Deletion of Tbc1d4/As160 abrogates cardiac glucose uptake and increases myocardial damage after ischemia/reperfusion.

BACKGROUND: Type 2 Diabetes mellitus (T2DM) is a major risk factor for cardiovascular disease and associated with poor outcome after myocardial infarction (MI). In T2DM, cardiac metabolic flexibility, i.e. the switch between carbohydrates and lipids as energy source, is disturbed. The RabGTPase-activating protein TBC1D4 represents a crucial regulator of insulin-stimulated glucose uptake in skeletal muscle by controlling glucose transporter GLUT4 translocation. A human loss-of-function mutation in TBC1D4 is associated with impaired glycemic control and elevated T2DM risk. The study's aim was to investigate TBC1D4 function in cardiac substrate metabolism and adaptation to MI. METHODS: Cardiac glucose metabolism of male Tbc1d4-deficient (D4KO) and wild type (WT) mice was characterized using in vivo [18F]-FDG PET imaging after glucose injection and ex vivo basal/insulin-stimulated [3H]-2-deoxyglucose uptake in left ventricular (LV) papillary muscle. Mice were subjected to cardiac ischemia/reperfusion (I/R). Heart structure and function were analyzed until 3 weeks post-MI using echocardiography, morphometric and ultrastructural analysis of heart sections, complemented by whole heart transcriptome and protein measurements. RESULTS: Tbc1d4-knockout abolished insulin-stimulated glucose uptake in ex vivo LV papillary muscle and in vivo cardiac glucose uptake after glucose injection, accompanied by a marked reduction of GLUT4. Basal cardiac glucose uptake and GLUT1 abundance were not changed compared to WT controls. D4KO mice showed mild impairments in glycemia but normal cardiac function. However, after I/R D4KO mice showed progressively increased LV endsystolic volume and substantially increased infarction area compared to WT controls. Cardiac transcriptome analysis revealed upregulation of the unfolded protein response via ATF4/eIF2α in D4KO mice at baseline. Transmission electron microscopy revealed largely increased extracellular matrix (ECM) area, in line with decreased cardiac expression of matrix metalloproteinases of D4KO mice. CONCLUSIONS: TBC1D4 is essential for insulin-stimulated cardiac glucose uptake and metabolic flexibility. Tbc1d4-deficiency results in elevated cardiac endoplasmic reticulum (ER)-stress response, increased deposition of ECM and aggravated cardiac damage following MI. Hence, impaired TBC1D4 signaling contributes to poor outcome after MI.

[Radiculomyelopathy in schistosomiasis]. / Radikulomyelopathie bei Schistosomiasis.

The increasing migration of people from their homeland in far distant regions to Europe in the last few years has strongly influenced the rise of previously rarely seen diseases. They not only originate from the respective homeland but also from the transit countries during the migration process. We report the case of a 27-year-old male migrant from Eritrea, who after months of flight as a refugee travelling through various African countries, presented at our hospital with a progressive, painful radiculopathy. Whole spine magnetic resonance imaging (MRI) showed a focus located in the myelon, extending from T11 to the medullary conus. The differential diagnostic clarification ultimately revealed an infection with Schistosoma mansoni. After guideline-conform treatment with praziquantel for 3 days and additional administration of corticosteroids for 3 months, a slow regression of the findings and improvement of the symptoms could be shown clinically and by MRI. This case study shows the importance of taking the medical history and that a closer look at the potential exposure in the homeland and transit countries should be of great benefit in reaching the diagnosis, especially in patients with a migration background.

In vivo analysis of neuroinflammation in the late chronic phase after experimental stroke.

BACKGROUND AND PURPOSE: In vivo imaging of inflammatory processes is a valuable tool in stroke research. We here investigated the combination of two imaging modalities in the chronic phase after cerebral ischemia: magnetic resonance imaging (MRI) using intravenously applied ultra small supraparamagnetic iron oxide particles (USPIO), and positron emission tomography (PET) with the tracer [(11)C]PK11195. METHODS: Rats were subjected to permanent middle cerebral artery occlusion (pMCAO) by the macrosphere model and monitored by MRI and PET for 28 or 56 days, followed by immunohistochemical endpoint analysis. To our knowledge, this is the first study providing USPIO-MRI data in the chronic phase up to 8 weeks after stroke. RESULTS: Phagocytes with internalized USPIOs induced MRI-T2(∗) signal alterations in the brain. Combined analysis with [(11)C]PK11195-PET allowed quantification of phagocytic activity and other neuroinflammatory processes. From 4 weeks after induction of ischemia, inflammation was dominated by phagocytes. Immunohistochemistry revealed colocalization of Iba1+ microglia with [(11)C]PK11195 and ED1/CD68 with USPIOs. USPIO-related iron was distinguished from alternatively deposited iron by assessing MRI before and after USPIO application. Tissue affected by non-phagocytic inflammation during the first week mostly remained in a viably vital but remodeled state after 4 or 8 weeks, while phagocytic activity was associated with severe injury and necrosis accordingly. CONCLUSIONS: We conclude that the combined approach of USPIO-MRI and [(11)C]PK11195-PET allows to observe post-stroke inflammatory processes in the living animal in an intraindividual and longitudinal fashion, predicting long-term tissue fate. The non-invasive imaging methods do not affect the immune system and have been applied to human subjects before. Translation into clinical applications is therefore feasible.

Device for simultaneous positron emission tomography, laser speckle imaging and RGB reflectometry: validation and application to cortical spreading depression and brain ischemia in rats.

Brain function critically relies on the supply with energy substrates (oxygen and glucose) via blood flow. Alterations in energy demand as during neuronal activation induce dynamic changes in substrate fluxes and blood flow. To study the complex system that regulates cerebral metabolism requires the combination of methods for the simultaneous assessment of multiple parameters. We developed a multimodal imaging device to combine positron emission tomography (PET) with laser speckle imaging (LSI) and RGB reflectometry (RGBR). Depending on the radiotracer, PET provides 3-dimensional quantitative information of specific molecular processes, while LSI and RGBR measure cerebral blood flow (CBF) and hemoglobin oxygenation at high temporal and spatial resolution. We first tested the functional capability of each modality within our system and showed that interference between the modalities is negligible. We then cross-calibrated the system by simultaneously measuring absolute CBF using (15)O-H2O PET (CBF(PET)) and the inverse correlation time (ICT), the LSI surrogate for CBF. ICT and CBF(PET) correlated in multiple measurements in individuals as well as across different animals (R(2)=0.87, n=44 measurements) indicating that ICT can be used for absolute quantitative assessment of CBF. To demonstrate the potential of the combined system, we applied it to cortical spreading depression (CSD), a wave of transient cellular depolarization that served here as a model system for neurovascular and neurometabolic coupling. We analyzed time courses of hemoglobin oxygenation and CBF alterations coupled to CSD, and simultaneously measured regional uptake of (18)F-2-fluoro-2-deoxy-D-glucose ((18)F-FDG) used as a radiotracer for regional glucose metabolism, in response to a single CSD and to a cluster of CSD waves. With this unique combination, we characterized the changes in cerebral metabolic rate of oxygen (CMRO2) in real-time and showed a correlation between (18)F-FDG uptake and the number of CSD waves that passed the local tissue. Finally, we examined CSD spontaneously occurring during focal ischemia also referred to as peri-infarct depolarization (PID). In the vicinity of the ischemic territory, we observed PIDs that were characterized by reduced CMRO2 and increased oxygen extraction fraction (OEF), indicating a limitation of oxygen supply. Simultaneously measured PET showed an increased (18)F-FDG uptake in these regions. Our combined system proved to be a novel tool for the simultaneous study of dynamic spatiotemporal alterations of cortical blood flow, oxygen metabolism and glucose consumption under normal and pathologic conditions.

Sexual quality of life in Hodgkin Lymphoma: a longitudinal analysis by the German Hodgkin Study Group.

BACKGROUND: Health-related quality of life (HRQoL) comprises different domains of physical, mental, and social well-being. In this analysis, we focus on sexual quality of life in Hodgkin Lymphoma (HL) patients. METHODS: Four-thousand one-hundred and sixty patients enroled in the HD10-HD12 trials underwent HRQoL assessment. Instruments included the Quality of Life Questionnaire for survivors (QLQ-S), combining the European Organisation for Research and Treatment of Cancer QLQ-C30, Multidimensional fatigue (FA) inventory (MFI-20) and an additional sexual functioning (SX) scale. We describe SX up to 27 months after therapy and analyse relationship to stage, age, gender, FA, social functioning, and therapy. Statistical methods range from descriptive statistics to a classification of SX courses, and a longitudinal structural equations model with full information maximum likelihood estimation of missing data. In the analysis, a score below 50 was used to describe severe sexual dysfunction. RESULTS: Three-thousand two-hundred and eight patients provided data on SX. Patients in advanced stages reported lower SX than patients in early stages both, before and after the treatment. During follow-up, an improvement of SX compared with baseline was detected, except for those ≥50 years. Patients in early stages reached normal SX, whereas advanced-stage patients remained below the reference value for healthy controls. Sexual functioning during follow-up was significantly and strongly related to previous SX, other HRQoL measures, age, and stage, and to lesser degree with gender and chemotherapy. CONCLUSION: Overall, HL patients have a decreased sexual quality of life at baseline, which improves after therapy and normalises in early-stage patients. Importantly, long-term SX is more closely related to patient characteristics and SX at baseline than to the intensity of treatment.

Effects of minocycline on endogenous neural stem cells after experimental stroke.

Minocycline has been reported to reduce infarct size after focal cerebral ischemia, due to an attenuation of microglia activation and prevention of secondary damage from stroke-induced neuroinflammation. We here investigated the effects of minocycline on endogenous neural stem cells (NSCs) in vitro and in a rat stroke model. Primary cultures of fetal rat NSCs were exposed to minocycline to characterize its effects on cell survival and proliferation. To assess these effects in vivo, permanent cerebral ischemia was induced in adult rats, treated systemically with minocycline or placebo. Imaging 7 days after ischemia comprised (i) Magnetic Resonance Imaging (MRI), assessing the extent of infarcts, (ii) Positron Emission Tomography (PET) with [(11)C]PK11195, characterizing neuroinflammation, and (iii) PET with 3'-deoxy-3'-[(18)F]fluoro-L-thymidine ([(18)F]FLT), detecting proliferating endogenous NSCs. Immunohistochemistry was used to verify ischemic damage and characterize cellular inflammatory and repair processes in more detail. In vitro, specific concentrations of minocycline significantly increased NSC numbers without increasing their proliferation, indicating a positive effect of minocycline on NSC survival. In vivo, endogenous NSC activation in the subventricular zone (SVZ) measured by [(18)F]FLT PET correlated well with infarct volumes. Similar to in vitro findings, minocycline led to a specific increase in endogenous NSC activity in both the SVZ as well as the hippocampus. [(11)C]PK11195 PET detected neuroinflammation in the infarct core as well as in peri-infarct regions, with both its extent and location independent of the infarct size. The data did not reveal an effect of minocycline on stroke-induced neuroinflammation. We show that multimodal PET imaging can be used to characterize and quantify complex cellular processes occurring after stroke, as well as their modulation by therapeutic agents. We found minocycline, previously implied in attenuating microglial activation, to have positive effects on endogenous NSC survival. These findings hold promise for the development of novel treatments in stroke therapy.

A fully automated two-step synthesis of an (18)F-labelled tyrosine kinase inhibitor for EGFR kinase activity imaging in tumors.

Radiolabelled epidermal growth factor receptor (EGFR) tyrosine kinase (TK) inhibitors potentially facilitate the assessment of EGFR overexpression in tumors. Since elaborate multi-step radiosyntheses are required for (18)F-labelling of EGFR-specific anilinoquinazolines we report on the development of a two-step click labelling approach that was adapted to a fully automated synthesis module. 6-(4-N,N-Dimethylaminocrotonyl)amido-4-(3-chloro-4-fluoro)phenylamino-7-{3-[4-(2-[(18)F]fluoroethyl)-2,3,4-triazol-1-yl]propoxy}quinazoline ([(18)F]6) was synthesized via Huisgen 1,3-dipolar cycloaddition between 2-[(18)F]fluoroethylazide ([(18)F]4) and the alkyne modified anilinoquinazoline precursor 5. PET images of PC9 tumor xenograft using the novel biomarker showed promising results to visualize EGFR overexpression.

Successful treatment of drooling in children with neurological disorders with botulinum toxin A or B.

Drooling is a common and severe problem in children with neurological disorders and is caused by a disturbed coordination of orofacial and palatolingual muscles. Botulinum toxin could be a successful option to reduce excessive sialorrhea in children with neurological disorders. In 30 children with cerebral palsy or neurodegenerative disorder we injected under ultrasound guidance either botulinum toxin A or botulinum toxin B into the parotid and submandibular glands on both sides. All injections were well tolerated without general anaesthesia. Drooling severity at baseline and reduction of sialorrhea during treatment was measured using a parent's questionnaire and rated using the Teachers Drooling Scale (TDS). Reduction of sialorrhea was achieved two weeks after injection, with a positive effect lasting about three to four months in most children. 83% showed a good response to botulinum toxin after first injection, but only in 50% treatment was continued. We found no significant differences between botulinum toxin A or B. Side effects were observed in 5 children with viscous saliva and in one child a unilateral parotitis was observed. Treatment of drooling with botulinum toxin into the salivary glands is a safe and easy therapeutic option for children with neurological disorders to improve life quality.

Male gonadal dysfunction in patients with Hodgkin's disease prior to treatment.

UNLABELLED: Infertility after treatment of patients with Hodgkin's disease (HD) is considered as a side effect of alkylating agent containing chemotherapy regimens. To investigate whether gonadal failure is related primarily to the toxic effect of chemotherapy or rather to the disease itself, we investigated the fertility status before the onset of treatment. PATIENTS AND METHODS: Semen quality and hormonal status were evaluated in 158 patients with first diagnosis of HD enrolled into trials of the German Hodgkin Lymphoma Study Group (GHSG). The median age of the patients was 28 years (range 16-52). Twenty patients (13%) were classified as early stage HD, 63 patients (40%) as intermediate stage, and 75 patients (47%)) as advanced stage according GHSG grading. Sixty-seven patients (42%) showed systemic symptoms. Semen analysis was performed according to WHO guidelines. Follicle-stimulating hormone (FSH) and luteinising hormone (LH) plasma levels were measured by specific double-antibody radio-immune-assay (RIA) methods. RESULTS: Prior to treatment, severe damage of fertility, i.e.. azoospermia and oligoasthenoteratospermia (OAT-syndrome) was found in 13 (8%) and 20 patients (13%), respectively. Thirty-eight patients (24%) had single, i.e., oligo-(O), astheno-(A) or teratospermia-(T), and 40 patients (26%) showed combined damages, i.e., OA, OT or AT. In 47 patients (30%) a normal sperm count was found. Thus, III patients (70%) showed semen abnormalities before the onset of treatment. In a multivariate analysis elevated ESR (P < 0.003) and advanced stage of disease (P < 0.01) could be distinguished as prognostic factors for severe damage of fertility. No correlation was found between pre-therapeutic gonadotropine levels and fertility status. CONCLUSION: Patients with HD have an increased risk for inadequate semen quality even prior to treatment. Infertility is more frequent in patients with elevated ESR and advanced stage of disease. This association demonstrates the predominant influence of the disease on fertility. Assuming HD is the major initial cause for infertility efforts should be made to identify new non-gonadal toxic chemotherapies to be able to regain fertility after effective therapy. Further investigations have to be performed to clarify mechanisms inducing fertility defects in patients with HD.

In vitro activities of fluoroquinolones against the spirochete Borrelia burgdorferi.

Little is known to date about the in vitro activity of fluoroquinolones against Borrelia species. Our study aimed at determining the in vitro activities of 15 quinolones against nine isolates of the Borrelia burgdorferi sensu lato complex in addition to one Borrelia valaisiana and one Borrelia bissettii tick isolate. For the determination of MICs, a standardized colorimetric microdilution method was applied. Determination of minimal borreliacidal concentrations providing 100% killing of the final inoculum (MBCs) after 72 h and time-kill experiments were performed by conventional culture in Barbour-Stoenner-Kelly medium in combination with dark-field microscopy. The rank order of potency on a microgram-per-milliliter basis for the substances with in vitro activity against B. burgdorferi was gemifloxacin (MIC at which 90% of the isolates tested are inhibited [MIC(90)], 0.12 microg/ml) > sitafloxacin (MIC(90), 0.5 microg/ml), grepafloxacin (MIC(90), 0.5 microg/ml) > gatifloxacin (MIC(90), 1 microg/ml), sparfloxacin (MIC(90), 1 microg/ml), trovafloxacin (MIC(90), 1 microg/ml) > moxifloxacin (MIC(90), 2 microg/ml), ciprofloxacin (MIC(90), 2 microg/ml) > levofloxacin (MIC(90), 4 microg/ml) > ofloxacin (MIC(90), 8 microg/ml), norfloxacin (MIC(90), 8 microg/ml) > fleroxacin (MIC(90), >16 microg/ml), and pefloxacin (MIC(90), 32 microg/ml) > nalidixic acid (MIC(90), 256 microg/ml). After 72 h of exposure, gemifloxacin was borreliacidal (100% killing) against the isolates investigated at a median MBC of 4 microg/ml. In the other compounds tested, median MBCs were higher (> or =8 microg/ml). Results of electron microscopy and time-kill studies clearly support an in vitro activity of some fluoroquinolones against borreliae. Our study demonstrates for the first time the enhanced in vitro effectiveness of some of the recently introduced 4-quinolones against B. burgdorferi.

A miniaturised semiautomated system for the identification of Yersinia species within the genus Yersinia.

Commercially available identification systems based on biochemical reactions of bacteria are not suited for typing the species of the genus Yersinia (Y.) or the biovars (BV) of the species Y. enterocolitica. This failure is caused by the limited number of biochemical reactions applied, resulting in the absence of important discriminatory key reactions. The MICRONAUT identification system (Merlin, Bornheim-Hersel) makes use of dried substrates/enzymes reactions in the wells of a 96-well microtitration plate, reading of the results by a scanner device and typing of the isolate by the calculation of probabilities according to a data base. For this study a special identification panel was designed on which 38 substrates and enzyme reactions were configurated including 20 reactions for the identification of the species of the genus and the Y. enterocolitica biovars. The database was calculated using the results obtained from a total of 250 Yersinia strains of the eleven species of the genus. Reevaluation of the results of these strains revealed an overall sensitivity of 98%, as only four strains were not identified satisfactorily. Considering also questionable results the sensitivity was still 85%. The system was also used to identify Y. pestis isolates, but in this case reading was done visually. The printouts usually cite species designation, identification quality and probabilities. The sealing of the plates in an aluminium bag guarantees long life and long lasting quality. However, an evaluation of the system with a considerable number of strains has to be done in a next step. The 'Yersinia identification set' can replace time-consuming tube testing in the future and is a big step forward towards a sensitive identification of Yersinia isolates in the routine laboratory.

Prognostic factors for subdiaphragmatic involvement in clinical stage I-II supradiaphragmatic Hodgkin's disease: a retrospective analysis of the GHSG.

BACKGROUND: Staging laparotomy and splenectomy were routinely performed in patients with early-stage Hodgkin's disease (HD) qualifying for radiotherapy alone to determine the exact extent of disease. However, staging laparotomy is associated with a considerable number of side effects, warranting more sophisticated diagnostic procedures and new therapy strategies. We retrospectively analyzed patients undergoing staging laparotomy to identify pretherapy risk factors predicting the probability of abdominal disease and to define high-risk groups that might benefit from staging laparotomy and subsequent stage-adjusted treatment. PATIENTS AND METHODS: Between February 1988 and January 1993, 391 patients with CS I-II supradiaphragmatic Hodgkin's disease underwent staging laparotomy and splenectomy according to the treatment policy of the German Hodgkin's Lymphoma Study Group (GHSG) for early stages of Hodgkin's disease. Univariate and multivariate analysis of pretherapeutic clinical characteristics were performed in an attempt to predict staging laparotomy results and to identify risk groups. RESULTS: Of the 391 patients, 81 (21%) had subdiaphragmatic disease. Eighteen percent were upstaged to PS III and three percent to PS IV. By a multivariate model the following parameters were independent risk factors for positive surgical staging: left cervical involvement (P < 0.001), mediastinal involvement (P < 0.009), Karnofsky performance status (P < 0.004) and histology (P < 0.04). In our analysis gender (P < 0.08) and ESR (P < 0.06), often described as of high prognostic value, was not significant. The presence of systemic symptoms, number of involved areas and clinical stage were not associated with abdominal disease, as described in several former publications. To define high-risk groups, which comprise at least 15% of patients of the cohort and have a risk of subdiaphragmatic involvement of > 35%, combinations of only two or three of the predictive factors were analyzed. With respect to these criteria the following subgroups of patients were identified as having a high risk for subdiaphragmatic disease (> 35%): a) left cervical lymph node involvement and no mediastinal involvement (n = 98, observed risk 36%); b) no mediastinal involvement and MC/LD histology (n = 113, observed risk 40%). CONCLUSIONS: We conclude that initial clinical characteristics are predictive for occult abdominal involvement in early clinical stages of Hodgkin's disease. The impact of these risk factors on future therapeutical strategies have to be evaluated.

Dose-response relationship of complementary radiotherapy following four cycles of combination chemotherapy in intermediate-stage Hodgkin's disease.

PURPOSE: To determine the appropriate irradiation dose after four cycles of modern combination chemotherapy in nonbulky involved field (IF/BF) and noninvolved extended-field (EF/IF) sites in patients with intermediate-stage Hodgkin's disease (HD). MATERIALS AND METHODS: HD patients in stage I to IIIA with a large mediastinal mass, E stage, or massive spleen involvement were treated with two double cycles of alternating cyclophosphamide, vincristine, procarbazine, and prednisone (COPP) plus doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) followed by EF irradiation in two successive trials (HD1 and HD5). In the HD1 trial (1983 to 1988), 146 patients who responded to chemotherapy were randomized to receive 20 Gy (70 patients) or 40 Gy (76 patients) of EF irradiation in all fields outside bulky disease sites. A cohort of 111 patients who fulfilled the same inclusion criteria in the subsequent trial HD5 (1988 to 1993) were treated with 30 Gy. Bulky disease always received 40 Gy. RESULTS: Freedom-from-treatment-failure (FFTF) and survival (SV) curves showed no differences between the 20-, 30-, and 40-Gy groups. However, acute toxicities were more frequent in the 40-Gy arm. Analysis of relapse patterns showed that 18 of 26 relapsing patients either failed to respond in initial bulky sites (n = 5) or had an extranodal relapse (n = 9) or both (n = 4). After 5 years, the cumulative risk for relapse in bulky sites is 10%, despite 40 Gy of radiation. CONCLUSION: Our results strongly suggest that there is no relevant radiotherapy dose effect in the range between 20 Gy and 40 Gy in IF/BF and EF/IF after 4 months of modern polychemotherapy in patients with intermediate-stage HD. Relapse patterns indicate that patients destined to relapse need more systemic, rather than local, treatment. Based on our data, we conclude that 20 Gy is sufficient in EF/IF of intermediate-stage HD following four cycles of modern polychemotherapy.

Combinations of the alpha-helix-turn-alpha-helix motif of TetR with respective residues from LacI or 434Cro: DNA recognition, inducer binding, and urea-dependent denaturation.

We constructed 10 different variants of TetR by substituting all or some of the residues in the alpha-helix-turn-alpha-helix (HTH) operator binding motif with the respective amino acids from LacI or 434Cro. The variants were soluble, negative transdominant over tetR in vivo, and as active as wild-type TetR in tetracycline binding in vitro. The urea-induced denaturation of the 10 variants occurs in single reversible transitions, which are centered around 4.3 M urea. Denaturation is concentration-dependent, supporting a simple two-state mechanism in which the folded dimeric protein is in equilibrium with unfolded monomers. An analysis according to the two-state model yields a Gibbs free energy of stabilization (at 0 M urea, 25 degrees C) of about 75 kJ/mol, typical for dimeric proteins of this size. Even a deletion of 24 residues from the reading head decreased the stability by only 2.7 kJ/mol. These results suggest that the DNA reading head of Tet repressor is a thermodynamically independent domain and that the thermodynamic stability of the Tet repressor dimer is determined by the association of the dimerization domains of the individual monomers. Variants containing replacements in the first alpha-helix of HTH did not show any DNA binding activity whatsoever. We attribute this to the alteration of the two N-terminal residues in this alpha-helix. TetR variants were active in nonspecific DNA binding, when either all or only the solvent-exposed residues in the recognition alpha-helix of HTH were exchanged to the respective LacI sequence. Replacement of the same residues by the respective amino acids from 434Cro yielded hybrid proteins that specifically recognize tetO in vitro. Taken together, these results establish that the similarity of operator recognition between 434Cro and TetR is greater than between TetR and LacI and confirm that prediction of the recognized DNA sequence is not obvious from the sequence of the respective HTH or recognition alpha-helix.

Fast large-scale purification of tetracycline repressor variants from overproducing Escherichia coli strains.

We constructed a plasmid for overexpression of Tn10 Tet repressor (TetR) by placing a synthetic tetR gene under control of the Pc promoter. Active TetR is expressed up to 30% of the total soluble cell protein. A protocol containing anion-exchange, cation-exchange, and size-exclusion chromatography steps is described for the large-scale purification of milligram amounts of TetR in three days. Cation-exchange chromatography already yields almost homogenous TetR. Purification of about fifty TetR mutants demonstrates that this protocol is generally applicable. No correlation between net charge of TetR variants and elution behaviour was detected for the anion-exchange column. On the other hand, TetR mutants with increased negative charge in their DNA binding domain eluted at lower NaCl concentration from the cation-exchange column. The applicability of this purification protocol to the wide variety of TetR variants suggests that it can be used for the rapid purification of other DNA binding proteins as well.

Further chemotherapy versus low-dose involved-field radiotherapy as consolidation of complete remission after six cycles of alternating chemotherapy in patients with advance Hodgkin's disease. German Hodgkins' Study Group (GHSG).

OBJECTIVE: It was the aim of this prospective randomized multicenter study to compare chemotherapy and radiotherapy as consolidation treatments in patients achieving complete remission (CR) after 6 cycles of doxorubicin-containing chemotherapy in advanced-stage Hodgkin's disease (HD). METHODS: A total of 288 previously untreated patients aged 18-60 years with stage IIIB or IV HD received induction chemotherapy with 3 X (COPP + ABVD). Patients achieving CR were eligible for randomisation to either 20 Gy radiotherapy to initially involved fields (RT-arm) or to an additional 1 X (Copp + ABVD) (CT-arm ). Patients with nodal PR were allocated to more intense radiotherapy (IRT-arm: 20 Gy IF, 40 Gy to persisting tumor). Four patients with persisting organ involvement after induction received salvage chemotherapy. RESULTS: Of 288 patients, 171 (59%) achieved CR after induction chemotherapy. Of these, 100 patients were successfully randomized to RT or CT. In the CT arm relapses were observed on 10 of 49 patients compared with 13 of 51 patients in the RT arm (p = n.s.). Fifty patients refused randomisation and for them a treatment was chosen, and 21 patients refused any further treatment. Of these 21 patients with no consolidation therapy, 9 relapsed, indicating an approximately 3-fold increased relapse risk compared with those receiving either of the consolidation therapies. No relapse was observed in initially involved lung or liver sites. Adverse prognostic factors for freedom from treatment failure and survival were low hemoglobin and large mediastinal mass at initial presentation. CONCLUSIONS: No statistically significant differences in treatment efficacy were detected between 20 Gy IF radiotherapy and 1X (COPP + ABVD) chemotherapy following CR after six cycles of alternating chemotherapy in patients with advanced-stage HD. However, limited observations in a non-randomized cohort indicate that patients without consolidation treatment of CR after 6 cycles of chemotherapy may have an elevated risk of relapse.

[Conconi tests in children]. / Conconi-Tests bei Kindern.

From 1990 to 1992 we carried out 158 Conconi-Tests on children aged from 7 to 15. Of these tests 128 were carried out on the 400 m-track, and further 30 were Conconi-Intervall-Tests (Probst-Test). The testing was done on the members of the Swiss Figure-Skating Team, on the best runners of the Volksbank Grand Prix St. Gallen 1991/92 and on the youngest girls and boys of the Athletic Club Brühl St. Gallen. 89 tests were performed on girls and 69 tests on boys. In 84% of all cases (133 tests) the results were open to unambiguous interpretation, and were determined by the anaerobic threshold, 14% (22 tests), however, could not be clearly interpreted or had to be done again, and in 2% of all cases (3 tests) the results delivered no analysable information. In the results we only considered the 133 tests where clear interpretation was possible (114 from 128 Conconi-Tests, i.e. 89%, and 19 from 30 Probst-Tests, i.e. 63%). Thus we achieved the first aim of our research, which was to investigate the feasibility of carrying out Conconi-Tests on children and analysing the subsequent results thereof (with very interesting threshold results). From this, it is hoped, that norm data can be established, on which the anaerobic threshold and the threshold pulse of children active in sports can be based. At this point it must be stated that the classical Conconi-Test was found to deliver data easily and clearly interpretable, while the Intervall-Test was less easily analyzable.(ABSTRACT TRUNCATED AT 250 WORDS)

The promoter region of the Escherichia coli pepD gene: deletion analysis and control by phosphate concentration.

A series of deletions removing progressively larger parts of the 5' flanking region of the Escherichia coli pepD gene was constructed. After fusing the resulting promoter fragments to the chromosomal malPQ operon, their activities were determined by assaying for amylomaltase, the product of the malQ gene. Transcription from the pepD promoter region in exponentially growing cells was estimated to be about 5 times less efficient than transcription from the induced lac promoter. Approximately 115 bp preceding the translation start site of the pepD gene are important for regular promoter functioning, whereas the more distal sequences could be deleted without any significant effects. In bacterial cultures containing limiting amounts of inorganic phosphate, the rate of de novo synthesis of peptidase D, simultaneously with the derepression of alkaline phosphatase, increased about fivefold as a consequence of phosphate starvation. This regulation was shown to occur at the transcriptional level by the use of chromosomal pepD promoter-malPQ fusions. The inducibility by phosphate limitation was conserved in all of the deletion clones in which the pepD promoter region was still functional. As demonstrated by the use of phoB, R, and M mutants, the modulation of pepD expression is independent of the genetic system controlling the pho regulon.