricular surface in the dog, during normal and stimulated beats].

Previous work on the spread of excitation on the dog's ventricular surface enabled us to locate up to 30 breakthrough points (BKTPs) where excitation reaches the ventricular surface. In particular the equipotential contour maps enabled us to detect 3 to 5 BKTPs on the anterior right ventricular surface, near the a-v groove when a large part of ventricular surface was still at rest. With a view to investigating the mechanism underlying the early excitation of these basal regions, we stimulated the heart at several right ventricular BKTPs and in other points located at a distance from the BKTPs. The instantaneous equipotential maps showed that after stimulation most right ventricular BKTPs remained in the same position as observed the normal beats. The early appearance of epicardial wavefronts in the basal region and generally in other areas of the right ventricle was attributed to the rapid propagation of excitation waves through the Purkinje network, probably associated to a short transmural crossing time, due to a local thinness of the ventricular wall.

Animals↗
PubMed1981

[Kinetic and clinical study of bacampicillin].

A mean plasma concentration curve, with peaks within the first hour and moderate individual variations, was obtained after a single administration of 800 mg of bacampicillin to 5 healthy volunteers. An adequate antibiotic transfer from the circulation to the bronchial apparatus was demonstrated. Treatment of 34 patients suffering from ampicillin-sensitive bacterial diseases permitted clinical cure of all patients, without onset of side-effects. It is concluded that bacampicillin is preferable to oral ampicillin because of its kinetic and tolerance features.

Adolescent↗
PubMed1981

[Treatment of acute myocardial infarction with verapamil. Hemodynamic effects and electrical changes studied by body surface maps (author's transl)].

The effects of Verapamil on main haemodinamic parameters and on Max sigma pos., sigma Q15, Max sigma pos./Max sigma neg. and sigma ST, studied by automatic recording of thoracic maps, were evaluated in 11 patients with acute myocardial infarction within 6 hours from pain onset. Verapamil was given at the dose of 0.1 mg/Kg followed by infusion of 0.035 mg/min. Hemodynamic measurements were made before and 15 minutes after Verapamil; the maps were recorded before and 5, 15 and 30 minutes after Verapamil. Heart rate and sistolic arterial pressure were reduced, though not significantly: right atrial pressure, pulmonary pressures and capillary pulmonary pressure remained unchanged. On the contrary, the reduction of diastolic arterial pressure (from 94 +/- 4.2 to 88 +/- 4.5 mmHg; P less than 0.05) and of cardiac index (from 3.1 +/- 0.11 to 3 +/- 0.11; P less than 0.05) was important. Max sigma pos. increased after 15 minutes from 11619 +/- 1970 to 12349 +/- 2151 microV (P less than 0.01), but il decreased after 30 minutes to 11037 +/- 2042 microV (P less than 0.05). Max sigma pos./Max sigma neg. ratio increased significantly after 5 and 15 minutes. Sigma Q15 increased significantly only after 30 minutes (from 7198 +/- 1643 to 8688 +/- 1541 microV; P less than 0.05). Sigma ST showed a transient, non significant increase after 5 minutes, but decreased significantly after 30 minutes (from 76664 +/- 19505 to 67157 +/- 18581 microV; P less than 0.05). The results show that Verapamil does not cause worsening of main haemodinamic parameters during acute, non complicated myocardial infarction and reduces significantly ST segment elevation. The Authors discuss also a possible electrophysiological effect of Verapamil on action potential of ischemic cells, responsible for early increase of sigma ST observed in some patients.

Aged↗
PubMed1978

Effects of norepinephine, calcium, and rate of discharge on 42K movements in canine cardiac Purkinje fibers.

We studied the effect of norepinephrine, calcium concentration, and rate of discharge in the presence of different [Ca2+]0 on radioactive potassium movements in cardiac Purkinje fibers. The following results were obtained: (1) norepinephrine increases potassium uptake in quiescent fibers and in fibers driven at constant rate, but more in the latter; (2) norepinephrine also increases potassium uptake in quiescent fibers depolarized at the plateau; (3) increasing [Ca2+]0 increases potassium uptake in fibers driven at constant rate; (4) increasing [Ca2+]0 may decrease K+ uptake in quiescent fibers; (5) increasing [Ca2+]0 decreases the rate of loss of tissue radioactivity in quiescent fibers and increases it in a driven fiber; (6) increasing the driving rate increases potassium uptake in low and high [Ca2+]0; (7) high [Ca2+]0 increases K+ uptake, especially at low rates; (8) norepinephrine is less effective in increasing K+ uptake in the presence of a high [Ca2+]0. We conclude that: (a) norepinephrine increases potassium uptake by different mechanisms; (b) calcium affects potassium movements when it is allowed to enter the cell, presumably by affecting potassium conductance; (c) the effect of an increased rate of discharge on K+ uptake may involve stimulation of active K+ uptake and may include a calcium-dependent component which is largest at high [Ca2+]0 and a slow rate of drive; (d) simultaneous application of two interventions results in a summation that is smallest when one of the mechanisms is already substantially activated.

Action Potentials↗
PubMed1977

Evidence for a nicotinic receptor in the sinus node.

The sinus node of the guinea pig was perfused in vitro and potassium uptake was studied in the absence and in the presence of several nicotinic agonists and antagonists. The following results were obtained: (1) the decrease in K uptake caused by a low (10(-9)M) concentration of acetylcholine was changed to an increase when acetylcholine was given in the presence of nicotinic blockade; (2) a small concentration (10(-10)M) of atropine potentiated the decrease in K uptake induced by a low concentration of acetylcholine and 10(-8)M atropine abolished it: (3) a small concentration of nicotine (10(-10)M) decreased K uptake; (4) 1,1-dimethyl-4-phenylpiperazinium (DMPP) did not modify K uptake; (5) the lack of effect of DMPP was not affected by hexamethonium; (6) trimethylphenylammonium (TMPA) decreased K uptake; and (7) the inhibitory effect of TMPA was abolished by decamethonium. It is concluded that a nicotinic receptor in the sinus node mediates the inhibitory action of a low concentration of acetylcholine on K uptake.

Acetylcholine↗