Increasing isoflurane dose reduces homotopic correlation and functional segregation of brain networks in mice as revealed by resting-state fMRI

Effects of anesthetics on brain functional networks are not fully understood. In this work, we investigated functional brain networks derived from resting-state fMRI data obtained under different doses of isoflurane in mice using stationary and dynamic functional connectivity (dFC) analysis. Stationary network analysis using FSL Nets revealed a modular structure of functional networks, which could be segregated into a lateral cortical, an associative cortical network, elements of the prefrontal network, a subcortical network, and a thalamic network. Increasing isoflurane dose led to a loss of functional connectivity between the bilateral cortical regions. In addition, dFC analysis revealed a dominance of dynamic functional states (dFS) exhibiting modular structure in mice anesthetized with a low dose of isoflurane, while at high isoflurane levels dFS showing widespread unstructured correlation displayed highest weights. This indicates that spatial segregation across brain functional networks is lost with increasing dose of the anesthetic drug used. To what extent this indicates a state of deep anesthesia remains to be shown. Combining the results of stationary and dynamic FC analysis indicates that increasing isoflurane levels leads to loss of modular network organization, which includes loss of the strong bilateral interactions between homotopic brain areas.

Computational design of protein antigens that interact with the CDR H3 loop of HIV broadly neutralizing antibody 2F5

Rational design of proteins with novel binding specificities and increased affinity is one of the major goals of computational protein design. Epitope-scaffolds are a new class of antigens engineered by transplanting viral epitopes of predefined structure to protein scaffolds, or by building protein scaffolds around such epitopes. Epitope-scaffolds are of interest as vaccine components to attempt to elicit neutralizing antibodies targeting the specified epitope. In this study we developed a new computational protocol, MultiGraft Interface, that transplants epitopes but also designs additional scaffold features outside the epitope to enhance antibody-binding specificity and potentially influence the specificity of elicited antibodies. We employed MultiGraft Interface to engineer novel epitope-scaffolds that display the known epitope of human immunodeficiency virus 1 (HIV-1) neutralizing antibody 2F5 and that also interact with the functionally important CDR H3 antibody loop. MultiGraft Interface generated an epitope-scaffold that bound 2F5 with subnanomolar affinity (K(D) = 400 pM) and that interacted with the antibody CDR H3 loop through computationally designed contacts. Substantial structural modifications were necessary to engineer this antigen, with the 2F5 epitope replacing a helix in the native scaffold and with 15% of the native scaffold sequence being modified in the design stage. This epitope-scaffold represents a successful example of rational protein backbone engineering and protein-protein interface design and could prove useful in the field of HIV vaccine design. MultiGraft Interface can be generally applied to engineer novel binding partners with altered specificity and optimized affinity.

Physiologische Bedeutung der „Stringent Control“ bei Escherichia coli unter extremen Hungerbedingungen / Stringent Control and Starvation Survival in Escherichia coli

The viability of three isogenic relA+/relA strain pairs of Escherichia coli (CP78/CP79; NF 161/ NF162; CP 107/CP 143) was studied during prolonged starvation for amino acids, glucose or phosphate. After amino acid limitation we found a prolonged viability of all relA+ strains which synthesized ppGpp. We suggest that some ppGpp-mediated pleiotropic effects of the stringent response (e.g. glykogen accumulation, enhanced protein turnover) might be involved in this prolongation of survival. After glucose or phosphate starvation there was no difference in the relA+/relA strains either in the ppGpp content or in the survival.

Methicillin-resistant Staphylococcus aureus in cattle food chains - prevalence, diversity, and antimicrobial resistance in Germany

Livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) have been found in various farm animal species throughout the world. It was the objective of this study to estimate the prevalence of MRSA in different cattle food chains (milk, beef, and veal) in Germany, to analyze the MRSA diversity along each food chain and to compare the characteristics of the different subtypes. Samples were collected between 2009 and 2012 from dairy herds (bulk tank milk), veal herds (dust from the stables), veal calves, and beef cattle at slaughter (nasal swabs) and carcasses of veal calves (surface cuts) and beef as well as veal at retail. Sampling was proportionally distributed over the country according to the cattle population (on-farm sampling), slaughterhouse capacity (abattoir samples), and the human population (meat at retail). Methicillin-resistant S. aureus were isolated using harmonized methods from all sample types and populations investigated. The highest proportion of positive samples was found in nasal swabs from veal calves at slaughter in 2012 (144/320; 45.0%) and the lowest rate in bulk tank milk in 2009 (14/388; 4.1%). Most isolates, irrespective of the origin, were from spa types t011 and t034. Both have been assigned to the clonal complex (CC) 398. Few isolates (15/632; 2.4%) were from spa types not associated with the CC398. Spa-type patterns were similar along individual food chains but differed between food chains. Antimicrobial resistance patterns differed between isolates from the different food chains and spa types. Isolates from the veal chain displayed the highest resistance rates. We conclude that there is substantial diversity in the MRSA prevalence across different cattle production sectors.

Emerging antimicrobial resistance in commensal Escherichia coli with public health relevance

In 2009, 1462 Escherichia coli isolates were collected in a systematic resistance monitoring approach from primary production, slaughterhouses and at retail and evaluated on the basis of epidemiological cut-off values. Besides resistance to antimicrobial classes that have been extensively used for a long time (e.g. sulphonamides and tetracyclines), resistance to (fluoro)quinolones and third-generation cephalosporins was observed. While in the poultry production chain the majority (60%) of isolates from laying hens was susceptible to all antimicrobials tested, most isolates from broilers, chicken meat and turkey meat showed resistance to at least one (85-93%) but frequently even to several antimicrobial classes (73-84%). In the cattle and pig production chain, the share of isolates showing resistance to at least one antimicrobial was lowest (16%) in dairy cows, whereas resistance to at least one antimicrobial ranged between 43% and 73% in veal calves, veal and pork. Resistance rates to ciprofloxacin and nalidixic acid in isolates from broilers were 41.1% and 43.1%, respectively. Likewise, high resistance rates to (fluoro)quinolones were observed in isolates from chicken meat and turkey meat. In contrast, ciprofloxacin resistance was less frequent in E. coli isolates from the cattle and pig production chain with highest rate in veal calves (13.3%). Highest resistance rates to cephalosporins were observed in broilers and chicken meat, with 5.9% and 6.2% of the isolates showing resistance. In dairy cattle and veal, no isolates with cephalosporin resistance were detected, whereas 3.3% of the isolates from veal calves showed resistance to ceftazidime. Resistance to (fluoro)quinolones and cephalosporins in E. coli isolates is of special concern because they are critically important antimicrobials in human antimicrobial therapy. The emergence of this resistance warrants increased monitoring. Together with continuous monitoring of antimicrobial usage, management strategies should be regularly assessed and adapted.

Quo vadis? - Monitoring Campylobacter in Germany

Campylobacter is a poorly recognized foodborne pathogen, leading the statistics of bacterially caused human diarrhoea in Europe during the last years. In this review, we present qualitative and quantitative German data obtained in the framework of specific monitoring programs and from routine surveillance. These also comprise recent data on antimicrobial resistances of food isolates. Due to the considerable reduction of in vitro growth capabilities of stressed bacteria, there is a clear discrepancy between the detection limit of Campylobacter by cultivation and its infection potential. Moreover, antimicrobial resistances of Campylobacter isolates established during fattening of livestock are alarming, since they constitute an additional threat to human health. The European Food Safety Authority (EFSA) discusses the establishment of a quantitative limit for Campylobacter contamination of broiler carcasses in order to achieve an appropriate level of protection for consumers. Currently, a considerable amount of German broiler carcasses would not comply with this future criterion. We recommend Campylobacter reduction strategies to be focussed on the prevention of fecal contamination during slaughter. Decontamination is only a sparse option, since the reduction efficiency is low and its success depends on the initial contamination concentration.

High heterogeneity within methicillin-resistant Staphylococcus aureus ST398 isolates, defined by Cfr9I macrorestriction-pulsed-field gel electrophoresis profiles and spa and SCCmec types

During recent years, the animal-associated methicillin-resistant Staphylococcus aureus clone ST398 has extensively been studied. The DNA of these isolates turned out to be refractory to SmaI restriction, and consequently, SmaI is unsuitable for subtyping this clone by standard pulsed-field gel electrophoresis (PFGE). Very recently, ST398 DNA was shown to be digested by Cfr9I, a neoschizomer of SmaI. In the present study, we employed Cfr9I PFGE on 100 German and 5 Dutch ST398 isolates and compared their PFGE profiles, protein A gene variable repeat regions (spa types), and types of the staphylococcal cassette chromosome mec (SCCmec). The isolates (from healthy carrier pigs, clinical samples from pigs, dust from farms, milk, and meat) were assigned to 35 profiles, which were correlated to the SCCmec type. A dendrogram with the Cfr9I patterns assigned all profiles to two clusters. Cluster A grouped nearly all isolates with SCCmec type V, and cluster B comprised all SCCmec type IVa and V* (a type V variant first identified as III) carriers plus one isolate with SCCmec type V. Both clusters also grouped methicillin-susceptible S. aureus isolates. The association of the majority of isolates with SCCmec type V in one large cluster indicated the presence of a successful subclone within the clonal complex CC398 from pigs, which has diversified. In general, the combination of Cfr9I PFGE with spa and SCCmec typing demonstrated the heterogeneity of the series analyzed and can be further used for outbreak investigations and traceability studies of the MRSA ST398 emerging clone.

Antibiotic resistance in Salmonella isolates from imported chicken carcasses in Bhutan and from pig carcasses in Vietnam

The antibiotic resistance in Salmonella isolates from 400 imported chicken carcasses in Bhutan and from 178 pig carcasses in Vietnam were analyzed on a random basis against 14 antimicrobial agents. Among the poultry samples tested, 13% were positive for Salmonella. Salmonella Enteritidis dominated with a prevalence of 80.7%, and 40 of the 42 isolates harbored two or more resistance determinants. For the 178 pigs investigated, 49.4% of the swabs and 34.8% of the lymph nodes were Salmonella positive. The most prevalent serotypes in lymph nodes were Salmonella Derby (50.0%) and Salmonella Typhimurium (27.4%). From the Salmonella isolates from pigs, only 6% were sensitive to the antimicrobial agents tested. The high resistance level of Salmonella isolates from pigs and chicken carcasses to different classes of antimicrobials should be emphasized and encourage a prudent use of these agents in animal farming, especially in pig production.

Prevalence of MRSA types in slaughter pigs in different German abattoirs

To investigate the prevalence of types of meticillin-resistant Staphylococcus aureus (MRSA) in slaughter pigs in German abattoirs, nasal swabs were collected from a total of 1026 pigs in five abattoirs after stunning in the course of two studies, and examined for MRSA. Study 1 included four abattoirs; study 2 was carried out in one large abattoir. Isolates were tested for antimicrobial susceptibility and characterised using spa-typing, multilocus sequence typing (MLST) and typing of the staphylococcal cassette chromosome, SCCmec. Overall, MRSA was isolated from 70.8 per cent of 520 samples in study 1 and from 49.0 per cent of 506 samples in study 2. The proportion of positive samples varied substantially between the abattoirs in study 1. Most isolates belonged to spa-types t011 and t034 and SCCmec types III and V. MLST of selected isolates revealed that they were all MLST ST398. Besides beta-lactams, 100 per cent of the isolates were resistant to tetracycline, 80.5 per cent were resistant to erythromycin and 80.7 per cent were resistant to clindamycin. Less than 5 per cent of the isolates were resistant to other antimicrobials.

Plasmid-mediated quinolone resistance conferred by qnrS1 in Salmonella enterica serovar Virchow isolated from Turkish food of avian origin

OBJECTIVES

To study the molecular characteristics of the quinolone and associated ampicillin resistance mechanisms present in Salmonella enterica serovar Virchow isolated from Turkish foods.

METHODS

Nine epidemiologically unrelated Salmonella Virchow strains isolated from foods (chicken and minced meat) sold in different markets in Ankara were analysed for their susceptibility to 17 antimicrobials. The strains were typed by PFGE and plasmid profiling and investigated by molecular methods (PCR/sequencing) for the presence of several resistance genes, class 1 integrons and mutations in the quinolone resistance-determining regions. Plasmids conferring quinolone resistance were analysed by restriction fragment length polymorphism (RFLP) analysis, DNA hybridization, sequencing, replicon-typing PCR and mating experiments.

RESULTS

All strains showed nalidixic acid resistance (MIC >or= 128 mg/L) together with a decreased susceptibility to ciprofloxacin (three strains with an MIC of 1 mg/L and six with an MIC of 0.25 mg/L), associated with mutations within the gyrA gene (Asp-87 --> Tyr-87). In three strains, qnrS1 genes were detected. Ampicillin resistance encoded by a bla(CTX-M3) gene and/or bla(TEM-1-like) gene was found in four strains. Three of these strains carried an approximately 45 kb conjugative plasmid, designated pRQ2006, harbouring qnrS1 and a Tn3-like transposon. Partial sequencing and RFLP of pRQ2006 indicated its similarity to the qnrS1 plasmid pAH03786 found in a Japanese Shigella flexneri 2b isolate.

CONCLUSIONS

This is the first study describing the presence of qnrS1 genes in bacterial isolates from Turkey. The pRQ2006 plasmid seems to be more related to the S. flexneri 2b qnrS1 plasmid pAH0376 than to the Salmonella qnrS1-carrying plasmids pINF5 and TPqnrS-2.

Pulsed-field gel electrophoresis, plasmid profiles and phage types for the human isolates of Salmonella enterica serovar Enteritidis obtained over 13 years in Taiwan

AIMS

Plasmid profile, phage typing, and pulsed-field gel electrophoresis (PFGE) patterns of 124 Salmonella Enteritidis strains isolated in 1998-2002 in Taiwan were analysed and the results were compared with those of the 63 strains obtained in 1991-1997, so that molecular subtypes and epidemic strains for Salmonella Enteritidis over a 13-year period (1991-2002) could be elucidated.

METHODS AND RESULTS

A total of 124 strains of Salmonella Enteritidis isolated from human in Taiwan between 1998 and 2002 were analysed by PFGE, plasmid analysis and phage typing. The results obtained were compared with those of the 63 strains obtained in 1991-1997, so that the clonal relationships for a total of 187 strains obtained over 13 years could be elucidated. For PFGE, restriction enzymes XbaI, SpeI and NotI were used for chromosomal DNA digestion. Results showed 28 PFGE pattern combinations for the 187 Salmonella strains. Of them, pattern X3S3N3 was the major subtype as 130 strains isolated from different locations during 1991-2002 showed this PFGE pattern. For all these 187 strains, the genetic similarity was higher than 80%. Plasmid analysis showed 17 distinct types, which consist of one to four plasmids and the predominant phage type of those strains was PT4 (71.6%) and PT6a (13.4%). The three methods identified different degrees of polymorphism in the following order: plasmid profile (18 types, D = 0.659) > PFGE (28 types, D = 0.512) > phage typing (13 types, D = 0.438). As PFGE patterns, phage type and plasmid profile were combined for subtyping, the 187 strains could be grouped into 46 subtypes and the discriminatory index was raised to 0.795. For these 46 subtypes, the predominant one was X3S3N3/P1/PT4, which contained 77 (41%) isolates.

CONCLUSIONS

Most of the Salmonella Enteritidis strains from sporadic cases were with pattern X3S3N3. They were the prevalent and may be the epidemic strains found in Taiwan during 1991-2002. The present study suggested that the several variants were derived from a single clonal line and the genome for strains of Salmonella Enteritidis are highly conserved over a 13-year period (1991-2002).

SIGNIFICANCE AND IMPACT OF THE STUDY

The results obtained here are useful for epidemiolgical study of salmonellosis caused by Salmonella Enteritidis in Taiwan. Comparing the data of the present study with those obtained for strains from other countries, the major subtypes for Salmonella Enteritidis infection in the world can be elucidated.

Resistance of Salmonella Isolates in Germany

During 2000-2002 the National Veterinary Reference Laboratory for Salmonella (NRL-Salm) in Germany typed 11,911 isolates from animals, food, feed and the environment. All of them were tested for their susceptibility to 17 anti-microbial agents. Sixty-three per cent of all isolates were resistant and 40% were multiresistant (resistant against more than one anti-microbial). This general resistance level was strongly influenced by those specific serotypes which dominate the Salmonella epidemiology in Germany. Salmonella Typhimurium DT104 isolates from pig and cattle, and their resulting food products, were multiresistant in 98 and 94% of the cases respectively. During the period 2000-2003 an increasing quinolone resistance especially in Salmonella isolates from poultry and poultry meat (to 26%) and in S. Paratyphi B D-tartrate positive isolates (to 64%) could be observed. This increase was accompanied by a shift towards higher minimal inhibitory concentrations for ciprofloxacin.

Internationalization of Healthcare Applications: A Generic Approach for PACS Workstations

Objectives: Along with the revolution of information technology and the increasing use of computers worldwide, software providers recognize the emerging need for internationalized, or global, software applications. The importance of internationalization comes from its benefits such as addressing a broader audience, making the software applications more accessible, easier to use, more flexible to support and providing users with more consistent information. In addition, some governmental agencies, e.g., in Spain, accept only fully localized software. Although the healthcare communication standards, namely, Digital Imaging and Communication in Medicine (DICOM) and Health Level Seven (HL7) support wide areas of internationalization, most of the implementers are still protective about supporting the complex languages. This paper describes a generic internationalization approach for Picture Archiving and Communication System (PACS) workstations.

Methods: The Unicode standard is used to internationalize the application user interface. An encoding converter was developed to encode and decode the data between the rendering module (in Unicode encoding) and the DICOM data (in ISO 8859 encoding). An integration gateway was required to integrate the inter-nationalized PACS components with the different PACS installations. To introduce a pragmatic example, the described approach was applied to the CHILI PACS workstation.

Results: The approach has enabled the application to handle the different internationalization aspects transparently, such as supporting complex languages, switching between different languages at runtime, and supporting multilingual clinical reports.

Conclusions: In the healthcare enterprises, internationalized applications play an essential role in supporting a seamless flow of information between the heterogeneous multivendor information systems.

Internationalization of healthcare applications: a generic approach for PACS workstations

OBJECTIVES

Along with the revolution of information technology and the increasing use of computers world-wide, software providers recognize the emerging need for internationalized, or global, software applications. The importance of internationalization comes from its benefits such as addressing a broader audience, making the software applications more accessible, easier to use, more flexible to support and providing users with more consistent information. In addition, some governmental agencies, e.g., in Spain, accept only fully localized software. Although the healthcare communication standards, namely, Digital Imaging and Communication in Medicine (DICOM) and Health Level Seven (HL7) support wide areas of internationalization, most of the implementers are still protective about supporting the complex languages. This paper describes a generic internationalization approach for Picture Archiving and Communication System (PACS) workstations.

METHODS

The Unicode standard is used to internationalize the application user interface. An encoding converter was developed to encode and decode the data between the rendering module (in Unicode encoding) and the DICOM data (in ISO 8859 encoding). An integration gateway was required to integrate the internationalized PACS components with the different PACS installations. To introduce a pragmatic example, the described approach was applied to the CHILI PACS workstation.

RESULTS

The approach has enabled the application to handle the different internationalization aspects transparently, such as supporting complex languages, switching between different languages at runtime, and supporting multilingual clinical reports.

CONCLUSIONS

In the healthcare enterprises, internationalized applications play an essential role in supporting a seamless flow of information between the heterogeneous multivendor information systems.

Incidence of quinolone resistance in strains of Salmonella isolated from poultry. cattle and pigs in Germany between 1998 and 2001

This paper reports the susceptibility to the quinolone nalidixic acid and the fluoroquinolone ciprofloxacin of 14,514 strains of Salmonella isolated in Germany from poultry, cattle and pigs between 1998 and 2001. Quinolone-resistant salmonellae were most frequently isolated from poultry, with a prevalence of 10.2 to 16.8 per cent. Poultry-associated serotypes, such as Salmonella Paratyphi B (d-tartrate positive), Salmonella Hadar and Salmonella Virchow, had the highest prevalence of quinolone resistance, ranging between 35 and 74 per cent. All the nalidixic acid-resistant strains also had a reduced susceptibility to ciprofloxacin, with minimum inhibitory concentrations (MICS) of 0.125 to 2 microg/ml. A comparison of the MICS for ciprofloxacin of the strains of these poultry-associated serotypes and Salmonella Enteritidis phage type 4 isolated in 1998/99 and 2000/01 indicated that there had been a shift towards higher MIC values of up to 2 microg/ml. The quinolone resistance-determining region (QRDR) of the gyrA gene and the homologue region of the parC gene of 31 selected strains were sequenced. Several different amino acid changes were observed in gyrA of the quinolone-resistant isolates at positions 83 and 87, but no substitutions were observed in parC.

Evaluation of molecular typing methods for Salmonella enterica serovar Typhimurium DT104 isolated in Germany from healthy pigs

The discriminatory power of four different DNA based typing methods was tested for the molecular subtyping of Salmonella Typhimurium phage type DT104 isolates. German DT104 strains (n = 133) originating from slaughter pigs were analysed by plasmid profiling, and 32 of them by pulsed-field gel electrophoresis (PFGE) using the restriction enzymes XbaI, SpeI or BlnI, random amplification of polymorphic DNA (RAPD) using 13 different primers and IS200 typing. A resulting subtyping scheme was obtained which is based on the most discriminatory power of the individual methods i.e. plasmid profiling and PFGE with all three enzymes. The index of discrimination obtained by the subtyping scheme was 0.909 closely approaching the maximum value of one. Although minor differences occurred in the molecular DNA pattern of single DT104 strains, a dominating subtyping pattern was observed confirming other studies which showed, that S. Typhimurium DT104 isolates are highly clonal.

[Increasing number of Salmonella paratyphi B isolates from slaughtered poultry sent in to the national Salmonella reference laboratory]

In the last years the number of isolations of Salmonella enterica subspecies enterica serovar paratyphi B (S. paratyphi B) sent to the national salmonella reference laboratory of Germany has increased steadily. Most of the isolates originated from fowl or poultry products. The bacteriological, serological and biochemical properties of the isolates were investigated. Special emphasis was given to the utilization of d-tartrate which subgroups the serovar. All of them belonged to the d-tartrate positive variant, which is generally considered less virulent for humans and was formerly called S. java. The performance of various tests is compared and in addition the possibility of the spread within the production line is discussed.

Clinical and differential diagnosis of Creutzfeldt-Jakob disease

Until recently, the clinical diagnosis of CJD relied mainly on three criteria. These include patient history (rapidly progressive dementia), neurological findings (ataxia, pyramidal/extrapyramidal signs, myoclonus, akinetic mutism) and typical electroencephalographic (EEG) findings. These criteria are fulfilled in typical cases. The occurrence or increase of certain proteins in cerebrospinal fluid (CSF; 14-3-3, neuron-specific enolase) now provide important adjuncts in recognizing variant forms. Although these proteins can be detected in other neurological diseases accompanied with substantial brain damage such as encephalitis, they are also characterized by their high sensitivity and specificity with regard to other dementing processes (Alzheimer and vascular dementia). The increase in the number of positive cases during the last years in Germany reflects an improved case ascertainment rather than the appearance of the variant CJD (vCJD). Although several recent cases with a long duration of the disease were actually recognized, they did not reveal the typical florid plaques at autopsy. They were revealed as a rare variant of sporadic CJD, which is characterized by homocygosity for valine at codon 129 and PrP(Sc) type 1. This variant is positive for the 14-3-3 protein in CSF. Further subtypes described by Parchi et al. can also be characterized by a certain pattern of clinical symptomatology, EEG- and 14-3-3-findings. In addition, differential diagnosis revealed some treatable dementias among the most common diseases (Alzheimer and vascular dementia) such as herpes encephalitis, multiple sclerosis and Hashimoto encephalitis, particularly in the younger age group.

Borderless teleradiology with CHILI

Teleradiology is one of the most evolved areas of telemedicine, but one of the basic problems which remains unsolved concerns system compatibility. The DICOM (Digital Imaging and Communications in Medicine) standard is a prerequisite, but it is not sufficient in all aspects. Examples of other currently open issues are security and cooperative work in synchronous teleconferences. Users without a DICOM radiological workstation would benefit from the ability to join a teleradiology network without any special tools. Drawbacks of many teleradiology systems are that they are monolithic in their software design and cannot be adapted to the actual user's environment. Existing radiological systems currently cannot be extended with additional software components. Consequently, every new application usually needs a new workstation with a different look and feel, which must be connected and integrated into the existing infrastructure. This paper introduces the second generation teleradiology system CHILI. The system has been designed to match both the teleradiology requirements of the American College of Radiology (ACR), and the functionality and usability needs of the users. The experiences of software developers and teleradiology users who participated in the first years of the clinical use of CHILI's predecessor MEDICUS have been integrated into a new design. The system has been designed as a component-based architecture. The most powerful communication protocol for data exchange and teleconferencing is the CHILI protocol, which includes a strong data security concept. The system offers, in addition to its own secure protocol, several different communication Methods: DICOM, classic e-mail, Remote Copy functions (RCP), File Transfer Protocol (FTP), the internet protocols HTTP (HyperText Transfer Protocol) and HTTPS (HyperText Transfer Protocol Secure),and CD-ROMs for off-line communication. These transfer METHODS allow the user to send images to nearly anyone with a computer and a network. The drawbacks of the non-CHILI protocols are that teleconferences are not possible, and that the user must take reasonable precautions for data privacy and security. The CHILI PlugIn mechanism enables the users or third parties to extend the system capabilities by adding powerful image postprocessing functions or interfaces to other information systems. Suitable PlugIns can be either existing programs, or dedicated applications programmed with interfaces to the CHILI components. The developer may freely choose programming languages and interface toolkits. The CHILI architecture is a powerful and flexible environment for Picture Archiving and Communications Systems (PACS)and teleradiology. More than 40 systems are currently running in clinical routine in Germany. More than 300,000 images have been distributed among the communication partners in the last two years. Feedback and suggestions from the users influenced the system architecture by a great extent. The proposed and implemented system has been optimized to be as platform independent, open, and secure as possible.

How to improve the clinical diagnosis of Creutzfeldt-Jakob disease

This paper describes a prospective follow-up of 364 patients initially notified as suspected Creutzfeldt-Jakob disease to a Surveillance Unit in Göttingen, Germany. Six patients were diagnosed as having genetic prion disease by blood analysis and were excluded from the study. After examination and review of the remaining 358, 193 were classified as probable Creutzfeldt-Jakob disease. However, autopsy revealed that five of the 193 did not have Creutzfeldt-Jakob disease (four cases, Alzheimer's disease; one case, cerebral lymphoma). Of the 54 patients classified as possible Creutzfeldt-Jakob disease, 10 had another diagnosis made at autopsy. Two of the 111 cases originally classified as having other diseases were found to have Creutzfeldt-Jakob disease on autopsy. Autopsy evidence, together with follow-up of the patients still living and those who died without autopsy, revealed a broad range of other diagnoses. In the younger age groups, the commonest were chronic inflammatory diseases including Hashimoto encephalitis, whilst rapidly progressive Alzheimer's disease was most common in the older age groups. The presence of 14-3-3 protein in the CSF discriminated better between Creutzfeldt-Jakob disease and other rapidly progressive dementias than did the EEG pattern or the MRI. The inclusion of this CSF protein in the criteria of Masters and colleagues (Ann Neurol 1979; 5: 177-88) improves the accuracy and confidence in the clinical diagnosis of Creutzfeldt-Jakob disease.

Incidence of quinolone resistance over the period 1986 to 1998 in veterinary Salmonella isolates from Germany

A total of 24,591 nonhuman salmonella strains isolated in Germany between 1986 and 1998 were examined for their resistance to nalidixic acid by an agar diffusion method. The rate of resistance (inhibition zone, </=13 mm) ranged from 0.2% in 1986 to a peak of 14. 8% in 1990. Between 1991 and 1998 the MICs for nalidixic acid-resistant strains ranged from more than 256 microg/ml for nalidixic acid to between 0.25 and 128 microg/ml for enrofloxacin. In the early 1990s a particularly high incidence of fluoroquinolone resistance (49.5%) was seen among isolates of Salmonella enterica serotype Typhimurium (Salmonella Typhimurium) definitive phage type 204c that mainly originated from cattle. Among isolates from poultry an increase in the incidence of nalidixic acid resistance to a peak of 14.4% was observed in 1994. This peak was due to the presence of specific resistant serotypes, mainly serotypes Hadar, Saintpaul, Paratyphi B (D-tartrate positive; formerly serotype Java) and Newport. Such strains exhibited a decreased susceptibility to enrofloxacin (MIC, 1 microg/ml). Among isolates from pigs the peak incidence of resistance was reached in 1993, with 7.5% of isolates resistant to nalidixic acid and enrofloxacin. The study demonstrates an increase in the incidence of strains that are resistant to nalidixic acid and that have decreased susceptibility to enrofloxacin after the licensing of enrofloxacin. In addition, the number of other serotypes that exhibited nalidixic acid resistance or reduced enrofloxacin susceptibility increased among the total number of isolates investigated between 1992 and 1998.

[Investigation of foodborne outbreak due to Salmonella infantis using epidemiological and microbiological methods]

In foodborne outbreaks, direct microbiological diagnosis is often not possible due to lack of remaining food samples. Therefore, in this investigation of an outbreak of Salmonella infantis at a fair, we chose an epidemiological approach in addition to microbiological testing. In a case control study, fair participants with symptoms of acute gastroenteritis as well as participants showing no signs of disease were interviewed by telephone. Questions concerning what food had been eaten at the fair and the course of disease had priority. Data analysis showed a significantly elevated odds ratio of 144 (p < 0.00001) for the consumption of potato salad. Salmonella infantis was cultured in faeces of symptomatic individuals as well as from left-over potato salad in high concentration. In conclusion, our data show that the cause of a foodborne outbreak can be detected through the application of epidemiologic methods with a high degree of certainty. In order to eliminate memory bias, a structured interview should be carried out as soon as possible after the initial outbreak.

[Immunization with potential Salmonella enteritidis mutants--1. Production and in vitro characterization]

Production and in vitro characterization of potential vaccine strains are the first steps leading to an efficient Salmonella Enteritidis oral live vaccine for homologous immunization of poultry. The paper presents the results of the production of adenine-amino acid auxotrophic mutants using N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis. The mutant strains were characterized using the following properties: auxotrophy, stability of mutation, reversion rate, generation time, metabolic properties, serotype, motility, plasmid content, phage type, SDS-PAGE patterns, as well as cell culture adhesion and invasion. Ten S. Enteritidis double auxotrophic mutants were obtained which are stable auxotrophically and where the risk of reversion was minimal. All strains were found to be plasmid-free. 5 mutants were selected for further investigations concerning their attenuation and immunological value.

[Prevalence of motile salmonellae in egg-laying hens at the end of the laying period]

A total of 3504 hens of the layer-type from 122 flocks (belonging to 89 farms), each with more than 10,000 animals, were culturally examined at the time of slaughter. Of these hens, 2112 (60.3%) from 74 flocks (60.7%) were obtained from 21.3% of the laying-hen farms in a selected region of Lower Saxony in Germany. The other hens came from the remaining part of Lower Saxony and seven other German states (Brandenburg, Mecklenburg Vorpommern, North Rhine Westphalia, Schleswig Holstein, Saxony, Saxony Anhalt, and Thuringia). After arrival at the slaughter house, a random sample of 29 layers was collected from each of the flocks, and liver and spleen, as well as cecal samples, were separately cultured for each bird. Motile salmonellae could be proved in 365 (10.4%) layers from 67 flocks (54.9%). In the selected region, 48 out of 74 flocks (64.9%) and 289 out of 2112 layers (13.7%) were Salmonella-positive. However, the isolation frequency of salmonellae did not differ significantly between flocks of brown and white layers. These Salmonella (S.) isolates could be serologically assigned to 6 different serovars, namely S. enteritidis (SE), S. infantis (SI), S. livingstone (SL), S. typhimurium (ST), S. indiana (SID) and S. cerro; only one isolate of serogroup D1 was incompletely serotyped. SE was detected in 5.8% of the hens from 47.5% of the tested flocks, of which 4.6% of the animals and 32.8% of the flocks came from the selected region in Lower Saxony. The SE isolates were classified into 12 different lysotypes. In 41 out of 58 SE-positive flocks (70.7%), the isolates belonged to lysotype (lt) 4, in 12 flocks (20.7%) to lt 8, in 5 flocks (8.6%) to lt 7, and in 3 flocks (5.2%) to lt 11. A total of 190 (93.1%) out of 204 isolates of the serovar SE carried plasmids. All the plasmid-positive SE-strains harboured the serovar-specific 37 MD virulence-plasmid, nine of them (4.4%) in conjunction with a second and eight strains (3.9%) with a second and a third smaller plasmid.

Salmonella enteritidis phage types in Germany

In order to monitor the epidemiological situation of S. enteritidis in Germany, in 1990-91 1138 isolates from more than 180 locations in West Germany were phage typed. 1124 strains (98.8%) from all sources were typeable, belonging to 21 different phage types (PT). PT4 strains were isolated most frequently (70.8%). In addition, PT7, 25, 34 and 8 were of epidemiological relevance with incidences of 7.2 to 4.5%. The comparison of data shows that in Germany, like in other parts of Europe, PT4 predominates. This phage type is, however, infrequent in North America, where PT8 has the highest incidence.

Molecular typing methods for S. enteritidis

The predominance of certain phage types of Salmonella enteritidis in various countries makes further epidemiological subgrouping necessary. Today this is achieved by using molecular typing methods. For various bacterial species, plasmid profiling, the pattern of outer membrane proteins and lipopolysaccharides, the fingerprinting of total genomic DNA including ribotyping, and multilocus enzyme electrophoretic typing, have proven very useful. When such methods have been applied to S. enteritidis, they revealed a homogeneous, clonal structure in contemporary PT4 isolates. Furthermore they indicate that the clone observed today emerged from a heterogeneous population before the onset of the epidemic.

[Plasmid profiles of different Salmonella serovars from poultry flocks in Germany]

151 salmonella isolates belonging to 6 serotypes and originating from diverse material collected in broiler chicken farms, hatcheries and poultry slaughteries in Northern Germany during 1984 and 1990 were investigated for their plasmid DNA content. This is the first report describing plasmids of S. saint-paul, isolated from poultry lines. The different plasmids of 22 Md, 3.1 Md, 2.4 Md and 1.1 Md molecular weight can be used for further epidemiological studies of salmonellosis in poultry. The 62 Md plasmid of S. typhimurium and the 36 Md plasmid of S. enteritidis have been found to be serovar specific. The smaller plasmids (m. w. less than 5.0 Md), found in S. virchow and S. blockley can be used for further epidemiological studies.

RelA mutation and pBR322 plasmid amplification in amino acid-starved cells of Escherichia coli

Plasmid pBR322 is amplified following amino-acid limitation in Escherichia coli relA hosts. In relA+ hosts there was no significant amplification or a much smaller one. Plasmid amplification is due to the relA mutation; when the relA+ allele is transferred into the relA mutant CP79 this strain no longer amplifies plasmid DNA during amino acid starvation. It is concluded that ppGpp is a negative effector of plasmid replication. Amplification is temperature dependent, being maximal at 32 degrees C and negligible at 37 degrees C.

[Physiologic significance of "stringent control" in Escherichia coli under extreme starvation]

The viability of three isogenic relA+/relA strain pairs of Escherichia coli (CP78/CP79; NF161/NF162; CP107/CP143) was studied during prolonged starvation for amino acids, glucose or phosphate. After amino acid limitation we found a prolonged viability of all relA+ strains which synthesized ppGpp. We suggest that some ppGpp-mediated pleiotropic effects of the stringent response (e.g. glykogen accumulation, enhanced protein turnover) might be involved in this prolongation of survival. After glucose or phosphate starvation there was no difference in the relA+/relA strains either in the ppGpp content or in the survival.

Cutaneous T cell lymphoma with suppressor phenotype and function

Cutaneous T cell lymphomas (CTCL) are typically malignancies of postthymic helper T cells which retain helper function when assayed in vitro. We have described a case clinically and morphologically consistent with CTCL, but in which the tumor cells unequivocally had a suppressor T cell phenotype and suppressor function. This case could be differentiated from other varieties of peripheral T cell lymphomas by multiple clinical and laboratory parameters. The increasingly routine use of immune phenotyping in the evaluation of malignant lymphomas will likely result in the identification of additional cases of this entity, which should be studied to assess its clinical and prognostic relationship to the more common helper cell CTCL.

Expression of a cloned beta-glucanase gene from Bacillus amyloliquefaciens in an Escherichia coli relA strain after plasmid amplification

Amino acid starvation of cells of the Escherichia coli relA strain, CP79, which cannot accumulate guanosine tetraphosphate (ppGpp) in response to amino acid limitation, increased the pEG1 plasmid content about 5- to 7-fold in comparison with exponentially growing cells (pEG1:pBR322 with an insertion of Bacillus amyloliquefaciens DNA coding for beta-glucanase). In contrast, no pEG1 amplification occurred in E. coli CP78, the stringently controlled counterpart, after amino acid starvation. In order to verify these results, the plasmid DNA content was monitored by measuring the expression of pEG1-encoded beta-glucanase from B. amyloliquefaciens both before and after plasmid amplification. When amino acid starved CP79 cells were given an additional dose of amino acids, a more than 10-fold increase in pEG1-encoded beta-glucanase activity (per cell mass) was measured. This increase in enzyme activity correlates with pEG1 amplification during amino acid limitation. Under comparable conditions the activity of beta-glucanase was not increased in strain CP78, which did not amplify the plasmid. We suggest that the replication of pEG1 in amino acid starved E. coli cells is somehow under negative control by ppGpp. Moreover, we found the Bacillus beta-glucanase in E. coli relA cells to be excreted into the growth medium after starvation and overexpression.

Amplification of different ColE1 plasmids in an Escherichia coli relA strain

Amino acid starved cells of an E. coli relA strain accumulate a large amount of pBR322 plasmid DNA. In this study ColE1 related plasmids of different copy number and size including a high copy number plasmid mutant of pBR322 were amplified in a relA strain of E. coli K-12 under amino acid limitation in order to determine the upper plasmid level in amino acid starved cells. In all cases we measured a 4 to 6 fold increase of the plasmid copy number in comparison to log-phase cells independent of the size, the number of origins per plasmid molecule or the copy number in log-phase cells. The plasmid copy number in amino acid starved cells varies from about 200 (pBR322-dimer) to about 2000 (high copy number plasmid pERIII-BPL4, see Boros et al. 1986). Rop+ and rop- plasmids show the same amplification rate under the used conditions.

Synthese von Hitzeschockproteinen nach einer Aminosäure-und Sauerstofflimitation in Bacillus subtilis relA+-und relA-Stämmen / Synthesis of Heat Shock Proteins during Amino Acid or Oxygen Limitation Bacillus subtilis relA+ and relA

Some of the presumable heat shock proteins will be produced in Bacillus subtilis in response to different environmental conditions, e.g. heat shock, amino acid limitation or oxygen limitation. During amino acid limitation or during oxygen limitation the relA+ strain is able of synthesizing this set of proteins but the relA strain is not. We suggest that the accelerated rate of the synthesis of some heat shock proteins depends on the induction of the stringent response because the (p)ppGpp production does not occur in the relA strain during amino acid or oxygen limitation. On the other hand the relA strain can produce heat shock proteins under heat stress. Therefore different mechanisms must be responsible for the expression of this set of genes during heat and other stress stimuli.

It can be supposed that in B. subtilis the (p)ppGpp-dependent stringent control is a central defense reaction against different adverse environmental conditions and furthermore, that the synthesis of “stress” proteins as an essential component of the stringent response is part of a general adaptation mechanism under non-growing conditions.

[Synthesis of heat shock proteins following amino acid or oxygen limitation in Bacillus subtilis relA+ and relA strains]

Some of the presumable heat shock proteins will be produced in Bacillus subtilis in response to different environmental conditions, e.g. heat shock, amino acid limitation or oxygen limitation. During amino acid limitation or during oxygen limitation the relA+ strain is able of synthesizing this set of proteins but the relA strain is not. We suggest that the accelerated rate of the synthesis of some heat shock proteins depends on the induction of the stringent response because the (p)ppGpp production does not occur in the relA strain during amino acid or oxygen limitation. On the other hand the relA strain can produce heat shock proteins under heat stress. Therefore different mechanisms must be responsible for the expression of this set of genes during heat and other stress stimuli. It can be supposed that in B. subtilis the (p)ppGpp-dependent stringent control is a central defense reaction against different adverse environmental conditions and furthermore, that the synthesis of "stress" proteins as an essential component of the stringent response is part of a general adaptation mechanism under non-growing conditions.

Formation of extracellular neutral proteinase and the stringent response in Bacillus subtilis

The kinetics of extracellular neutral proteinase synthesis by an isogenic stringent (IS58) and a relaxed (IS56) strain of B. subtilis were compared. The specific enzyme formation rate by the stringent strain was higher than that of the relaxed one. Norvaline addition (1 mg/mL) induced the formation of pppGpp and ppGpp, respectively, as well as the appearance of extracellular neutral proteinase activities in cultures of the stringent strain IS58 and a strain with high proteinase production (ZF-178) only. These correlations support the suggestion that (p)ppGpp are involved in the regulation processes responsible for production of extracellular neutral proteinases by B. subtilis.

Physiological studies on pBR 322 DNA amplification in an Escherichia coli relA strain

Amino acid limitation leads in E. coli relA cells which cannot synthesize guanosine tetraphosphate (ppGpp) under these conditions to an amplification of pBR 322 DNA. We previously proposed that ppGpp produced in E. coli relA+ cells subjected to amino acid limitation inhibits pBR 322 DNA replication (Hecker et al. 1983). In further experiments it was established that an E. coli relA strain shows plasmid amplification during amino acid limitation (arginine, threonine, leucine or histidine) only in the presence of sufficient concentrations of phosphate, ammonia and glucose. Plasmid amplification does not occur if ammonia or phosphate is depleted. We suggest that glucose, ammonia and phosphate are needed for nucleotide and deoxynucleotide synthesis as the essential prerequisite for plasmid amplification. The activity of beta-lactamase was determined as an indicator for the expression of plasmid-encoded genes. The enzyme activity remains on a low level during plasmid amplification because of arginine exhaustion. A remarkable increase in the activity of beta-lactamase was observed after resumption of growth of relA cells containing amplified plasmid DNA. The plasmid content decreased as the cells continued to grow. We found that plasmid amplification and expression of plasmid-localized genes are opposite reactions which do not occur at the same time.

Role of relA mutation in the survival of amino acid-starved Escherichia coli

Amino acid-starved cells of Escherichia coli relA+, which contain a large number of glycogen particles, are able to survive in phosphate buffer for a longer time period than their relaxed counterparts. With regard to NH4+ starvation differences in the survival of both strains were not found. NH4+ starved cells of E. coli relA are able to synthesize glycogen but amino acid-starved cells of the relA strain are not. We suggest that the synthesis of glycogen triggered by guanosine tetraphosphate during amino acid starvation is responsible for the prolonged viability of the E. coli relA+ strain.

[Synthesis of alkaline phosphatase in a stringent and a relaxed strain of Escherichia coli under amino acid and phosphate limitation]

Synthesis of alkaline phosphatase in Escherichia coli is derepressed under phosphate starvation in the stringent strain CP78 as well as in its relaxed counterpart CP79. During limitation of phosphate as well as of amino acids a decrease of enzyme activity is observed, especially in the relaxed strain, which can not produce ppGpp under this conditions. After phosphate limitation synthesis of ppGpp is not stimulated and the kinetics of RNA synthesis is similar in both strains. We suggest that ppGpp is not directly involved in the regulation of gene expression during phosphate starvation.

Characterization of the glucocorticoid receptor in human skin

Because of the profound importance glucocorticoids have in dermatologic therapy, we studied the glucocorticoid receptor in human skin. A cytosol fraction was prepared from frozen skin by homogenization and centrifugation. When reacted with [3H]dexamethasone, this cytosol contained saturable, low-capacity binding. The glucocorticoid binding was stabilized by a protease inhibitor, phenylmethylsulfonylfluoride, and by sodium molybdate and was destroyed by trypsin. Sedimentation analysis of the glucocorticoid binding protein showed an 8S to 4S transition in high salt, a property of many known steroid hormone receptors. The binding was steroid specific, supporting the conclusion that this binding protein was a glucocorticoid receptor. The receptor molecule had a frictional ratio of 1.60 and a Mr of about 226,000 under low-salt conditions (0.05 M KCl) and a frictional ratio of 1.86 and a Mr of about 100,000 under high-salt conditions (0.3 M KCl) consistent with a nonglobular, elongated molecule. Isoelectric focusing showed that the receptor had 2 molecular species with isoelectric points of approximately 5.8 and 7.5. Quantitation of receptor in human skin showed 4-7 times more receptors in the epidermis and papillary dermis than in the lower dermis and nearly equal numbers in epidermis and papillary dermis. The concentration of receptors varied in different anatomic areas, with male foreskin showing the highest concentration, followed by female face, breast, and abdominal skin. Interestingly, the concentration of glucocorticoid receptors also varied with age; the highest levels were present at the extremes of life and a significantly lower level at midlife.

Replication of pBR322 DNA in stringent and relaxed strains of Escherichia coli

Synthesis of both chromosomal and plasmid (pBR322) DNA was measured in E. coli strains differing in their relA allele (relA+:CP78; relA:CP79). It was found that upon limitation of a required amino acid or after valine treatment to trigger a stringent response synthesis of pBR322 DNA was stimulated only in the relaxed strain and was inhibited in its stringent counterpart. The results suggest that replication of plasmid DNA is negatively controlled by the relA+ allele.

[Replication and expression of plasmid pBR 322 during discontinuous culture of a stringent and relaxed Escherichia coli strain]

The E. coli strains CP78 and CP79 carrying the plasmid pBR 322 display similar growth kinetics in discontinuous culture. During limitation of amino acids the stringent strain CP78 is able to synthesize guanosine-5'diphosphate-3'-diphosphate (ppGpp) and guanosine-5'-triphosphate-3' diphosphate, but the relaxed strain can not produce highly phosphorylated guanosine nucleotides. During the logarithmic phase of growth both strains contain similar amounts of plasmid DNA. During amino acid starvation plasmid DNA is amplified in the relaxed strain only, whereas in the stringent strain the plasmid content per cell remains constant. In stationary phase cells of CP78 a higher activity of plasmid-coded beta-lactamase than in CP79 cells was detected. Furthermore, remarkable differences between both strains were observed in the composition of proteins derived from the periplasmic fraction and separated by polyacrylamide gel electrophoresis. Our results might indicate a negative control of pBR 322 DNA replication by ppGpp during amino acid starvation.

[Lysine biosynthesis of Pseudomonas aeruginosa PAO1. III. Further characterization of lysine auxotrophic mutant of Ps. aeruginosa PAO1]

A number of lysine-auxotrophic mutants of Pseudomonas aeruginosa PAO1 were isolated through mutagenesis by means of N-methyl-N-nitrosoguaniine (Mach et al., unpublished). Using the cross feeding test and growth tests classification of lysine mutants was not possible. The investigation of diaminopimelic acid decarboxylase (DAP-DC) showed, that none of these mutants had an active enzyme, except for the mutants with a high number of revertants. The appearance of only one mutant type is attributed to the insufficient availability of DAP.