Search PubMed⌕ Search

Biomedical subjects

S Ruggieri

Publications and source records attributed to S Ruggieri.

213 records · Page 12Linked to original sources
PubMedDate not supplied

Pyrimidine nucleotidases/phosphotransferases from human erythrocyte.

Two cytoplasmic pyrimidine 5'-nucleotidase have been purified from human erythrocytes to homogeneity and partially characterized. The two enzymes, indicated as PN-I and PN-II, preferentially hydrolyse pyrimidine 5'-monophosphates and 3'-monophosphates, respectively. The kinetic analysis demonstrate that pyrimidine 5'-nucleotidases, in the presence of suitable nucleoside substrates, can operate as phosphotransferases by transferring phosphate to various nucleoside acceptors, including nucleoside analogues known as important drugs widely used in chemotherapy.

5'-Nucleotidase↗
PubMedDate not supplied

Effect of phenobarbital on cerebral energy state and metabolism. Enzymatic activities.

The changes induced by phenobarbital in cerebral enzymatic activities of the Krebs' cycle (citrate synthase, malate dehydrogenase) and electron transfer chain (total NADH-cytochrome c reductase and cytochrome oxidase) were studied. In addition, the activity of lactate dehydrogenase of acetylcholine esterase and of glutamate dehydrogenase was also studied. These enzymatic activities were evaluated in the homogenate in toto and in a crude mitochondrial fraction from rat brain. The modifications in some of these activities indicate that several new metabolic situations occur in brain tissue after phenobarbital treatment.

Animals↗
PubMedDate not supplied

[Changes in the nigrostriatal dopamine receptor compartment after continuous dopaminergic infusions in Parkinson disease].

Motor fluctuations often complicate chronic levodopa treatment of Parkinson's disease. Pharmacologically, these phenomena are characterized by a progressive shortening of the duration of action of levodopa and a gradual narrowing of the range of "optimally effective" doses, able to improve parkinsonian akinesia without inducing abnormal involuntary movements. The effects of a continuous intravenous infusion of levodopa lasting 9 +/- 0.3 days on these clinical-pharmacological indices have been studied in 12 parkinsonian patients. Continuous infusion therapy gradually ameliorated motor fluctuations by more than 40%, and this improvement lasted for at least 6 days after resuming standard oral therapy. Moreover, levodopa duration of action was prolonged by about 30%, and the range of "optimally effective" dose was widened by about 50%. The above data suggest the possibility of plastic modifications of the pathogenetic mechanisms underlying motor fluctuations in Parkinson's disease, and a potential deleterious effect of intermittent oral therapy. Consequently, continuous dopaminergic stimulation, when used in the early stages of the disease, might theoretically have a prophylactic role on the development or worsening of motor fluctuations.

Aged↗
PubMedDate not supplied

Parkinsonian tremor: a neuropharmacological study.

In the Parkinsonian syndrome tremor is the symptom which still eludes pharmacological therapy. The authors report the results of nine cases of Parkinsonian tremor in which agonist and antagonist drugs acting on the receptors were employed. These were dopaminergics, acetylcholinergics, serotoninergics, histaminics, and alpha- and beta-adrenergics. The data obtained demonstrate the involvement of all the neurotransmitters studied, some directly through quantitative modifications, others indirectly through their involvement in reciprocal functional equilibria. A sytem of equilibria is hypothesized in which the histamine: serotonin ratio is given greater emphasis. (Acta neurol belg., 1977, 77, 213-229).

Acetylcholine↗
PubMedDate not supplied

Purification of cytidine deaminase from chicken liver.

Cytidine deaminase (cytidine aminohydrolase, EC 3.5.4.5) from chicken liver has been obtained in pure form through a rapid procedure consisting of organic solvent precipitation, heat treatment, anionic-exchange chromatography, hydrophobic interaction chromatography followed by two rapid chromatographies using an FPLC system. The final preparation is pure but shows microheterogeneity as judged by a single band obtained by SDS-gel electrophoresis and a series of superimposed active bands obtained on native gel electrophoresis and gel isoelectrofocusing. The native protein molecular weight determined by gel filtration is 50,000. SDS-gel electrophoresis experiments conducted in the presence and in the absence of reducing agents, suggest an oligomeric structure of four apparently identical subunits of 12,000 molecular weight. The absorption spectrum of the native protein reveals a maximum at 278 nm and a minimum at 261 nm with a small shoulder at 285 nm. The isoelectric point has an average value around pH 4.45.

Animals↗
PubMedDate not supplied

The clinical efficacy of a single afternoon dose of levodopa methyl ester: a double-blind cross-over study versus placebo.

Levodopa methyl ester (LDME) is a highly water soluble derivative produced by esterification of the carboxilic acid moiety of the L-Dopa molecule that is rapidly hydrolyzed to L-Dopa and can be administered orally in an easily dosable liquid form. In this study the relative efficacy and tolerability of a single dose of an oral solution of 250 mg of LDME was compared to that of placebo in reversing afternoon off period. A controlled double-blind cross-over study versus placebo had previously been carried out in 25 idiopathic parkinsonian patients with predictable fluctuations in motor performances. The study design stipulated the sequential administration of LDME and placebo in group A and placebo and LDME in group B on two consecutive days. All patients turned "on" with LDME and none with placebo solution. The mean latency to "on" was 25.3 +/- 13.5 min for the A group and 27.6 +/- 3.9 min for group B (Fig. 2) and the "on" duration was 147.7 +/- 50.3 min and 163.3 +/- 39.3 min for the A and B groups respectively. Five patients suffering from drug resistant "off" phenomena turned "on" with LDME solution showing a mean latency to "on" of 31.4 +/- 6.2 min.

Administration, Oral↗