Protocols in expedited review: tackling the workload of ethics committees.

PURPOSE: This paper describes the experience of the Ethics Committee of the Medical University of Vienna, Austria, while managing the workload of clinical study applications. METHODS: An expedited review process was introduced for initial review of study protocols regarded as minimal risk interventions in March 2004. RESULTS: A total of 504 study protocols were submitted for review in 2003 and this number has increased to 743 in 2007. Two hundred sixty eight studies were classified as minimal risk in 2007 and allocated to a subgroup of the Committee for review. The time to full approval was shorter for these studies as compared to other protocols. CONCLUSIONS: Implementation of initial expedited review can improve the performance of an Ethics Committee. A framework to achieve a single opinion for multisite research of minimal risk interventions should be considered to facilitate these low risk studies.

Enhanced serotonin transporter function during depression in seasonal affective disorder.

Decreased synaptic serotonin during depressive episodes is a central element of the monoamine hypothesis of depression. The serotonin transporter (5-HTT, SERT) is a key molecule for the control of synaptic serotonin levels. Here we aimed to detect state-related alterations in the efficiency of 5-HTT-mediated inward and outward transport in platelets of drug-free depressed patients suffering from seasonal affective disorder (SAD). 5-HTT turnover rate, a measure for the number of inward transport events per minute, and tyramine-induced, 5-HTT-mediated outward transport were assessed at baseline, after 4 weeks of bright light therapy, and in summer using a case-control design in a consecutive sample of 73 drug-free depressed patients with SAD and 70 nonseasonal healthy controls. Patients were drug-naive or medication-free for at least 6 months prior to study inclusion, females patients were studied in the follicular phase of the menstrual cycle. All participants were genotyped for a 5-HTT-promoter polymorphism (5-HTTLPR) to assess the influence of this polymorphism on 5-HTT parameters. Efficiency of 5-HTT-mediated inward (p=0.014) and outward (p=0.003) transport was enhanced in depressed patients. Both measures normalized toward control levels after therapy and in natural summer remission. Changes in outward transport showed a clear correlation with treatment response (rho=0.421, p=0.001). Changes in inward transport were mediated by changes in 5-HTT transport efficiency rather than affinity or density. 5-HTTLPR was not associated with any of the 5-HTT parameters. In sum, we conclude that the 5-HTT is in a hyperfunctional state during depression in SAD and normalizes after light therapy and in natural summer remission.

Report of the 1st meeting of the "Vienna Initiative to Save European Academic Research (VISAER)".

The European Directive 2001/20/EC ("Clinical Trials Directive") was aimed at simplifying and harmonising European clinical research. The directive's attempt represents an important step because many European Member States lack national laws that specifically address details of research, but the goal has been only partly achieved. For academic investigators doing national or multi-national research the new European law and the requirements following its implementation are likely to have the opposite effect. Some areas seem to be of particular concern: trial sponsorship, the ethical review process, the participation of patients who are temporarily not able to consent in clinical trials, in particular the informed consent process, an accepted European registry for all clinical trials, insurance and pharmacovigilance. Furthermore there are fundamental problems of the conduct of clinical trials that could have been foreseen at the time of implementation of the new law, which are impeding academic basic clinical research. The bureaucratic burden for academic investigators has tremendously increased without representing any contribution to patients' safety or to the scientific value of research. Furthermore some large European academic trials cannot be conducted anymore due to the new regulations. This result in a reduction in the number of trials and additionally in a reduction in the number of patients enrolled in a study. European research and thus European patients will suffer from the loss of potential benefits of research. The Vienna Initiative to Save European Academic Research (VISEAR) brings together leading stakeholders from academic research groups and interested parties from industry, international organisations and regulatory authorities to focus on the issues of concern regarding the organisational and funding of academic clinical research in order to improve the development and use of medicines in Europe. The first step of the initiative was a meeting held on May 30, 2005 in Vienna. The resumés of the six parallel working groups are presented in this supplement of the Wiener Klinische Wochenschrift, a position paper with recommendations in relation to the EU Clinical Trials Directive and medical research involving incapacitated adults has been published separately.

Serotonin-transporter mediated efflux: a pharmacological analysis of amphetamines and non-amphetamines.

The physiological function of neurotransmitter transporter proteins like the serotonin transporter (SERT) is reuptake of neurotransmitter that terminates synaptic serotoninergic transmission. SERT can operate in reverse direction and be induced by SERT substrates including 5-HT, tyramine and the positively charged methyl-phenylpyridinium (MPP(+)), as well as the amphetamine derivatives para-chloroamphetamine (pCA) and methylene-dioxy-methamphetamine (MDMA). These substrates also induce inwardly directed sodium currents that are predominantly carried by sodium ions. Efflux via SERT depends on this sodium flux that is believed to be a prerequisite for outward transport. However, in recent studies, it has been suggested that substrates may be distinct in their properties to induce efflux. Therefore, the aim of the present study was a pharmacological characterization of different SERT substrates in uptake experiments, their abilities to induce transporter-mediated efflux and currents. In conclusion, the rank order of affinities in uptake and electrophysiological experiments correlate well, while the potencies of the amphetamine derivatives for the induction of efflux are clearly higher than those of the other substrates. These discrepancies can be only explained by mechanisms that can be induced by amphetamines. Therefore, based on our pharmacological observations, we conclude that amphetamines distinctly differ from non-amphetamine SERT substrates.

Amphetamines take two to tango: an oligomer-based counter-transport model of neurotransmitter transport explores the amphetamine action.

Amphetamine congeners [e.g., 3,4-methylenedioxymetamphetamine (MDMA), or "ecstasy"] are substrates for monoamine transporters (i.e., the transporters for serotonin, norepinephrine, and dopamine); however, their in vivo-action relies on their ability to promote monoamine efflux. The mechanistic basis for this counter transport remains enigmatic. We tested the hypothesis that outward transport is contingent on the oligomeric nature of neurotransmitter transporters by creating a concatemer of the serotonin transporter and the amphetamine-resistant GABA transporter. In cells expressing the concatemer, amphetamine analogs promoted GABA efflux and blunted GABA influx. In contrast, the natural substrates serotonin and GABA only cause mutual inhibition of influx via the other transporter moiety in the concatemer. GABA efflux through the concatemer that was promoted by amphetamine analogs was blocked by the protein kinase C inhibitors GF109203X (bisindoylmaleimide I) and Go6983 (2-[1-(3-dimethylaminopropyl)-5-methoxyindol-3-yl]-3-(1H-indol-3-yl)maleimide). Thus, based on our observations, we propose that, in the presence of amphetamine analogs, monoamine transporters operate as counter-transporters; influx and efflux occur through separate but coupled moieties. Influx and efflux are coupled via changes in the ionic gradients, but these do not suffice to account for the action of amphetamines; the activity of a protein kinase C isoform provides a second stimulus that primes the inward facing conformation for outward transport.

The necessity and the value of placebo.

The use of placebo in clinical trials has been repeatedly challenged as being unacceptable from an ethical point of view. The present paper responds to this criticism by taking up the issue in the light of the pertinent provisions of the Helsinki Declaration. Examples from different therapeutic areas are given that highlight the importance of placebo in situations in which its use is acceptable according to the Declaration. Particular emphasis is given to the question of active control trials, which, under conditions of low assay sensitivity, may become an ethically less acceptable approach than the use of a placebo control.

The role of zinc ions in reverse transport mediated by monoamine transporters.

The human dopamine transporter (hDAT) contains an endogenous high affinity Zn2+ binding site with three coordinating residues on its extracellular face (His193, His375, and Glu396). Upon binding to this site, Zn2+ causes inhibition of [3H]1-methyl-4-phenylpyridinium ([3H]MPP+) uptake. We investigated the effect of Zn2+ on outward transport by superfusing hDAT-expressing HEK-293 cells preloaded with [3H]MPP+. Although Zn2+ inhibited uptake, Zn2+ facilitated [3H]MPP+ release induced by amphetamine, MPP+, or K+-induced depolarization specifically at hDAT but not at the human serotonin and the norepinephrine transporter (hNET). Mutation of the Zn2+ coordinating residue His(193) to Lys (the corresponding residue in hNET) eliminated the effect of Zn2+ on efflux. Conversely, the reciprocal mutation (K189H) conferred Zn2+ sensitivity to hNET. The intracellular [3H]MPP+ concentration was varied to generate saturation isotherms; these showed that Zn2+ increased V(max) for efflux (rather than K(M-Efflux-intracellular)). Thus, blockage of inward transport by Zn2+ is not due to a simple inhibition of the transporter turnover rate. The observations provide evidence against the model of facilitated exchange-diffusion and support the concept that inward and outward transport represent discrete operational modes of the transporter. In addition, they indicate a physiological role of Zn2+, because Zn2+ also facilitated transport reversal of DAT in rat striatal slices.

Bi-directional transport of GABA in human embryonic kidney (HEK-293) cells stably expressing the rat GABA transporter GAT-1.

1. Bi-directional GABA-transport was studied by performing uptake and superfusion experiments in human embryonic kidney 293 cells stably expressing the rat GABA transporter rGAT-1. 2. K(M) and V(max) values for [(3)H]-GABA uptake were 11.7+/-1.8 microM and 403+/-55 pmol min(-1) 10(-6) cells (n=9), respectively. 3. Kinetic analysis of outward transport was performed by pre-labelling the cells with increasing concentrations of [(3)H]-GABA and triggering outward transport with 333 microM GABA. Approximate apparent K(M) and V(max) values were 12 mM and 50 pmol min(-1) 10(-6) cells, respectively. 4. GABA re-uptake inhibitors (RI; e.g. tiagabine), as well as, substrates of the rGAT-1 (e.g. GABA, nipecotic acid) concentration dependently decreased [(3)H]-GABA uptake and increased efflux of [(3)H]-GABA from pre-labelled cells. The IC(50) values for inhibiting uptake and the EC(50) values for increasing efflux were significantly correlated (r(2)=0.99). 5. On superfusion, RI antagonized the efflux-enhancing effect of the substrates. The effect of the latter was markedly augmented in the presence of ouabain (100 microM), whereas the effect of RI remained unchanged. The most likely explanation for the release enhancing effect of RI is interruption of ongoing re-uptake. 6. The structural GABA-analogue 2,4-diamino-n-butyric acid (DABA) exhibited a bell-shaped concentration response curve on [(3)H]-GABA efflux with the maximum at 1 mM, and displayed a deviation from the sigmoidal inhibition curve in uptake experiments in the same concentration range. At concentrations below 1 mM, DABA inhibited [(3)H]-GABA uptake non-competitively, while at 1 mM and above the inhibition of uptake followed a competitive manner. 7. The results provide information of GABA inward and outward transport, and document a complex interaction of the rGAT-1 with its substrate DABA.