[Who can provide a translation when I cannot be understood? Or the art of holding a medical conversation]. / "Wer bietet Übersetzung an, wenn man mich nicht verstehen kann?" oder von der Kunst, ein ärztliches Gespräch zu führen.

A transfacultary seminar of students with a patient resulted in a theatre performance based on Goethe's "Faustus" demonstrating the patient's treatment marathon in our current health-care system. Core demands and results are (i) simple access to evidence-based patient information, (ii) communication skills in the selection and education of medical students. and (iii) active involvement of patients in the self-management of their illness.

Rational design of a room temperature molecular spin switch. The light-driven coordination induced spin state switch (LD-CISSS) approach.

Extensive use of quantum chemical calculations has been made to rationally design a molecule whose spin state can be switched reversibly using light of two different wavelengths at room temperature in solution. Spin change is induced by changing the coordination number of a nickel complex. The coordination number in turn is switched using a photochromic ligand that binds in one configuration and dissociates in the other. We demonstrate that successful design relies on a precise geometry fit and delicate electronic tuning. Our designer complex exhibits an extremely high long-term switching stability (more than 20 000 cycles) and a high switching efficiency. The high-spin state is extraordinarily stable with a half-life of 400 days at room temperature. Switching between the dia- and paramagnetic state is achieved with visible light (500 and 430 nm). The compound can also be used as a molecular logic gate with light and pH as input and the magnetic state as non-destructive read-out.

Detrimental role for CD4+ T lymphocytes in murine diffuse peritonitis due to inhibition of local bacterial elimination.

BACKGROUND: Abdominal sepsis due to intestinal leakage of endogenous gut bacteria is a life-threatening condition. In healthy individuals, T lymphocytes have essential functions in balancing the immune response to the commensal gut flora. AIM: To determine how T lymphocytes shape the process of diffuse faecal peritonitis. METHODS: In colon ascendens stent peritonitis (CASP), a clinically relevant mouse model of diffuse peritonitis, the kinetics of systemic T cell activation were investigated by assessment of activation markers. CD4(+) T cells were then depleted with monoclonal antibodies, and survival, bacterial dissemination and cytokine concentrations were measured. T cell receptor signalling was blocked with tacrolimus. RESULTS: In diffuse peritonitis, CD4(+) T cells, both Foxp3(-) and Foxp3(+), became systemically involved within hours and upregulated CTLA-4 and other activation markers. Depletion of the CD4(+) T cells enhanced local bacterial clearance from the peritoneal cavity, reduced bacterial dissemination and improved survival. This was accompanied by increased immigration of granulocytes and macrophages into the peritoneum, indicating that CD4(+) T cells inhibit the local innate immune response. Blockade of T cell receptor (TCR) signalling by tacrolimus did not influence the survival in this peritonitis model, showing that the inhibitory effects of the CD4(+) T lymphocytes were independent of TCR-mediated antigen recognition. CONCLUSION: In diffuse peritonitis caused by commensal gut bacteria the CD4(+) T lymphocytes exert a net negative effect on the local anti-bacterial defence, and thereby contribute to bacterial dissemination and poor outcome.

Serum osmolality and outcome in intensive care unit patients.

BACKGROUND: The aim of the present study was to compare 16 routine clinical and laboratory parameters, acute physiologic and chronic health evaluation (APACHE) and sequential organ failure assessment (SOFA) score for their value in predicting mortality during hospital stay in patients admitted to a general intensive care unit (ICU). METHODS: A retrospective observational clinical study was carried out in a 15-bed ICU in a university hospital. Nine hundred and thirty-three consecutive patients with ICU stay > 24 h (36.2% surgical, 29.1% medical and 34.7% trauma) were observed. Blood sampling, patient surveillance and data collection were performed. The primary outcome was mortality in the hospital. We used receiver operating characteristic (ROC) analyses and logistic regression to compare the 16 relevant parameters, APACHE II and SOFA scores. RESULTS: Two hundred and thirty-three out of the 933 patients died (mortality 25.0%). One laboratory parameter, serum osmolality [area under the curve (AUC) 0.732] had a predictive value for mortality which lay between that of APACHE II (AUC 0.784) and SOFA (AUC 0.720) scores. When outcome prediction was restricted to long-term patients (ICU stay > 5 days), serum osmolality (AUC 0.711) performed better than either of the standard scores (APACHE AUC 0.655, SOFA AUC 0.636). Using logistic regression analysis, the association of clinical parameters, age and diagnosis group with mortality was determined. CONCLUSION: Elevated serum osmolality at ICU admission is associated with an increased mortality risk in critically ill patients. Serum osmolality is cheaper and more rapid to determine than the scoring systems. However, further studies are needed to evaluate the predictive value of serum osmolality in different patient populations.

Stress susceptibility predicts the severity of immune depression and the failure to combat bacterial infections in chronically stressed mice.

Chronic psychological stress has been suggested to play a role in disorders in which the immune system unexpectedly fails to respond in a protective manner. Chronic combined acoustic and restraint stress compromises the anti-bacterial defense mechanisms of female BALB/c mice. The immunodeficiency is characterized by an apoptotic loss of lymphocytes, reduced ex vivo-inducibility of TNF but increased inducibility of IL10, reduced T-cell proliferation, and impaired phagocyte functions. Stressed mice develop depression-like behavior that was monitored by a stress severity score (SSS). Besides a strain (BALB/c>CBA) and gender (male>female) dependent susceptibility to chronic stress, inbred mice have an individual coping ability. Importantly, the individual SSS strongly correlates with Escherichia coli dissemination after infection as well as with IL10-inducibility and circulating corticosterone levels of each animal.

A multigeneration analysis of cytochrome b(562) redox variants: evolutionary strategies for modulating redox potential revealed using a library approach.

The redox potential of cytochromes sets the energy yield possible in metabolism and is also a key determinant of the rate at which redox reactions proceed. Here, the heme protein, cytochrome b(562), is used to study the in vitro evolution of redox potential within a library of variants containing the same structural archetype, the four-helix bundle. Multisite variations in the active site of cytochrome b(562) were introduced. A library of variants containing random mutations in place of R98 and R106 was created, and the redox potentials of a statistical sampling of this library were measured. This procedure was carried out for both the low- and high-potential variants of a previously studied F61X/F65X, first-generation library [Springs, S. L., Bass, S. E., and McLendon, G. L. (2000) Biochemistry 39, 6075]. The second-generation library reported here has a range of redox potentials which is greater than 40% (160 mV) of the known accessible potential among cytochromes with identical axial ligands (but different folds) and exceeds the range exhibited phylogenetically by the cytochrome c' family which internally maintains the same axial ligation and fold. A statistical analysis of the libraries examined reveals that the redox potential of WT cyt b(562) is found at the high-potential extremum of the distribution, indicating that this protein apparently evolved to differentially stabilize the reduced protein. The 2.7 A crystal structure of F61I/F65Y/R106L (low-potential variant of the second-generation library) was solved and is compared to the wild-type structure and the 2.2 A resolution structure of the F61I/F65Y variant (low-potential variant of the first-generation library). The structures indicate that charge-dipole effects are responsible for shifting the redox equilibrium toward the oxidized state in both the F61I/F65Y and F61I/F65Y/R106L variants. Specifically, a new protein dipole is introduced into the heme microenvironment as a result of the F65Y mutation, two new internal water molecules (one in hydrogen-bonding distance of Y65) are found, and in the case of F61I/F65Y/R106L (DeltaE(m) = 158 mV vs NHE), increased solvent exposure of the heme as a result of the R106L substitution is identified.

LBP, CD14, TLR4 and the murine innate immune response to a peritoneal Salmonella infection.

In mice, defense against an intraperitoneal Salmonella infection depends on a vigorous innate immune response. Mutations which lead to an inadequate early response to the pathogen thus identify genes involved in innate immunity. The best studied host resistance factor, NRAMP-1, is an endosomal membrane protein whose loss leads to an inability of the animals to hold the infection in check. However, innate defense against Salmonella is not restricted to mechanisms which directly attack the pathogen within macrophages. Here we have examined the contribution of the LBP, CD14 and TLR4 gene products to innate defense against Salmonella. To this end, we have generated mice which carry a wild-type allele of NRAMP-1, but which are deficient for the LBP, CD14 or TLR4 genes. Loss of any of these genes leads to a susceptibility to Salmonella as dramatic as that seen in animals lacking functional NRAMP-1 protein. This indicates that LBP, CD14 and TLR4 are all critical elements required in the proper induction of this innate defense system.

Lipopolysaccharide and ceramide docking to CD14 provokes ligand-specific receptor clustering in rafts.

The glycosylphosphatidylinositol-anchored receptor CD14 plays a major role in the inflammatory response of monocytes to lipopolysaccharide. Here, we describe that ceramide, a constituent of atherogenic lipoproteins, binds to CD14 and induces clustering of CD14 to co-receptors in rafts. In resting cells, CD14 was associated with CD55, the Fcgamma-receptors CD32 and CD64 and the pentaspan CD47. Ceramide further recruited the complement receptor 3 (CD11b/CD18) and CD36 into proximity of CD14. Lipopolysaccharide, in addition, induced co-clustering with Toll-like receptor 4, Fcgamma-RIIIa (CD16a) and the tetraspanin CD81 while CD47 was dissociated. The different receptor complexes may be linked to ligand-specific cellular responses initiated by CD14.

The enhancement of PCR amplification by low molecular-weight sulfones.

DNA amplification by polymerase chain reaction (PCR) is frequently complicated by the problems of low yield and specificity, especially when the GC content of the target sequence is high. A common approach to the optimization of such reactions is the addition of small quantities of certain organic chemicals, such as dimethylsulfoxide (DMSO), betaine, polyethylene glycol and formamide, to the reaction mixture. Even in the presence of such additives, however, the amplification of GC-rich templates is often ineffective. In this paper, we introduce a novel class of PCR-enhancing compounds, the low molecular-weight sulfones, that are effective in the optimization of high GC template amplification. We describe here the results of an extensive structure-activity investigation in which we studied the effects of a series of six different sulfones on PCR amplification. We identify two sulfones, sulfolane and methyl sulfone, that are especially potent enhancers of high GC template amplification, and show that these compounds often outperform DMSO and betaine, two of the most effective PCR enhancers currently used. We conclude with a brief discussion of the role that the sulfone functional group may play in such enhancement.

The essential role of lipopolysaccharide-binding protein in protection of mice against a peritoneal Salmonella infection involves the rapid induction of an inflammatory response.

Acute and chronic hyperinflammation are of major clinical concern, and many treatment strategies are therefore directed to inactivating parts of the inflammatory system. However, survival depends on responding quickly to pathogen attack, and since the adaptive immune system requires several days to adequately react, we rely initially on a range of innate defenses, many of which operate by activating parts of the inflammatory network. For example, LPS-binding protein (LBP) can transfer the LPS of Gram-negative bacteria to CD14 on the surface of macrophages, and this initiates an inflammatory reaction. However, the importance of this chain of events in infection is unclear. First, the innate system is redundant, and bacteria have many components that may serve as targets for it. Second, LBP can transfer LPS to other acceptors that do not induce inflammation. In this study, we show that innate defense against a lethal peritoneal infection with Salmonella requires a direct proinflammatory involvement of LBP, and that this is a major nonredundant function of LBP in this infection model. This emphasizes that blocking the LBP-initiated inflammatory cascade disables an essential defense pathway. Any anti-inflammatory protection that may be achieved must be balanced against the risks inherent in blinding the innate system to the presence of Gram-negative pathogens.

The enhancement of PCR amplification by low molecular weight amides.

Amplification of a DNA target by the polymerase chain reaction (PCR) often requires laborious optimization efforts. In this regard, the use of certain organic chemicals such as dimethyl sulfoxide, polyethylene glycol, betaine and formamide as cosolvents has been found to be very helpful. Unfortunately, very little is known about the precise structural features that make these additives effective and, accordingly, the number of such chemicals currently known to enhance PCR is limited. In order to address these issues, we decided to focus on formamide and undertook an extensive study of low molecular weight amides as a class to see how changing the substituents in the amide structure influences its effect on PCR. We describe here the results of this study, which involved 11 different amides, and present observations that provide a cohesive picture of structure-activity relations in this group of additives. We found several of these amides to be exceptionally effective and introduce them as novel PCR enhancers.

ApoE-containing high density lipoproteins and phospholipid transfer protein activity increase in patients with a systemic inflammatory response.

High density lipoproteins (HDL) mediate reverse cholesterol transport as well as the clearance of oxidation products or inflammatory mediators, thereby contributing to tissue integrity. The decrease in HDL in inflammation has been attributed to decreased lecithin:cholesterol acyltransferase activity, whereas the role of phospholipid transfer protein (PLTP) and cholesteryl ester transfer protein has not been analyzed in detail. We have studied the activities of HDL-modifying proteins and the heterogeneity of HDL in healthy control subjects and three groups of postsurgery patients: no bacterial infection (group 1), bacterial focus and systemic inflammatory response (group 2), and severe sepsis (group 3). For all patients, a decrease in total HDL could be demonstrated, with a loss of mainly large, apolipoprotein A-I (apoA-I) HDL particles, an almost total loss of apoC-I, and an increase in apoE HDL (200-500 kDa), which did not contain significant amounts of apoA-I, apoA-II, or apoC-I. PLTP activity was increased in patients of groups 2 and 3, paralleled by a redistribution of PLTP into a population of small (120- to 200-kDa) particles, probably representing PLTP homodimers or lipid-complexed PLTP. In summary, the increase in apoE HDL and PLTP activity may improve the delivery of energy substrates and phospholipids to tissues that must maintain cellular membrane homeostasis under conditions of inflammatory stress.

Crystal structure of the oligomerization domain of NSP4 from rotavirus reveals a core metal-binding site.

During the maturation of rotaviral particles, non-structural protein 4 (NSP4) plays a critical role in the translocation of the immature capsid into the lumen of the endoplasmic reticulum. Full-length NSP4 and a 22 amino acid peptide (NSP4(114-135)) derived from this protein have been shown to induce diarrhea in young mice in an age-dependent manner, and may therefore be the agent responsible for rotavirally-induced symptoms. We have determined the crystal structure of the oligomerization domain of NSP4 which spans residues 95 to 137 (NSP4(95-137)). NSP4(95-137) self-associates into a parallel, tetrameric coiled-coil, with the hydrophobic core interrupted by three polar layers occupying a and d-heptad positions. Side-chains from two consecutive polar layers, consisting of four Gln123 and two of the four Glu120 residues, coordinate a divalent cation. Two independent structures built from MAD-phased data indicated the presence of a strontium and calcium ion bound at this site, respectively. This metal-binding site appears to play an important role in stabilizing the homo-tetramer, which has implications for the engagement of NSP4 as an enterotoxin.

The new architectonics: an invitation to structural biology.

The philosophy of art might offer an epistemological basis for talking about the complexity of biological molecules in a meaningful way. The analysis of artistic compositions requires the resolution of intrinsic tensions between disparate sensory categories-color, line and form-not unlike those encountered in looking at the surfaces of protein molecules, where charge, polarity, hydrophobicity, and shape compete for our attentions. Complex living systems exhibit behaviors such as contraction waves moving along muscle fibers, or shivers passing through the growth cones of migrating neurons, that are easy to describe with common words, but difficult to explain in terms of the language of chemistry. The problem follows from a lack of everyday experience with processes that move towards equilibrium by switching between crystalline order and chain-like disorder, a commonplace occurrence in the submicroscopic world of proteins. Since most of what is understood about protein function comes from studies of isolated macromolecules in solution, a serious gap exists between what we know and what we would like to know about organized biological systems. Closing this gap can be achieved by recognizing that protein molecules reside in gradients of Gibbs free energy, where local forces and movements can be large compared with Brownian motion. Architectonics, a term borrowed from the philosophical literature, symbolizes the eventual union of the structure of theories-how our minds construct the world-with the theory of structures-or how stability is maintained in the chaotic world of microsystems.

A comparative structural analysis of the ADF/cofilin family.

Actin-depolymerizing factor (ADF) and cofilin define a family of actin-binding proteins essential for the rapid turnover of filamentous actin in vivo. Here we present the 2.0 A crystal structure of Arabidopsis thaliana ADF1 (AtADF1), the first plant crystal structure from the ADF/cofilin (AC) family. Superposition of the four AC isoform structures permits an accurate sequence alignment that differs from previously reported data for the location of vertebrate-specific inserts and reveals a contiguous, vertebrate-specific surface opposite the putative actin-binding surface. Extending the structure-based sequence alignment to include 30 additional isoforms indicates three major groups: vertebrates, plants, and "other eukaryotes." Within these groups, several structurally conserved residues that are not conserved throughout the entire AC family have been identified. Residues that are highly conserved among all isoforms tend to cluster around the tryptophan at position 90 and a structurally conserved kink in alpha-helix 3. Analysis of surface character shows the presence of a hydrophobic patch and a highly conserved acidic cluster, both of which include several residues previously implicated in actin binding.

Covalent binding of ATPgammaS to the nucleotide-binding site in S14C-actin.

We have recently reported on the characterization of beta-actin carrying the mutation S14C in one of the phosphate-binding loops. The present paper describes the attachment of the adenosine 5'-[gamma-thio]-triphosphate (ATPgammaS) to actin containing this mutation. Treatment of S14C-actin with ATPgammaS blocked further nucleotide exchange and raised the thermal stability of the protein, suggesting the formation of a covalent bond between the sulfhydryl on the terminal phosphate of ATPgammaS and cysteine-14 of the mutant actin. The affinity of the derivatized G-actin for DNase I as compared to wild-type ATP-actin was lowered to a similar extent as that of ADP.AlF(4)-actin. The derivatized actin polymerized slower than ATP-actin but faster than ADP-actin. Under these conditions the bound ATPgammaS was hydrolyzed, suggesting the formation of a state corresponding to the transient ADP.P(i)-state. ATPgammaS-actin interacted normally with profilin, whereas the interaction with actin depolymerizing factor (ADF) was disturbed, as judged on the effects of these proteins on actin polymerization.

Mutational analysis of arginine 177 in the nucleotide binding site of beta-actin.

Actin ADP-ribosylated at arginine 177 is unable to hydrolyze ATP, and the R177 side chain is in a position similar to that of the catalytically essential lysine 71 in heat shock cognate protein Hsc70, another member of the actin-fold family of proteins. Therefore, actin residue R177 has been implicated in the mechanism of ATP hydrolysis. This paper compares wild-type beta-actin with a mutant in which R177 has been replaced by aspartic acid. The mutant beta-actin was expressed in Saccharomyces cerevisiae and purified by DNase I-affinity chromatography. The mutant protein exhibited a reduced thermal stability and an increased nucleotide exchange rate, suggesting a weakened interdomain connection. The ATPase activity of G-actin and the ATPase activity expressed during polymerization were unaffected by the R177D replacement, showing that this residue is not involved in catalysis. In the presence of polymerizing salts, ATP hydrolysis by both wild-type Mg-beta-actin and the mutant protein preceded filament formation. With the mutant actin, the initial rate of ATP hydrolysis was as high as with wild-type actin, but polymer formation was slower, reached lower steady-state levels, and the polymers formed exhibited much lower viscosity. The critical concentration of polymerization (Acc) of the mutant actin was increased 10-fold as compared to wild-type actin. Filaments formed from the R177D mutant beta-actin bound phalloidin.