Early bloodstream infection after pediatric living donor living transplantation.

To determine the perioperative risk factors for bacterial infections after pediatric living donor liver transplantation (LDLT), we investigated the clinical profiles of 149 children who underwent pediatric LDLT between 1994 and 2008. Bacterial infections were diagnosed based on guidelines proposed by the Centers for Disease Control. We observed 36 bloodstream infections (BSIs) in 32/149 (21.5%) patients (0.24 infections per patient), which, 21 (58.3%) BSIs in 19 patients were due to gram-positive and 15 (41.7%) in 13 patients to gram-negative organisms. The most common pathogens of early BSI were coagulase-negative Staphylococcus; (n = 11; 30.6%) and Klebsiella pneumoniae (n = 8; 22.2%). The most common site of early BSI was catheter-related (n = 14; 38.9%). Multivariate analysis showed that age ≤ 1 year (P < .05; odds ratio [OR] = 3.90; 95% CI, 1.83-15.26) and bile duct complications (P < .05; OR = 6.2, 95% CI = 3.21-35.23) were significant independent risk factors for early BSIs. More cautious management of pediatric LDLTs may be necessary for younger age children particularly with postoperative biliary complications.

De novo autoimmune hepatitis in Korean children after liver transplantation: a single institution's experience.

INTRODUCTION: De novo autoimmune hepatitis (AIH) after orthotopic liver transplantation (OLT) has been described as a new type of late graft dysfunction in children who have not undergone transplantation for previous autoimmune liver disease. The purpose of this study was to evaluate the clinical aspects of de novo AIH among children following OLT. PATIENTS AND METHODS: Between January 1994 and May 2007, 149 children underwent OLT, including 1 with recurrent AIH who was excluded from this study, whereas 4 others developed de novo AIH (2.7%; n = 4/148). We analyzed the demographics, laboratory characteristics, and response to treatment of the 4 children with de novo AIH following OLT. RESULTS: The 4 patients were all girls with a median interval after OLT to presentation of 6.5 years (range, 0.7-8.8 years). The median age when de novo AIH developed was 12.4 years (range, 8.7-17.3 years). All cases were detected by abnormal liver function tests, namely, increased aspartate aminotransferase (AST; median, 322 IU/L; range, 181-919 IU/L). One patient showed elevated immunoglobulin G. Three patients displayed positive antinuclear antibodies. All were seronegative for smooth muscle antibody and liver-kidney microsomal type 1 antibody. One patient showed anti-mitochondrial antibody. All patients were treated with steroids with or without azathioprine. The liver function tests in these 4 patients, improved by at least 50% during the first month of treatment, responding to steroid treatment with or without azathioprine. CONCLUSION: In preadolescent or adolescent female patients with unexplained graft dysfunction after OLT, it is important to recognize de novo AIH rapidly and to develop an adequate diagnostic strategy, including evaluation of serum autoantibodies, immunoglobulin G, and liver biopsy.

Molecular properties of p-(dimethylamino)benzaldehyde bound to liver alcohol dehydrogenase: a Raman spectroscopic study.

We have studied the binding nature of an aromatic aldehyde to the catalytic site of liver alcohol dehydrogenase from horse (LADH) using preresonance Raman spectroscopy. The compound p-(dimethylamino)benzaldehyde (DABA) is converted to the corresponding alcohol in the presence of nicotinamide adenine dinucleotide (NADH) and a catalytic amount of enzyme at neutral pH. A stable ternary complex of LADH/NADH/DABA can be formed if enzyme and coenzyme are in excess at high pH [Jagodzinski, P. W., Funk, G. F., & Peticolas, W. L. (1982) Biochemistry 21, 2193-2202]. We have obtained the preresonance Raman spectrum of bound DABA by subtracting the contribution of the binary complex of LADH/NADH from the spectrum of this stable ternary complex. In order to understand the normal mode patterns of DABA, four isotopically labeled DABA derivatives were synthesized and their Raman spectra, in solution and in the ternary complex, were measured. Three of these compounds contain substitutions in the functionally important aldehyde moiety: (i) In one such substitution, the aldehydic hydrogen atom was replaced by a deuterium; (ii) in another, this hydrogen atom was replaced by deuterium, and the aldehydic carbon atom was replaced by 13C; and (iii) in the third derivative, only the carbon atom was replaced by 13C. The fourth derivative has had the two hydrogen atoms at the 3- and 5-positions of the DABA ring replaced by deuterium atoms. We find that many of the spectral modes are fairly extended, involving both stretching and bending motions of the entire molecule, although a few modes are quite localized. We find that the normal mode structure of DABA changes considerably when it binds to LADH/NADH. As a model for the bound DABA, we have examined the zinc complexes of DABA (and all four isotopically labeled samples) in anhydrous diethyl ether and methylene chloride. A striking correspondence between the Raman spectra of the enzyme-bound DABA and DABA-Zn complexes in solution is found, which extends to all the isotopically labeled derivatives. This suggests that one of the major roles of LADH in the binding of DABA is to provide a divalent zinc ion to form a first-sphere Lewis acid complex. The data also suggest other interactions between enzyme-bound DABA with its protein surroundings and with the coenzyme NADH are quite minor. An estimate of the carbonyl bond character of bound DABA had been made on the basis of the response of Raman bands to isotopic labeling and on trends observed in spectra of DABA in solvents of various polarities.(ABSTRACT TRUNCATED AT 400 WORDS)

Classical Raman spectroscopic studies of NADH and NAD+ bound to liver alcohol dehydrogenase by difference techniques.

We report the Raman spectra of reduced and oxidized nicotinamide adenine dinucleotide (NADH and NAD+, respectively) and adenosine 5'-diphosphate ribose (ADPR) when bound to the coenzyme site of liver alcohol dehydrogenase (LADH). The bound NADH spectrum is calculated by taking the classical Raman difference spectrum of the binary complex, LADH/NADH, with that of LADH. We have investigated how the bound NADH spectrum is affected when the ternary complexes with inhibitors are formed with dimethyl sulfoxide (Me2SO) or isobutyramide (IBA), i.e., LADH/NADH/Me2SO or LADH/NADH/IBA. Similarly, the difference spectra of LADH/NAD+/pyrazole or LADH/ADPR with LADH are calculated. The magnitude of these difference spectra is on the order of a few percent of the protein Raman spectrum. We report and discuss the experimental configuration and control procedures we use in reliably calculating such small difference signals. These sensitive difference techniques could be applied to a large number of problems where the classical Raman spectrum of a "small" molecule, like adenine, bound to the active site of a protein is of interest. The spectrum of bound ADPR allows an assignment of the bands of the bound NADH and NAD+ spectra to normal coordinates located primarily on either the nicotinamide or the adenine moiety. By comparing the spectra of the bound coenzymes with model compound data and through the use of deuterated compounds, we confirm and characterize how the adenine moiety is involved in coenzyme binding and discuss the validity of the suggestion that the adenine ring is protonated upon binding. The nicotinamide moiety of NADH shows significant molecular changes upon binding.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of the translational diffusion constant of G-actin by photon correlation spectroscopy.

Photon correlation spectroscopic measurements on monomeric actin have yielded a translational diffusion constant of 8.13 X 10(-7) cm2 s-1 after correction for the contribution of the back-reflections of the main beam. This value corresponds to a sphere with a radius of 2.6 nm and 50% hydration, or to a prolate ellipsoid with axes 2.0 and 4.0 nm and 30% hydration.

Effects of magnesium and ionic strength on the diffusion and charge properties of several single tRNA species.

The technique of laser light scattering was used to evaluate the effects of Mg+2 and ionic strength on the solution structures of seven tRNA species. Information about ion effects on both conformation and electric charge were derived from measurements of the translational diffusion constants and diffusive virial coefficients. E. coli tRNAMetf and six elongator tRNAs from both Class I and II were studied. The diffusion measurements show that the responses of all but the initiator species are qualitatively similar to each other and to that of bulk tRNA, but that significant quantitative differences also obtain. All of the elongator species exhibited an anomolous increase in diffusivity reported earlier by us for bulk tRNA when placed in a low salt-low Mg+2 condition. The initiator tRNA did not undergo this transition and unlike the other tRNAs tested was apparently more compact in 1 mM Mg+2 than 10 mM Mg+2 at ionic strengths in excess of 0.1 M. At 0.1 M ionic strength, pH 7.2, the average net charge of the tRNAs ranged from 7-12 e- in 1 mM Mg+2 and 3-7 e- in 10 mM Mg+2, consistent with the binding of 1-2 additional Mg+2 ions in the higher Mg+2 condition.