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Biomedical subjects

P Alberti

Publications and source records attributed to P Alberti.

At least 37 records · Page 2Linked to original sources
PubMed1992

[Tumors of the small intestine. Case reports and comments].

Tumours of the small intestine are extremely rare and have a particularly severe prognosis. The impossibility of making an early diagnosis due to the scarcity of precise symptoms during the early stages of the disease and the lack of safe instrumental tests limits the results of treatment which is essentially surgical. In order to contribute to the study of the disease and improve its prognosis, the authors report the cases which they have observed and review the literature.

Adult↗
PubMed1990

Picotamide protects mice from death in a pulmonary embolism model by a mechanism independent from thromboxane suppression.

We have previously characterized the new antiplatelet agent picotamide as a dual thromboxane synthase inhibitor/thromboxane A2 receptor antagonist in human platelets. We have now studied the antithrombotic activity of this drug in a simple animal model of lung platelet thromboembolism in the mouse. Picotamide, given i.p. 1 hr before the thrombotic challenge, protected mice from death caused by the i.v. injection of collagen plus epinephrine in a dose-dependent way; the dose reducing mortality by 50% was 277 mg/kg while for aspirin it was 300 mg/kg. Picotamide was also able to reduce the mortality provoked by the i.v. injection of the stable TxA2 mimetic U46619; BM 13.505, a pure TxA2-receptor blocker, was also effective while aspirin was totally inactive. Picotamide, finally, reduced the lethal consequences of the i.v. injection of a 12.5% suspension of hardened rat red blood cells, a model in which platelets are not involved; aspirin was totally ineffective in this model while nicardipine, a calcium channel blocker, was active. Picotamide did not inhibit the formation of TxB2 in serum at any of the doses tested (100 to 750 mg/kg i.p.) while it did enhance significantly PGI2-synthesis from mice aortae and, even more, from mice lungs. The i.v. administration of picotamide (250 mg/kg 2 min before the thrombotic challenge) lead to a strong inhibition of serum TxB2 (-84.6%) and was associated with a higher antithrombotic effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Activation of a ribosomal S6 protein kinase in rapidly emerging diethylnitrosamine-induced gamma-glutamyltranspeptidase-positive hyperplastic liver lesions of the rat.

The gamma-glutamyl transpeptidase (GGT)-positive hyperplastic liver lesions which developed in the Fisher 344 rat 7 and 60 days following a single carcinogenic dose of diethylnitrosamine (DENA, 200 mg/kg body weight), short-term dietary exposure to 0.02% 2-acetylaminofluorene (AAF) to suppress the growth of normal hepatocytes, and partial hepatectomy to actuate rapid growth of DENA altered hepatocytes not suppressed by AFF, showed an increased activity of a kinase which specifically phosphorylates the ribosomal S6 protein in vitro. Sham-operated animals showed, on the contrary, no GGT-positive cells and low S6 kinase activity, under the same conditions. After partial hepatectomy, activation of S6 kinase and elevated levels of phosphorylated S6 protein in vitro were detected in the early phases of "normal" hepatocyte proliferation, during liver regeneration, in DENA-treated, GGT-negative preparations, when the "selection" agent AAF was omitted from the diet. The observed activation of S6 kinase in GGT-positive hepatocytes and/or liver nodules could represent an early manifestation of the enhanced proliferation of altered hepatocytes during tumor induction and/or promotion under these conditions.

Animals↗
PubMed1989

Comparison of faecal blood loss, upper gastrointestinal mucosal integrity and symptoms after piroxicam beta-cyclodextrin, piroxicam and placebo administration.

In order to evaluate the gastric tolerance of the new piroxicam formulation CHF 1194 (piroxicam complexed with beta-cyclodextrin), a double-blind randomized trial was carried out in 21 young healthy volunteers comparing CHF 1194 with piroxicam and placebo. Faecal blood loss measurement by the Cr-51 labelled red blood cell technique, upper gastrointestinal endoscopic evaluation, titration of gastric pH and gastric biopsies before, during and after treatment were used to assess drug tolerability. Four out of 7 volunteers in the piroxicam-treated group withdrew because of severe gastrointestinal symptoms and oesophageal and/or gastroduodenal lesions, while all subjects treated with CHF 1194 or placebo completed the treatment. There was a significant difference between the endoscopic scores of the piroxicam and placebo groups, whereas no differences were found between CHF 1194 and placebo, nor between piroxicam and CHF 1194. Daily mean gastrointestinal blood loss was greater in the piroxicam group than in either the CHF 1194 or placebo groups, but the difference was not significant, due to the small number of piroxicam-treated subjects who completed the study. When administered for a short period to healthy young subjects, CHF 1194 caused less gastric damage and was better tolerated than piroxicam.

Adult↗
PubMed1989

Ontogeny of CA 125 antigen in pregnancy: immunoradiometric determination in amniotic fluid and immunohistochemical localization in fetal membranes.

CA 125 antigen was measured in amniotic fluid, maternal blood, cord blood, and fetal urine by a commercially available immunoradiometric assay kit. The amniotic fluid was obtained from 99 normal pregnancies at various gestational ages. The mean antigen levels were 29,676, 3350, and 1680 U/ml in amniotic fluid of the first, second, and third trimesters, respectively. In maternal blood, 12.5% of pregnant women in the first trimester of pregnancy showed elevated levels of CA 125 (65 to 100 U/ml). Late in gestation, CA 125 levels in cord blood and fetal urine were always less than 65 U/ml. Immunohistochemical study of CA 125 in fetal membranes, placenta, and decidua showed the presence of antigen only in the amnion. These results suggest that CA 125 is shed into amniotic fluid directly from the amniotic membrane.

Amniotic Fluid↗
PubMed1989

[Dyspeptic syndrome in heart diseases].

Many investigations have ascertained the relation between dyspepsia and diseases or disorders of gastrointestinal tract; on the contrary, the topics concerning the dyspeptic syndrome during acute cardiac disorders are very few. For this reason, Authors studied the upper tract of digestive apparatus in some patients affected with congestive heart failure and ischemic heart disease. Data have showed alterations of motility in esophagus, stomach and duodenum in every patient and lesions of gastric mucous membrane in more than half of them.

Adult↗
PubMed1988

Activation of a ribosomal protein S6 kinase during the 4-dimethylaminoazobenzene-induced rat hepatocarcinogenesis.

During the induction of 4-dimethylaminoazobenzene (DAB) hepatocarcinogenesis there was a progressive increase in the activity of a kinase which specifically phosphorylated S6 ribosomal protein in vitro. Liver tumour tissue (hepatocellular carcinoma and cholangioma) showed maximal activation of this kinase and elevated levels of S6 phosphorylation. Control rats fed with the same diet containing no dye showed a gradual decline of this activity, with low or lacking phosphorylation at the end of the experimental regimen, suggesting close correlation between tumor cell growth and phosphorylation of this ribosomal protein, under these conditions.

Animals↗
PubMed1988

Heat shock, protein synthesis and ribosomal protein S6 phosphorylation in vitro in Yoshida AH 130 ascites hepatoma cells.

An activated 40S ribosomal protein S6 kinase has been demonstrated previously in cytosolic extracts from proliferating as well as resting cells of a very undifferentiated rat ascites hepatoma cell line (Yoshida AH 130), grown in vivo (Cell Biol. Int. Rep., 1986, 10, 821-831). In the present report we present evidence of unmodified activity of this kinase and S6 phosphorylation in vitro in cells submitted to a physiological stress such as a sublethal temperature elevation (heat shock: 42 degrees C for 2 h). The heat treatment causes a progressive decline in the number of active ribosomes and of L-35S methionine incorporation into total protein, suggesting drastically decreased synthesis of cellular proteins under these conditions. Cells recovering from heat shock show the induced synthesis of a protein with an apparent Mr of 50 kDa. Spontaneous high expression of heat shock proteins (HSP 70, 89, 100), without heat shock, occurs in these tumor cells.

Animals↗
PubMed1986

Protein synthesis, ribosomal protein S6 phosphorylation in vitro and the effects of amiloride: SDS gel electrophoresis studies in the Yoshida ascites tumor (AH 130) grown in vivo.

Cell-free cytosolic extracts from the Yoshida (AH 130) rat ascites hepatoma cell line, grown in vivo, showed high ribosomal protein S6 kinase activity in vitro, as measured by transfer of 32P to exogenous 40S rat liver ribosomal subunits, in both exponential growing and stationary phase cells. A significant decrease of protein synthesis (3H-leucine incorporation into total cell protein) was found to occur in cells reaching the stationary phase of growth, suggesting that S6 phosphorylation was not tightly coupled to the rate of the intraperitoneal cell growth and of protein synthesis in these tumor cells. When the cell-free cytosolic extracts were prepared from cells exposed to amiloride, at concentrations that inhibit the Na+/H+ exchange, a decrease of S6 kinase activity was observed only in exponential growing cells, suggesting the possibility of coupling of the Na+/H+ exchange with phosphorylation of intracellular proteins in these tumor cells. Actually, stationary phase cells showed unchanged S6 kinase activity under the same conditions, possibly due to the extremely low Na+/H+ exchange activity, previously demonstrated (Cell Biol. Int. Rep., 1985, 9, 1017-1025). The present experiments support the hypothesis that the regulation of protein synthesis is not tightly coupled to phosphorylation-dephosphorylation cycles, at least of ribosomal protein S6, in cells characterized by a rather uncontrolled growth such as the Yoshida (AH 130) rat ascites hepatoma. In this connection, an elevated degree of protein phosphorylation, such as that of the ribosomal protein S6, could be a general phenomenon of neoplastic transformation.

Amiloride↗
PubMed1984

[Ultrasound echography (A-scan) of the cerebral ventricles in newborn infants: its relation to the degree of maturity and clinical significance].

Since during fetal development the intracerebral ventricular system shows characteristic changes wer tried to varify wether there is a relationship between the width of the ventricles of the newborn and the degree of maturity. In 304 neurologically healthy newborn infants (28. until 42. weeks of gestation) the ventricular diameters in the region of body of the lateral ventricles were measured by ultrasound (A-mode) once between the third and eight day of life. In addition the cella-media-indices were calculated. With increasing maturation we found wider ventricles. Also the cella-media-indices were higher in the more mature infants which we believe is the result from growth of cerebral substance in the last third of pregnancy. Small-for-date infants born at term showed significantly lower cella-media-indices than normal weight term babies (p less than 0,01). These results may help interprete sonographic and computertomographic measurements of the premature ventricles. The significance of ventricular diameters smaller or larger than our normal values is not yet exactly understood and further studies are needed.

Alpha Rhythm↗
PubMedDate not supplied

Molecular recognition of quadruplex DNA by quinacridine derivatives.

The interaction of monomeric and dimeric quinacridines with quadruplex DNA has been investigated using a variety of biophysical methods. Both series of compounds were shown to exhibit a high affinity for the G4 conformation with two equivalent binding sites. As shown from the SPR and dialysis experiments the macrocyclic dimer appears more selective than its monomeric counterpart.

Base Sequence↗
PubMedDate not supplied

Auditory evoked potentials in audiometric assessment of compensation and medicolegal patients.

The clinical utility of auditory evoked potentials for validation of the pure tone audiogram in adult compensation claimants and medicolegal patients is examined. Large sample comparisons of evoked potential and conventional pure tone thresholds showed that the slow vertex response can estimate true hearing levels within 10 dB in almost all patients. Given adequate tester skills, it is the tool of choice, and it merits more widespread implementation. Properly used, it can improve and abbreviate the assessment battery for detection and quantification of nonorganic hearing loss. The 40-Hz middle latency response is useful as a secondary tool, but at present, cochlear nerve and brain stem potentials have limited audiometric value in this population.

Adult↗