Brain imaging of chill reactions to pleasant and unpleasant sounds.

The term 'chill' refers to a short-term bodily event of high arousal, which marks an emotional peak experience when occurring in response to music. Chill responses arise in a clearly circumscribed time frame and can also be reliably elicited by unpleasant sounds. Previous research, however, mostly focused on individually selected stimuli and positive contexts, thus, limiting the scope of interpretation. Hence, we developed a standardized chill paradigm and used fMRI to test neural responses of 16 healthy volunteers to pleasant and unpleasant emotional sound material while collecting subjective reports of chill intensity and skin conductance response data. As predicted, we found chill-associated increases in autonomic arousal regardless of the valence of the sound material. Apart from activity in primary and higher auditory cortices, both pleasant and unpleasant chills were associated with anterior insula, thalamus and basal ganglia activity. In contrast, amygdala responses were observed only in association with chills elicited by unpleasant sounds. Thus, chills elicited by pleasant and unpleasant sounds share activity in a neural network that may be specifically involved in the arousal component of an emotional experience.

Demonstration by PCR and DNA sequencing of Corynebacterium pseudodiphtheriticum as a cause of joint infection and isolation of the same organism from a surface swab specimen from the patient.

A case of infectious arthritis following arthroscopy is described. Real-time PCR, using universal bacterial primers targeting the 16S rRNA gene, and subsequent DNA sequencing of the PCR product demonstrated the presence of DNA from Corynebacterium pseudodiphtheriticum in the synovial fluid from the affected knee. Culture from a surface swab from the site of purulent discharge from the knee was initially reported as growing normal skin microbiota. Knowing the result of the DNA analysis, the specimen was re-examined and a diphtheroid bacterium was isolated. The DNA sequence of the isolated bacterium was identical to that of the DNA in the joint. The isolated bacterium was tested for susceptibility to relevant antibiotics. Demonstration and identification of bacterial DNA by PCR and gene sequencing may not by itself give information on important characteristics such as susceptibility to antibiotics of the infecting bacterium. The present case illustrates that the results obtained by the method can be used to isolate the relevant bacterium in culture from other sites and thereby characterize it. It furthermore demonstrates that C. pseudodiphtheriticum can cause severe arthritis when inoculated into joints.

Patterns of abnormal motor cortex excitability in atypical parkinsonian syndromes.

OBJECTIVE: Multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal-ganglionic degeneration (CBGD) are all clinically characterized by an akinetic-rigid syndrome together with a variety of additional signs. We hypothesised that these atypical parkinsonian syndromes (APS) will show distinctive patterns in their motor output upon transcranial magnetic stimulation (TMS) due to their different underlying anatomico-functional deficits. METHODS: We performed single and paired-pulse TMS and assessed inhibitory and excitatory response parameters from the first dorsal interosseus muscles in 13 patients with MSA, 18 with PSP, 13 with CBGD, 15 patients with Parkinson's disease and 17 healthy subjects. RESULTS: PSP and MSA patients had significantly enlarged response amplitudes at rest, reduced intracortical inhibition (ICI) and prolonged ipsi- and contralateral silent periods, whereas CBGD patients showed significantly increased motor thresholds, smaller response amplitudes at rest, shortened contralateral silent period, reduced transcallosal inhibition and a reduced ICI. In 22% of APS patients ipsilateral motor responses occurred in upper limb muscles irrespective of the underlying disease. CONCLUSIONS: Our results indicate that motor cortex disinhibition is predominant in patients with PSP and MSA. In CBGD more severe neuronal cell loss in the motor cortex itself may lead to hypoexcitability of corticospinal and transcallosal pathways.

Effect of an intervention to reduce procedural pain and distress for children with HIV infection.

OBJECTIVE: To evaluate a multicomponent pain management intervention, including cognitive behavioral strategies, for children with human immunodeficiency virus (HIV) infection undergoing routine venipuncture. METHODS: Following a baseline venipuncture, children were exposed to an intervention including preparation, relaxation, distraction, reinforcement, parent involvement, and EMLA (eutectic mixture of local anesthetics) cream, and followed for three additional venipuncture procedures. After each procedure, child distress was rated on the Procedure Behavior Checklist (PBCL), child self-report of pain was obtained using the FACES scale, and parent anxiety was reported on the State Trait Anxiety Inventory-State Scale (STAI). RESULTS: Significant reductions in child distress and pain were found by the second postintervention procedure and maintained at the third. Parent anxiety was significantly reduced by the second postintervention procedure, but many parents chose not to participate in the third postintervention procedure. CONCLUSIONS: With repeated exposure, a multicomponent pain management intervention, including cognitive behavioral strategies and EMLA, appears effective at reducing pain, distress, and parent anxiety for children with HIV.

Development of a computerized screening system to identify substance abuse in primary care.

The Drug and Alcohol Problem Assessment for Primary Care (DAPA-PC), developed under a contract from the National Institute on Drug Abuse, is a comprehensive screening system developed for quickly identifying and addressing substance abuse and related problems in a primary care setting. The DAPA-PC system includes a two-level screening instrument, resources for scoring and reporting results, motivational messages, treatment referrals, and informative links, which together address the multifaceted needs of patients dealing with addiction problems and their providers. The need for such a system, preliminary reactions to the instrument, and future course of research are discussed.

Mutation of Arg-166 of alkaline phosphatase alters the thio effect but not the transition state for phosphoryl transfer. Implications for the interpretation of thio effects in reactions of phosphatases.

It has been suggested that the mechanism of alkaline phosphatase (AP) is associative, or triester-like, because phosphorothioate monoesters are hydrolyzed by AP approximately 10(2)-fold slower than phosphate monoesters. This "thio effect" is similar to that observed for the nonenzymatic hydrolysis of phosphate triesters, and is the inverse of that observed for the nonenzymatic hydrolysis of phosphate monoesters. The latter reactions proceed by loose, dissociative transition states, in contrast to reactions of triesters, which have tight, associative transition states. Wild-type alkaline phosphatase catalyzes the hydrolysis of p-nitrophenyl phosphate approximately 70 times faster than p-nitrophenyl phosphorothioate. In contrast, the R166A mutant alkaline phosphatase enzyme, in which the active site arginine at position 166 is replaced with an alanine, hydrolyzes p-nitrophenyl phosphate only about 3 times faster than p-nitrophenyl phosphorothioate. Despite this approximately 23-fold change in the magnitude of the thio effects, the magnitudes of Bronsted beta(lg) for the native AP (-0.77 +/- 0.09) and the R166A mutant (-0.78 +/- 0. 06) are the same. The identical values for the beta(lg) indicate that the transition states are similar for the reactions catalyzed by the wild-type and the R166A mutant enzymes. The fact that a significant change in the thio effect is not accompanied by a change in the beta(lg) indicates that the thio effect is not a reliable reporter for the transition state of the enzymatic phosphoryl transfer reaction. This result has important implications for the interpretation of thio effects in enzymatic reactions.

Alternate modes of binding in two crystal structures of alkaline phosphatase-inhibitor complexes.

Two high resolution crystal structures of Escherichia coli alkaline phosphatase (AP) in the presence of phosphonate inhibitors are reported. The phosphonate compounds, phosphonoacetic acid (PAA) and mercaptomethylphosphonic acid (MMP), bind competitively to AP with dissociation constants of 5.5 and 0.6 mM, respectively. The structures of the complexes of AP with PAA and MMP were refined at high resolution to crystallographic R-values of 19.0 and 17.5%, respectively. Refinement of the AP-inhibitor complexes was carried out using X-PLOR. The final round of refinement was done using SHELXL-97. Crystallographic analyses of the inhibitor complexes reveal different binding modes for the two phosphonate compounds. The significant difference in binding constants can be attributed to these alternative binding modes observed in the high resolution X-ray structures. The phosphinyl group of PAA coordinates to the active site zinc ions in a manner similar to the competitive inhibitor and product inorganic phosphate. In contrast, MMP binds with its phosphonate moiety directed toward solvent. Both enzyme-inhibitor complexes exhibit close contacts, one of which has the chemical and geometrical potential to be considered an unconventional hydrogen bond of the type C-H...X.

A revised mechanism for the alkaline phosphatase reaction involving three metal ions.

Here, X-ray crystallography has been used to investigate the proposed double in-line displacement mechanism of Escherichia coli alkaline phosphatase in which two of the three active-site metal ions have a direct role in catalysis. Two new X-ray crystal structures of the wild-type enzyme in the absence and presence of inorganic phosphate have been refined at 1.75 A to final working R-factors of 15.4% and 16.4%, respectively. In the refinement of both structures, residues in the active sites were treated anisotropically. The ellipsoids resulting from the partial anisotropic refinement show a clear route for the binding and release of substrate/product. In addition, a direct comparison of the refined structures with and without phosphate reveal a strong correlation between the occupancy of the third metal-binding site and the conformation of the Ser102 nucleophile. These findings clarify two important and unresolved aspects of the previously proposed catalytic mechanism, how Ser102 is activated for nucleophilic attack and why a magnesium ion in the third metal site is required for catalysis. Analysis of these results suggest that three metal-ion assisted catalysis is a more accurate description of the mechanism of the alkaline phosphatase reaction. A revised mechanism for the catalytic reaction of alkaline phosphatase is proposed on the basis of the two new X-ray crystal structures reported.

The mechanism of the alkaline phosphatase reaction: insights from NMR, crystallography and site-specific mutagenesis.

The proposed double in-line displacement mechanism of Escherichia coli alkaline phosphatase (AP) involving two-metal ion catalysis is based on NMR spectroscopic and X-ray crystallographic studies. This mechanism is further supported by the X-ray crystal structures of the covalent phospho-enzyme intermediate of the H331Q mutant AP and of the transition state complex between the wild-type enzyme and vanadate, a transition state analog. Kinetic and structural studies on several genetically engineered versions of AP illustrate the overall importance of the active site's metal geometry, hydrogen bonding network and electrostatic potential in the catalytic mechanism.

A model of the transition state in the alkaline phosphatase reaction.

A high resolution crystal structure of Escherichia coli alkaline phosphatase in the presence of vanadate has been refined to 1.9 A resolution. The vanadate ion takes on a trigonal bipyramidal geometry and is covalently bound by the active site serine nucleophile. A coordinated water molecule occupies the axial position opposite the serine nucleophile, whereas the equatorial oxygen atoms of the vanadate ion are stabilized by interactions with both Arg-166 and the zinc metal ions of the active site. This structural complex supports the in-line displacement mechanism of phosphomonoester hydrolysis by alkaline phosphatase and provides a model for the proposed transition state in the enzyme-catalyzed reaction.

The road less travelled: taming phosphatases.

Phosphatases are important in signal transduction, bacterial pathogenesis and several human diseases. So far, however, it is their opposite numbers, the kinases, that have received more attention from chemists. Recent progress in inhibitor development offers hope that new probes of cellular processes, and perhaps novel therapeutic agents, may soon become available.

[Thrombotic obstruction with tilting disc valves (author's transl)]. / Thrombotische Obstruktion von Kippscheibenklappen. Diagnostik und Therapie.

Valve thromboses were observed in nine patients, seven females and two males, aged 46 years on average, between 1/2 and 5 1/2 years after replacement of a mitral valve (n = 6) or an aortic valve (n = 3) by a tilting disc valve (Björk-Shiley, n = 6; Lillehei-Kaster n = 3). In eight cases reoperation was necessary, mainly as an emergency. One patient died preoperatively, five died intra- or postoperatively. Besides the adequate valve type, prophylaxis of valve thrombosis by conscientious anticoagulation is the most important measure. Should leading symptoms - disappearance of valve click and increasing cardiac insufficiency during irregular anticoagulation - occur, immediate referral to cardiac surgery is required.