Electrically detected displacement assay (EDDA): a practical approach to nucleic acid testing in clinical or medical diagnosis.

This paper introduces the electrically detected displacement assay (EDDA), a electrical biosensor detection principle for applications in medical and clinical diagnosis, and compares the method to currently available microarray technologies in this field. The sensor can be integrated into automated systems of routine diagnosis, but may also be used as a sensor that is directly applied to the polymerase chain reaction (PCR) reaction vessel to detect unlabeled target amplicons within a few minutes. Major aspects of sensor assembly like immobilization procedure, accessibility of the capture probes, and prevention from nonspecific target adsorption, that are a prerequisite for a robust and reliable performance of the sensor, are demonstrated. Additionally, exemplary results from a human papillomavirus assay are presented.

Determination of Q(A)-content in bacterial reaction centers: an indispensable requirement for quantifying B-branch charge separation

We have been able to determine the occupancy of the quinone site at the A-branch (Q(A)) of a reaction center preparation with an accuracy of 2%. This is achieved by accumulating the P(+)Q(-)(A) state after multiple actinic excitation and monitoring the extent of the 30 ms ground state bleaching. This bleaching is corrected for deviations from complete saturation due to competing charge separation to the B-branch. On the other hand, knowledge of the Q(A) content is indispensable for determining the yield of B-branch charge separation from nanosecond transients associated with the recombination of P(+)H(-)(B), which have to be corrected for the nanosecond signal originating from P(+)H(-)(A) of RCs having lost Q(A).

Triplet energy transfer in bacterial photosynthetic reaction centres.

[3-vinyl]-132-OH-bacteriochlorophyll a has been selectively exchanged against native bacteriochlorophyll a in the monomer binding sites at the A- and B-branch of the photosynthetic reaction centre from Rhodobacter sphaeroides. Transient absorption difference measurements were performed on these samples over a temperature range from 4.2 to 300 K with 20 ns time resolution. Specifically the decay of the primary donor triplet state, 3P870, as well as the rise and decay rates of the carotenoid triplet state, 3Car (spheroidene), were measured. The observed rates revealed a thermally activated carotenoid triplet formation corresponding to the decay of the primary donor triplet state. The activation energies for the triplet energy transfer process were 100(+/-10) cm-1 for reaction centers from wild-type Rhodobacter sphaeroides 2.4.1, with and without exchange of the monomeric bacteriochlorophyll on the electron transfer-active branch, BA. For reaction centers from Rhodobacter sphaeroides R26.1 with both monomers exchanged against [3-vinyl]-132-OH-bacteriochlorophyll a, and subsequent spheroidene reconstitution the activation energy was 460(+/-20) cm-1. These activation energies correspond to the energy difference between the triplet states of the accessory BChl monomer, BB, and the primary donor when native BChl a or [3-vinyl]-132-OH-BChl a is present in the BB binding site. In all samples the 3Car formation rates were bi-phasic over a large temperature range. A fast temperature-independent rate was observed on the wavelength of the carotenoid triplet-triplet absorption which dominated at very low temperatures. Additionally, a slower temperature-independent 3Car formation rate was observed at low temperatures which could be explained with the assumption of heterogeneity in the energy barrier (3BB) and/or the primary donor triplet state (3P870). A tunneling mechanism as proposed earlier by Kolaczkowski (PhD thesis, Brown University, 1989) is not only unnecessary but also incompatible with the available experimental data.

DNA-arrays with electrical detection: a label-free low cost technology for routine use in life sciences and diagnostics.

Fast and highly parallel DNA analysis are essential for improved biomedical research and development. Currently fluorescence-based methods are state of the art in DNA microarray analysis. The necessity to modify the target DNA with labels is costly, laborious and requires skilled personnel. Moreover, false positive calls from unspecific adsorption are possible and it is difficult to discriminate perfect matching target sequences from those with a single mismatch. In this paper a new and simple electrochemical approach for hybridisation detection without the need of labelling the target DNA is described. The EDDA (Electrically Detected Displacement Assay) method uses a solution of short redox-labelled signalling oligonucleotides (oligonucleotides carrying a covalently attached redox active compound like ferrocene) to characterize the hybridisation state of label-free capture probe DNA immobilised on gold electrodes. The number of capture probes associated with signalling oligonucleotides is determined by chronocoulometry. This technique allows to separate the electrochemical response of capture probe associated signal probes from the response of freely diffusing signalling probes. In the absence of the complementary target sequences the redox-labelled signalling probes at the surface give rise to an instantaneous increase of the detection signal, while freely diffusing signalling probes show a significantly delayed response. Hybridisation with targets complementary to the capture probe displace the loosely associated signalling probes thereby decreasing the instantaneous signal. Besides an introduction to the EDDA technology, data validating the method for biological material will be presented and an outlook to the detection of single nucleotide polymorphisms (SNPs) is given.

Epirubicin and ifosfamide in metastatic breast cancer.

In a randomized, phase II trial, we evaluated the effectiveness of continued chemotherapy with epirubicin/ ifosfamide versus unmaintained treatment interruption in advanced metastatic breast cancer. Three hundred fifty-seven patients were enrolled and 331 were evaluable for response. Complete response was achieved in 25 patients (8%) and partial response in 121 patients (37%). Pretreatment status correlated significantly with response (complete and partial response). While 54% of unpretreated patients responded, only 42% of the patients responded who had been pretreated with adjuvant chemotherapy and 33% who had been pretreated in the metastatic stage of disease; 69 patients (21%) had disease progression. Of 11 patients pretreated in both the adjuvant and metastatic setting, only two responded. Toxicity of treatment was mild, with leukopenia being the treatment-limiting factor. Thrombocyte levels were not altered significantly by treatment. Thus, there seems to be room for dose escalation using granulocyte colony-stimulating factor. There was no considerable cardiotoxicity, central nervous system toxicity, or cystitis observed. The low rate of cardiotoxicity appeared to be related to dose fractionation of epirubicin. After randomization of patients to treatment interruption versus continuation of chemotherapy, a longer relapse-free survival was observed for patients who continued chemotherapy (mean relapse-free survival, 2+ months); however, this did not translate into prolonged survival. The cumulative scores of toxicity and quality of life parameters showed increasing superiority for treatment interruption. Therefore, a strategy of treatment until maximum response and subsequent treatment interruption seems to be superior to treatment continuation.

Comparison of ftorafur with 5-fluorouracil in combination chemotherapy of advanced gastrointestinal carcinoma.

The aim of the study was to compare the combination 5-FU-carmustine with ftorafur-carmustine in the treatment of advanced gastrointestinal cancer. To this end, a prospective, multicenter, randomized trial was initiated. Part I of this trial showed that similar response rates can be obtained with 5-FU-carmustine and ftorafur-carmustine in 109 patients (32.7% versus 26.3%). However, median survival was better in patients treated with 5-FU-carmustine (307 days versus 163 days). Part II of the trial revealed that neither a higher dosage of ftorafur (2 g/m2/day X 5 days) nor the addition of vincristine to both regimens changed the previously obtained results significantly. Again, median survival was found to be better in patients treated with 5-FU combination chemotherapy (304 days versus 144 days). Both the 5-FU and the ftorafur combination were tolerated reasonably well. The results suggest that combination chemotherapy including 5-FU is superior to ftorafur at the applied dosages in terms of survival.

Triplet state energy transfer between the primary donor and the carotenoid in Rhodobacter sphaeroides R-26.1 reaction centers exchanged with modified bacteriochlorophyll pigments and reconstituted with spheroidene.

The dynamics of triplet energy transfer between the primary donor and the carotenoid were measured on several photosynthetic bacterial reaction center preparations from Rhodobacter sphaeroides: (a) wild-type strain 2.4.1, (b) strain R-26.1, (c) strain R-26.1 exchanged with 13(2)-hydroxy-[Zn]-bacteriochlorophyll at the accessory bacteriochlorophyll (BChl) sites and reconstituted with spheroidene and (d) strain R-26.1 exchanged with [3-vinyl]-13(2)-hydroxy-bacteriochlorophyll at the accessory BChl sites and reconstituted with spheroidene. The rise and decay times of the primary donor and carotenoid triplet-triplet absorption signals were monitored in the visible wavelength region between 538 and 555 nm as a function of temperature from 4 to 300 K. For the samples containing carotenoids, all of the decay times correspond well to the previously observed times for spheroidene (5 +/- 2 microseconds). The rise times of the carotenoid triplets were found in all cases to be biexponential and comprised of a strongly temperature-dependent component and a temperature-independent component. From a comparison of the behavior of the carotenoid-containing samples with that from the reaction center of the carotenoidless mutant Rb. sphaeroides R-26.1, the temperature-independent component has been assigned to the buildup of the primary donor triplet state resulting from charge recombination in the reaction center. Arrhenius plots of the buildup of the carotenoid triplet states were used to determine the activation energies for triplet energy transfer from the primary donor to the carotenoid. A model for the process of triplet energy transfer that is consistent with the data suggests that the activation barrier is strongly dependent on the triplet state energy of the accessory BChl pigment, BChlB.

[Type identity of the swine parasites Globocephalus longemucronatus and G. urosubulatus (Nematoda, Strongyloidea)]. / Zur Artidentität der Schweineparasiten Globocephalus longemucronatus und G. urosubulatus (Nematoda, Strongyloidea).

On the basis of a critical analysis of the literature and of our own investigations, it is pointed out that the two hookworm species known from European swine, namely Globocephalus longemucronatus Molin, 1861 and G. urosobulatus (Alessandrini, 1909), are identical. All the differences hitherto used to distinguish these species are shown to be due to incorrect descriptions of the taxonomic characters or to misinterpretations of statements made by former authors. Accordingly, only one species of Globocephalus occurs in Europe, which has to be named G. longemucronatus Molin, 1861, with Crassisoma urosubulatum Alessandrini, 1909 as its junior synonym. A short diagnosis of this species is given.

[Gamma globulin in secondary antibody deficiency syndrome]. / Gammaglobulin bei sekundärem Antikörper-Mangelsyndrom.

12 patients with secondary antibody deficiency syndrome received a new gammaglobulin compound intravenously (lyoph. SRK Sandoz). The drug was given in a 3% NaCl-solution once to four times. At the end of the infusion of 6 g gammaglobulin and after one week, serum levels were significantly higher. Gammaglobulin intravenously was well tolerated in all cases. Severe infections during the period of treatment were not observed.

[Chemotherapy of bronchial carcinoma]. / Chemotherapie des Bronchialkarzinoms.

Prognosis of bronchial carcinoma remains poor despite improved early diagnosis and campaigns of informing the public about the risk factors. In the majority of histological entities chemotherapy cannot change this situation. However, in case of oat cell carcinoma a high rate of responders together with prolongation of survival rate can be achieved by chemotherapy. The best results are obtained with combined chemotherapy and early radiation therapy.

[Plasmacytoma]. / Plasmozytom.

Plasmocytoma is generally a systemic disorder and has to be differentiated from solitary plasmocytoma of bones and connective tissue. Diagnosis is based on the typical bone marrow findings, the demonstration of monoclonal paraprotein and the radiological skeletal changes. Prognosis is poor, life expectancy limited to about 18 months. Specific therapy with cytotoxic drugs leads in many cases to marked improvement of the general condition, relative freedom of pain and a decreased complication rate.

[Ascaridia platyceri n.sp., a new species of nematode from parrots]. / Ascaridia platyceri n. sp., eine neue Spulwurmart aus Papageien.

A new species of bird parasitic nematode, Ascaridia platyceri n. sp., is described from the small intestine of Platycerus eximius and 8 further species of Psittacidae maintained in Zoological Gardens and private holdings in the GDR. The new species differs from the 3 species of Ascaridia hitherto known from parrots mainly in the shape of the anterior border of the lips as well as in the number and position of the caudal papillae in the male.

[Co-existence of chronic myeloid leukaemia and carcinoma of the breast (author's transl)]. / Gleichzeitiges Vorkommen von chronisch-myeloischer Leukämie und Mammakarzinom

Chronic myeloid leukaemia and carcinoma of the breast co-existed in three women. This combination is exceedingly rare. Although the cancerogenic properties of ionizing radiation and cytostatic drugs could be held responsible for the occurrence of two malignant tumours, no definitive conclusions can be drawn in the individual case. Co-existence of leukaemia and carcinoma does not occur more frequently than could be predicted statistically from the incidence of each.