Tuning methods for multigap drift tube linacs

Multigap cavities are used extensively in linear accelerators to achieve velocities up to a few percent of the speed of light, driving nuclear physics research around the world. Unlike for single-gap structures, there is no closed-form expression to calculate the output beam parameters from the cavity voltage and phase. To overcome this, we propose to use a method based on the integration of the first and second moments of the beam distribution through the axially symmetric time-dependent fields of the cavity. A beam-based calibration between the model's electric field scaling and the machine's rf amplitudes is presented, yielding a fast online energy change method, returning cavity amplitude and phase necessary for a desired output beam energy and energy spread. The method is validated with 23Na6+ beam energy measurements.

How to design information strategies on e-mental health services for prospective healthcare providers

Background

Among prospective healthcare providers (HCPs) such as medical students, mental health problems are prevalent, but they seem reluctant to seek help. Barriers include fear of stigmatization or limited resources of counseling centers. Electronic mental health services (eMHSs) seem to be promising low-threshold and evidence-based tools for increasing treatment availability. However, uptake rates remain low. Reasons include skepticism and lacking awareness, which can be addressed through acceptance-facilitating interventions (AFIs) such as multi-attributes information strategies. To date little is known about how to design AFIs to meet prospect HCPs’ information needs and preferences.

Methods

Between August 2021 and June 2022, n = 21 semi-structured online interviews and n = 3 co-design workshops were conducted with medical and psychology students across Germany to define attributes and levels of information strategies. Interviews were recorded, transcribed and content-analyzed using MAXQDA.

Results

Most students reported having little knowledge about eMHSs but would have liked to be informed at the beginning of their studies or as an integral part of their study program. We identified 5 attributes that information strategies should consist of: information source (e.g., student counseling center), information path (e.g., flyer), timing (e.g., during freshman week), recommendation (e.g., from HCPs), and quality criterion (e.g., evidence-base). Attributes included 4 to 6 levels. Concerning design preferences, students favored green or blue as colors, and short texts with images.

Conclusions

For a comprehensive dissemination of eMHSs into the healthcare system, prospective HCPs need to be educated on eMHSs. This study gives first insight into how AFIs should be designed to inform prospective HCPs. Future research should focus on systematic variations of AFIs’ attributes and their levels mimicking real-world decision scenarios through discrete choice experiments.

Key messages

• Through tailored AFIs, prospective HCPs can be informed about eMHSs for both personal and professional needs.

• Our results give student counseling centers with limited resources clear guidelines on how to inform prospective HCPs on low-threshold eMHSs.

How to raise awareness about electronic mental health services among prospect healthcare providers: a qualitative study on information preferences

Introduction

Since fall 2020, electronic mental health services (eMHSs) like apps can be prescribed by physicians and psychotherapists in Germany. However, future healthcare providers such as medical and psychology students remain reluctant to adopt eMHSs, even though they represent a vulnerable group with respect to developing mental health problems themselves. Reasons include scepticism and lacking awareness, which can be addressed by tailored multi-component information material. However, to date little is known about the most important information attributes to educate prospect healthcare providers on eMHSs.

Objectives

The objective of this study is to explore information preferences on eMHSs among medical and psychology students.

Methods

A total of 21 semi-structured interviews were conducted (n=16 medical and n=5 psychology students) across Germany based on a topic guide. Interviews were recorded, transcribed and content-analyzed using MAXQDA.

Results

Most students reported having little knowledge about eMHSs and that the issue of digital health has never been raised in their study, even though it is perceived as important. Concerning information design preferences, students favored light, neutral colors and a combination of short, compressible texts with matching images. Regarding the content, information about data protection, the underlying evidence base and the match with personal needs were perceived as important for utilization intentions, while there was little interest in tailored information focusing exclusively on psychology or medical students.

Conclusions

This study provides first insights into eMHS information preferences among prospect healthcare providers. In a next step, a discrete-choice conjoint experiment will be conducted to test the relevant information features on eMHSs.

Disclosure

No significant relationships.

Reevaluating limits of detection of 12 lateral flow immunoassays for the detection of Yersinia pestis, Francisella tularensis, and Bacillus anthracis spores using viable risk group-3 strains

AIM

Rapid detection of biological agents in biodefense is critical for operational, tactical and strategic levels as well as for medical countermeasures. Yersinia pestis, Francisella tularensis, and Bacillus anthracis are high priority agents of biological warfare or bioterrorism and many response forces use lateral flow assays (LFAs) for their detection. Several companies produce these assays, which offer results in short time and are easy to use. Despite their importance, only few publications on the limits of detection (LOD) for LFAs are available. Most of these studies used inactivated bacteria or risk group-2 strains. As the inactivation process in previous studies might have affected the tests' performances, it was our aim in this study to determine and compare the LOD of several commercially available LFAs using viable risk group-3 strains.

METHODS AND RESULTS

Lateral flow assays from four different companies for the detection of following bacteria were evaluated: Y. pestis, F. tularensis and B. anthracis spores. Two independent quantification methods for each target organism were applied, in order to ensure high quantification accuracy. LODs varied greatly between tests and organisms and ranged between 10⁴ for Y. pestis-tests and as high as >10⁹ for one B. anthracis-test.

CONCLUSION

This work precisely determined the LODs of LFAs from four commercial suppliers. The herein determined LODs differed from results of previous studies. This illustrates the need for using accurately quantified viable risk group 3-strains for determining such LODs.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our work bridges an important knowledge gap with regard to LFA LOD. The LODs determined in this study will facilitate better assessment of LFA-results. They illustrate that a negative LFA result is not suited to exclude the presence of the respective agent in the analyzed sample.

Theta and high-beta networks for feedback processing: a simultaneous EEG-fMRI study in healthy male subjects

The reward system is important in assessing outcomes to guide behavior. To achieve these purposes, its core components interact with several brain areas involved in cognitive and emotional processing. A key mechanism suggested to subserve these interactions is oscillatory activity, with a prominent role of theta and high-beta oscillations. The present study used single-trial coupling of simultaneously recorded electroencephalography and functional magnetic resonance imaging data to investigate networks associated with oscillatory responses to feedback during a two-choice gambling task in healthy male participants (n=19). Differential associations of theta and high-beta oscillations with non-overlapping brain networks were observed: Increase of high-beta power in response to positive feedback was associated with activations in a largely subcortical network encompassing core areas of the reward network. In contrast, theta-band power increase upon loss was associated with activations in a frontoparietal network that included the anterior cingulate cortex. Trait impulsivity correlated significantly with activations in areas of the theta-associated network. Our results suggest that positive and negative feedback is processed by separate brain networks associated with different cognitive functions. Communication within these networks is mediated by oscillations of different frequency, possibly reflecting different modes of dopaminergic signaling.

Significance of HCV RNA monitoring in the era of new potent therapies

INTRODUCTION

The development and approval of direct-acting-antivirals (DAA) has revolutionized the treatment of hepatitis C within a few years and opened the door to a new era of shorter, well-tolerated but also highly expensive treatment options.

AREAS COVERED

Nowadays, reductions of viral load below quantification limits may often be achieved within the first weeks of therapy. Viral breakthroughs during treatment are rarely observed and unfavourable viral genotypes or an advanced liver disease do not necessarily lower the prospect of eradication. For this reason, pan-genotypic DAA-only therapies are about to replace interferon/ribavirin-regimens as the standard of care worldwide. Expert commentary: Consequently, it has become essential to reevaluate the utility of HCV RNA quantification in predicting treatment outcomes and to guide clinical decisions. Is there still a need for a close-meshed monitoring or is it reasonable to limit HCV RNA monitoring to baseline and post-treatment results? This review discusses the pro- and contra arguments in this regard.

Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

Variation analysis of six HCV viral load assays using low viremic HCV samples in the range of the clinical decision points for HCV protease inhibitors

In the range of clinical decision points for response-guided therapy of HCV, there is still insufficient data concerning the conformity of quantification results obtained by different assays and their correlation with the HPS/CTM v2 assay which was used for initial clinical studies. In a head-to-head comparison, assay accuracy and detection rates of six quantitative assays [artus HCV QS-RGQ, COBAS Ampliprep/COBAS TaqMan HCV v1/v2, High Pure System/COBAS TaqMan (HPS), RealTime HCV, and Versant HCV1.0] were assessed by measuring WHO and PEI standards at dilution steps near clinical decision points. Detection rates and mean differences between assays were evaluated by analyzing twenty clinical samples at 10, 100, and 1,000 IU/mL. Ten replicates from specimens with different HCV genotypes were used to analyze pan-genotypic intra-assay variation. At ≤ 25 IU/mL, RealTime demonstrated the highest detection rates. With 0.1 log difference when testing clinical samples, results obtained from the Versant and RealTime assays matched best with results from HPS. Mean difference analysis across all assay results revealed wide differences between 0.01 and 0.75 log IU/mL. RealTime showed the lowest intra-assay variation across genotypes 1-4 (25, 100, 1,000 IU/mL). There are substantial analytical differences between viral load assays clinicians should be aware of. These variations may have impact on clinical decisions for patients on HCV triple therapy and may argue for assay-specific decision points equivalent to reference values established in studies using HPS. A comparison of quantification is recommended prior to a switch of assays during ongoing therapy.

Ribulose-1,5-bisphosphate Carboxylase-Oxygenase: New Aspects Respective the pH-Dependance of the Carboxylation Reaction

The investigation was directed towards the effects of reaction conditions, substrates and pH on the carboxylation reaction of ribulose-1 ,5-bisphosphate carboxylase-oxygenase in the crude enzyme extracts from several plants. Optimal substrate concentrations (HCO3 - and RubP) were determined. The highest carboxylase activity was attained with Tris/HCl buffer. The pH activity profile was quite sharp with an optimum at pH 7.8. Purified and crystallized carboxylase yielded a broad optimum curve under the same reaction conditions

The platypnea-orthodeoxia syndrome

The platypnea orthodeoxia syndrome (POS) is a rare condition characterized by dyspnea and hypoxia in upright position. Pathopysiologic underlying mechanisms are determined by an atrial right-to-left shunt. Coexisting conditions that evolve POS can be of anatomical nature causing interatrial communication or of functional nature producing a deformity of the atrial septum in upright position. Diagnosis is difficult, as it needs to mention about POS. Classically, transthoracic and transesophageal echocardiography in supine and upright position with use of contrast medium and/or Doppler will point the diagnosis. Treatment is predominantly carried out by interventional closure of atrial septal defect that promptly resolves clinical symptoms.

DNA-damage caused by antibiotic drugs - quinolones

In the present investigation, the genotoxic potencies (SOSIP) of 10 antibiotic quinolones (topoisomerase LT inhibitors) were tested in the sfiA::lacZ fusion containing strain Escherichia coli PQ37 using a modified procedure of the SOS chromotest. A number of quinolones exhibited extremely high DNA damaging effects in the absence of an exogenous metabolizing system. The highest SOS inducing potencies (SOSIP) exhibited sparfloxacin with 2,400 Delta IF/nmole, ciprofloxacin (SOSIP = 184 Delta IF/nmole) and norfloxacin (SOSIP=120 Delta IF/nmole), whereas pipemic acid (SOSIP=4.6 Delta IF/nmole), cinoxacin (SOSIP=0.5 Delta IF/nmole) and nalidixic acid (SOSIP=0.5 Delta IF/nmole) showed only weak genotoxicity. The possibility of mutagenic effects caused by quinolones in eukaryotic cells is discussed.

Transition in young adults with spina bifida: a qualitative study

BACKGROUND

Adolescents and young adults with spina bifida are an at-risk population because of the complexity of their condition, developmental stage and social challenges. The purpose of this qualitative study was to examine the transition to adulthood in young adults with spina bifida and to explore condition-related needs and life skills required during the transition process.

METHODS

This qualitative study using narrative inquiry was part of a larger multi-site study of adaptation in young adults with spina bifida. Interviews were completed with 10 participants ranging in age from 18 to 25 years. The guided interview questions focused on specific dimensions of the transition experience related to the ecological model: self-management, independence and inner strength.

RESULTS

Three themes capturing different dimensions of the young adults' transition experiences emerged in the analysis. The themes included: (1) Struggling for independence, (2) Limiting social interactions and experiences with stigma, and (3) Building inner strength.

CONCLUSION

The qualitative study contributes to a better understanding of the challenges of transition to achieve self-management and social development for young adults with spina bifida. Findings in the life stories highlighted issues that necessitate increased advocacy and interventions from professionals within the health and social system.

[Percutaneous nephrolithotomy of an upper pole calix stone in a transplanted kidney]

INTRODUCTION

Nephrolithiasis in a transplanted kidney is an uncommon complication and may lead to an acute deterioration in renal function. Different techniques for stone treatment are known. In this case, we were successful by using percutaneous nephrolithotomy for the removal of the stone.

CASE REPORT

A 65-year-old male patient was found with urinary retention II degrees two months after renal transplantation. A stone in the upper pole calix was found as the probable cause. Percutaneous nephrolithotomy with a 15-Charr Storz mininephroscope was used successfully to disintegrate and remove the stone.

CONCLUSION

In comparison to other techniques for the removal of stones, percutaneous nephrolithotomy is a secure method in the treatment of nephrolithiasis in a transplanted kidney. This technique treats the renal stone in one session. We used a 15-Charr Storz mininephroscope which is less invasive than the usually used nephroscopes with a bigger lumen.

Distal embolic protection during percutaneous intervention of aorto-coronary venous bypass grafts: The FIRST Trial

OBJECTIVE

Interventions in aorto-coronary venous bypass grafts (CABG) can cause acute procedural complications due to distal embolization of debris. In the FIRST (First European Investigation Regarding the Systematic use of the TriActiv device) multicenter trial the distal endovascular protection system TriActiv (Kensey Nash) was evaluated during intervention of CABG.

METHODS

195 patients in 17 centers in Germany with significant disease of a vein graft were enrolled. Inclusion and exclusion criteria were comparable to the SAFER trial.

RESULTS

Acute procedural success was achieved in 98% of cases. Aspirated debris was found in 96.5% of patients. Primary endpoints (MACE at 30 days) occurred in 8.7% of all pts. (ITT). No patient died and 7.2% of patients suffered from MI. The rate of early revascularization was 1.5%. Secondary endpoints (MACCE at 30 days) were found in 9.2% and at hospital discharge in 8.7% of patients.

CONCLUSIONS

The TriActiv system is safe and effective. Normal post procedural flow can be preserved and the MACE rate is with 8.7% considerably low. The FIRST trial supports the growing belief that PCI of CABG should be performed with protection systems.

Differences of nine drug resistance interpretation systems in predicting short-term therapy outcomes of treatment-experienced HIV-1 infected patients: a retrospective observational cohort study

OBJECTIVE

Drug resistance interpretation systems are used to select the optimal antiretroviral therapy in HIV-infected patients. It is unclear how the systems perform in predicting therapy success and failure and in how far the interpretations are affected by insufficient drug levels.

METHODS

The accuracy of nine different interpretation systems in predicting therapy outcomes was evaluated using virological, immunological, pharmacological, and clinical data of 130 patients treated at 13 outpatient centers. Individual susceptibility scores of the interpretation systems were converted into active drug scores (ADS) and correlated with therapy success and failure, defined as viral load reduction of equal to or more (n=66) and less than 1 log10 copies/ml (n=64) at three months after drug resistance testing.

RESULTS

Three interpretation systems considered the respective therapies as more active compared to the other interpretation systems (p<0.01). These systems predicted therapy success better than the other systems, while the others performed better in predicting therapy failure. Thus, the overall rate of correctly predicted treatment outcomes was comparable between the different systems (73.1-80.0 %). Univariate and multivariate regression analysis revealed significant correlations between the ADS of all interpretation systems and virological therapy outcomes (p<0.0001). In contrast, only three interpretation systems were significantly correlated with immunological therapy outcomes in univariate and just one in multivariate models (p<0.05). Among 128 determinations of drug levels in 64 patient samples, 19.4 % revealed no detectable drug levels. The consideration of insufficient drug levels significantly improved the prediction accuracy of all interpretation systems (p<0.005).

CONCLUSION

Differences between interpretation systems in predicting therapy failures and success need to be considered for future consensus algorithms. The prediction accuracy of interpretation systems can be improved by consideration of plasma drug levels.

[Multislice CT arteriography in the pre-surgical evaluation of patients with ureteropelvic junction stenosis]

INTRODUCTION

The current treatment of choice for ureteropelvic stenosis is endopyelotomy, but the presence of vessels in contact with the stenotic area of the ureteropelvic junction reduces the success of these interventions and increases vascular and hemorrhagic complications. The aim of our study was to use multislice CT arteriography to evaluate patients prior to surgery for ureteropelvic junction stenosis.

PATIENTS AND METHODS

16 patients with ureteropelvic junction stenosis underwent multislice CT arteriography; multidirectional images and three-dimensional reconstructions were used to identify and characterize vessels in contact with the stenotic area of the ureteropelvic junction.

RESULTS

A total of eight vessels (four arteries and four veins) in six (38%) patients were found in contact with or passing within 2 mm of the ureteropelvic junction. The vessels were located anterior to the junction in four cases; it was posterior in one case, and anteromedial in the other. Endopyelotomy was contraindicated in the six patients in whom vessels were found in contact with the ureteropelvic junction. The presence of the vessels was confirmed during surgery in five of these patients; the remaining patient did not undergo surgery).

CONCLUSION

Multislice CT arteriography allows adequate presurgical evaluation of ureteropelvic junction stenosis, detecting the presence of crossing vessels and facilitating the planning of the surgical approach in these patients.

[Spontaneous spinal subdural hematoma: MRI findings in two cases]

Spontaneous spinal subdural hematoma is an uncommon finding. This report of two cases of spinal subdural hematoma (one hyperacute and one subacute) discusses the current theory of how it develops, the MRI findings, its differentiation from spinal epidural hematoma, and the value of MRI in monitoring patients undergoing conservative treatment. The most significant MRI findings in the hyperacute phase were isointense signal on T1-weighted sequences and hyperintense signal on T2-weighted sequences. Moreover, T2-weighted gradient-echo sequences showed a hypointense peripheral ring. In the subacute phase, a hyperintense signal was seen on T1-, T1-fat-suppression, and T2-weighted sequences.

Refluxing Chimney Versus Nonrefluxing LeDuc Ureteroileal Anastomosis for Orthotopic Ileal Neobladder: A Comparative Analysis for Patients With Bladder Cancer

PURPOSE

Radical cystectomy and various techniques of urinary diversion are gold standard treatments for invasive bladder cancer. However, postoperative hydronephrosis is a common complication in these patients. A special focus was placed on the type of ureteroileal anastomosis used with 2 different techniques performed at 1 institution.

MATERIALS AND METHODS

Between 1995 and 2003 a total of 106 consecutive patients with bladder cancer underwent cystectomy followed by construction of an ileal neobladder. The nonrefluxing technique of ureter tunneling described by LeDuc and the refluxing chimney technique used for ureter implantation into the ileum-neobladder were compared. Hydronephrosis due to ureteral strictures was studied immediately following surgery and up to 5 years after surgery.

RESULTS

A total of 204 RU were included in the study. The LeDuc technique was used in 132 RU (64%) and the chimney technique was used in 72 RU (36%). Hydronephrosis rate of 2% were found in each of the 2 groups after 5 years of followup.

CONCLUSIONS

Postoperative hydronephrosis due to ureteral strictures is observed at the same rate during long-term followup with the LeDuc and chimney techniques. We favor the chimney technique compared to the LeDuc tunnel due to easier technical preparation and a better chance to identify the ureters endoscopically at a later time. The chimney does give extra length to reach the ureteral stump, especially in cases of distal ureteral carcinoma in situ.

Predictive modelling of growth and measurement of enzymatic synthesis and activity by a cocktail of selected Enterobacteriaceae and Aeromonas hydrophila

The possibility was examined of developing a predictive model that would predict food spoilage by combining microbial growth (increase in cellular number) with extracellular enzymatic activity of a cocktail of five strains of Enterobacteriaceae: Escherichia coli, Enterobacter agglomerans, Klebsiella oxytoca, Klebsiella pneumoniae and Proteus vulgaris and one Aeromonas hydrophila strain. Estimations of growth and enzyme activity were made within a three-dimensional matrix of conditions: temperature 2-20 degrees C, pH value 4.0-7.5 and water activity (a(w)) 0.95-0.995. A mathematical model was constructed which predicted growth based on increases in cell number. However, although notable effects of extracellular lipases and proteases were detected, it was not possible to model enzymatic activity and prepare a combined model because the data did not follow the characteristic profile that would allow curve-fitting. Nevertheless, the model for microbial growth and information relating to enzyme activity will be made freely available in a database on the internet.

High pressure near infrared study of the mutated light-harvesting complex LH2

The pressure sensitivities of the near infrared spectra of the light-harvesting (LH2) complex and a mutant complex with a simplified BChl-B850 binding pocket were compared. In the mutant an abrupt change in the spectral properties occurred at 250 MPa, which was not observed with the native sample. Increased disorder due to collapse of the chromophore pocket is suggested.

Predictive modelling of growth and measurement of enzymatic synthesis and activity by a cocktail of Brochothrix thermosphacta

The possibility was examined of developing a predictive model that combined microbial growth (increase in cellular number) and extracellular enzyme activity of a cocktail of three strains of Brochothrix thermosphacta. Estimations of growth and enzyme activity were made within a three-dimensional matrix of conditions: temperature 2-20 degrees C, pH value 4.0-7.5 and water activity (a(w)) 0.95-0.995. A model which predicted growth based on increases in cell number was constructed. No extracellular lipases were detected, but slight proteolytic reactions were observed. Although it was not possible to model protease activity, the growth model and information relating to enzyme activity will be made freely available in a database on the Internet.

Identification of intramembrane hydrogen bonding between 131 keto group of bacteriochlorophyll and serine residue α27 in the LH2 light-harvesting complex

Intramembrane hydrogen bonding and its effect on the structural integrity of purple bacterial light-harvesting complex 2, LH2, have been assessed in the native membrane environment. A novel hydrogen bond has been identified by Raman resonance spectroscopy between a serine residue of the membrane-spanning region of LH2 alpha-subunit, and the C-13(1) keto carbonyl of bacteriochlorophyll (BChl) B850 bound to the beta-subunit. Replacement of the serine by alanine disrupts this strong hydrogen bond, but this neither alters the strongly red-shifted absorption nor the structural arrangement of the BChls, as judged from circular dichroism. It also decreases only slightly the thermal stability of the mutated LH2 in the native membrane environment. The possibility is discussed that weak H-bonding between the C-13(1) keto carbonyl and a methyl hydrogen of the alanine replacing serine(-4) or the imidazole group of the nearby histidine maintains structural integrity in this very stable bacterial light-harvesting complex. A more widespread occurrence of H-bonding to C-13(1) not only in BChl, but also in chlorophyll proteins, is indicated by a theoretical analysis of chlorophyll/polypeptide contacts at <3.5 A in the high-resolution structure of Photosystem I. Nearly half of the 96 chlorophylls have aa residues suitable as hydrogen bond donors to their keto groups.

Predictive modelling of growth and enzyme production and activity by a cocktail of Pseudomonas spp., Shewanella putrefaciens and Acinetobacter sp

The possibility was examined of developing a predictive model that combined microbial growth (increase in cellular number) with extracellular lipolytic and proteolytic enzyme activity of a cocktail of four strains of Pseudomonas spp. and one strain each of Acinetobacter sp. and Shewanella putrefaciens. Environmental conditions within the following matrix of conditions were examined: temperature 2-20 degrees C, pH value 4.0-7.5 and water activity (a(w)) 0.95-0.995 and a model was constructed, which predicted growth based on increase in cell number. Data on lipase production and protease activity were generated and will be available as a database, but no function could be identified, which was a good fit to these data, since most enzymatic production and activity occurred, as expected, during transition from exponential to stationary phase. Even at lower cell numbers, in more unfavourable conditions, hydrolysing effects were detectable, which made it difficult to construct a model combining both microbiological and enzymatic data.

[Prevalence of intimal pathogen burden in acute coronary syndromes]

Increasing evidence supports a link between serological evidence of prior exposure to infectious pathogens, pathogen burden, and the risk for future myocardial infarction and death in patients with coronary artery disease. Based on this concept, we evaluated the intimal presence of four pathogens in human coronary atheroma, clinically associated with acute coronary syndromes (ACS) and stable angina (SA), and the effect of pathogen burden on the expression of human heatshock protein 60 (hHSP60), a key protein in (auto-)immune pathogenesis of atherosclerosis. Coronary atherectomy specimens retrieved from 53 primary target lesions of patients with ACS (n=33) or SA (n=20) were assessed immunohistochemically for the presence of Chlamydia pneumoniae (C. pn.), Helicobacter pylori (H.p.), Cytomegalovirus (CMV) and Epstein-Barr Virus (EBV), and for the expression of hHSP60. Chlamydia pneumoniae was present in 74%, Helicobacter pylori in 32%, CMV in 13% and EBV in 42%. Exclusively C.pn. revealed a prevalence in ACS (91%) vs SA (45%; p<0.001). Immunohistochemical analysis revealed 6 lesions without, 21 lesions with 1, 17 lesions with 2, 6 lesions with 3 and 3 lesions with 4 infectious agents. As an important finding, the mean value in ACS lesions was significantly increased compared to those in SA (1.9 vs 1.1; p<0.01). ACS-subgroup analysis revealed the highest mean value in patients with pain at rest within the last two days (Braunwald class III). In addition, expression of hHSP60 was significantly higher in ACS (8.7%) compared to SA (1.3%; p<0.001). Pathogen burden correlated highly significant (p<0.01) with the expression of hHSP60 (r=0.44).Our data demonstrate the impact of intimal pathogen burden in plaque instability, and suggest the presence of (auto-)immunoreactions against upregulated hHSP60 as an important pathomechanism that may contribute to acute coronary syndromes.

[Chlamydial and human heat shock protein 60 homologues in acute coronary syndromes. (Auto-)immune reactions as a link between infection and atherosclerosis]

Recent studies provide evidence that infectious agents play a causal role in the pathogenesis of atherosclerosis. In this respect, a chronic persistent Chlamydia pneumoniae infection, indicated by the presence of chlamydial heat shock protein 60 (cHSP 60), is of central interest. Both cHSP60 and endogenous human (h) HSP60 are upregulated under stress conditions in intimal cells and serve as a target for cross-reactive cytotoxic HSP-serum-antibodies. Therefore, the present study evaluates the expressions of both HSP60 homologues in advanced human coronary lesions and a correlation between intimal tissuebound protein and serum antibodies (Ab) to HSP65. Coronary atherectomy specimens retrieved from 114 primary target lesions of patients with acute coronary syndrome (ACS; n=46) or stable angina (SA; n=68) were assessed immunohistochemically for the presence of cHSP60 and hHSP60. Chronic persistency of Chlamydia pneumoniae was additionally examined by transmission electron microscopy. Blood samples from30 patients were tested for anti-Chlamydia pneumoniae-IgG/IgA- and anti-HSP65-Ab titers and for serum CRP levels. Coronary plaques revealed immunoreactive cHSP60 in 47% and hHSP60 in 57% of the lesions colocalized within macrophages/foam cells. Chlamydia in foam cells most often presented ultrastructural patterns that pointed to the persistency of the pathogen. Intact, non-atherosclerotic vessels showed no signals. Mean expressions were 3.1% for cHSP60 and 3.3% for hHSP60. As a central finding, the expression of both HSP homologues was significantly (each p<0.001) higher in ACS lesions compared to SA lesions (cHSP60: 6.2 vs 1.0%, and hHSP60: 7.2 vs 0.7%). Moreover, we found positive correlations between both determinants in ACS and SA lesions (r=0.41, r=0.37; p<0.01). Most interestingly, cHSP60 revealed no relationship with anti-Chlamydia pneumoniae-IgG/IgA titers, whereas expression of cHSP60 as well as that of hHSP60 correlated with anti-HSP65-Ab titers (r=0.50, p<0.01, and r=0.42, p<0.05, respectively).cHSP60 and hHSP60 colocalize within coronary primary atheroma, most prevalent in lesions associated with ACS. For the first time, our data demonstrate a significant correlation between the intimal expression of these HSP60 homologues and serum HSP65 antibodies, thereby suggesting that humoral immune reactions to bacterial and human HSPs may play an important role in coronary atherosclerosis and plaque instability.

Trace analysis of technical nonylphenol, bisphenol A and 17alpha-ethinylestradiol in wastewater using solid-phase microextraction and gas chromatography-mass spectrometry

To enable high sample throughput, an automated solid-phase microextraction (SPME) method coupled with GC-MS for the trace analysis of technical nonylphenol, bisphenol A and 17alpha-ethinylestradiol was developed. The extraction performance of different SPME fibre coatings was examined, with polyacrylate proving most suitable. Although study of the extraction time showed that the analytes have not reached equilibrium after 3 h, as a compromise an extraction time of 1 h was applied in all the experiments with detection limits between 0.04 and 1 microg l(-1) for wastewater effluent. The mean reproducibility of the technique is 8% RSD. Carry-over effects are negligible. The linearity of calibration curves ranges over three orders of magnitude. The method was tested for determining the analytes in influents and effluents of constructed wetland plants and in model wastewater used in laboratory experiments.

[The role of intravascular ultrasound examination for assessment of graft vasculopathy]

Long-run development of heart transplanted patients is predominantly determined by the occurrence of graft vasculopathy. Due to the commonly diffuse and concentrical appearance of plaque in the coronary vessels, the disease defies, at least in the early stage, the conventionally used angiographic diagnostic procedures with radiocontrast agents. With the possibility to differentiate not only the lumen but also structures of the vessel walls and different tissue types, intracoronary ultrasound (IVUS) of coronary vessels yields entirely new insights in the development, the course and the prognostic importance of graft vasculopathy. Besides the extended scientific application in order to investigate the pathophysiology of graft vasculopathy and the assessment of therapeutic strategies, regular follow-ups with IVUS are nowadays used in many centers in routine care after heart transplant.

[C-reactive protein in coronary plaques -- prevalence with acute coronary syndrome]

Inflammatory mechanisms are central in human atherosclerosis. Although C-reactive protein (CRP) as a serum marker is highly predictive for cardiovascular events, the intimal expression of CRP in clinically relevant coronary lesions is unknown, in particular in acute coronary syndromes (ACS). Shown by reduced CRP serum values, statins have antiinflammatory and plaque-stabilizing effects. In the present study, the presence of CRP in coronary atheromas with ACS versus stable angina (SA) as well as its possible modification by chronic statin medication was assessed. Coronary atherectomy probes from 90 primary stenoses were immunohistochemically analyzed with regard to the presence and the localization of CRP. Intimal results of patients with ACS (n=36), categorized according to the Braunwald classification, were compared with those of patients with SA (n=54). In 40 of 90 lesions (44%), immunoreaction specific for CRP was observed demonstrating a mean CRP expression of 1.7%. CRP was focally localized in a maximum of 69% of all plaque cells, the most in macrophages/foam cells, infrequently in smooth muscle cells. CRP-positive plaques showed more thrombus than plaques without CRP (63% vs 41%). Intact non-atherosclerotic control tissue revealed no signaling. As a central finding, intimal presence and expression were higher (each p<0.001) with ACS (69% and 3.1%, respectively) compared to SA (28% and 0.8%, respective). Subgroup analysis of target lesions associated with ACS according to the clinical Braunwald classification showed an increase of intimal CRP with classes I-III. In the presence of statin medication, intimal CRP was significantly lower than that without statin therapy (29 and 1.3%, vs 61 and 2.6%, respectively; p<0.01), in particular in the subgroup of ACS patients. Intimal CRP is frequently found in coronary primary stenoses, very often with macrophages/foam cells, and shows a highly significant prevalence with ACS. In this subgroup of patients, statin therapy is associated with significantly reduced intimal CRP. Our in situ findings as shown might explain the well-known serum constellations with statin therapy.

Assembly of light-harvesting bacteriochlorophyll in a model transmembrane helix in its natural environment

The transmembrane, bacteriochlorophyll-binding region of a bacterial light-harvesting complex, (LH2-alpha from the photosynthetic bacterium Rhodobacter sphaeroides) was redesigned and overexpressed in a mutant of Rb. sphaeroides lacking LH2. Bacteriochlorophyll served as internal probe for the fitness of this new region for the assembly and energy transfer function of the LH2 complex. The ability to absorb and transfer light energy is practically undisturbed by the exchange of the transmembrane segment, valine -7 to threonine +6, of LH2-alpha with a 14 residue Ala-Leu sequence. This stretch makes up the residues of the transmembrane helix that are in close contact (< or =4.5 A) with the bacteriochlorophyll molecules that are coordinated through His of both the alpha and beta-subunits. In this Ala-Leu stretch, neither alpha-His0, which binds the bacteriochlorophyll, nor the adjacent alpha-Ile-1, were replaced. Novel LH2 complexes composed of LH2-alpha with a model transmembrane sequence and a normal LH2-beta are assembled in vivo into a complex, the biochemical and spectroscopic properties of which closely resemble the native one. In contrast, the additional insertion of four residues just outside the C-terminal end of the model transmembrane helix leads to complete loss of functional antenna complex. The results suggest that light energy can be harvested and transferred efficiently by bacteriochlorophyll molecules attached to only few key residues distributed over the polypeptide, while residues at the bacteriochlorophyll-helix interface seem to be largely dispensable for the functional assembly of this membrane protein complex. This novel antenna with a simplified transmembrane domain and a built-in probe for assembly and function provides a powerful model system for investigation of the factors that contribute to the assembly of chromophores in membrane-embedded proteins.

[Influence of spiced feed additives on taste of hen's eggs]

The effect of the spices garlic (Allium sativum), extract from garlic, sage (Salvia officinalis), caraway (Carum carvi), peppermint (Mentha piperita), fennel (Foeniculum vulgare), thyme (Thymus vulgaris), paprika (Capsicum annuum), marjoram (Majorana hortensis), cardamom (Elettaria cardamomum) and sausage-mix fed to white hybrides on the quality of eggs (n = 705) was tested by 10 qualified persons. Changes in smell or taste were partly significant; a direct improvement is hard to induce. A well seasoned taste was obtained by feeding of garlic, fennel, peppermint and marjoram. They produce an aromatic flavor. A practical application is possible but limited by higher production prices. Further, it is uncertain if there is a need for "taste-manipulated" eggs.

[Quantitative determination of lipases and their heat stability in food of animal origin]

Quality deterioration and food spoilage in fat-containing food is mostly caused by bacterial and endogenous lipases. Quantitative data on the concentration of lipases for a possibly better evaluation of shelf life do not exist. Own investigations for detecting lipases and evaluating their heat stability in selected food of animal origin (meat-products, fish-products, porcine liver) were carried out using the Reflektoquant Lipasetest (Merck). Extreme high values could be found in porcine liver and in muscles of fat fish such as herring. Pork contained 46 micrograms/kg, beef 86 micrograms/kg and poultry a 3-fold higher value. Significant differences could be observed in parts within poultry (breast 139 micrograms/kg, leg 259 micrograms/kg). Heated sausage and hot smoked fish were largely lipase-free, raw sausages contained up to 283 micrograms/kg lipases. Fish- and meat-lipases were not as heat stable as investigated bacterial lipases which makes them distinguishable.

FLEXGene repository: from sequenced genomes to gene repositories for high-throughput functional biology and proteomics

The vast amount of information generated by the human genome sequencing project and related projects has given rise to a new paradigm in experimental biology. This new paradigm invokes the experimentation and data analysis at genome-wide scales, as well as the generation of new technologies and resources that take full advantage of the available sequence information. The Institute of Proteomics at Harvard Medical School is building a comprehensive, characterized, arrayed and flexible gene repository that will allow full exploitation of the genomic information by enabling functional genomics as well as protein expression, purification and analysis at genome wide scale. The FLEXGene repository (Full Length EXpression-ready) will contain clones representing the complete set of open reading frames (ORFs) of different organisms including H. sapiens and several pathogens and model organisms. The clones are constructed using recombination-based cloning technology so that hundreds or thousands of coding regions can be transferred into any expression vector in a parallel and timely mode, allowing the broadest variety of experiments to be carried out.