PubMed Health⌕ Search

Biomedical subjects

S Ruggieri

Publications and source records attributed to S Ruggieri.

At least 19 recordsLinked to original sources
PubMed1992

Nuclear matrix-associated NMN adenylyltransferase activity in human placenta.

This paper presents data about the presence of the NMN adenylyltransferase at the nuclear matrix level of human placenta nuclei. It was found that 40-45% of the activity (depending on the extraction procedure) referred to the total nuclear NMN adenylyltransferase was tightly associated with this subnuclear compartment. The matrices purified by two different procedures exhibited DNA, RNA and protein contents comparable with those described in literature. Extensive digestion of human placenta nuclei with DNase I was not able to solubilize the NMN adenylyltransferase activity. Therefore, the data we present are consistent with the conclusion that a part of the total nuclear NMN adenylyltransferase is associated with the nuclear matrix.

Cell Fractionation↗
PubMed1992

Intravenous boluses and continuous infusions of L-dopa methyl ester in fluctuating patients with Parkinson's disease.

In six patients with Parkinson's disease exhibiting severe "on-off" phenomena, a 200-mg intravenous bolus of either L-DOPA or of its methyl ester were equally effective in reversing motor deficits, although the duration of action of the methyl ester was shorter. There were no marked differences in pharmacokinetic parameters for L-DOPA plasma levels after administration of L-DOPA and the methyl ester. In three patients, optimal infusion rates for the maintenance of mobility were established for L-DOPA and L-DOPA methyl ester. Both drugs were able to maintain patients "on" throughout a 12-h infusion period. However, on average the optimal infusion rate of L-DOPA methyl ester was 2.7 times greater than that for L-DOPA. There was no marked difference in the plasma levels of L-DOPA achieved, but 3-O-methyl DOPA levels increased more after infusion of L-DOPA methyl ester than after infusion of L-DOPA itself. The half-life of elimination and volume of distribution of L-DOPA formed from the methyl ester were markedly increased compared with values obtained after either an intravenous bolus of methyl ester or after an intravenous infusion of L-DOPA itself. An intravenous bolus of L-DOPA methyl ester produces an equivalent magnitude of clinical response to the same dose of L-DOPA. However, higher optimal infusion rates of methyl ester than L-DOPA are required to produce continuous effect. The pharmacokinetic handling of L-DOPA methyl ester given by intravenous infusion may differ from that of L-DOPA when given by the same route.

Aged↗
PubMed1992

NAD biosynthesis in human placenta: purification and characterization of homogeneous NMN adenylyltransferase.

Nicotinamide mononucleotide (NMN) adenylyltransferase has been purified to homogeneity from human placenta. The purification procedure consists of several chromatographic steps, including dye-ligand, adsorption, and hydrophobic interaction chromatography. The final enzyme preparation is homogeneous as judged by a single silver stainable band on both nondenaturating and denaturating polyacrylamide gels. The native enzyme shows a molecular weight of about 132,000, as determined by gel filtration on a Superose 12 HR 10/30 fast protein liquid chromatography column. The protein possesses a quaternary structure and is composed of four apparently identical M(r) 33,000 subunits. Isoelectrofocusing experiments give multiple pI values ranging from pH 4.7 to 6.6. Optimum pH study shows a plateau extending from pH 6.0 to pH 9.0. Km values for NMN, ATP, NAD+, and PPi are 38, 23, 67, and 125 microM, respectively. Kinetic analysis reveals a behavior consistent with an ordered sequential Bi-Bi mechanism. Among several metabolites tested only ADP-ribose and beta-NMNH were found to significantly inhibit the enzyme activity.

Amino Acids↗
PubMed1992

The clinical efficacy of single morning doses of levodopa methyl ester: dispersible Madopar and Sinemet plus in Parkinson disease.

For many patients with Parkinson disease and levodopa-related motor fluctuations, the latency to onset of action of a single dose of a levodopa preparation may be both long and variable. In an effort to find a more rapidly acting and reliable preparation of levodopa, we therefore studied the efficacy of single doses of an oral solution of 250 mg of levodopa methyl ester (ME) with benserazide, 50 mg and of a molar equivalent dose of dispersible Madopar (DM) (50/200) in 13 patients in the fasting state after overnight drug withdrawal. The response of seven of these patients was compared to that after two Sinemet 25/100. The latency to "on" was equally fast with ME and DM, and significantly faster than after standard Sinemet. The duration of "on" was similar with all three. Because of this more rapid relief of "off" periods, both ME and DM offer a potential clinical advantage over standard preparations of levodopa.

Benserazide↗
PubMed1992

Reduction of the metastatic potential of a RSV-transformed fibroblastic line (B77-AA6 cells) upon transplantation in essential fatty acid-deficient mice.

Metastatic dissemination has been shown to be influenced by dietary lipids. In particular, diets enriched with linoleic acid have been consistently found to be effective in enhancing the metastatic potential of murine mammary tumors. This study explored whether an essential fatty acid (EFA)-deficient host can affect the capacity of a tumor to metastasize to the lung. Tumors were developed by subcutaneously injecting high metastatic B77-AA6 cells (a subclone isolated from the Balb/c 3T3 cells transformed by the B77 strain of RSV) into syngeneic mice which had been fed either a control or an EFA-deficient diet for 9 weeks. EFA deficiency did not modify the incidence, latency and growth rate of primary tumors developed from B77-AA6 cells, while it markedly reduced their capacity to reproduce lung macro- and micrometastases. These findings demonstrate that physiological levels of EFA are important for a tumor to metastasize in secondary organs.

3T3 Cells↗
PubMed1991

Purification of human cytidine deaminase: molecular and enzymatic characterization and inhibition by synthetic pyrimidine analogs.

Cytidine deaminase has been purified to homogeneity from human placenta by a rapid and efficient procedure consisting of affinity chromatography followed by hydrophobic interaction chromatography. The final enzyme preparation showed a specific activity of 64.1 units/mg, corresponding to about 46,000-fold purification with respect to the crude extract. The enzyme is a 52-kDa oligomeric protein composed of four apparently identical subunits. The acidic isoelectric point is 4.5. The enzyme's stability is strictly dependent on the presence of reducing agents. Amino acid analysis reveals the presence of five thiol groups per monomer which cannot be titrated by Ellman's reagent in the native enzyme. However, the presence of sulfhydryl groups involved in the catalytic activity was evidenced by the inhibition exerted by p-chloromercuribenzoate and heavy metal ions. In addition, the protection effected by the substrate against the p-chloromercuribenzoate inhibition and the competitive inhibition exerted by 5-(chloromercuri)cytidine suggest the presence of a thiol group(s) in the catalytic site of the enzyme. pH studies have shown that the rapid decline of activity occurring at pH 4.5 might result from the protonation of the pyrimidine ring at the N-3 position. The enzyme catalyzes the deamination of cytidine, deoxycytidine, and several analogs, including antineoplastic agents, thus abolishing their pharmacological activity. Therefore, several pyrimidine nucleoside analogs have been tested as potential inhibitors of the enzyme. The competitive inhibition exerted by cytidine analogs having the ribose moiety replaced by aliphatic chains is interesting.

Amino Acids↗
PubMed1991

Use of N-acetylpsychosine as internal standard for quantitative high-performance liquid chromatographic analysis of glycosphingolipids.

The use of N-acetylpsychosine as an internal standard for the quantitative high-performance liquid chromatography (HPLC) of p-nitrobenzoyl derivatives of glycosphingolipids is described. It is suitable because the chromogen reacts on equimolar basis with both N-acetylpsychosine and sample glycosphingolipids. The use of N-acetylpsychosine as an internal standard was validated by determining the glycosphingolipid content of a system of metastatic variants selected from a murine fibrosarcoma line (T3 cells). Reproducible results were obtained throughout several quantitative analyses of cellular glycosphingolipids and it was possible to determine the glycosphingolipid content of as few as 5 x 10(6) cells.

Animals↗
PubMed1991

Presence of NAD pyrophosphorylase in skeletal muscle in dystrophic mice.

NAD pyrophosphorylase (ATP:NMN adenylyltransferase) activity has been measured in the skeletal muscle of dystrophic mice. The amount of this enzyme in the dystrophic mice, as determined by three different methods, was about one half of that in the controls. In addition, the concentration of ATP was too low to be detected in crude extracts of dystrophic mouse skeletal muscle, which were prepared using Tris buffer alone or Tris buffer containing either 3 M KCl, or 1 mM PMSF.

Adenosine Triphosphate↗
PubMed1991

Lectin reactivity of murine fibrosarcoma lines with a different metastatic potential.

Lectins are suitable tools for investigating the glycoconjugate characteristics of metastatic cells. In the present study, we investigated whether there were differences between high metastatic T3 cells and a low metastatic isolate in their reactivities to several lectins specific for galactosyl and sialyl groups. Analysis of reactivity of the two cell lines to wheat germ agglutinin revealed a complex pattern. In fact, T3 cells had high-affinity, neuraminidase-resistant as well as low-affinity, neuraminidase-sensitive receptors. Instead, the low metastatic isolate showed only high-affinity receptors, both neuraminidase-resistant and neuraminidase-sensitive The two cell lines reacted similarly to galactose-specific lectins. These findings indicate that sialyl groups, rather than galactosyl groups, affect the metastatic behavior of our cell system.

Animals↗
PubMed1991

The clinical efficacy of oral levodopa methyl ester solution in reversing afternoon "off" periods in Parkinson's disease.

We compared the efficacy of a single dose of an oral solution of levodopa methyl ester (ME) to that of standard levodopa, in the form of a single dose of Madopar, in reversing afternoon "off" periods in 12 patients with Parkinson's disease (PD). The highly soluble ME solution led to a significantly more rapid reversal of "off" periods. This preparation may therefore convey a clinical advantage in patients experiencing motor fluctuations whilst taking multiple daily dosages of levodopa, particularly in those with long or highly variable latency to the next "on" period.

Administration, Oral↗
PubMed1991

Antagonist effect of terguride in Parkinson's disease.

The effects of the partial dopamine agonist terguride (9,10 transdihydrolisuride; THDL) on striatal dopamine receptors were studied by its i.v. administration to 13 patients with Parkinson's disease. Patients were maintained in a steadily mobile state with abnormal involuntary movements by a constant i.v. infusion of levodopa. Terguride showed dopamine antagonist properties in nine patients. In two of these nine patients, a decrease in dyskinesia score was observed without a concomitant worsening of parkinsonian symptoms, whereas in the remaining seven, full parkinsonian akinesia followed THDL administration. The subsequent i.v. injection of the dopamine agonist lisuride reversed THDL-induced akinesia in these seven patients. In the remaining four patients, no clinically significant motor effects were observed. These results show dopamine antagonist activity of terguride in patients with Parkinson's disease treated with Levodopa. Further studies using a wider dose titration are required to evaluate the possible role of dopamine partial agonists in the therapy of levodopa-induced dyskinesias.

Adult↗
PubMed1991

Continuous intravenous infusion of TRH-T: clinical, cardiovascular and endocrinological effects.

Seven patients, six suffering from amyotrophic lateral sclerosis (ALS) and one from Friedreich ataxia, were treated with a placebo i.v. infusion during the first day and with TRH-T i.v. infusion at a rate of 2 mg/h for 8 h daily (total daily dosage 16 mg) on the 2 consecutive days. Continuous blood pressure (BP) and EKG monitorings were performed during 3 days infusion. Blood samples were collected for endocrinological evaluations. The neurological evaluation after acute TRH-T treatment showed an objective improvement in 3 of the 8. We found significantly higher values of systolic (max. difference of 10.1 mm Hg) and diastolic (max. difference of 8.8 mm Hg) BP than during placebo, beginning from the 5th h of the infusion (p less than 0.05). A trend in progressive increase of the heart rate (HR) reached statistical significance (p less than 0.01) at the 8th h of the second TRH-T infusion. The cardiovascular changes during the i.v. continuous TRH-T infusions were clinically irrelevant and never required the interruption of the treatment.

Adult↗
PubMed1990

Role of glycolipids in the metastatic process: characteristics of neutral glycolipids in clones with different metastatic potentials isolated from a murine fibrosarcoma cell line.

We investigated whether metastatic phenotype is associated with a characteristic glycolipid pattern. For this study, we developed a system of variants with different metastatic potentials that we isolated from the highly metastatic T3 murine fibrosarcoma line by culture in 0.3% agar or on plastic. The glycolipid profiles of T3 cells and of their highly metastatic isolates were characterized by a high level of globotriaosylceramide (Gb3ose). On the other hand, Gb3ose was reduced in a weakly metastatic clone isolated from T3 cells. A reduced level of Gb3ose was also found in a weakly metastatic subclone isolated from a highly metastatic T3 clone. Propagation of this subclone led to the emergence of a series of variants which expressed a high metastatic potential together with a high Gb3ose level. We also observed that Gb3ose was 10 times more prevalent on the cell surface in T3 cells than in a weakly metastatic clone. On the whole, these findings indicate that, in our system of metastatic cells, a high Gb3ose level correlates with metastatic phenotype. It is possible that the highly exposed Gb3ose in metastatic cells is relevant to the metastatic process in view of the role played by the unique molecular structure of this glycolipid in other models of cell-to-cell interaction.

Animals↗
PubMed1990

Evidence for an inhibitory effect exerted by yeast NMN adenylyltransferase on poly(ADP-ribose) polymerase activity.

We have previously reported for the first time the purification to homogeneity of the enzyme NMN adenylyltransferase (EC 2.7.7.1) from yeast and its major molecular and catalytic properties. The homogeneous enzyme was found to be a glycoprotein containing 2% carbohydrate and 1 mol of adenine residue and 2 mol of phosphate covalently bound per mole of protein. Such a stoichiometry, apparently consistent with that of ADP-ribose, prompted us to further investigate the possibility that NMN adenylyltransferase could be subjected to poly(ADP-ribosylation) in vitro in a reconstituted system. Poly(ADP-ribose) polymerase was purified to homogeneity from bull testis by means of a rapid procedure involving two batchwise steps on DNA-agarose and Reactive Blue 2 cross-linked agarose and a column affinity chromatography step on 3-aminobenzamide-Sepharose; the optimal conditions for the poly(ADP-ribosylation) of exogenous substrates were determined. When pure NMN adenylyltransferase was incubated in the presence of the homogeneous poly(ADP-ribose) polymerase, a marked inhibition of the polymerase was observed, both in the presence and in the absence of histones, while the activity of NMN adenylyltransferase was not affected. The inhibition could not be prevented by increasing the concentrations of either DNA or NAD. Mg2+ did not affect the activity or the inhibition. The significance of such a phenomenon is at present unknown, but it may be of biological relevance in view of the close topological and metabolic relationship between the two enzymes.

Animals↗
PubMed1989

Eradication of Mycoplasma contamination from cell lines of different origin by the 5-bromouracil-fluorochrome procedure.

Because mycoplasmas contaminate irreplaceable, established cell lines, several laboratories have been looking for effective procedures to eradicate the infection. This report presents the experience of our laboratory in using the 5-bromouracil-fluorochrome method developed by Marcus et al. which turned out to be effective in eliminating Mycoplasma orale, M. hyorhinis and M. hominis from transformed cell lines of different origin. The metastatic potential of a highly metastatic murine fibroblastic cell line infected with M. orale was restored to its original level after the contamination was eliminated.

Animals↗