[How does the surgical society (DGAV) support the continuing medical training in general and visceral surgery?]

The medical councils (Ärztekammern) develop the contents of the further training regulations with the support of the specialist society. The hospitals with the training supervisors have to implement these contents for the trainees in continuing education and confirm the acquisition of competence for the individual tasks. Surveys of young surgeons in recent years have shown that many participants do not receive structured continuing education, so that there is general dissatisfaction. Therefore, the German Society for General and Visceral Surgery (DGAV) is required to provide assistance to its members to improve continuing education in the departments. For example, the DGAV organizes more than 100 surgical courses annually on all topics of visceral surgery, anatomy, skills courses and revision courses with the Further Education and Advanced Training Quality Center (WeiFoQ). This year a continuing education curriculum was developed over the 6‑year continuing education period, so that a structured continuing education is achievable. The contents of the continuing education regulations are included in this continuing education curriculum with explanations, video clips, and graphics, thus providing quick information on each individual surgical clinical picture. A digital surgical catalog provides a quick overview of the status of personal continuing education. It is planned to set up an interface to the eLogbook of the medical councils.

Correction: Luedemann et al. Prostate Cancer-Associated miRNAs in Saliva: First Steps to an Easily Accessible and Reliable Screening Tool. Biomolecules 2022, 12, 1366

The authors wish to make the following corrections to their paper [...]

[Impact of the COVID pandemic on treatment of bariatric patients in Germany-An analysis of the national StuDoQ/MBE register]

BACKGROUND

During the coronavirus disease 2019 (COVID-19) pandemic the standard inpatient care of patients was restricted to increase overall and intensive care capacity reserves for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected persons.

OBJECTIVE

This article presents the impact of the COVID-19 pandemic on the surgical and postoperative care of bariatric patients in Germany.

MATERIAL AND METHODS

A statistical analysis of the national StuDoQ/MBE register data for the period from 1 May 2018 until 31 May 2022 was performed.

RESULTS

Throughout the entire study period there was a continuous increase in documented operations, which continued even during the COVID-19 pandemic. A significant intermittent decline in surgery performed was observed only during the imposition of first lockdown in the months of March to May 2020, with a minimum number of 194 cases performed monthly in April 2020. The pandemic had no measurable effect on the surgically treated patient population, the type of surgical procedure, the perioperative and postoperative outcomes and follow-up care.

CONCLUSION

Based on the results of the StuDoQ data and the current literature, it can be deduced that bariatric surgery can be carried out with no increased risk during the COVID-19 pandemic and the quality of postoperative care is not impaired.

Prostate Cancer-Associated miRNAs in Saliva: First Steps to an Easily Accessible and Reliable Screening Tool

Background: Common diagnostic tools for prostate cancer—prostate-specific antigen and transrectal biopsy—show only low predictive value and poor sensitivity. This study examines circulating miRNA in saliva to explore the possibility of a non-invasive and easy-to-execute diagnostic tool for prostate cancer screenings. Methods: 16 miRNAs were extracted from salivary exosomes and analyzed via the delta-CT method. The presented method enables an application of the test in any health institution and even outpatient sector. Recruited participants were suspected to suffer from prostate cancer due to elevated PSA serum levels. Of these participants, 43 were diagnosed with prostate cancer, while 31 suffered from benign diseases and served as control group. Results: hsa-mir-331-3p and hsa-mir-200b were significantly reduced in prostate cancer patients compared to the control group. ROC curve analysis revealed a reliable differentiation strength (AUC > 0.6) for both miRNAs with positive predictive values of 71% indicating prostate cancer. Differentiation of both groups based on PSA serum measurements was insufficient. The other 14 examined miRNAs showed no significant group differences. Conclusions: The presented method and miRNA are promising non-invasive tools to augment the current prostate cancer screening, thereby improving screening sensitivity and reducing numbers of false positive cancer suspects admitted to further invasive diagnostic and therapeutic steps.

Small RNAs as biomarkers to differentiate benign and malign prostate diseases: An alternative for transrectal punch biopsy of the prostate?

Prostate cancer (PCa) is the most common cancer and the third most frequent cause of male cancer death in Germany. MicroRNAs (miRNA) appear to be involved in the development and progression of PCa. A diagnostic differentiation from benign prostate hyperplasia (BPH) is often only possible through transrectal punch biopsy. This procedure is described as painful and carries risks. It was investigated whether urinary miRNAs can be used as biomarkers to differentiate the prostate diseases above. Therefore urine samples from urological patients with BPH (25) or PCa (28) were analysed using Next-Generation Sequencing to detect the expression profile of total and exosomal miRNA/piRNA.

79 miRNAs and 5 piwi-interacting RNAs (piRNAs) were significantly differentially expressed (adjusted p-value < 0.05 and log2-Fc > 1 or < -1). Of these, 6 miRNAs and 2 piRNAs could be statistically validated (AUC on test cohort > = 0.7). In addition, machine-learning algorithms were used to identify a panel of 22 additional miRNAs, whose interaction makes it possible to differentiate the groups as well. There are promising individual candidates for potential use as biomarkers in prostate cancer. The innovative approach of applying machine learning methods to this kind of data could lead to further small RNAs coming into scientific focus, which have so far been neglected.

See (n)One, Do (n)One, Teach (n)One: Reality of Surgical Resident Training in Germany

Introduction

Due to technological changes, working time restrictions and the creation of specialized centers, surgical training has changed. A competence-based learning technique of surgical skills is the sub-step practice approach, which has been proven important in nationwide opinion surveys. The aim of this prospective multi-center trial was to determine the status quo of the sub-step concept in Germany.

Methods

Over 6 months, the voluntarily participating centers evaluated the following index procedures: laparoscopic cholecystectomy (LCHE), laparoscopic and open sigmoid resection, minimally invasive inguinal hernia repair, thyroid resection and pylorus-preserving pancreaticoduodenectomy (PPPD). Patients with private insurance were excluded. The detailed sub-steps were documented as well as the reason why these were not performed. In addition, an online survey regarding the sub-step concept was performed before and after the study.

Results

In total, 21 centers included 2969 surgical procedures in 2018 for final analyses. While 24.4% of the procedures were performed by residents, sub-steps were performed in 22.2%. LCHE was most often performed completely by residents (43.3%), and PPPD revealed the highest rate of performed sub-steps (43.3%). Reasons for not assisting sub-steps to residents were often organizational and other reasons. After an initial increase, the number of performed sub-steps decreased significantly during the second half of the survey. The opinion survey revealed a high importance of the sub-step concept. The number of resident procedures was overestimated, and the number of performed sub-steps was underestimated. After the study, these estimations were more realistic.

Conclusion

Even though the sub-step practice concept is considered highly important for surgical education, it needs to be put into practice more consequently. The current data suggest a low participation of surgical residents in the operating room, although the participating hospitals are most likely highly interested in surgical education, hence their voluntary participation. Conceptual changes and a control of surgical education are needed.

Electronic supplementary material

The online version of this article (10.1007/s00268-020-05539-6) contains supplementary material, which is available to authorized users.

[Quality indicators for colon cancer surgery : Evidence-based development of a set of indicators for the outcome quality]

BACKGROUND

Quality assessment in surgery is gaining in importance. Although sporadic recommendations for quality indicators (QI) in oncological colon surgery can be found in the literature, these are usually not systematically derived from a solid evidence base. Moreover, reference ranges for QI are unknown.

OBJECTIVE

The aim of this initiative was the development of evidence-based QI for oncological colon resections by an expert panel invited by the German Society of General and Visceral Surgery (DGAV). Reference ranges from the literature and reference values from the Study, Documentation, and Quality Center (StuDoQ)|Colon Cancer Register were compared in order to deduce recommendations which are tailored to the German healthcare system.

RESULTS

Based on the most recent scientific evidence and agreed by expert consensus, five QI for oncological colon surgery were defined and evaluated according to the QUALIFY tool. Mortality, MTL30 (mortality, transfer to another acute care hospital, or length of stay ≥30 days), anastomotic leakage requiring reintervention, surgical site infections necessitating reopening of the wound and ≥12 lymph nodes in the specimen qualified as QI owing to their relevance, scientific nature, and practicability. Based on the results of the systematic literature search and the statistical analysis of the StuDoQ|Colon Cancer Register, preliminary reference values are proposed for each QI.

CONCLUSION

The presented set of QI seems appropriate for quality assessment of oncological colon surgery in the context of the German healthcare system. The validity of the QI and the reference values must be reviewed within the framework of their implementation. The StuDoQ|Colon Cancer Register provides a suitable infrastructure for collecting clinical data for quality assessment and risk adjustment.

MTL, a composite measure for objectively profiling hospitals on surgical performance in colorectal cancer surgery

PURPOSE

MTL is a composite outcome measure based on routine administrative data defined as (a) postoperative mortality and/or (b) postoperative transfer to another hospital and/or (c) length of hospital stay ≥ the prespecified time period. Aim of the present study was to investigate MTL for profiling hospitals on surgical performance in colorectal cancer surgery, using data from the national registers of the German Society of General and Visceral Surgery (DGAV) and to determine the time interval for length of stay with the highest accuracy regarding major complications (Clavien-Dindo grade ≥ 3).

METHODS

All patients undergoing colorectal cancer resection between January 2010 and February 2017 were included. MTL rates were calculated and compared to well-established single outcome measures using multivariate regression analysis. For each outcome measure, postoperative complications were tested regarding their predictability.

RESULTS

Data from 14,978 patients were analyzed. Length of stay was significantly prolonged if postoperative complications occurred (p < 0.0001). Thirty-day mortality and the indication for a transfer to another hospital mainly resulted from cardiopulmonary complications. MTL occurs significantly more often than any of the single-outcome parameters. The time interval of 22 days demonstrated the highest accuracy regarding severe complications (Clavien-Dindo grade ≥ 3).

CONCLUSIONS

MTL reflects the complete spectrum of postoperative complications. Compared to individual surgical outcome parameters, MTL may have a better discriminatory power and is therefore suitable to mirror surgical quality. Because of its high accuracy regarding surgical major morbidity, 22 days is the best cut-off for length of stay within the German healthcare system.

Variation in pancreatoduodenectomy as delivered in two national audits

Background

Nationwide audits facilitate quality and outcome assessment of pancreatoduodenectomy. Differences may exist between countries but studies comparing nationwide outcomes of pancreatoduodenectomy based on audits are lacking. This study aimed to compare the German and Dutch audits for external data validation.

Methods

Anonymized data from patients undergoing pancreatoduodenectomy between 2014 and 2016 were extracted from the German Society for General and Visceral Surgery StuDoQ|Pancreas and Dutch Pancreatic Cancer Audit, and compared using descriptive statistics. Univariable and multivariable risk analyses were undertaken.

Results

Overall, 4495 patients were included, 2489 in Germany and 2006 in the Netherlands. Adenocarcinoma was a more frequent indication for pancreatoduodenectomy in the Netherlands. German patients had worse ASA fitness grades, but Dutch patients had more pulmonary co-morbidity. Dutch patients underwent more minimally invasive surgery and venous resections, but fewer multivisceral resections. No difference was found in rates of grade B/C postoperative pancreatic fistula, grade C postpancreatectomy haemorrhage and in-hospital mortality. There was more centralization in the Netherlands (1·3 versus 13·3 per cent of pancreatoduodenectomies in very low-volume centres; P &lt; 0·001). In multivariable analysis, both hospital stay (difference 2·49 (95 per cent c.i. 1·18 to 3·80) days) and risk of reoperation (odds ratio (OR) 1·55, 95 per cent c.i. 1·22 to 1·97) were higher in the German audit, whereas risk of postoperative pneumonia (OR 0·57, 0·37 to 0·88) and readmission (OR 0·38, 0·30 to 0·49) were lower. Several baseline and surgical characteristics, including hospital volume, but not country, predicted mortality.

Conclusion

This comparison of the German and Dutch audits showed variation in case mix, surgical technique and centralization for pancreatoduodenectomy, but no difference in mortality and pancreas-specific complications.

[Acute right-sided upper abdominal pain in a 46-year-old woman]

A 46-year-old woman presented with acute abdominal pain in the right upper quadrant. Esophagogastroduodenoscopy revealed a duodenal stenosis within the horizontal part of the duodenum. Based on the findings of abdominal computed tomography (CT), endosonography, Doppler duplex sonography and angiography, the diagnosis of an aneurysm of a branch of the inferior pancreaticoduodenal artery was established. This arterial branch was part of a collateral circulation between the superior mesenteric artery and the proper hepatic artery caused by obturation of the celiac artery. The symptomatic duodenal stenosis was the result of a local hematoma due to prior rupture of an aneurysm. After successful coiling of the afferent vessels to the aneurysm follow-up examinations showed progredient resorption of the hematoma and the patient was free of complaints.

Preliminary evaluation of cytosine-phosphate-guanine oligodeoxynucleotides bound to gelatine nanoparticles as immunotherapy for canine atopic dermatitis

Cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODN) are a promising new immunotherapeutic treatment option for canine atopic dermatitis (AD). The aim of this uncontrolled pilot study was to evaluate clinical and immunological effects of gelatine nanoparticle (GNP)-bound CpG ODN (CpG GNP) on atopic dogs. Eighteen dogs with AD were treated for 8 weeks (group 1, n=8) or 18 weeks (group 2, n=10). Before inclusion and after 2 weeks, 4 weeks, 6 weeks (group 1+2), 8 weeks, 12 weeks and 16 weeks (group 2) 75 µg CpG ODN/dog (bound to 1.5 mg GNP) were injected subcutaneously. Pruritus was evaluated daily by the owner. Lesions were evaluated and serum concentrations and mRNA expressions of interferon-γ, tumour necrosis factor-α, transforming growth factor-β, interleukin (IL) 10 and IL-4 (only mRNA expression) were determined at inclusion and after 8 weeks (group 1+2) and 18 weeks (group 2). Lesions and pruritus improved significantly from baseline to week 8. Mean improvements from baseline to week 18 were 23 per cent and 44 per cent for lesions and pruritus, respectively, an improvement of ≥50 per cent was seen in six out of nine and three out of six dogs, respectively. IL-4 mRNA expression decreased significantly. The results of this study show a clinical improvement of canine AD with CpG GNP comparable to allergen immunotherapy. Controlled studies are needed to confirm these findings.

[Are there too many conferences for general and visceral surgery in Germany? : A survey of DGAV members]

BACKGROUND

Human and financial resources are increasingly bound due to economic pressure and the working hours Act whereby the already restricted further training times are further limited. The industry also has less funding available for sponsorship of conferences and workshops. Against this background the question arises whether a reduction or focusing of the conferences is necessary; therefore, the aim of this survey was to obtain an opinion from members of the German Society of General and Visceral Surgery (DGAV) and possibly to derive a need for action to submit to the board members.

METHODS

From 7 February to 18 March 2015 an online survey was conducted by the DGAV with their members regarding the number of necessary congress events in Germany.

RESULTS

A total of 670 responses were received (return rate 16 %). In total, 56 % of participants felt that there are too many conferences. A differentiation according to the position of the respondent and the level of the associated hospital resulted in the following: 69.3 % of the participating head physicians (HP) shared this opinion, compared to 48.6 % of senior physicians (SP) and 34.4 % of residents (RP). Of the participants from basic and standard care hospitals (B/SC) 50 % shared this opinion, compared to 59.2 % from maximum care hospitals (MC) and 63.6 % from university hospitals (UH). In addition, a total of 75 % of the participants (HP 82.9 %, SP 78.4 %, RP 70.5 %) were in favor of keeping the congress of the DGAV (annual meeting of the German Society for Digestive and Metabolic Diseases in conjunction with the Autumn meeting of the DGAV) in its previous form, regardless of the underlying level of care of the associated hospital (B/SC 77 %, MC 79 %, UC 68 %).

CONCLUSION

More experienced surgeons in particular tended to favor a reduction of events with a focus on the major conferences; however, younger colleagues preferred a wider spectrum of meetings. In order to comply with both positions a wide range of events should be continued to be provided in the future so that surgeons can choose which to attend according to the individual preferences.

ANCAC: amino acid, nucleotide, and codon analysis of COGs--a tool for sequence bias analysis in microbial orthologs

BACKGROUND

The COG database is the most popular collection of orthologous proteins from many different completely sequenced microbial genomes. Per definition, a cluster of orthologous groups (COG) within this database exclusively contains proteins that most likely achieve the same cellular function. Recently, the COG database was extended by assigning to every protein both the corresponding amino acid and its encoding nucleotide sequence resulting in the NUCOCOG database. This extended version of the COG database is a valuable resource connecting sequence features with the functionality of the respective proteins.

RESULTS

Here we present ANCAC, a web tool and MySQL database for the analysis of amino acid, nucleotide, and codon frequencies in COGs on the basis of freely definable phylogenetic patterns. We demonstrate the usefulness of ANCAC by analyzing amino acid frequencies, codon usage, and GC-content in a species- or function-specific context. With respect to amino acids we, at least in part, confirm the cognate bias hypothesis by using ANCAC's NUCOCOG dataset as the largest one available for that purpose thus far.

CONCLUSIONS

Using the NUCOCOG datasets, ANCAC connects taxonomic, amino acid, and nucleotide sequence information with the functional classification via COGs and provides a GUI for flexible mining for sequence-bias. Thereby, to our knowledge, it is the only tool for the analysis of sequence composition in the light of physiological roles and phylogenetic context without requirement of substantial programming-skills.

On the cytotoxicity of HCR-NTPase in the neuroblastoma cell line SH-SY5Y

Background

The human cancer-related nucleoside triphosphatase (HCR-NTPase) is overexpressed in several tumour tissues including neuroblastoma. HCR-NTPase is an enzyme exhibiting a slow in vitro activity in hydrolysing nucleosidetriphosphates. However, its in vivo function is still unknown. To learn more about the physiological role of HCR-NTPase, we both overexpressed and silenced it in the neuroblastoma cell line SH-SY5Y.

Findings

No effect was observed when the expression of endogenously expressed HCR-NTPase in the cells was silenced by RNA interference. On the other hand, overexpression of HCR-NTPase led to cytotoxicity of the protein in SH-SY5Y cells. Even if the catalytic essential amino acid glutamate 114 was replaced by alanine (E114A-HCR-NTPase), the protein remained cytotoxic. The results could be confirmed by successfully rescuing the cells via RNA interference.

Conclusion

Although expressed in several tumours, at least in SH-SY5Y, HCR-NTPase is not essential for the cells to survive. Increased levels of the protein lead to cytotoxicity due to physical intracellular interactions rather than hydrolysis of nucleosidetriphosphates by its intrinsic residual enzymatic activity.

Direct decompressive surgery with post-operative radiotherapy (S + RT) versus radiotherapy (RT) alone for the treatment of metastatic epidural spinal cord compression (MESCC): A cost-utility analysis using Ontario health economic data

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Background: For selected patients with MESCC, S + RT has recently been shown to improve patients’ ability to ambulate and reduce opioid and corticosteroid use when compared with RT alone, with a trend towards survival benefit. (Patchell et al Lancet 2005) The economic impact of adopting this intervention has not been assessed previously. Methods: An analytic decision model was constructed based on the results from Patchell et al. (2005) The perspective of the public health care insurer of Ontario was adopted for the analysis. Costing was performed by using Ontario data for the following items: surgery, radiotherapy, hospitalization, home care services, palliative hospice, and medications. Utilities were obtained from the Harvard University Catalogue of preference score (HUC) and the Health Outcomes Data Repository Data - Health Utility list (HODaR). The primary analysis is a cost-utility analysis comparing surgery and radiotherapy (S+RT) with radiotherapy alone (RT). A probabilistic sensitivity analysis with Monte-Carlo simulation was performed. Results: When comparing S+ RT with RT alone, the incremental cost-effectiveness ratio (ICER) is CAD$ 43,796 per QALY gained. The cost-utility of S + RT is CAD$ 509,084 per QALY and that of RT alone is CAD$ 2,381,246 per QALY. S + RT costs approximately CAD$ 33 more when compared with RT alone per ambulatory day gained. The cost of surgery is partially offset by the decreased cost of hospice palliative care since more patients remain ambulatory and stay at home. Monte-Carlo simulation showed that there is a 25% chance that S + RT may dominate RT alone. The results are sensitive but generally robust to changes in assumptions about the costs of surgery, home care and palliative hospice care. Conclusions: S+RT is likely cost-effective when compared with RT alone for the treatment of MESCC in selected patients, and should be considered by health care policy makers.

No significant financial relationships to disclose.

Crystal structure of THEP1 from the hyperthermophile Aquifex aeolicus: a variation of the RecA fold

Background

aaTHEP1, the gene product of aq_1292 from Aquifex aeolicus, shows sequence homology to proteins from most thermophiles, hyperthermophiles, and higher organisms such as man, mouse, and fly. In contrast, there are almost no homologous proteins in mesophilic unicellular microorganisms. aaTHEP1 is a thermophilic enzyme exhibiting both ATPase and GTPase activity in vitro. Although annotated as a nucleotide kinase, such an activity could not be confirmed for aaTHEP1 experimentally and the in vivo function of aaTHEP1 is still unknown.

Results

Here we report the crystal structure of selenomethionine substituted nucleotide-free aaTHEP1 at 1.4 Å resolution using a multiple anomalous dispersion phasing protocol. The protein is composed of a single domain that belongs to the family of 3-layer (α/β/α)-structures consisting of nine central strands flanked by six helices. The closest structural homologue as determined by DALI is the RecA family. In contrast to the latter proteins, aaTHEP1 possesses an extension of the β-sheet consisting of four additional β-strands.

Conclusion

We conclude that the structure of aaTHEP1 represents a variation of the RecA fold. Although the catalytic function of aaTHEP1 remains unclear, structural details indicate that it does not belong to the group of GTPases, kinases or adenosyltransferases. A mainly positive electrostatic surface indicates that aaTHEP1 might be a DNA/RNA modifying enzyme. The resolved structure of aaTHEP1 can serve as paradigm for the complete THEP1 family.

Metal concentrations in soil and seepage water due to infiltration of roof runoff by long term numerical modelling

The qualitative effects of stormwater infiltration on soil and seepage water are investigated with long term numerical modelling. The retention behaviour of different soils and materials used in infiltration devices is determined with batch and column tests. Results of the laboratory tests are adsorption isotherms which represent input data for numerical transport modelling. The long term simulations are performed with combinations of different solutions (types of roof runoff) and infiltration devices (swale and trench) under different hydrogeological conditions. The presented results contain the infiltration of low polluted roof runoff, runoff from a roof with zinc sheets and from a roof with copper sheets concerning the heavy metals zinc, copper and lead. The increase of concentrations in the infiltration body is high. For the infiltrated water, the results show a migration to groundwater only for the low adsorbing soil.

Thermophile-specific proteins: the gene product of aq_1292 from Aquifex aeolicus is an NTPase

Background

To identify thermophile-specific proteins, we performed phylogenetic patterns searches of 66 completely sequenced microbial genomes. This analysis revealed a cluster of orthologous groups (COG1618) which contains a protein from every thermophile and no sequence from 52 out of 53 mesophilic genomes. Thus, COG1618 proteins belong to the group of thermophile-specific proteins (THEPs) and therefore we here designate COG1618 proteins as THEP1s. Since no THEP1 had been analyzed biochemically thus far, we characterized the gene product of aq_1292 which is THEP1 from the hyperthermophilic bacterium Aquifex aeolicus (aaTHEP1).

Results

aaTHEP1 was cloned in E. coli, expressed and purified to homogeneity. At a temperature optimum between 70 and 80°C, aaTHEP1 shows enzymatic activity in hydrolyzing ATP to ADP + P_i with k_cat = 5 × 10^-3 s^-1 and K_m = 5.5 × 10^-6 M. In addition, the enzyme exhibits GTPase activity (k_cat = 9 × 10^-3 s^-1 and K_m= 45 × 10^-6 M). aaTHEP1 is inhibited competitively by CTP, UTP, dATP, dGTP, dCTP, and dTTP. As shown by gel filtration, aaTHEP1 in its purified state appears as a monomer. The enzyme is resistant to limited proteolysis suggesting that it consists of a single domain. Although THEP1s are annotated as "predicted nucleotide kinases" we could not confirm such an activity experimentally.

Conclusion

Since aaTHEP1 is the first member of COG1618 that is characterized biochemically and functional information about one member of a COG may be transferred to the entire COG, we conclude that COG1618 proteins are a family of thermophilic NTPases.

Multifunctional tryptophan-synthesizing enzyme. The molecular weight of the Euglena gracilis protein is unexpectedly low

After developing a suitable procedure to produce large amounts of Euglena gracilis as well as a reliable protocol to purify the multifunctional tryptophan-synthesizing enzyme derived from it (Schwarz, T., Bartholmes, P., and Kaufmann, M. (1995) Biotechnol. Appl. Biochem. 22, 179-190), we here describe structural and catalytic properties of the multifunctional tryptophan-synthesizing enzyme. The kinetic parameters kcat of all five activities and Km for the main substrates were determined. The relative molecular weight under denaturing conditions as judged by SDS-polyacrylamide gel electrophoresis is 136,000. Cross-linking as well as gel filtration experiments revealed that the enzyme exists as a homodimer. Neither intersubunit disulfide linkages nor glycosylations were detected. On the other hand, the polypeptide chains are blocked N-terminally. Complete tryptic digestion of the protomer, high pressure liquid chromatography separation of the resulting peptides, and N-terminal sequence analysis of homogenous peaks as judged by matrix-assisted laser/desorption ionization time-of-flight mass spectrometry was performed. Depending on the sequenced peptides, alignments to all entries of the SwissProt data base resulted in both strong sequence homologies to known Trp sequences and no similarities at all. Proteolytic digestion under native conditions using endoproteinase Glu-C uncovered one major cleavage site yielding a semistable, N-terminally blocked fragment with a molecular weight of 119,000. In addition, an increase in beta-elimination accompanied by a decrease in beta-replacement activity of the beta-reaction during proteolysis was observed.

A shared subunit belongs to the eukaryotic core RNA polymerase

The yeast RNA polymerase I is a multimeric complex composed of 14 distinct subunits, 5 of which are shared by the three forms of nuclear RNA polymerase. The reasons for this structural complexity are still largely unknown. Isolation of an inactive form of RNA Pol I lacking the A43, ABC23, and A14 subunits (RNA Pol I delta) allowed us to investigate the function of the shared subunit ABC23 by in vitro reconstitution experiments. Addition of recombinant ABC23 alone to the RNA Pol I delta reactivated the enzyme to up to 50% of the wild-type enzyme activity. The recombinant subunit was stably and stoichiometrically reassociated within the enzymatic complex. ABC23 was found to be required for the formation of the first phosphodiester bond, but it was not involved in DNA binding by RNA Pol I, as shown by gel retardation and surface plasmon resonance experiments, and did not recycle during transcription. Electron microscopic visualization and electrophoretic analysis of the subunit depleted and reactivated forms of the enzyme indicate that binding of ABC23 caused a major conformational change leading to a transcriptionally competent enzyme. Altogether, our results demonstrate that the ABC23 subunit is required for the structural and functional integrity of RNA Pol I and thus should be considered as part of the core enzyme.

Localization of yeast RNA polymerase I core subunits by immunoelectron microscopy

Immunoelectron microscopy was used to determine the spatial organization of the yeast RNA polymerase I core subunits on a three-dimensional model of the enzyme. Images of antibody-labeled enzymes were compared with the native enzyme to determine the localization of the antibody binding site on the surface of the model. Monoclonal antibodies were used as probes to identify the two largest subunits homologous to the bacterial beta and beta' subunits. The epitopes for the two monoclonal antibodies were mapped using subunit-specific phage display libraries, thus allowing a direct correlation of the structural data with functional information on conserved sequence elements. An epitope close to conserved region C of the beta-like subunit is located at the base of the finger-like domain, whereas a sequence between conserved regions C and D of the beta'-like subunit is located in the apical region of the enzyme. Polyclonal antibodies outlined the alpha-like subunit AC40 and subunit AC19 which were found co-localized also in the apical region of the enzyme. The spatial location of the subunits is correlated with their biological activity and the inhibitory effect of the antibodies.

Effect of (E)-5-(2-bromovinyl)- and 5-vinyl-1-beta-D-arabinofuranosyluracil on Epstein-Barr virus antigen expression in P3HR-1 cells: comparison with acyclovir

The effect of (E)-5-(2-bromovinyl)- and 5-vinyl-1-beta-D-arabinofuranosyluracil (BrVaraU, VaraU) in comparison to 9-(2-hydroxyethoxymethyl)guanine (ACV) on the proliferation of human lymphoblastoid P3HR-1 cells in culture and on the expression of Epstein-Barr virus capsid antigen (VCA) in the same cells was evaluated. After 7 days of cell growth, at 100 mumol/l the total number of new generations in drug-treated cultures was similar or 5 and 10% below that in drug-free control cultures, for VaraU, ACV, and BrVaraU, respectively. During the same time the percentage of VCA-expressing cells decreased from 6.3% in drug-free cultures to 1.3, 1.5, and 2.0% in cultures treated with VaraU, ACV and BrVaraU, respectively. In VaraU-treated cultures a further decrease in the percentage of VCA-positive cells down to 0.5% was revealed 7 days after drug removal. VaraU was also effective in reducing the proportion of VCA-expressing cells at 10 and 1 mumol/l. At 14 days after drug removal, the inhibitory effect of ACV was nearly reversed, whereas BrVaraU showed a prolonged VCA- suppressing effect.

[Electromyographic investigations of the sphincter systems in the diagnosis of female urinary incontinence (author's transl)]

Electromyographic investigations of the sphincters of bladder and rectum allow reproduceable and objective signs of possible lesions of this region. That's why we use this method to identify preoperatively the pathogenesis of female urinary incontinence.