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Biomedical subjects

M Lazzari

Publications and source records attributed to M Lazzari.

50 records · Page 3Linked to original sources
PubMed1987

Ultrastructural analysis and cholinesterase activity in the brain capillaries of Bufo bufo and Rana esculenta.

We have investigated the structure and the cholinesterase features of the brain capillaries in two adult Amphibians (Rana esculenta and Bufo bufo). We found that brain capillaries are un-fenestrated and the endothelial cell edges are joined by tight junctions. The brain capillaries in both species are characterized by high levels of AChE. This enzyme is only localized in the basal membrane, whereas we have found the reaction product neither in the endoplasmatic reticulum nor in the Golgi apparatus. On the contrary the brain capillaries are deprived of BuChE. Only in one experiment traces of reaction product were found. The significance of this datum and the non-nervous role of cholinesterase is discussed.

Acetylcholinesterase↗
PubMed1986

Clinical application of monitoring techniques: hemodynamic monitoring.

In the diagnosis of myocardial ischemia continuous hemodynamic monitoring may contribute to detection of transient ischemia, to definition of location and to elimination of its pathogenesis, and to characterization of hemodynamic response to ischemia. It can be helpful in investigating the significance of negligible, non specific and/or short-lasting electrocardiographic changes accompanying typical anginal symptoms. Simultaneous right ventricular and left ventricular pressure monitoring gives information regarding biventricular interaction during episodes of transient ischemia: an early left ventricular dysfunction, with or without a late right ventricular impairment, a selective right dysfunction, and a simultaneous left ventricular and right ventricular impairment all represent the hemodynamic patterns associated with left, right and biventricular ischemia respectively. Monitoring of hemodynamic parameters related to myocardial oxygen consumption and the study of their changes preceding the onset of ischemia during both spontaneous and provoked episodes of ischemia, may help in identifying whether functional or organic factors or both are involved in the pathogenesis of transient ischemia in individual patients. Two principal hemodynamic patterns appear to be associated with transient ischemia: a) left ventricular and/or right ventricular impairment, usually beginning shortly before the onset of electrocardiographic changes, followed by a rapid recovery and often an overshooting, b) a sudden and sustained increase in systolic pressure and heart rate, simultaneous with the onset of ST-T changes. In both cases, the 'excitatory' pattern appears to be unrelated to pain.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗
PubMed1985

[Auriculo-ventricular block upon swallowing].

A case of recurrent syncopal attacks in a 70-year-old woman with oesophageal hiatus hernia is reported. Dynamic ECG recording showed paroxysmal II and III degree A-V block during solid food swallowing. Electrophysiologic examination was normal in the basal condition and showed a II degree A-V nodal block with 2: 1 conduction ratio during solid food swallowing. This phenomenon was not reproducible after atropine administration. A permanent cardiac pacemaker (VVIP) rendered the patient completely symptomfree. The likely pathogenetic mechanism of "swallowing A-V block" is described.

Aged↗
PubMed1983

Impairment of myocardial perfusion and function during painless myocardial ischemia.

Left ventricular (or pulmonary and systemic arterial) hemodynamics were measured for a mean of 13.6 hours during continuous electrocardiographic monitoring in 14 patients admitted to the coronary care unit because of angina at rest. Of 293 episodes of transient ST segment and T wave changes identified, 247 (84%) were completely asymptomatic. Sixty-three percent of asymptomatic episodes were associated with an elevation of the left ventricular end-diastolic or pulmonary artery diastolic pressure of 5 mm Hg or more; in 15% there were smaller elevations (2 to 4 mm Hg) and in 22% there were no changes or less than a 2 mm Hg elevation of pressure. The peak contraction and relaxation dP/dt (first derivative of left ventricular pressure) were reduced to 100 mm Hg/s or more in 84 and 81% of asymptomatic episodes, respectively. Great cardiac vein oxygen saturation measured in three patients showed an increased myocardial oxygen extraction similar to that seen in painful episodes, which preceded and accompanied asymptomatic electrocardiographic changes. These results indicate that asymptomatic electrocardiographic changes represent transient myocardial ischemia. Comparison of asymptomatic and symptomatic episodes revealed that asymptomatic episodes were generally shorter (253 +/- 159 versus 674 +/- 396 seconds, probability [p] less than 0.001) and produced less impairment of left ventricular function: there were smaller elevations of left ventricular end-diastolic or pulmonary artery diastolic pressure (5.9 +/- 5.0 versus 16.5 +/- 6.9 mm Hg, p less than 0.001), and smaller reductions of peak left ventricular contraction dP/dt (252 +/- 156 versus 395 +/- 199 mm Hg/s, p less than 0.001) and relaxation dP/dt (259 +/- 191 versus 413 +/- 209 mm Hg/s, p less than 0.001). In individual patients, however, asymptomatic and symptomatic episodes of similar duration and severity were observed. The duration and severity of ischemia appear important for the genesis of anginal pain, but additional factors must be involved.

Adult↗
PubMed1981

Does hypoxia selectively stimulate the generation of prostaglandin E1 by the isolated rat uterus?

The contractile activity of uterine horns maintained for 90 to 120 minutes under normal oxygenation (carbogen or 100% O2) became undetectable. When in this condition the gassing was stopped one or two minutes later, regular phasic contractions appeared super-imposed on a small increment of the basal resting tone. Indomethacin and aspirin well known inhibitors of prostaglandin (PG) synthesis, blocked the contractile influence of hypoxia whereas neither tranylcypromine or imidazole were able to alter the stimulatory action. PGE2, PGE1 and PGF2 alpha released into the bathing solution during 10 minutes of normoxia or 10 minutes of hypoxia, were measured. Under O2, PGE2 and PGF2 alpha production diminished significantly (P less than 0.05 and P less than 0.01, normoxia vs. hypoxia, respectively) whereas PGe1 increased (P less than 0.05). "PGI2-like material" generated was also detected and it was found that the values during hypoxia were lower than those observed in O2; however the difference was not statistically significant. Dose-response contractile activity to PGs with and without gassing was explored. It was necessary to add 100 times more PGF2 alpha to obtain the minimal response under hypoxic conditions as compared to normoxia. On the other hand the threshold response to PGE1 was 10 times lower under hypoxic conditions than in normoxia. The possible mechanism(s) that induce an increment in PGE1 generation accompanied by a simultaneous decrement of PGE2 during hypoxia is discussed in connection with a possible role of PGE1 evoking uterine contractions when the gassing of the suspending solution is stopped.

Alprostadil↗
PubMed1980

Sequence of events in angina at rest: primary reduction in coronary flow.

To investigate the events that lead to acute myocardial ischemia we monitored continuously the ECG, the left ventricular (four patients) or aortic (two patients) pressure and the great cardiac vein oxygen saturation (CSO2S) by a fiberoptic catheter in six patients with frequent anginal attacks at rest. We recorded 137 transient ischemic episodes (10 with chest pain) characterized by ST-segment elevation in 28 episodes, depression in three episodes and by pseudonormalization of previously inverted or flat T waves in 106 episodes. The onset of electrocardiographic and hemodynamic changes was preceded by a large drop in CSO2S in all 135 episodes with ST-T changes in the anterior leads but not in two episodes with ST elevation on inferior leads. The fall in CSO2S, consistently followed by signs of left ventricular function impairment and never preceded by any detectable increase in the hemodynamic determinants of myocardial oxygen consumption, probably reflects a reduction in regional perfusion. Thus, a reduction in coronary flow may cause transient ischemia in patients with angina at rest. These episodes may be associated with variable, often minor electrocardiographic changes and occasionally with anginal pain.

Adult↗
PubMed1980

[Analysis of Holter monitoring for detection of myocardial ischemia episodes (author's transl)].

While the use of the 24 hour Holter monitoring for the detection of the cardiac arrhythmias and conduction disturbances is well established, its applicability to the monitoring of the ST segment and T wave for the detection of myocardial ischemia is controversial. For these reasons the Holter monitoring is mainly confined to the detection of cadiac arrhythmias and is used in those centers where computer facilities are available. We proposed to record the electrocardiographic tape replayed at 60 times the real time on a direct recording ultraviolet oscillograph running at low speed obtaining a fast compact analogue representation of the Holter recording where the 24 hour Holter recording is compressed into cm 480 of paper. The analogue compact representation described allows an easy detection of the transient displacement of the ST segment and/or changes in the T wave amplitude and direction and/or QRS pattern all due to myocardial ischemia without the use of any expensive computer facilities.

Coronary Disease↗
PubMedDate not supplied

[Liver abscess in children].

A case of solitary hepatic abscess in an apparently normal 5-year old infant is described. The symptoms in this patient were generally nonspecific and the child were erroneously operated with a presumptive diagnosis of acute appendicitis. Subsequently, because of persistence of isolated abdominal signs, abdominal ultrasonography were performed, and an abscess of the right hepatic lobe was evidenced. The pathogenesis of the hepatic abscess in this child is unclear.

Acute Disease↗