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Biomedical subjects

A Crema

Publications and source records attributed to A Crema.

At least 55 records · Page 3Linked to original sources
PubMed1985

Reevaluation of prognostic significance of symptoms in Hodgkin's disease.

The prognostic value--at diagnosis--of fever, sweating and weight loss, which enter the Ann Arbor B category, and of pruritus, whose influence on survival is still debated, were systematically reevaluated in 635 patients with Hodgkin's disease, observed between 1972 and 1982. By means of multivariate analysis an intrinsic, more negative prognostic value was demonstrated for each of the following symptoms: fever over 38 degrees C, weight loss more than 10% of body weight in the 6 months before admission, and severe pruritus, which is defined as being generalized, causing multiple excoriations and resisting local and systemic antipruritics. Patients with the mild counterparts of these symptoms, as well as sweats, were found to have a survival rate quite comparable with that of fully asymptomatic patients. A rearrangement of the Ann Arbor B constitutional symptoms which would replace sweats with severe pruritus might be more correct and more suitable for better selecting the patients who require more aggressive therapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1985

Depression by morphine of the excitability of intrinsic inhibitory neurons in the guinea-pig colon.

The mechanical responses to morphine were examined in isolated preparations of longitudinal and circular muscle of the guinea-pig colon. In the longitudinal coat, morphine induced a relaxation which was prevented by naloxone, hyoscine and tetrodotoxin. Conversely, in the circular coat morphine caused a contraction which was antagonized by naloxone, mimicked by tetrodotoxin and left unaltered by hyoscine, chlorpheniramine and methysergide. In both muscular layers, morphine depressed (and tetrodotoxin abolished) the non-adrenergic relaxation induced by field stimulation. The action of morphine in the two preparations can thus be explained in terms of inhibition of the tonic excitatory cholinergic or inhibitory non-adrenergic neural control prevailing in the longitudinal and circular muscle respectively.

Animals↗
PubMed1985

Serum albumin in Hodgkin's disease.

Serum albumin levels were measured by electrophoresis in 552 evaluable patients with Hodgkin's disease. Determinations were made on all patients at onset, on 224 after induction therapy and on 78 in relapse after remissions of variable length. At onset a discrete hypoalbuminemia was evident, inversely related to stage and more marked in symptomatic cases and elder patients. Little or no differences in albumin levels were found with relation to histologic subtypes, sex and presence of weight loss or hepatic damage. Posttherapeutic normalization of serum albumin occurred only after achievement of complete remission and failed after partial remission, while a new clear decrease became evident in relapse. On the basis of 799 albumin measurements during active disease and in remission, the albumin/alpha 2-globulin ratio demonstrated a clear and useful clinical advantage over either albumin or alpha 2-globulin fractions alone as indicator of active disease and relapse. If defective synthesis is the most accepted mechanism for hypoalbuminemia in Hodgkin's disease, these results suggest a casual factor somehow related to the tumoral mass.

Adult↗
PubMed1985

Subsensitivity of enteric cholinergic neurones to alpha 2-adrenoceptor agonists after chronic sympathetic denervation.

The concentration-effect relationships of noradrenaline, dopamine and clonidine in inhibiting resting and stimulated acetylcholine output have been studied in intact and in sympathetically denervated preparations of guinea pig isolated distal colon. The order of potencies for the inhibition of resting acetylcholine release in intact preparations was clonidine greater than dopamine greater than noradrenaline while the order of intrinsic activities was noradrenaline greater than dopamine greater than clonidine. Sympathetic denervation was able to modify the potency of either clonidine, dopamine and noradrenaline. Noradrenaline was 6 times more potent in inhibiting resting acetylcholine release in denervated than in intact preparations, while clonidine and dopamine underwent a 18-fold and a 11-fold decrease in potency after denervation. The potency of clonidine relative to noradrenaline was 110 in intact preparations and only 1.2 in denervated organs. The intrinsic activities of noradrenaline, dopamine and clonidine were almost unchanged in denervated organs. A dose-dependent facilitatory effect of yohimbine on both the resting acetylcholine output and the peristaltic reflex could be observed in intact but not in sympathetically denervated preparations at concentrations ranging from 2.5 X 10(-8) M to 2.5 X 10(-7) M. Yohimbine was able to counteract the inhibitory effect of dopamine and to remove the inhibitory effect of periarterial nerve stimulation on both acetylcholine release and the peristaltic reflex. Our results are consistent with the existence of a tonic physiological modulation of enteric cholinergic neurones by postganglionic sympathetic fibres. The order of potencies of adrenoceptor agonists and the antagonism by yohimbine is consistent with such a modulation being entirely carried out through alpha 2-heteroceptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1985

Effect of chronic anticonvulsant monotherapy on lymphocyte subpopulations in adult epileptic patients.

Sixty-five patients undergoing long-term monotherapy for at least 3 months with phenytoin, carbamazepine or phenobarbital were screened for lymphocyte and immunoglobulin abnormalities. In 57% of patients the duration of therapy was longer than 12 months. The control subjects were matched for sex and age and none of them was taking drugs. The average serum immunoglobulin (IgG, IgA, IgM) values did not differ in control and patient groups. A significant decrease of OKT4+ cells was seen with all drugs, while other lymphocyte subpopulations were differently affected depending on the drug used. It is concluded that long-term single-drug treatment with phenytoin, carbamazepine and phenobarbital exhibits immunosuppressant effects through a complex action which involves more than one lymphocyte subpopulation. Moreover, the possible interference of the disease state with the immune functions of epileptic patients is discussed.

Adolescent↗
PubMed1984

Changes in sensitivity to the inhibitory effects of adrenergic agonists on intestinal motor activity after chronic sympathetic denervation.

The concentration-effect relationships of adrenergic agonists in inhibiting muscular tone, carbachol-induced contraction of circular muscle strips and nerve-mediated motor activity during the peristaltic reflex have been studied in intact and sympathetically denervated preparations of isolated guinea-pig colon. The order of potencies of adrenergic agonists was different for muscular and nerve-mediated effects, being clonidine greater than noradrenaline greater than methoxamine greater than isoprenaline for the inhibition of peristalsis and isoprenaline greater than noradrenaline greater than methoxamine greater than clonidine for the relaxation of circular muscle. Denervation supersensitivity was specific for the adrenergic agonists and developed both to the muscular and nerve-mediated effects, involving both alpha and beta receptors. The degree of potentiation was similar for noradrenaline and isoprenaline when measured for the muscular effects but was significantly higher for noradrenaline than for isoprenaline or methoxamine when measured for peristalsis inhibition. No potentiation could be observed for papaverine and for the muscular effects of methoxamine and phenylephrine. The increase in potency of noradrenaline ranged from a 26-fold increase for the inhibition of propulsion velocity to a 2.5-fold increase for the inhibition of carbachol-induced contraction. A much narrower range was observed for isoprenaline. Potentiation could also be observed for the inhibitory effect of noradrenaline on acetylcholine release. Clonidine was the most potent agonist against peristaltic reflex and the weakest agonist in relaxing circular muscle. Denervated preparations became subsensitive to the inhibitory effect of clonidine on peristaltic reflex. The potency of clonidine relative to noradrenaline was 488 in intact preparations and only 3.1 in denervated organs.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1984

Antenatal diagnosis of haemoglobinopathies by improved method of isoelectric focusing of haemoglobins.

An improved method of isoelectric focusing (IEF) of haemoglobins, utilizing a spacer molecule to increase the separation between HbA and acetylated HbF, was carried out in parallel with carboxymethylcellulose (CMC) chromatography in 85 antenatal diagnoses for haemoglobinopathies (mainly thalassaemia). In 19 of 21 affected fetuses no HbA band was detectable on IEF while in two a very faint band was observed; in heterozygotes or normal fetuses a more obvious HbA band was present. Moreover, IEF was useful for the demonstration of HbLepore in two cases at risk for beta-thalassaemia/ HbLepore and for interpreting a radioactive pre-beta globin peak on CMC chromatography. Pure fetal blood is needed for IEF. It can therefore be used for most cases in centres using fetoscopy for fetal blood sampling. About 80% of antenatal diagnosis of haemoglobinopathies may be carried out by IEF which is a very simple, rapid and inexpensive method.

Female↗
PubMed1983

5-HT mediated GABA excitatory responses in the guinea-pig proximal ileum.

GABA (3--100 microM) and 5-HT (0.03--30 microM) caused concentration-dependent transient contractions of the longitudinal muscle of the guinea-pig ileum. The contractile response to GABA was antagonized by hyoscine (2.2 microM). TTX (0.7 microM), bicuculline (3 microM), furosemide (25 microM) and desensitization to GABA itself, while hexamethonium (20 microM) and methysergide (20 microM) were without effect. The contractile response to 5-HT was antagonized by hyoscine (2.2 microM), TTX (0.7 microM) and desensitization to 5-HT itself and was unaffected by bicuculline (10 microM), hexamethonium (20 microM), furosemide (25 microM) and methysergide (20 microM). A desensitization procedure that caused a 84.7-fold increase in the 5-HT EC50 also resulted in a 74.1-fold increase of the GABA EC50. Desensitization to GABA caused a reduction of 5-HT induced response but only in preparations desensitized by high (50 microM) concentrations of GABA. The results indicate that GABA-induced contractions in the guinea-pig ileum are mediated by activation of cholinergic motor neurones. This effect appears to be mediated by interneuronal release of 5-HT rather than by a direct stimulatory action of GABA on the effector neurones.

Animals↗
PubMed1983

Reduction of phenytoin clearance caused by cimetidine.

The effect of cimetidine on the disposition kinetics of phenytoin was investigated in 7 healthy volunteers. Each subject received a single intravenous dose of phenytoin on two occasions, in the control state, and during concurrent treatment with cimetidine 1 200 mg/day for 6 days. A slight but statistically significant decrease both in the rate of elimination and total body clearance of phenytoin was observed during the administration of cimetidine. The effect is probably due to inhibition of metabolism.

Adult↗
PubMed1983

Purine receptors in the guinea-pig internal anal sphincter.

1 In the isolated internal anal sphincter of the guinea-pig, adenosine 5'-triphosphate (ATP) and adenosine induced a concentration-dependent and tetrodotoxin-insensitive relaxation. 2 Pretreatment with theophylline (25-50 microM) had no significant effect on the concentration-response curves obtained with either purine compound. 3 Reactive blue 2 (25-100 microM) shifted the curve to ATP to the right in a dose-dependent fashion leaving that to adenosine unaltered. The antagonism appeared to be non-competitive. 4 Neither reactive blue 2 nor purine receptor occupation by ATP or adenosine altered the electrically-induced non-adrenergic, non-cholinergic inhibitory response. 5 The actions of ATP and adenosine in the guinea-pig internal anal sphincter appear to be mediated by separate receptors. These receptors are not involved in the nerve-mediated relaxation.

Adenosine↗
PubMed1982

Mode of action of ATP on propulsive activity in rabbit colon.

ATP induced a concentration-dependent reduction of the velocity of propulsion in isolated segments of rabbit colon as assessed by the aboral displacement of an intraluminal rubber balloon, and delayed the onset of the propulsive wave. ATP depressed both the reflex contraction of the circular coat above the distended balloon and the response of the circular muscle to transmural (cholinergic) stimulation. On the contrary, ATP (up to 200 muM), while causing relaxation of the circular muscle, had no effect on either the muscular contractile response induced by carbachol and histamine or the non-adrenergic inhibitory responses elicited by electrical stimulation and by radial distension of the gut wall. Within the concentration range used (10-200 muM), ATP concentration-depression curves for propulsion and transmural excitatory stimulation were shifted to the right in the presence of theophylline (10 muM). Theophylline, however, had no influence on either the direct inhibitory action of ATP on circular smooth muscle or the non-adrenergic relaxation in response to electrical stimulation. These data are consistent with the concept that at least two populations of purinergic receptors are present in intestinal tissue. Those populations located presynaptically, unlike those located postsynaptically, are blocked by theophylline. Since the contractile machinery does not appear to be affected by ATP concentrations up to 200 muM, the mechanism by which ATP impairs propulsive activity is probably dependent on activation of presynaptic purinergic receptors located on the nervous pathways subserving the wave of contraction, without having any appreciable influence on descending inhibition.

Adenosine Triphosphate↗
PubMed1982

Effects of desensitization to adenosine 5'-triphosphate and adenosine on non-adrenergic inhibitory responses in the circular muscle of rabbit colon.

An approximate eight fold desensitization of the circular coat of the distal rabbit colon to adenosine 5'-triphosphate (ATP) and adenosine could be achieved by repeatedly exposing the organ to relatively low concentrations (10-100 microM) of these compounds. The desensitization was specific and reversible after prolonged washing. It could be overcome by increasing the concentrations of the purine agonists. Dipyridamole potentiated the non-adrenergic inhibition in response to transmural stimulation but failed to influence the caudad relaxation evoked by radial distension. Desensitization to ATP and adenosine (and to ATP + adenosine simultaneously) did not affect the non-adrenergic inhibition in response to radial distension or transmural stimulation. These results suggest that neither ATP nor adenosine are the final transmitters mediating the non-adrenergic inhibitory responses in the distal colon of the rabbit.

Adenosine↗
PubMed1982

Motor responses of rat stomach in vitro after subacute oral administration of trithiozine.

The effects of ten days' oral treatment with 200 mg/kg/d of 4-(3,4,5-trimethoxythiobenzoyl)tetrahydro-1,4-oxazine (trithiozine) on the mechanical responses of rat stomach in vitro have been studied. Gastric muscular excitation due to vagal stimulation was partially reduced in the trithiozine-pretreated animals, while the amount of acetylcholine (Ach) released both at rest conditions and in response to field stimulation was similar in both controls and drug-pretreated rats. Also muscular responses induced by dopamine (DA) and by serotonin (5-HT) were of similar degree in both groups of rats. On the contrary, the nonadrenergic and non-cholinergic inhibitory response evoked by vagal stimulation in the presence of muscarinic and alpha- and beta-adrenergic receptor blockade, respectively, was enhanced in the drug-pretreated animals. Moreover, trithiozine pretreatment caused an increase of spontaneous motor activity and a remarkable degree of potentiation of the contractile response to prostaglandins (PGs), both exogenously applied or endogenously released by ATP. Our results give further evidence that trithiozine has no anticholinergic activity and that some therapeutic properties of the molecule could be accounted for by an involvement of endogenous PGs.

Acetylcholine↗
PubMed1981

Hyoscine-resistant peristalsis in guinea-pig ileum.

The effect of hyoscine on the peristaltic activity of the proximal and distal ileum of the guinea-pig was studied. Hyoscine strongly impaired peristalsis as indicated by the elevation of the threshold pressure and by the increased number of incomplete peristalses and blockades. Functional activity of the circular musculature was more markedly impaired. However, particularly in the distal ileum, complete peristalses occurred even after 70 min exposure to hyoscine at a concentration of 10(-6) g/ml. A tenfold increase in hyoscine concentration failed to produce further impairment of peristaltic activity and of the oral reflex contraction. The activity which remained in the presence of hyoscine was blocked by methysergide and by d-tubocurarine. The hypothesis is advanced that once the muscarinic receptors have been blocked, increased radial stretch of the circular coat results in activation of a separate, tetrodotoxin sensitive, excitatory nervous pathway, which is sufficient to maintain a discrete degree of peristaltic activity.

Animals↗