Registers for Networked Medical Research in Germany: Situation and prospects

BACKGROUND

Several disease specific registers are operated by members of the 'TMF - Technology, Methods, and Infrastructure for Networked Medical Research', an umbrella organization of research networks in Germany.

OBJECTIVE

To describe the coverage and the current state as well as financial and organizational issues of registers operated by member networks of the TMF, to identify their requirements and needs, and to recommend best practice models.

METHODS

A survey with a self-completion questionnaire including all 55 TMF member networks was carried out in winter 2007/2008. Interviews focusing on technological issues were conducted and analyzed in summer 2009 with a convenience sample of 10 registers.

RESULTS

From 55 TMF member networks, 11 provided information about 14 registers. Six registers address diseases of the circulatory system with more than 150,000 registered patients. The interviews revealed a typical setting of "research registers". Research registers are an important mean to generate hypotheses for clinical research, to identify eligible patients, and to share data with clinical trials. Concerning technical solutions, we found a remarkable heterogeneity. The analysis of the most efficient registers revealed a structure with five levels as best practice model of register management: executive, operations, IT-management, software, hardware.

CONCLUSION

In the last ten years, the TMF member networks established disease specific registers in Germany mainly to support clinical research. The heterogeneity of organizational and technical solutions as well as deficits in register planning motivated the development of respective recommendations. The TMF will continue to assist the registers in quality improvement.

Odor input generates approximately 1.5 Hz and approximately 3 Hz spectral peaks in the helix pedal ganglion

In 1999 we reported that odorants evoke in the Helix pedal ganglion (PG) activity patterns which are largely odorant-specific and related to the nature of odor and its behavioral output. Notably, some activities (for example, approximately 1.5 and approximately 3 Hz), nonspecific to odorants, were consistently evoked in PG. The present contribution goes farther in a deeper survey of the intrinsic and odorant-evoked activities of PG with special weight on the nonspecific fluctuations. We address the following questions. (i) What are the features of the activities? (ii) Are they comparable to the activities found in the motor systems of the other invertebrates? (iii) To what functions can they be related? Three main frequency components represented by power peaks at <1 Hz, 1-2 Hz and 2-8 Hz seem to feature the response activities of PG. (a) The aversive odorants induce odorant-specific patterns represented by peak power frequencies at <1 Hz. (b) The oscillation at approximately 1 Hz, which exists intrinsically in the Helix PG, can be specifically enhanced by appetitive odors. Activities induced in the procerebrum (PC), the visceral ganglion (VG) and PG by appetitive odorants, such as ethanol and apple, peak at 1.3-2 Hz, whereas those induced by aversive ones, such as formic acid and onion at <1 Hz. (c) The 2-8 Hz components always accompany the odorant-evoked activities of the PG either as the second or third strongest component, or in the form of conspicuous, long-lasting approximately 3 Hz oscillations. (d) The nonspecific odor-evoked 1-2 Hz and approximately 3 Hz activities, and the intrinsic approximately 1 Hz activity of the PG seem to be interrelated by a degree of mutual exclusion. We may therefore consider these activities as elementary, slow components that are involved in the processing of signals in this ganglion. It can be inferred from the findings in other invertebrates that the 1-3 Hz spontaneous discharge is strongly connected with motor activity that involves the feedback mechanism of the procerebro-cerebro-buccal or -procerebro-cerebro-pedal circuit. Our approach differs from most others reported so far in the following aspects: (i) use of gross steel electrodes for recording population activities; (ii) lengthy stimulation (10 min); (iii) long observation during and after stimulation; (iv) power spectral presentation of temporal evolution of activity patterns; (v) estimation of peak power frequency by Frequency-Amplitude Plot (FAP) (obtained from signals averaged in the frequency domain; a method based on systems theory).

Development and validation of a sensitive and specific radioimmunoassay for the determination of cicaprost in biological samples

Cicaprost is a potent, chemically and metabolically stable PGI2-mimetic. Pharmacodynamic effects were observed after oral administration of approximately 10 micrograms in man when plasma levels were in the low pg-range. The present report describes the development of a selective antiserum and a tracer with high specific activity and their use for the RIA determination of Cicaprost in biological samples. Cicaprost-[3H]-methylester with a specific activity of 819 GBq/mmol was used as a tracer. RIA-analyses were carried out with 0.05-0.5 ml plasma adjusted to pH 2 with 1 N HCl and extracted with 2.5 ml diethylether. Separation of antiserum bound and unbound Cicaprost was achieved by the charcoal method. Extraction recovery of Cicaprost was approximately 90% at pH approximately 2. The detection limit of the assay was 10-20 pg/ml plasma. Coefficients of variations were 6, 3 and 9% (within-day, n = 5) and 25, 12 and 10% (day-to-day, n = 11) at 50, 100 and 200 pg/ml. HPLC-chromatograms of plasma extracts did not reveal any peak apart from Cicaprost, demonstrating the specificity of the method. The present RIA for Cicaprost exhibits high specificity and sensitivity and will be used for further bioanalyses in pharmacokinetic study.

Antineoplastic activity in vitro of free and liposomal alkylphosphocholines

We investigated the liposome forming properties of three homologues of alkylphosphocholines: hexadecylphosphocholine (HPC), octadecylphosphocholine (OPC) and eicosanylphosphocholine (EPC). In the presence of cholesterol and dicetylphosphate, alkylphosphocholines form liposomes with slow permeability for entrapped carboxyfluorescein. We studied the direct cytotoxicity of alkylphosphocholine vesicles and their ability to attack MethA sarcoma cells, human skin and muscle fibroblasts (M22, GUS, Moscow), and human mouth epidermoid carcinoma cells (KB, ATCC, CCL 17). All alkylphosphocholines show cytotoxic activity against the investigated cells, the degree of which depends on the number of carbon atoms in the alkyl chain, concentration and incubation time. Whereas the etherlipid liposomes are less toxic to MethA cells than the free compounds, the liposomal alkylphosphocholines are more toxic toward KB and M22 cells than the corresponding free lipids.

The effects of acetylcholine, dopamine and noradrenaline on the visceral ganglion of Helix pomatia. I. Ongoing compound field potentials of low frequencies

1. The question was addressed what effects do some neurotransmitters exert upon the ongoing compound activity of an organized invertebrate ganglion, such as the visceral ganglion of the gastropod mollusc, Helix, recorded with extracellular semimicroelectrodes in the neuropile, avoiding dominating single units. 2. Methods of analysis based on systems theory are used: the electrical activity of the snail brain is considered to be a summation of different measurable variables or subsystems (in this case, "frequency components"). Frequency components were analyzed by the Fourier transform and, for quantification of each component, root-mean-square (RMS)-voltage of digitally filtered signals. 3. Spontaneous discharge of the untreated ganglion shows RMS-voltage of less than 10 microV in the 1-50 Hz range, most frequently 3-7 microV. Energy extended far above 50 Hz, with less decline than in vertebrates, but was quantified only up to 80 Hz due to the wider fluctuations of RMS-voltage in the range greater than 50 Hz. 4. ACh (10(-5)-10(-3) M) induces strong, dose-related increase of activity with spontaneous frequency responses in a broad band between 2 and 20 Hz which accompany fluctuations of minor peakings frequently centering at 2-4, 4-8, 9-15 and 20 Hz. These frequency centers still remain but as an impression since a statistical study on the reality and position of the peaks has not yet been done. ACh-induced excitation seems to be rather transient: all frequency components except the 4-8 Hz component decrease within 4-6 min. 5. DA (10(-4)-10(-3) M) induces a dose-related increase in the low frequency range (1-15 Hz) which reaches a maximum within 4 min and remains relatively unchanged for as long as 10 min. 6. NA (10(-5)-10(-2) M) mainly depresses the ganglionic activity, though moderately, reducing all components (-25%). The action of NA on the Helix ganglion seems to incline more towards inhibition of firing than towards excitation, especially depressing the 15-48 Hz activity, whereas that on the mammalian brain is known to be enhancement of alpha (8-13 Hz)- and beta (15-30 Hz)-activities. 7. The activities observed in the present investigation at several lower frequency power peaks are also commonly found in the electrograms of vertebrates and the EEG of higher animals. The manner, in which ACh and DA influence these peaks in Helix pomatia, are very similar to what has been reported on the EEG of mammals.(ABSTRACT TRUNCATED AT 400 WORDS)

The effects of acetylcholine, dopamine and noradrenaline on the visceral ganglion of Helix pomatia—II. Stimulus evoked field potentials

1. Neurophysiological effects of acetylcholine (ACh), dopamine (DA) and noradrenaline (NA) on stimulus evoked field potentials in the Helix pomatia visceral ganglion were investigated. Electrical stimuli were applied to nerve trunks. 2. For frequency analysis of evoked potentials (EPs) the Fourier transform was performed. For quantification of pre- as well as poststimulus activities, root-mean-square (RMS)-voltages of digitally filtered signals were used. 3. ACh at 10(-4)-10(-3) M selectively enhances the 4-15 Hz as well as the 30-70 Hz components and DA at 10(-5)-10(-3) M increases the 30-70 Hz activity. NA at 10(-5)-10(-4) M augments the 15-30 Hz response and only at 10(-5) M increases the 30-48 Hz response. 4. All transmitters at 10(-2) M show a strong tendency to suppression. 5. Prestimulus activities of ACh and DA are damped by 40-50% compared to the ongoing induced activities in the non-stimulus study (cf. Part I). These damped prestimulus activities may be considered as a late part of the prolonged evoked activity. 6. The 4-15, 15-30 and 30-70 Hz responses selectively increased by the transmitters may be compared to theta-alpha combined rhythm, beta-rhythm and 40 Hz rhythm in the mammalian EEG.

Pharmacokinetics of 3H-cicaprost in healthy volunteers

Cicaprost (5-[(E)-(1S,5S,6S,7R)-7-hydroxy-6-[(3S,4S)-3-hydroxy-4-methylnona- 1,6- diinyl]-bicyclo[3.3.0]octan-3-yliden]-3-oxapentanoic acid, ZK 96 480) is a novel PGI2-derivative, which is chemically stable and not subject to metabolic degradation in rats and cynomolgus monkeys. The pharmacokinetics of Cicaprost were studied in six healthy volunteers (age: 54-74 y) after i.v. infusion (2.1 micrograms over 60 min) and p.o. dosage (7.6 micrograms) of the tritiated compound. All treatments were well-tolerated by the test subjects. At the end of the infusion plasma levels of approximately 100 pg/ml were reached, declining biphasically with half-lives of 3-4 min and 64 +/- 21 min. Total clearance was 3.8 +/- 0.5 ml/min/kg. The oral dosage resulted in peak plasma levels of 251 +/- 90 pg/ml occurring at 23 +/- 5 min post dose. The terminal half-life in the plasma was 115 +/- 30 min. Gastro-intestinal absorption and absolute bioavailability of Cicaprost was complete. After both routes of administration approx. 60% of dose was excreted with the urine within 24 h, whereas fecal 3H-excretion lasted for several days and accounted for approx. 35%. Radiochromatography revealed that Cicaprost was metabolically stable in plasma and urine. In the feces several degradation products were observed apart from approx. 30% of the dose fraction being excreted unchanged by that route. The present results demonstrate that Cicaprost is an orally completely bioavailable, metabolically stable PGI2-mimetic which may be an ideal candidate for oral therapy because of its pharmacokinetic characteristics.

[Pacemakers of the upper urinary tract using power spectral analysis of spontaneous activity]

Spontaneous activity of isolated smooth muscle strips of the upper urinary tract has been analysed by time series analysis. Frequency components of spontaneous contractions of the human urinary tract have been determined quantitatively by means of power spectral analysis. This method allows to characterise exact frequency components of rhythmicity in various parts of the urinary tract and accordingly helps to localise the site of various pacemakers. The results indicate tentatively the existence of two different pacemakers located in the wall of calix and pelvis. Furthermore, it is assumed that these pacemakers complement each other both cooperatively and by additive functioning, as though in shifts (reverberation), to stimulate urine transport through the pyeloureter.

A new approach to endogenous event-related potentials in man: relation between EEG and P300-wave

The family of late positive waves which occur at latencies of 250 to 500 msec (P300) has been the most widely studied endogenous event related potential of the brain. We performed experiments with human subjects by applying repetitive acoustical tone bursts; every third or fourth signal was omitted. The endogenous potential related to the omitted stimulation was first averaged. The averaged record was then transformed to frequency domain with Fourier analysis in order to obtain the frequency characteristics. We observed frequency selectivities between 1-2.5 Hz, 3-8 Hz and between 8-13 Hz. After this procedure, single epochs of prestimulus EEG and endogenous potentials were pass-band filtered in the above frequency ranges. The comparison of filtered prestimulus EEG and of single endogenous responses gave the following results: In delta and theta frequency ranges the EEG prior to omitted stimulation showed in most of the trials a phase-reordering; the P300-wave seems to be a continuation of the ordered and stationary pre-EEG. In some cases the P300-wave depicts an amplitude-enhancement against the delta and theta components of the pre-EEG. Alpha-enhancement and alpha-blocking also make important contributions to the organization of the endogenous event-related potentials.

[Peripheral T-lymphocytes and delayed hypersensitivity in surgically and radiologically treated patients with early stages of larynx-carcinoma]

122 patients with squamous-cell-carcinoma of the larynx (T1-stage) were examined after surgical or radiological treatment. None of these patients showed evidence of tumor recurrence. Peripheral T-lymphocytes and delayed hypersensitivity were studied in all these patients. According to their treatment, the patients were allotted into three groups and compared with a control group, consisting of 20 patients with nonneoplastic head- and neck-disease. The main finding was a significant decrease in the peripheral T-lymphocytes in surgically- or radiologically-treated patients with a squamous-cell-carcinoma of the larynx (T1-stage). This reduction of T-cells must be interpreted as a congenital or acquired defect of the immunocompetent system. In about half of the control cases the DNCB-tests showed no evidence of delayed hypersensitivity. In view of these results and those reported in the literature, the test should be used critically. In contrast to our earlier findings, where patients received radiotherapy over large areas including big vessels, radiation over a smaller, localised area does not lead to a significant depression of peripheral T-lymphocytes.

Age-dependent change of the effect of a cytostatic drug on the proliferation kinetics of a solid tumor of the mouse

The aim of the present investigations was to study the effectiveness of a cytostatic drug (VCR) during different phases of tumor growth (1st, 7th, 14th days a.t.) and at the periphery and at the centre of the tumor (on the 14th day a.t.). Furthermore the inducement of a partial synchronization in the proliferation of tumor cells was attempted. It was found that the intensity of the cytostatic effect significantly decreased both with the passage of time after transplantation and within the tumor from the periphery to the centre. The changing cytostatic sensitivity probably is due to the diminishing vascular supply and the decreased rate of cell proliferation; especially the decline of the growth fraction. A partial synchronization of the proliferation of tumor cells could not be demonstrated.

Dose-dependent biliary and renal excretion of paracetamol in the rat

In rats, the biliary and renal excretion of paracetamol changed in a dose-dependent manner. After an oral nonhepatotoxic dose of 200 mg/kg paractamol, the drug excreted in the bile amonted to only 5.5% within 24 h, whereas 72% of the dose were excreted into the urine. Following an oral hepatoxic dose (1,000 mg/kg), the biliary excretion of thotal paracetamol was enhanced to 13.5% whereas the renal elimination was reduced to 51% of the dose. After a nontoxic intravenous treatment with paracetamol (25-100-400 mg/kg), both the excretion of paracetamol conjugates into the bile and the elimination of free paracetamol into the urine were augmented in a dose-dependent manner. Hepatic damage due to carbon tetrachloride pretreatment (0.5 ml/kg i.p. 24 h before 100 mg/kg paracetamol i.v.) diminished both the bile flow and the biliary excretion of paracetamol conjugates, whereas the renal elimination was not affected.

A rapid gas-chromatographic method for the determination of drugs in clinical toxicology

A rapid gas-chromatographic method for the qualitative and quantitative measurement of various drugs in human plasma and other body fluids has been developed. The extraction procedure is done within 5 min, and gas-chromatographic measurement carried out on 2 diverse columns with detection by flame ionisation detectors. The detection sensitivity of most drugs is high enough to determine their plasma levels in suicidally or accidentally poisoned patients. As shown for 6 different drugs, the limit of detection, the reproducibility and the accuracy are sufficient even for analysis of therapeutical plasma concentrations.

Relations between hepatotoxicity and pharmacokinetics of paracetamol in rats and mice

A dose-dependent increase of paracetamol serum half-life (t1/2) was found after oral and intravenous application in rats and oral application in mice. The hepatotoxic effects of paracetamol were not correlated with this prolongation of t1/2. Dithiocarb protected rats against paracetamol liver damage but did not change paracetamol t1/2. Paracetamol t1/2 was not influenced either by a hepatotoxic dose of carbon tetrachloride. In conclusion, the dose-dependent prolongation of paracetamol serum half-life is not due to paracetamol-induced liver damage but merely the consequence of saturated elimination processes.