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A Giorgetti

Publications and source records attributed to A Giorgetti.

48 records · Page 3Linked to original sources
PubMed1989

[Spontaneous platelet aggregation after experimental focal ischemia in the rabbit. "Sensitivity", "specificity" and value of the test used].

Within the framework of an investigation at present under way at the Neurological Clinic of Pavia on experimental focal ischaemia, the peculiarities of platelet aggregation observed, have led to a more accurate assessment of both the phenomenon itself and the validity of the method used. In a group of 30 rabbits (17 of them submitted to embolization by means of microspheres introduced into the carotid and 13 used as controls), biohumoral electrical and histological parameters were examined. The spontaneous platelet aggregation test proved significantly related to the extent of changes taking place, as measured by PDS levels and QEEG "delta" activity (respectively, P less than 0.005 and P less than 0.05). Platelet aggregation, in relation to the occurrence or absence of focal ischaemia, revealed a "sensitivity" of 80% and a "specificity" of 92.3%. When not only the onset of but also the increase in aggregation is taken into account, the "sensitivity" figure appears to go up to 93.3%. Endothelial damage and "cascade" platelet aggregation appeared to be a prerequisite for the occurrence of the changes found. In these changes, the pathogenetic role of the regional vasospasm as opposed to mere mechanical obstruction seems to be confirmed. On the basis of these findings, it is concluded that the identification of spontaneous platelet aggregation using K. Breddin's method and its quantification based on Born's turbidimetric principle, may be usefully employed to assess the risk factor constituted by an abnormal tendency to platelet hyperaggregation.

Animals↗
PubMed1988

Synchronization of the EEG and sedation induced by neuroleptics depend upon blockade of both D1 and D2 dopamine receptors.

Blockade of dopamine (DA) receptors by neuroleptics tends to produce sedation, as shown by increased sleeping time, reduction of the arousal response to sensory stimuli and slowing of the electrical (EEG) activity of the brain. The EEG and behavioural effects of the selective compounds, SCH 23390 and raclopride, which block either D1 or D2 receptor subtypes, respectively were evaluated. Groups of rabbits were prepared for the measurement of EEG activity (neocortex and hippocampus). The EEG was analyzed visually and by spectral power analysis. Gross behaviour was also observed. The D1 antagonist, SCH 23390, by itself (0.03-0.3 mg/kg i.v.) produced small changes in the EEG and no evidence of sedation. Periods of slow waves occurred sporadically. Computerized EEG analysis showed moderate increases of total power density. The D2 receptor blocker, raclopride, alone (1-3 mg/kg i.v.) produced changes of the activity of the EEG, mostly, short periods of slow waves and slight increases of total power. No sedation was noted. Although both selective antagonists were studied at larger doses than those minimally effective, they produced slight EEG and behavioural changes which were not comparable with the marked actions produced by classical neuroleptics, such as haloperidol. However, when raclopride (1 mg/kg) was given after treatment with SCH 23390 (0.03 mg/kg) there was a marked synchronized activity in the EEG, associated with a state of sedation and diminished responsiveness to sensory stimuli. The data indicate that EEG synchronization and sedation, classically associated with treatment with neuroleptics, do not depend upon the selective blockade of either D1 or D2 receptors but, instead, require concurrent blockade of both subtypes of receptor.

Animals↗
PubMed1988

Experimental study on central effects of carboxyethyl-gamma-aminobutyric acid (CEGABA).

The central effects of carboxyethyl-gamma-aminobutyric acid (CEGABA) have been studied both in rabbits and in the guinea pig myoclonus model. This drug caused EEG synchronization and behavioural sedation both after intravenous (i.v.) and intracerebroventricular (i.c.v.) administration in a dose-dependent manner, in rabbits. CEGABA showed a protective action against myoclonus induced by means of L-5-HTP in young guinea pigs. These data substantiate the hypothesis that CEGABA is a drug active on the central nervous system and probably exerts its action by strengthening cortical inhibition and/or directly acting on lower brainstem.

5-Hydroxytryptophan↗
PubMedDate not supplied

EEG and behavioural effects of polyamines (spermine and spermidine) on rabbits.

The EEG and behavioural changes induced by the administration of polyamines (spermine and spermidine) were studied in rabbit. Spermine and spermidine were administered at different doses (200 and 400 micrograms) into the mesencephalic ventricle (i.c.v.) both as a bolus and in constant perfusion (60 min duration). We also studied the effects of methamphetamine (MA) in a group of rabbits pretreated with spermine and spermidine 200 and 400 micrograms i.c.v. as bolus. Spermine caused a dose-related cortical synchronization associated with a partial sedation; spermidine induced cortical synchronization at a low dose without any behavioural changes while at higher dose (after perfusion) cortical desychronization with an arousal behavioural pattern occurred. The possible interaction of these substances with the mesolimbic dopaminergic system is discussed on the basis of their potential neuroleptic action.

Animals↗
PubMedDate not supplied

Regional concordance and discordance between rest thallium 201 and sestamibi imaging for assessing tissue viability: comparison with postrevascularization functional recovery.

BACKGROUND: Whether the combined analysis of rest 201Tl and sestamibi uptake provides additional information regarding myocardial viability in patients with coronary artery disease is still to be investigated. METHODS AND RESULTS: To this aim we studied 22 patients with previous myocardial infarction and regional ventricular dysfunction by quantitative rest sestamibi and 201Tl scintigraphy. All patients underwent revascularization, and echocardiography was repeated 11 +/- 2 weeks later. Concordant results were obtained in 80 of 105 dyssynergic segments. Fifty-one segments showed normal and 29 abnormal activity. Follow-up echocardiography showed increased wall motion contractility in 76% of segments with maintained 201Tl and sestamibi uptake and in only 17% of segments characterized by subthreshold activities. Twenty-five segments, or 24%, showed sestamibi/201Tl mismatch. Eleven of 12 segments with normal sestamibi/abnormal 201Tl activity did not improve after revascularization, whereas 11 of 13 segments with abnormal sestamibi but normal 201Tl showed postoperative improvement of regional wall motion. CONCLUSIONS: In patients with previous myocardial infarction, sestamibi and 201Tl showed concordant results in most segments. However, in segments with mismatch a maintained sestamibi uptake was a poor indicator of tissue viability, whereas significant 201Tl uptake reflected tissue viability in most segments.

Adult↗
PubMedDate not supplied

Myocardial blood flow and perfusion reserve in infarcted patients with stress-induced normalization of previously negative T waves: a positron emission tomography study.

BACKGROUND: The clinical correlations between stress-induced normalization of previously negative T waves (NTW) and regional myocardial blood flow (MBF) regulation and tissue viability remain debatable. METHODS AND RESULTS: To confirm these correlations, 14 patients with previous anterior myocardial infarction (13 Q waves) and NTW on baseline electrocardiographic precordial leads and 10 healthy subjects were studied by means of positron emission tomography (PET). The MBF values were obtained in the anterior infarcted myocardial regions in either resting condition or during dipyridamole infusion, using N-13 ammonia as a flow tracer. Seven subjects had normalization of NTW (Group 1) and 7 had persistent NTW (Group 2) during dipyridamole infusion. The resting MBF values were similar for both Group 1 and Group 2 (0.43+/-0.13 versus 0.51+/-0.15 mL.min(-1).g(-1), respectively; P = not significant) and were significantly lower than in the anterior myocardial regions of healthy subjects (1.03+/-0.23 mL.min(-1).g(-1), P < .001). After administration of dipyridamole, the MBF was significantly higher in Group 1 than in Group 2 (0.88 +/- 0.37 versus 0.55 +/- 0.17 mL.min(-1).g(-1), respectively; P < .05) and markedly lower than in healthy subjects (3.78+/-0.64 mL.min(-1).g(-1), P < .001). Coronary reserves (dipyridamole/resting MBF) were 2.03+/-0.40 and 1.14+/-0.44 in Group 1 and Group 2, respectively (P < .002). CONCLUSION: Despite similar values of resting perfusion, infarcted dysfunctional areas with or without NTW during stress may present different regional MBF responses; normalization of NTW demonstrates higher coronary flow reserve than persistent NTW, suggesting a better preserved coronary microcirculatory function in the former, indicative of the presence of myocardial viability.

Adult↗
PubMedDate not supplied

[Comparison of two methods to determine beta-lactoglobulin antibodies in children with cow's milk protein intolerance].

In the last years the evaluation of IgG against beta-lactoglobulin (beta LG-IgG) has been proposed as reliable test to diagnose Cow's Milk Protein Intolerance (CMPI). This test, associated with other diagnostic tools (such as eosinophilia, hemoccult, RAST, challenge, etc.) showed a good sensibility, but less specificity. In fact antibodies against beta-lactoglobulin were found in other gastrointestinal diseases (coeliac disease, inflammatory bowel diseases, cystic fibrosis, etc.). To determine the specificity of the test some Authors attributed great importance to the laboratory method (IFL, ELISA). They retained IFL more specific. In order to verify the behaviour of the two methods and their concordance we carried out a double bind determination of IgG against beta-lactoglobulin (beta LG-IgG) on serum samples from children affected by CMPI. For this study we chose 16 children, aged from 3 months and 6 years, suffering from CMPI of which 11 with gastrointestinal complaints and 5 from extraintestinal ones. All children were diagnosed on the basis of the following criteria: clinical picture, blood eosinophilia, positivity of hemoccult, amelioration after the withdrawal of cow's milk proteins from the diet, positivity of challenge test. All children at the time of the assessment assuming a diet containing cow's milk proteins. beta LG-IgG were measured using simultaneously immunofluorescent and micro-ELISA methods. The obtained data showed that 12 children (75%) had IgG versus beta-lactoglobulin in the serum. This result was obtained both with IFL and ELISA methods, showing a 100% of concordance.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗