Species differentiation within the Staphylococcus intermedius group using a refined MALDI-TOF MS database

Among coagulase-positive staphylococci of animal origin, the members of the Staphylococcus intermedius-group (SIG: S. intermedius, Staphylococcus pseudintermedius and Staphylococcus delphini) are important opportunistic pathogens in different animal hosts and occasionally in humans. However, the unambiguous species diagnosis of SIG is often challenging. Therefore, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) -based SIG-identification with Bruker Microflex LT in combination with Biotyper 3.0 software (Bruker Daltonics, Bremen, Germany) was evaluated using (i) the original database content and (ii) the database after extension with distinct hierarchical clustered reference spectra for 60 SIG. A convenience sample comprising 200 isolates was used to compare both database performances. As a result, 17 isolates initially diagnosed as S. intermedius with the current content of the Bruker database were identified as S. pseudintermedius by applying the in-house reference spectra extended version. Furthermore, a significant improvement (average rise of log score value: 0.24) of the SIG identification score values was achieved, emphasizing that further sequence-based refinement of the Bruker database content allows improvement of MALDI-TOF MS-based identification.

AIDA: web agents in dental treatment planning

The objective of the AIDA project (Artificial Intelligent Dental Agents, http://aida.uni-hd.de) is the analysis of dental decision-making, the design of a computer-based decision support system, as well as the testing of the decision structure in interactions with dental experts, practicing dentists, and patients. The planning of the solution alternatives for an individual patient is based on a top-down structure for dental decision-making, aiming at a standardization of the argumentation. From a theoretical point of view, decision support can be provided only for anticipated decisions (planning). Moreover, only parts of these anticipated decisions can be supported. Accordingly, a separation of these partial aspects has to take place before one is able to build decision support systems. For prosthetic dentistry, clinicians have been shown how to use individual patient findings to sketch the possible treatment alternatives and later derive guidelines for the treatment. The planning module for fixed prostheses has already been integrated into a software agent. Planning modules for other types of prostheses are currently specified, implemented, and verified.

AIDA: Web agents to support dental treatment planning

Dental treatment planning is highly dependent on the educational background and personal experience of the dentist and on the thoroughness with which findings are taken. The objective of research in the AIDA (Artificially Intelligent Dental Agents) project is therefore the analysis of dental decision making and the design of a decision-supportive software module to test the decision-making process and make it transparent for both dentists and patients. In the AIDA project (aida.uni-hd.de), an expert system has been set up to identify treatment alternatives with integrated decision rationale for experts, practicing dentists, and eventually also patients. It is based on a top-down structure for dental decision-making, which was developed to standardize argumentation. For prosthetic dentistry, how one uses individual patient findings to arrive at possible treatment alternatives was clarified in greater detail. The planning rules for fixed prostheses have already been integrated into a software agent. Other modules should soon specify and verify these suggestions in terms of further fields of dentistry (e.g., restorative dentistry). In the near future, AIDA will be able to deliver dentally-founded justifications for every individual decision.

Globotriaosylceramide (Gb(3)/CD77) is synthesized and surface expressed by bovine lymphocytes upon activation in vitro

Neutral glycosphingolipids (GSLs) are considered activation markers on human lymphocytes, which are fundamental for studying the immune system. For cattle, only a limited number of activation markers has yet been identified. We recently showed that Shiga toxin 1, known to use globotriaosylceramide (Gb(3) syn. CD77) as a cellular receptor, depresses proliferation of activated bovine lymphocytes [Infect. Immunol. 67 (1999b) 2209]. In order to confirm the expression of Gb(3)/CD77 on bovine lymphocytes, we flowcytometrically examined a bovine B-lymphoma cell line (BL-3) and bovine peripheral blood mononuclear cells (PBMC) before and after mitogenic stimulation and biochemically characterized neutral GSLs extracted from PBMC. CD77 was detected on the surface of BL-3 cells and cultured PBMC essentially after mitogenic stimulation. Although expressed by all PBMC subpopulations identified, the portion of CD7+ cells was highest for BoCD8+ cells, followed by B-cells and BoCD4+ cells at day 4 of cultivation. Ceramide trihexoside of stimulated PBMC was structurally determined as Gal(alpha1-4)Gal(1-4)Glc(1-1)ceramide (Gb(3)). Biochemically, Gb(3) was also detected within unstimulated PBMC which contained ceramide monohexoside (CMH) and Gb(3) in a ratio of about 4:1. However, stimulation induced an increase of CMH and Gb(3) by a factor of 2.5 and 10, respectively, implicating that bovine lymphocytes regulate surface expression of Gb(3)/CD77 predominantly by quantitative changes in the Gb(3) metabolism. This report presents Gb(3)/CD77 as the first GSL identified on bovine immune cells and highly recommends this activation dependent antigen as a useful tool to investigate lymphocyte activation within the bovine immune system.

Purification of cold-shock-like proteins from Stigmatella aurantiaca - molecular cloning and characterization of the cspA gene

Prominent low-molecular-weight proteins were isolated from vegetative cells of the myxobacterium Stigmatella aurantiaca and were found to be members of the cold-shock protein family. A first gene of this family (cspA) was cloned and sequenced. It encodes a protein of 68 amino acid residues that displays up to 71% sequence identity with other bacterial cold-shock(-like) proteins. A cysteine residue within the RNP-2 motif is a peculiarity of Stigmatella CspA. A cspA::(Deltatrp-lacZ) fusion gene construct was introduced into Stigmatella by electroporation, a method that has not been used previously for this strain. Analysis of the resultant transformants revealed that cspA transcription occurs at high levels during vegetative growth at 20 and 32 degrees C, and during fruiting body formation.

Intercellular signaling in Stigmatella aurantiaca: purification and characterization of stigmolone, a myxobacterial pheromone

The myxobacterium Stigmatella aurantiaca passes through a life cycle that involves formation of a multicellular fruiting body as the most complex stage. An early step in this differentiation process depends on a signal factor secreted by the cells when nutrients become limited. The formation of a fruiting body from a small cell population can be accelerated by addition of this secreted material. The bioactive compound was found to be steam volatile. It was purified to homogeneity by steam distillation followed by reversed-phase and normal-phase HPLC. The pheromone was named stigmolone, in accordance with the structure 2,5, 8-trimethyl-8-hydroxy-nonan-4-one, as determined by NMR and mass spectrometry. Stigmolone represents a structurally unique and highly bioactive prokaryotic pheromone that is effective in the bioassay at 1 nM concentration.

[Sonography in suspected appendicitis: a decisive factor in diagnosis and therapy? Results of a prospective study of 669 patients]

The appendectomy-rate in the Federal Republic of Germany is decreasing. German surgeons have begun to refuse appendectomy if there are no signs of acute inflammation. Preoperative assessment of patients with right lower quadrant pain has acquired new significance. The authors report on 2 years of experience with routine use of high-resolution ultrasonography in 669 cases of suspected acute appendicitis. Only 101 patients (= 15.1%) turned out to be suffering from acute appendicitis. Ultrasonography evaluation was found to have a sensitivity of 84.2%, a specificity of 96.8% and an overall accuracy of 94.9%. Ultrasonography was also useful in detecting mimicking diseases of acute appendicitis. Sonography should help to rule out severe disease in the frequent cases of functional abdominal pain.

[Guar II. Feeding Trials with Animals]

Feeding trials with guarbeans or its protein- or carbohdrat-rich fractions with cattle, poultry and rats are briefly summarized. The protein fraction of the bean contains toxic substances of unknown structure. The toxic effect is diminished by heating. In case of addition of the carbohydrate-rich fractions of the bean in the feeding experiments depression of growth is observed probably in connection with the bad utilization of the galactomannan or the decrease of fodder consumption due to the expanding volume of the fodder in the gut.