Biomedical subjects
E Poli
Publications and source records attributed to E Poli.
Assessment of depression: a comparison of rating scales.
Six depression rating scales (RS) (Beck Depression Inventory, BDI; Zung Self-Rating Scale, SDS; Visual Analogue Scale, VAS; Hamilton Depression Rating Scale, HRSD; Wechsler Depression Rating Scale; Bunney and Hamburg Rating Scale, BHRS) were administered to the same 100 depressed patients and compared as regards ease of use, reliability, distribution, and validity. Separate factor analyses carried out on the items of the single scales showed considerably different factorial structures, thus revealing that different concepts of depression are at the basis of the various scales. These differences suggest that comparison of results derived by the use of different scales must be regarded with caution.
Characterization of the spontaneous motor activity of the isolated human pregnant myometrium.
The motor activity of myometrial strips from pregnant human uterus was characterized in vitro by the use of inhibitory compounds acting on the smooth muscle contractility at different levels. Spontaneous contractions were not inhibited by tetrodotoxin or a series of membrane receptor antagonists, like anticholinergics, antihistaminics, alpha-adrenergic blocking agents, antiserotoninergics and opioid receptor antagonists, thus excluding neuronal involvements or a local release of endogenous mediators active on the respective membrane receptors. The ineffectiveness of indomethacin (10(-5) M) minimizes a role for excitatory prostaglandins. Isoprenaline and selective beta 2-adrenergic stimulants, like salbutamol and hexoprenaline (up to 10(-5) M), failed to affect the amplitude of spontaneous contractions. Conversely the adenylate cyclase activator, forskolin, had a concentration-dependent inhibitory effect. Ca2(+)-free medium, trifluoperazine and all the calcium channel blockers examined produced a concentration-dependent inhibition of the spontaneous contractions in the following order of sensitivity: nifedipine much greater than verapamil much greater than diltiazem greater than trifluoperazine. The inhibitory effect of nifedipine was not overcome by excess calcium concentration in the bathing medium, but was completely restored by addition of the calcium agonist Bay K 8644 10(-7) M. From these data it can be concluded that the spontaneous activity of pregnant human myometrium in vitro is independent of neural or humoral mechanisms. The inhibitory effect of Ca(+)-free medium and the efficacy of calcium channel blockers support the view that calcium influx is an important step in initiating the contractile activity of uterine smooth muscle.
Selective antimuscarinic effects of telenzepine and pirenzepine in the gastrointestinal tract.
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Histamine H3 receptors in the guinea pig small intestine.
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Synthesis of 1,2-benzisothiazole derivatives and investigation of their putative histaminergic activity.
Some new 2-(1,2-benzisothiazol-3-yl)ethylamine derivatives were synthesised and their putative histaminergic activity was investigated in in vitro gastrointestinal and cardiac preparations. In the isolated guinea pig duodenum, all the compounds induced a tetrodotoxin- and atropine-sensitive contractile activity, which was minimally affected by mepyramine in the case of the compound 2-(1,2-benzisothiazol-3-yl)ethylamine. In the same tissue, all the compounds were devoid of any H3 receptor agonistic or antagonistic activity, but caused a nicotinic and/or 5-HT3 receptor activation. None of these compounds induced any histamine H2 agonistic or antagonistic activity in the isolated guinea pig gastric mucosa or in the isolated papillary muscle. On this latter substrate, the compound N,N,N-trimethyl-2-(1,2-benzisothiazol-3-yl)ethylammonium iodide induced a positive inotropic activity, apparently due to a release of catecholamines. These results demonstrate the substantial inability of 1,2-benzisothiazole derivatives to interact with histamine receptors in functional tests. These compounds, however, possess gangliomimetic properties, related to the activation of 5HT3 and/or nicotinic receptors.
Role of histamine H(3) receptors in the control of gastrointestinal motility. An overview.
Over the last few years, the biochemical and functional characterization of H(3) receptors has been a matter for extensive investigation, culminating in the cloning of the human, guinea pig and rat receptor protein from brain tissues. This discovery contributed to determine the distribution of receptors in the body and to define the molecular mechanisms which follow activation. The major breakthrough in the histamine H(3) receptor field came with the synthesis of selective and potent agonists and antagonists, which unravelled the function of this receptor subtype in the different tissues. As expected from the ubiquitous location of histamine in the body, histamine H(3) receptors have also been identified in virtually every tissue, although they are quantitatively less abundant than H(1) and H(2) receptors. Concerning the gastrointestinal tract, this new receptor subtype seems to have multiple cellular locations, which include neurons, enteric ganglia, paracrine and immune cells and, in some tissues, also smooth muscle cells. Therefore it might be regarded as a general regulatory system of different digestive functions, including motility. The effects mediated by histamine H(3)-receptors mainly reflect the presynaptic inhibition of the release of either excitatory or inhibitory neurotransmitters from the myenteric plexus. The molecular mechanism of presynaptic inhibition seems to involve a restriction of calcium entry into the nerve endings, but other mechanisms (reduction of cAMP), possibly associated to different H(3) receptor subtypes, may be involved. Despite the widespread distribution and the well defined inhibitory effects evoked in the majority of in vitro models of intestinal motility, no clear cut evidence of its involvement in the control of peristalsis could be provided. In vivo models of gastrointestinal transit, indeed, did not reveal a defined effect of histamine H(3) receptor ligands, even though the possibility of a central inhibition was pointed out in several studies. Therefore, it is not clear at the present what is the physiological meaning of the histamine H(3) receptor in the control of gastrointestinal motility and whether it could represent a potential target for novel therapeutic interventions in deranged motility, taking into account that human gastrointestinal tissues are apparently devoid of this receptor.
Contractile effect of endothelin-2 on the isolated human saphenous vein.
The contractile effect of endothelin-2 was investigated in isolated human saphenous vein preparations. Spare segments taken from revascularized patients were set up in isolated organ chambers and mechanical activity was recorded under isometric conditions. Endothelin-2 (10(-11)-10(-7) M) evoked a dose-dependent contractile response, having the same efficacy as noradrenaline and 100 times its potency. Conversely, the "selective" ETB agonist, C-terminal hexapeptide endothelin (16-21), was completely ineffective. The activity of endothelin-2 was not modified by phentolamine, saralasin and indomethacin, thus excluding a direct or indirect activation of alpha-adrenoceptors and angiotensin receptors as well as the synthesis of cyclooxygenase products. Calcium removal from nutrient fluid depressed, but not fully abolished, the contractile effect of endothelin-2; furthermore, calcium channel blockers, verapamil and nifedipine, produced only a partial inhibition of the endothelin-2-induced contractions. These observations suggest that endothelin-2 induces a direct activation of specific receptors in the saphenous vein muscle and that both intracellular and extracellular calcium pools may be involved in the contractile effect of the peptide.
[Importance of oral rehydration in acute infantile diarrhea. Comparison of 2 rehydration solutions].
Oral rehydration therapy has gained worldwide acceptance as the standard treatment for acute diarrhoeal diseases in infants and children. Besides the high sodium glucose-electrolyte solution based on the WHO/UNICEF recommendations, many diverse formulations of oral rehydration solutions (ORS) have withstood the trial of prolonged clinical use, their main differences concerning the concentration of sodium, the choice of the glycidic component, the use of bicarbonate as buffer or its substitution with acetate or citrate. It was recently hypothesized that glucose polymers-containing ORS markedly improve the intestinal sodium/glucose cotransport by delivering glucose at its critical site on the luminal villous membrane and therefore diminish stool output and duration of the diarrhoea. To investigate this hypothesis, the efficacies of two marketed ORS (table I), one containing sucrose and maltodextrin (solution A) and the other containing glucose (solution B) were compared. The study group comprised 13 infants and toddlers, 1 to 18 months old, who presented with acute diarrhea; 5 were males and 8 females; 7 were randomly allocated to receive solution A (Group A), 6 solution B (Group B). There were no significant differences between the groups in age, sex, causation of diarrhea or severity of dehydration before receiving ORS. Both groups showed a satisfactory response to 24 hours of treatment with either ORS, but a significantly lower stool output (number and global weight of stools) and higher blood glucose and bicarbonate levels were detected in group A (table II).(ABSTRACT TRUNCATED AT 250 WORDS)
[Up-date on the etiopathogenesis of celiac disease].
Wheat, oat, rye and barley flours are toxic for celiac patients. Prevalence and incidence of Celiac Disease (CD), quite variable from country to country, are very high in Austria (1 out of 476 born alive) and low in France (1 out of 41.667 born alive). This difference is probably due to its multifactorial genesis. In a multicentric Italian study, histocompatibility antigens of HLA complex II were typed in 460 CD children. DR3 was present in 63% of the cases (Relative Risk = RR: 6.8), DR7 in 67% (RR: 3.8) and DR3/DR7 in 22.5% (RR: 10.5), while in 7.7 of patients both antigens were absent. Therefore in a certain percentage of CD patients these risk antigens are absent, while in the normal population they can be present. The probability of CD increases when HLA DR3 and DR7 are present (but their absence cannot exclude the disease. The main etiological factor is gluten and its fractions (B, B1, B2, fraction 9 etc.). It seems that breast feeding can prevent or delay the onset of CD, while the age at gluten introduction does not modify the risk. Pathogenetic mechanisms are still under discussion: 3 theories are under investigation. 1) Enzymatic theory: a proteolytic enzyme for gluten digestion could be lacking. This theory is not yet proven, while Bruce et al. found in the jejunal mucosa of CD patients an elevation of a transglutaminase, which binds the gluten to enterocytes. Its level does not seem to vary with the diet. 2) Lectinic theory: the gluten bind the enterocyte membrane by a lectinic mechanism and damage it.(ABSTRACT TRUNCATED AT 250 WORDS)
[Headache in depressive syndromes: a clinical study (author's transl)].
The possibility of a close relationship between depression and headache has been investigated by many authors; and supported by clinical, biochemical and pharmacological findings. In the present study the features of headaches were investigated in a sample of 58 depressed inpatients, selected according to Feighner's diagnostic criteria. Head pain was found in over 50% of the depressed, with a greater incidence within the psychogenic group. On the other hand headache did not correlate with the nuclear symptoms of depression (depressed mood, guilt, retardation, inadequacy); it correlated with tension and somatic anxiety. The authors conclude that headache, as a symptom of depressive syndrome, must be considered only an accessory component of depression, but not a central feature of the syndrome.
[Teaching methodology in medicine: experimentation].
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Different effects of the histamine H2 receptor blockers, famotidine and zolantidine, on the human atrium in vitro.
The effects of the histamine H2 receptor blocker famotidine were investigated on the human isolated myocardium, in comparison with zolantidine, a new member of the same family. Experiments were performed on human atrial fragments, taken from patients undergoing reconstructive heart surgery. Electrical pacing was applied and H2 receptor-evoked positive inotropic responses were induced with histamine. Famotidine (0.1-10 microM) shifted the concentration-response curve of histamine to the right in a competitive fashion, without affecting the basal contraction and the noradrenaline-induced positive inotropic activity up to 100 microM. Zolantidine (1-100 microM) antagonized the histamine-induced positive inotropic effect, but the rightward shifts were nonparallel and the maximum response was depressed, probably due to a nonspecific cardiodepressive activity at concentrations above 1 microM. Data obtained in the present study confirm the ability of famotidine to block cardiac histamine H2 receptors, but, in contrast with several studies on healthy volunteers, nonspecific effects on the myocardial contractility cannot be demonstrated. Conversely, zolantidine depresses the myocardial contractility with a mechanism differing from that of slow-channel blockers.