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P Visconti

Publications and source records attributed to P Visconti.

15 recordsLinked to original sources
PubMed1996

Molecular probe data base (MPDB).

The molecular probe data base (MPDB) contains detailed information on synthetic oligonucleotides, including their identification, target genes, applications and bibliographic references. It is available on-line through Internet and can be searched by using Network Information Retrieval tools. In this article the most recent enhancements of MPDB, both in terms of data contents and new ways of access, are described. These include a recently established collaboration with EMBL Data Library, in the sphere of SRSWWW network browser, in view of a better integration of MPDB with other molecular biology databases.

Computer Communication Networks↗
PubMed1994

p95, the major phosphotyrosine-containing protein in mouse spermatozoa, is a hexokinase with unique properties.

Mouse sperm contain a major phosphotyrosine-containing protein of M(r) 95,000 (nonreducing conditions) which has been implicated as a sperm membrane receptor for the egg zona pellucida glycoprotein, ZP3 (Leyton, L., and Saling, P. (1989) Cell 57, 1123-1130; Leyton, L., LeGuen, P., Bunch, D., and Saling, P. (1992) Proc. Natl. Acad. Sci. U. S. A. 89, 11692-11695). This protein was purified and subjected to limited tryptic digestion and subsequent amino acid analysis. Three sequenced peptides revealed 100% amino acid identity to a mouse hepatoma hexokinase (Arora, K. K., Fanciulli, M., and Pederson, P. L. (1990) J. Biol. Chem. 265, 6481-6488). The purified protein, which migrated at M(r) 116,000 under reducing conditions (p95/116), reacted with an antiserum to the purified rat brain hexokinase, type 1, and comigrated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with the purified rat brain enzyme under both nonreducing and reducing conditions. Unlike p95/116, the rat brain enzyme was not a phosphotyrosine-containing protein. The p95/116 protein could be immunoprecipitated with the hexokinase antiserum or an O-phosphotyrosine antibody. Limited tryptic digestion of the purified p95/116 and the rat brain enzyme generated subsets of identical peptides which reacted with the hexokinase antiserum. However, p95/116 also contained phosphotyrosine-containing peptides that were not present in the rat brain hexokinase. When different mouse tissues were probed with the hexokinase antiserum all tissues, with the exception of liver, contained immunoreactive protein. In contrast, only sperm and testis possessed a phosphotyrosine-containing form of hexokinase. These data suggest that the germ cell component of the testis possesses a unique tyrosine-phosphorylated form of hexokinase.

Amino Acid Sequence↗
PubMed1994

Effect of NPPB on chloride (Cl-) transport in distal colon of potassium (K+) adapted rats.

Secondary hyperaldosteronism enhances the rate of K secretion in distal colon, at least in part, through the stimulation of Na(+)-K(+)-Cl- cotransport across the basolateral membrane. To maintain a constant intracellular Cl- activity an increase in Cl- transport out of the cell must be assumed. We explored, under amiloride 10(-4) M and short circuited conditions, conductive pathways for Cl- exit in the distal colon of K(+)-adapted rats by means of a putative Cl- channel blocker, NPPB (5-nitro-2(3-phenyl-propylamino-benzoate. Results prior to NPPB showed an increase in JClms after K+ loading from 5.84 +/- 0.66 to 8.33 +/- 0.86 and JClsm from 4.77 +/- 0.55 to 8.16 +/- 0.96 microEq h-1 cm-2 (P < 0.001), when compared with controls. Net fluxes were not different between groups. Luminal NPPB in K+ adaptation resulted in a decrease of JClsm, from 7.85 +/- 1.5 to 6.69 +/- 1.5 microEq h-1 cm-2 (P < 0.05). There were no changes in both unidirectional Cl- fluxes in controls under luminal NPPB and in potential difference (V) and short-circuit current (Isc) under any condition. Finally, K+ adaptation resulted in an increase of luminal cyclic AMP (cAMP) concentration (0.09 +/- 0.02 to 0.20 +/- 0.03 pmol 100 microliters -1, P < 0.005), when compared with control rats. The data may suggest a transcellular recycling of Cl- and an activated NPPB inhibitable serosal to mucosal Cl- pathway on luminal membrane in the K+ adapted state, possibly mediated by an increase in cAMP production.

Adaptation, Physiological↗
PubMed1990

[Use of reconstituted basal membranes for the study of invasion of human tumor cells: current status and future prospects].

Tumor metastasis is the major cause of death of oncology patients. One of the characteristic properties acquired by the metastatic cell is the ability to cross basement membranes. These are compartments of extracellular matrix composed largely by collagen type IV, laminin and a heparan sulphate proteoglycan. Here we review the use of a reconstituted basement membrane (Matrigel) in the Boyden chamber assay (Chemoinvasion Assay) for the assessment of the invasiveness of tumor cells of human origin. The possibility of using this test for the rapid evaluation of human tumor specimens from operated patients is discussed.

Basement Membrane↗
PubMed1990

Effect of vitamin A on chemotactic and chemoinvasive behaviour of an osteosarcoma cell line.

Vitamin A is known to be able to modulate cell growth and differentiation and to act as an inhibitor of the process of carcinogenesis in some experimental models. Here we have studied the effect of different concentrations of vitamin A on chemotactic and chemoinvasive behaviour of a metastatic osteosarcoma cell line. The cell proliferation was partially inhibited in the presence of 10(-5) M retinol after 4 days of incubation. Retinol effect on chemotactic and chemoinvasive activity of osteosarcoma cells seemed to be dose-dependent. The highest retinol concentration used (10(-5) M) had an inhibitory effect on migratory and invasive cell response. Lower retinol concentrations seemed to be able to enhance (10(-8) M) both chemotactic and chemoinvasive activity of osteosarcoma cells. Chemotaxis and chemoinvasion assays provide rapid and quantitative tools to study the "in vitro" behaviour of metastatic cells. Furthermore, they represent a mean to screen for drugs, hormones and other substances able to alter the metastatic phenotype.

Chemotaxis↗
PubMed1985

[Binding capacity of albumin with bromcresol green in a group of women of fertile age].

Albumin binding ability was studied in 551 women of fertile age through the dye-binding test with BCG. In 61 cases (11.0%) no binding was found: 47 women (77.0%) were pregnant at the time the blood test was performed. Such a result agrees with previous studies which indicate a reduced albumin binding ability in the blood of near term pregnant women and in the umbilical cord.

Bromcresol Green↗
PubMedDate not supplied

EEG features and epilepsy in patients with autism.

Epileptic seizures are frequently reported (4-32%) in autism. These values are higher than in the normal population of children and adolescents (0.5%). In the literature there is no uniform description of epilepsy in autism. We examined 106 patients with autistic disorder divided into three groups on the basis of presence or absence of EEG paroxysmal abnormalities (PA) and / or epilepsy including febrile convulsions (FG). Our patients presented an autistic syndrome unrelated to clear congenital or acquired encephalopathy. The prevalence of epilepsy and EEG PA was 23.6% and 18.9%, respectively. Significant differences between the three groups appeared for (i) familial antecedents for epilepsy / FC and neurologic and psychiatric diseases (P < 0.004), (ii) a different proportion between the three groups for mental retardation (P < 0.03), (iii) and EEG fast activity (P < 0.04). Our patients showed several types of epilepsy, including idiopathic forms with seizure onset after the age of 10 in 45% of cases. Seizures were mainly partial, not frequent and controllable by anti-epileptic drugs. PA were mostly focal and multifocal and in 45% of cases were typical of benign childhood partial epilepsy with centro-temporal spikes. The higher incidence of epilepsy and EEG PA is apparently not related to organic pre-, peri- and postnatal antecedents or cerebral lesions. On the contrary, genetic factors responsible for autism and epilepsy seem important in the genesis of these two disorders.

Adolescent↗
PubMedDate not supplied

[The role of opioid antagonists in the treatment of obesity. Results of a clinical trial with naltrexone].

On the basis of literature data relative to the alteration of beta-endorphin tone in obese subjects, we conducted a clinical trial employing Naltrexone (a receptorial antagonist of endogen opioids) in order to evaluate its efficacy in increasing the compliance of these subjects on dietary treatment. The drug dosage was 50 mg/daily (100 mg/die). The clinical study was carried out following the double-blind crossover method for a period of 4 months in a group of 17 obese subjects who also underwent to psychodiagnostic interviews. Significant weight reduction was observed in the 9 patients who carried out the treatment by assuming Naltrexone (kg 4.00 +/- 3.97) rather than with placebo (kg 0.96 +/- 4.95). The drug was subjectively well tolerated and it did not alter the endocrine, metabolic, psychometric, and cardiovascular monitored parameters. The insulin secretion during OGTT did not show significant alterations. Our data emphasize the Naltrexone efficacy in improving the compliance of the obese subjects during dietary treatment.

Adult↗