Dynamic proteome allocation regulates the profile of interaction of auxotrophic bacterial consortia.

Microbial ecosystems are composed of multiple species in constant metabolic exchange. A pervasive interaction in microbial communities is metabolic cross-feeding and occurs when the metabolic burden of producing costly metabolites is distributed between community members, in some cases for the benefit of all interacting partners. In particular, amino acid auxotrophies generate obligate metabolic inter-dependencies in mixed populations and have been shown to produce a dynamic profile of interaction that depends upon nutrient availability. However, identifying the key components that determine the pair-wise interaction profile remains a challenging problem, partly because metabolic exchange has consequences on multiple levels, from allocating proteomic resources at a cellular level to modulating the structure, function and stability of microbial communities. To evaluate how ppGpp-mediated resource allocation drives the population-level profile of interaction, here we postulate a multi-scale mathematical model that incorporates dynamics of proteome partition into a population dynamics model. We compare our computational results with experimental data obtained from co-cultures of auxotrophic Escherichia coli K12 strains under a range of amino acid concentrations and population structures. We conclude by arguing that the stringent response promotes cooperation by inhibiting the growth of fast-growing strains and promoting the synthesis of metabolites essential for other community members.

Microwave Realization of the Gaussian Symplectic Ensemble.

Following an idea by Joyner et al. [Europhys. Lett. 107, 50004 (2014)], a microwave graph with an antiunitary symmetry T obeying T^{2}=-1 is realized. The Kramers doublets expected for such systems are clearly identified and can be lifted by a perturbation which breaks the antiunitary symmetry. The observed spectral level spacings distribution of the Kramers doublets is in agreement with the predictions from the Gaussian symplectic ensemble expected for chaotic systems with such a symmetry.

Azelaic acid: Properties and mode of action.

Acne is a common skin disorder that can be problematic for adults as well as for adolescents. It has several key pathophysiological features such as follicular hyperkeratosis, elevated Propionibacterium acnes proliferation, and reactive inflammation, all of which should be targeted for an optimal outcome. Azelaic acid (AzA) has profound anti-inflammatory, antioxidative effects, and is bactericidal against a range of Gram-negative and Gram-positive microorganisms as well, including antibiotic-resistant bacterial strains. In addition, AzA's antikeratinizing effects are inhibitory toward comedones. AzA is effective overall in targeting multiple causes of acne and has been proven to be well tolerated in numerous clinical trials.

Neuroprotective properties of nicotine.

Utilizing the intrinsic optical signal (IOS) of retinal Spreading Depression (rSD) waves and the concomitant transparency changes of the tissue, we show that nicotine, in an in vivo near tissue preparation, has neuroprotective effects against the excitotoxic cell death, mediated through the activation of glutamate-receptors. For this study the retinal tissue was treated with NMDA, an agonist for the NMDA-glutamate-receptor, being excitotoxic at higher concentrations, to induce tissue damage. The protective effects of nicotine against glutamate induced neurotoxicity are demonstrated, comparing the IOS with NMDA and NMDA + nicotine. We additionally present data about the decrease of the propagation velocity of rSD waves after nicotine application and show analogical effects obtained with epibatidine, a specific nicotinic acetylcholine receptor (nAChR) agonist.

The pharmacological control of neuronal excitability in the retinal spreading depression model of migraine.

Spreading Depression is the underlying patho physiological mechanism for the neurological symptoms of migraine aura and is thought to play a major role in triggering migraine. Therefore it seems reasonable to use the Spreading Depression as a pharmacological tool for anti migraine drugs. Drugs that are able to alter parameters of Spreading Depression should also influence appearance and course of migraine attacks. Concerning the classification on the different mechanisms of drug action, especially the retinal Spreading Depression is useful, due to the separation of vascular and neuronal effects. In this study we investigated substances from different classes of common anti migraine drugs on different parameters of the retinal spreading depression. The results are discussed according to the classification of the drug.

Inter-age variability of bona fide unvaried transcripts Normalization of quantitative PCR data in ischemic stroke.

BACKGROUND: Aging is a major risk factor for a variety of neurobiological diseases leading to variations of transcriptional expression in affected tissues. Reverse transcription of RNA followed by quantitative PCR is a powerful technique for detection and quantification of specific transcripts differentially expressed. An essential prerequisite for accurate interpretation of quantitative PCR data obtained from expression studies is an appropriate normalization process. Therefore we validated the expression of the most frequently used reference genes consisting of Gapdh and Actb as well as Hmbs, Hprt1 and Gusb in an animal model of mice in respect to two major influence factors, aging and ischemia. In the experimental settings we intended to reflect variations in both, the local and systemic immune response. RESULTS: The consistency in gene expression of the tested transcripts was quantified based on standard deviation, correlation analysis and two algorithms available as Visual Basic Applications (VBA) termed GeNorm and Normfinder. Overall, the results of the study proofed the suitability of Actb in combination with Gapdh and with tissue-specific limitations Hmbs in brain and Gusb in white blood cells as the most stable transcripts for accurate normalization. We clearly demonstrated that both, the aging process per se and aging in combination with ischemia are confounding factors with respect to the expression stability of Hprt1. CONCLUSIONS: The present study emphasizes the urgent need to validate the expression stability also from bona fide unvaried transcripts under specific conditions of investigation to ensure adequate normalization of qPCR data. Based on the expression stability, the use of Gapdh and Actb as highly abundant transcripts for normalization of qPCR data under conditions of aging and ischemia in a mouse model was evaluated. However, for low abundant genes the use of Hmbs in brain and Gusb in white blood cells is recommended.

The involvement of pro-inflammatory cytokines in nephrogenic systemic fibrosis - a mechanistic hypothesis based on preclinical results from a rat model treated with gadodiamide.

The evidence for the potential involvement of gadolinium-based contrast agents (GBCAs) in the pathomechanism of nephrogenic systemic fibrosis (NSF), a rare but serious disease occurring in patients with severe or end-stage renal failure, has grown due to recent epidemiological and preclinical research. Nevertheless there is still uncertainty with regard to the prevailing patho-physiological processes that may lead to NSF. To examine the potential mechanism of the fibrotic skin changes we applied a recently published rat model of NSF for investigations into serum markers for inflammation. For this purpose male Wistar rats were treated either once, three, or eight times with a daily intravenous injection of 2.5 mmol/kg gadodiamide, the drug substance of the magnetic resonance imaging (MRI) agent Omniscan. Clinical observations, hematology, clinical pathology, histopathology including electron microscopy and gadolinium (Gd) determination in serum, skin, femur and liver tissue, and a multiplexed analysis of 70 protein serum markers were performed. Gd was detectable in the skin, femur, and liver of the gadodiamide-treated rats 6h after the first administration. Macroscopic skin changes, appearing as reddening and early scab formation, were observed in one animal after the third daily administration and affected all animals after 8 daily administrations. Microscopy revealed dermal infiltrations after three administrations, progressing towards inflammatory lesions, ulcerations and crusts. Among the investigated serum marker panel 13 cytokines were significantly (p<0.01) elevated 6 h after the first injection, and eight stayed elevated over all time points: the monocyte chemotactic proteins MCP-1 and MCP-3, the macrophage inflammatory proteins MIP-1beta and MIP-2, the tumor necrosis factor TNF-alpha, the extracellular matrix regulator tissue inhibitor of metalloproteinase type 1 (TIMP-1), the vascular epithelial growth factor (VEGF) and osteopontin. The latter cytokine is of particular interest, since this matrix cellular glycoprotein is involved in the regulation of dystrophic calcification but also plays a role as a chemoattractant for dendritic cells, macrophages and T-lymphocytes, which in turn activate inflammatory pathways. Reflecting the physiological role of osteopontin, we hypothesize that Gd release from the GBCA-complex leads to the formation of insoluble Gd-deposits subsequently eliciting a physiological response similar to that seen during dystrophic calcification, i.e. an up-regulation of osteopontin and chemoattractant cytokines. Concomitant increase in vascular permeability caused by MIP-1, TNF-alpha and VEGF may lead to extravasation of chelated Gd or Gd-deposits. The inherent persistence of the Gd-deposits may subsequently result in an overactivation of pro-inflammatory pathways progressing towards overt skin effects.

[Identification of risk factors (the method of logistic regression)]. / Die Ermittlung von Risikofaktoren. Das Verfahren der logistischen Regression.

Logistic regression is a model used for prediction of an event (e.g. heart attack: yes/no) using several predictor variables whereas the output is confined to values between 0 and 1. The regression coefficients describe the size of the contribution of the risk factor. In this short introduction an example is used to explain the basic principle and the advantages of the logistic regression.

Semiclassical structure of chaotic resonance eigenfunctions.

We study the resonance (or Gamow) eigenstates of open chaotic systems in the semiclassical limit, distinguishing between left and right eigenstates of the nonunitary quantum propagator and also between short-lived and long-lived states. The long-lived left (right) eigenstates are shown to concentrate as variant Planck's over 2pi-->0 on the forward (backward) trapped set of the classical dynamics. The limit of a sequence of eigenstates [psi(variant Planck's over)] 2pi-->0 is found to exhibit a remarkably rich structure in phase space that depends on the corresponding limiting decay rate. These results are illustrated for the open baker's map, for which the probability density in position space is observed to have self-similarity properties.

Biotransformation and pharmacokinetics of the antiplasmodial naphthylisoquinoline alkaloid dioncophylline A.

The biotransformation of the antiplasmodial naphthylisoquinoline alkaloid dioncophylline A by rat liver microsomes and its pharmacokinetics in male rats were studied. Incubation of dioncophylline A with rat liver microsomes resulted in the formation of the major metabolite 5'-O-demethyldioncophylline A, and a second minor metabolite, corresponding to the mass of an as yet unknown 4-hydroxydioncophylline A. Kinetic constants of the formation of 5'-O-demethyldioncophylline A were Km = 32 nmol and Vmax = 20 pmol min-1 mg-1). Administration of dioncophylline A at a dose of 6.67 mg kg-1 body weight to rats intravenously and orally (n = 4 per group) resulted in peak plasma levels of 0.84 and 0.11 microg ml-1, respectively. Levels of metabolites were below the limit of quantitation (LOQ). The following pharmacokinetic parameters of dioncophylline A were determined: oral bioavailability of 25%, plasma half-life of 2.5 h and partition volume of 8 l kg-1 body weight. Concentrations of dioncophylline A metabolites in all plasma and urine samples were below the limit of detection (LOD) and recovery of dioncophylline A in urine was very low, suggesting distribution into lipid rich tissues.

Infradiaphragmatic versus supradiaphragmatic Hodgkin lymphoma: a retrospective review of 1,114 patients.

Infradiaphragmatic Hodgkin lymphoma (IDH) accounts for 4-13% of cases of stage I-II Hodgkin lymphoma (HD). It has been associated with distinct pre-treatment characteristics and outcomes when compared with supradiaphragmatic HD (SDH). The comparison of IDH vs SDH can only be made in early and intermediate stages (I-II), such a comparison is not possible for advanced stages (III-IV). This study retrospectively compared two groups of 1013 patients with stage I-II SDH and 101 patients with IDH (10%). These two sub-groups of patients were treated in 1988-1993 in 2 prospective randomized clinical trials in Germany for early and intermediate stages of Hodgkin lymphoma. IDH-patients were older (median 39 vs 31 years; p < 0.001), predominantly male (73% vs 52%; p < 0.001) and more often had involvement of 3 lymph node areas (LNA) (80% vs 55%; p < 0.001). Histology in IDH was more likely to be mixed cellularity (46.5% vs 23.6%, p < 0.001) or lymphocyte predominant (20 vs 10%, p = 0.003) and less likely nodular sclerosis (25% vs 63%, p < 0.001). In early-stage unfavorable disease, IDH was associated with a higher treatment failure rate (unadjusted hazard ratio 2, 95% CI, 1.3-3.4; p = 0.003). After controlling for age, sex, stage, histology, B-symptoms and involvement of 3 LNA, the adjusted hazard ratio was 1.25 (95% CI, 0.65-2.4; p = 0.51) so that IDH was no longer associated with a statistically significant treatment failure rate. Poorer outcomes with IDH as compared to SDH are attributable to its association with known adverse prognostic risk factors, but IDH, in itself, is not an independent adverse prognostic factor for treatment failure or survival.

BEACOPP and COPP/ABVD as salvage treatment after primary extended field radiation therapy of early stage Hodgkins disease - results of the German Hodgkin Study Group.

Patients with early stage favorable Hodgkin's disease who relapse after extended field radiotherapy have satisfactory results. We retrospectively analysed patients with relapsed HD after initial radiation therapy alone to determine treatment outcome and prognostic factors. Nine-hundred and forty five patients in localized stages without risk factors received either 40 Gy extended field RT or 30 Gy EF RT followed by an additional 10 Gy to involved lymph node regions. 107 patients relapsed and received salvage therapy. Characteristics of the 107 patients at relapse were as follows: median age was 34 years (range 18--75) with relapse occuring at a median of 19 months (range 4--98 months), 31% were female. The majority of patients (93%) were treated with conventional chemotherapy. Sixty-nine percent were treated with COPP/ABVD like regimens, 21% with BEACOPP, and 3% received various other regimens. Seven percent were treated with radiotherapy alone. Complete remission was achieved in 87% of all salvaged patients. The median follow-up after relapse was 45 months. FF2F (freedom from second treatment failure) and OS (overall survival) were 81% and 89%, respectively. In multivariate analysis age was the major prognostic factor for FF2F and OS (p<0.0001, for both). Further independent prognostic factors were B symptoms (p=0.05) and salvage chemotherapy (p=0.03) for FF2F, and B symptoms (p=0.03) and extranodal involvement (p=0.02) for OS. The long-term outcome of patients relapsing after EF RT is excellent. Age, B symptoms, extranodal involvement and salvage chemotherapy were identified as prognostic factors for second relapse and survival.

Cologne high-dose sequential chemotherapy in relapsed and refractory Hodgkin lymphoma: results of a large multicenter study of the German Hodgkin Lymphoma Study Group (GHSG).

BACKGROUND: We designed a dose- and time-intensified high-dose sequential chemotherapy regimen for patients with relapsed and refractory Hodgkin lymphoma (HD). PATIENTS AND METHODS: Eligibility criteria included age 18-65 years, histologically proven primary progressive (PD) or relapsed HD. Treatment consisted of two cycles DHAP (dexamethasone, high-dose cytarabine, cisplatinum); patients with chemosensitive disease received cyclophosphamide followed by peripheral blood stem cell harvest; methotrexate plus vincristine, etoposide and BEAM plus peripheral blood stem cell transplantation (PBSCT). RESULTS: A total of 102 patients (median age 34 years, range 18-64) were enrolled. The response rate was 80% (72% complete response, 8% partial response). With a median follow-up of 30 months (range 3-61 months), freedom from second failure (FF2F) and overall survival (OS) were 59% and 78% for all patients, respectively. FF2F and OS for patients with early relapse were 62% and 81%, for late relapse 65% and 81%; for PD 41% and 48%, and for multiple relapse 39% and 48%, respectively. In multivariate analysis response after DHAP (P <0.0001) and duration of first remission (PD and multiple relapse versus early and late relapse; P=0.0127) were prognostic factors for FF2F. Response after DHAP (P <0.0081), duration of first remission (P=0.0017) and anemia (P=0.019) were significant for OS. CONCLUSION: Based on the promising results of this study, a prospective randomized European intergroup study was started comparing this intensified regimen with two courses of DHAP followed by BEAM (HD-R2 protocol).

Treatment of advanced Hodgkin's disease with COPP/ABV/IMEP versus COPP/ABVD and consolidating radiotherapy: final results of the German Hodgkin's Lymphoma Study Group HD6 trial.

BACKGROUND: The purpose of this study was to compare the efficacy of the hybrid chemotherapeutic regimen COPP/ABV/IMEP (cyclophosphamide-vincristine-procarbazine-prednisone-doxorubicin-bleomycin-vinblastine-ifosfamide-methotrexate-etoposide) (CAI) with that of the standard regimen COPP/ABVD (COPP/ABV, dacarbacine) (CA) in the treatment of advanced-stage Hodgkin's disease (HD). PATIENTS AND METHODS: Between January 1988 and January 1993, 588 eligible patients with HD in stages IIIB and IV were randomly assigned to a treatment or control group. The treatment group received four cycles of CAI over a complete cycle duration of 43 days. The control group received four cycles of CA over 57 days. Both groups then received consolidating radiotherapy. RESULTS: Five hundred and eighty-four patients were suitable for arm comparison. Patients in each group were similar in age, sex, histological subtype and clinical risk factors. Complete remission rates, overall survival and freedom from treatment failure at 7 years were similar for the two groups: 77% versus 78%, 73% versus 73% and 54% versus 56% for CAI and CA, respectively. Differences in acute chemotherapy-related toxicity were significant, however. Prognostic factor analysis confirmed the relevance of the International Prognostic Index and revealed that stage IVB, low hemoglobin, low lymphocyte count, high age and male gender were associated with a poor prognosis CONCLUSION: The rapidly alternating hybrid CAI did not give superior results when compared with the standard regimen CA in advanced-stage HD.

Fatigue in long-term survivors of Hodgkin's lymphoma; a report from the German Hodgkin Lymphoma Study Group (GHSG).

Although treatment regimens for Hodgkin's lymphoma have become more sophisticated, little is known about the prevalence of fatigue in long-term survivors. Therefore, we investigated the fatigue status of long-term survivors of Hodgkin's lymphoma and a control group using a pre-validated questionnaire. In 1995/1996, we contacted 1981 patients, who were enrolled in the German Hodgkin Studies HD 1-6. All patients were treated according to the treatment protocols HD1-3 (1981-1988) and HD 4-6 (1988-1993). The patients with a current status of complete remission were asked to complete a quality-of-life (QoL) questionnaire (European Organisation for Research and Treatment of Cancer Quality of Life Core 30 (EORTC QLQ C-30)) and a fatigue questionnaire (Multidimensional Fatigue Inventory (MFI)). The results were compared with the data from 935 controls, matched for age, gender and living area. Eight-hundred and eighteen questionnaires from the patients were available for analysis. The median time between the end of treatment and completing the questionnaire is 5.2 years. Fatigue levels of patients with Hodgkin's lymphoma are high, even years after treatment. Fatigue dimensions are significantly influenced by several clinical and non-clinical factors. Fatigue levels of Hodgkin's lymphoma patients are significantly higher than those of the control group. Further investigations are warranted to explore the effectiveness of treatment strategies for fatigue.

BEACOPP therapeutic regimen for patients with Hodgkin's disease and HIV infection.

BACKGROUND: Hodgkin's disease (HD) is the most common non-AIDS-defining tumor diagnosed in HIV-infected patients. Antineoplastic treatment is difficult considering the underlying immunodeficiency caused by HIV itself and may increase the risk of opportunistic infections. The purpose of this study was to evaluate the efficacy and safety of the chemotherapeutic regimen bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine and prednisone (BEACOPP) in HIV-infected patients with HD (HIV-HD). PATIENTS AND METHODS: Twelve patients with HIV-HD were scheduled to receive six cycles of BEACOPP. Five patients received concomitant antiretroviral therapy. Two patients received additional radiotherapy. Restaging was carried out after three and six cycles of chemotherapy. CD4 counts and HIV RNA levels were regularly monitored during the course of chemotherapy. RESULTS: Complete remission (CR) was achieved in all patients. Of 12 patients, eight patients received the intended six cycles of BEACOPP. Two patients died of opportunistic infections within the treatment period, one patient died of a relapse after 26 months. The other nine patients remain in CR for their individual follow-up period, median 49 months (range 13-108). The most commonly observed toxicity was bone marrow suppression with National Cancer Institute Common Toxicity Criteria (NCI-CTC) grade 3/4 leukopenia in 75% of all cases. The mean decline of CD4+ lymphocytes was 238 +/- 230/ micro l, with a mean recovery of 272 +/- 329/ micro l 6 months after the last cycle. Plasma levels of HIV RNA increased moderately or even declined under chemotherapy if highly active anti-retroviral therapy was given concomitantly with BEACOPP. CONCLUSIONS: The BEACOPP regimen is feasible and highly effective in HIV-HD patients. With respect to its overall moderate toxicity, BEACOPP is a safe regimen even in the immunocompromised patient.

Spleen involvement in Hodgkin's lymphoma: assessment and risk profile.

Diagnostic laparotomy is no longer routinely performed in Hodgkin's lymphoma and noninvasive diagnosis of spleen involvement remains uncertain. In order to assess the probability of splenic involvement based on clinical parameters, we retrospectively analyzed data on patients of the German Hodgkin's Lymphoma Study Group (GHSG) who underwent staging laparotomy and for whom splenic weight and size were available. Our study included 376 patients with Hodgkin's lymphoma who underwent staging laparotomy and splenectomy according to the treatment policy of the GHSG between February 1981 and January 1993. Univariate and multivariate analyses of pretherapeutic clinical characteristics and splenic weight were performed in order to predict the probability of splenic involvement. Computed tomographic (CT) images of 25 patients were available and used to correlate radiological splenic size and pathological splenic weight. In 171 of 376 patients spleen involvement was found. Average weight of the spleens was 258 g (+/-257) ranging from 55 to 3290 g. All spleens with a weight above 2000 g showed disease involvement, while those under 150 g were never involved. In the multivariate analysis, splenic weight ( p<0.001), erythrocyte sedimentation rate ( p<0.001), and clinical stage ( p<0.01) were found to be independently prognostic for spleen involvement. Splenic weight was highly correlated with a spleen index defined as the product of length, width, and thickness measured by CT (correlation coefficient: 0.93). By applying the identified risk factors in clinically staged patients spleen involvement can be determined. Spleen weight can be estimated with the help of a spleen index. Above an index of 1000 the probability of spleen involvement is higher than 90%. This might be of outstanding importance for patients being scheduled for involved field radiation.

14-day variant of the bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone regimen in advanced-stage Hodgkin's lymphoma: results of a pilot study of the German Hodgkin's Lymphoma Study Group.

PURPOSE: This multicenter pilot study assessed the feasibility and efficacy of a time-intensified bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (BEACOPP) regimen given in 14-day intervals (BEACOPP-14) with granulocyte colony-stimulating factor (G-CSF) support in advanced Hodgkin's lymphoma. PATIENTS AND METHODS: From July 1997 until March 2000, 94 patients with Hodgkin's lymphoma stage IIB, III, and IV were scheduled to receive eight cycles of BEACOPP-14. Consolidation radiotherapy was administered to regions with initial bulky disease or residual tumor after chemotherapy. RESULTS: All patients were assessable for toxicity and treatment outcome. Eighty-six patients received the planned eight cycles of BEACOPP-14. Consolidation radiotherapy was given in 66 patients. Chemotherapy could generally be administered on schedule. Dose reductions varied among drugs but were generally low. Acute toxicity was moderate, with World Health Organization grade 3/4 leukopenia in 75%, thrombocytopenia in 23%, anemia in 65%, and infection in 12% of patients. A total of 88 patients (94%) achieved a complete remission. Four patients had progressive disease. At a median observation time of 34 months, five patients have relapsed, one patient developed a secondary non-Hodgkin's lymphoma, and three deaths were documented. The overall survival and freedom from treatment failure rates at 34 months were 97% (95% confidence interval [CI], 93% to 100%) and 90% (95% CI, 84% to 97%), respectively. CONCLUSION: Acceleration of the BEACOPP baseline regimen by shortening cycle duration with G-CSF support is feasible and effective with moderate acute toxicity. On the basis of these results, the German Hodgkin's Lymphoma Study Group will compare the BEACOPP-14 regimen with BEACOPP-21 escalated in a prospective multicenter randomized trial.