G.M. Frigo

Modifications of apoptosis-related protein levels in lymphocytes of patients with Parkinson’s disease. The effect of dopaminergic treatment

Summary.In this study, we investigated whether changes in the regulatory mechanisms of apoptosis and oxidative stress may be detected, peripherally, in patients with Parkinson’s disease (PD). For this purpose, we measured caspase-3 activity, Bcl-2 concentrations, peripheral benzodiazepine receptor (PBR) expression and Cu/Zn superoxide dismutase (SOD) concentrations in lymphocytes of untreated PD patients, patients treated only with L-Dopa or with L-Dopa and dopamine agonists and healthy volunteers. Caspase-3 activity was significantly increased in all PD patient groups. Patients treated with L-Dopa and dopamine agonists showed the lowest values of Bcl-2, coupled with the highest density of PBRs, while increased levels of Cu/Zn SOD were found in the group under monotherapy with L-Dopa. We also found, in PD patients, clear, negative correlations between Bcl-2 levels and both duration and severity of the disease. Our findings point to the existence of changes in the regulatory mechanisms of apoptosis in PD patients – observable outside the central nervous system – which seem to be modulated by the pharmacological treatment with dopaminergic agents.

An approach for the estimation of drug prescribing using the defined daily dose methodology and drug dispensation data

AbstractObjective: To test the hypothesis that comparison of defined daily dose (DDD) and drug user data may help to estimate drug exposure in a defined population and provide information about drug prescribing patterns. Methods and results: First, comparison of DDD figures with the number of apparent drug users (ADU, i.e., individuals for whom at least one prescription of the drug had been dispensed during a given time period) is demonstrated to correspond to the product of the prescribed daily dose (PDD) and the proportion of days in which the drug had been taken (days of treatment/days in a time period, D). The resulting equation (DDD/day)/ADU in a time period=PDD × D is then applied to the analysis of different sets of drug dispensation data. Examples show that this approach may be helpful to monitor drug prescribing patterns over time. Moreover, in definite situations, it may provide reliable estimates of either PDD or D. Conclusions: Comparison of DDD and drug user data is suggested to be a cost-effective strategy to monitor drug prescribing patterns from an epidemiological perspective, which may be useful to researchers involved in drug utilisation studies as well as to health authorities for monitoring and regulatory purposes.

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.

Interleukin-8 production induced by the endozepine triakontatetraneuropeptide in human neutrophils: role of calcium and pharmacological investigation of signal transduction pathways

The endozepine triakontatetraneuropeptide (TTN) induces intracellular calcium ([Ca(2+)](i)) changes and is chemotactic for human neutrophils (PMNs). Because interleukin-8 (IL-8) production is Ca(2+) dependent and can be induced by chemotactic stimuli, we have investigated the ability of TTN to induce IL-8 production in PMNs, as well as the signal transduction mechanisms involved. Our results show that TTN increases IL-8 release and IL-8 mRNA expression in a concentration- and time-dependent fashion, and these effects are prevented by the Ca(2+) chelator BAPTA-AM. TTN-induced [Ca(2+)](i) changes and IL-8 mRNA expression are sensitive to pertussis toxin, to the phospholipase C (PLC) inhibitor U73122 (but not to its inactive analogue U73343) and to the protein kinase C (PKC) inhibitor calphostin C. It is therefore suggested that TTN-induced IL-8 production in human PMNs results from a G protein-operated, PLC-activated [Ca(2+)](i) rise, and PKC contributes to this effect. These findings further support the possible role of TTN in the modulation of the inflammatory processes.

Role of neuronal and inducible nitric oxide synthases in the guinea pig ileum myenteric plexus during in vitro ischemia and reperfusion

Background  Intestinal ischemia and reperfusion (I/R) injury leads to abnormalities in motility, namely delay of transit, caused by damage to myenteric neurons. Alterations of the nitrergic transmission may occur in these conditions. This study investigated whether an in vitro I/R injury may affect nitric oxide (NO) production from the myenteric plexus of the guinea pig ileum and which NO synthase (NOS) isoform is involved.

Intracellular calcium changes induced by the endozepine triakontatetraneuropeptide in human polymorphonuclear leukocytes: role of protein kinase C and effect of calcium channel blockers

BackgroundThe endozepine triakontatetraneuropeptide (TTN) induces intracellular calcium ([Ca++]i) changes followed by activation in human polymorphonuclear leukocytes (PMNs). The present study was undertaken to investigate the role of protein kinase (PK) C in the modulation of the response to TTN by human PMNs, and to examine the pharmacology of TTN-induced Ca++ entry through the plasma membrane of these cells.ResultsThe PKC activator 12-O-tetradecanoylphorbol-13-acetate (PMA) concentration-dependently inhibited TTN-induced [Ca++]i rise, and this effect was reverted by the PKC inhibitors rottlerin (partially) and Ro 32-0432 (completely). PMA also inhibited TTN-induced IL-8 mRNA expression. In the absence of PMA, however, rottlerin (but not Ro 32-0432) per se partially inhibited TTN-induced [Ca++]i rise. The response of [Ca++]i to TTN was also sensitive to mibefradil and flunarizine (T-type Ca++-channel blockers), but not to nifedipine, verapamil (L-type) or ω-conotoxin GVIA (N-type). In agreement with this observation, PCR analysis showed the expression in human PMNs of the mRNA for all the α1 subunits of T-type Ca++ channels (namely, α1G, α1H, and α1I).ConclusionsIn human PMNs TTN activates PKC-modulated pathways leading to Ca++ entry possibly through T-type Ca++ channels.

In memoriam R.J. Domenjoz

On March 7 this year, Prof. Robert J. Domenjoz died at the age of 89 years. Pharmacology is extremely indebted to him. He founded the journal in 1959, which was named Medicina Experimentalis and some years later renamed Medicina et Pharmacologia Experimentalis still in the tradition that Latin was the medical language.