Here, we report for the first time quinol peroxidase (QPO), an enzyme that uses ubiquinol‐1 as an electron donor for the reduction of H2O2 to water. We purified QPO to > 90% purity from the membrane fraction of Actinobacillus actinomycetemcomitans. QPO is a 53.6‐kDa protein that contains three heme c molecules. The qpo gene was predicted to encode a putative bacterial cytochrome c peroxidase with N‐terminal extensions containing an additional potential heme c‐binding motif. Although qpo has high sequence homology to bacterial cytochrome c peroxidases, QPO did not catalyze peroxidation in the presence of horse heart cytochrome c. In addition, the cytoplasmic membrane of A. actinomycetemcomitans had apparent QPO‐dependent peroxidase activity in the presence of NADH or succinate, which are substrates for the respiratory chain. Based on these findings, we present a new mechanism for the scavenging of reactive oxygen species in which quinol in the respiratory chain is consumed.
Previous studies suggested that the interaction between proteins modified by advanced glycation end products (AGEs) and cells, such as macrophages, may be involved in diabetic angiopathy. Pyrraline is one of the AGEs and known to be elevated in plasma of diabetic rats and humans, and is present in vascular lesions of diabetic and elderly subjects. We examined whether modification of albumin by pyrraline influences its degradation by macrophage-like cell line, P388D 1 cells. Degradation of pyrraline-modified albumin by these cells was diminished, causing accumulation of the albumin in these cells. The susceptibility of pyrraline-modified albumin to lysosomal proteolytic enzymes was reduced by approximately 40% in vitro, while lysosomal activity in the cells per se was not affected. This phenomenon was also observed when human monocytes were used instead of P388D 1 cells. Our results suggest that accumulation of pyrraline-modified albumin in P388D 1 cells is due to the reduced susceptibility of the protein to lysosomal enzymatic degradation. Such alterations in the interaction between AGEs-modified protein and phagocytes may contribute to angiopathy in elderly subjects and patients with diabetes.
PFAPA syndrome is a clinical entity of unknown etiology characterized by periodic episodes of high fever accompanied by aphthous stomatitis, pharyngitis/tonsillitis, and cervical adenitis [3,5]. Since specific laboratory abnormalities for the PFAPA syndrome are inexistent, it is usually diagnosed clinically after excluding other probable causes of the fever, such as infection [1]. In PFAPA patients, discriminating between a fever attack due to bacterial infection and a fever attack due to noninfectious inflammation constitutes a major difficulty. Because procalcitonin, a propeptide of calcitonin, is reported to be a sensitive marker of systemic bacterial infection [2, 4], we followed peripheral leukocyte counts, CRP values and procalcitonin concentrations during the fever attacks associated with PFAPA syndrome in the hope of defining reliable criteria for its diagnosis. We determined serum procalcitonin concentrations in six PFAPA syndrome patients (two males and four females) with a median age of 7.5 (range 3-10) years and in 32 controls (bacterial, n=10 and non-bacterial, n=22). Sampling was performed on the third to fifth day of fever. In the PFAPA syndrome patients, febrile episodes started at the median age of 2.5 (range 1-7) years with each episode lasting 5-7 days and recurring every 3-4 weeks. The ethical committees of our institutes approved the study protocol and the guardians of all the patients gave their informed consent. Serum procalcitonin concentrations were measured by using the fully automated enzyme immunoluminescent assay (Wako Pure Chemical Industries, Ltd.), which employs katacalcin monoclonal antibody and calcitonin polyclonal antibody labeled with peroxidase for SphereLight 180 (Olympus Corporation). The detection limit was 0.1 ng/ml and the normal reference was set at <0.5 ng/ml. In PFAPA patients, the correlations between procalcitonin, CRP values and leukocyte counts were examined over 13 febrile episodes. Serum procalcitonin values ranged from 0.20 to 11.36 (median value 1.05) ng/ml in positive control subjects (Table 1), while all the negative controls had undetectable levels.During febrile episodes in PFAPA patients, which were confirmed not to be due to adenoviral or group A streptococcal infections, leukocyte counts and serum concentrations of CRP were invariably and significantly Eur J Pediatr (2007) 166:621-622
Objective. To assess anxiety among pediatric patients and their parents related to initial gastrointestinal endoscopy. Methods. Patients aged <19 years undergoing initial gastrointestinal (GI) endoscopy and their parents were invited to complete a self-administered questionnaire related to endoscopy in 13 institutions in Japan. Results. The subjects were 128 children, aged 1 month to 17 years. Forty-eight patients (37.5%) underwent esophagogastroduodenoscopy (EGD), 32 (25%) underwent colonoscopy (CS), 39 (30.5%) underwent both EGD and CS, 3 (2.3%) underwent balloon enteroscopy (BE), 3 (2.3%) underwent capsule endoscopy (CE), and 3 (2.3%) underwent CE and other endoscopic procedures. In the preendoscopy questionnaire, the most common concerns of the patients and parents before undergoing the procedure were “Pain” (45% of the patients underwent EGD or BE via the oral approach, and 52% of the patients underwent CS or BE via the anal approach) and “Procedural accidents related to the endoscopy” (63% of parents). In the postendoscopy questionnaire, the most common difficulty that patients and parents actually experienced before and after undergoing the procedure was “Hunger.” Conclusion. A preparatory intervention including an explanation regarding specific concerns before initial GI endoscopy, which this study revealed, could reduce anxiety experienced by both pediatric patients and parents.
The subcellular localization of the nonstructural protein C of Sendai virus was investigated by means of indirect immunofluorescence microscopy of Sendai virus-infected cells, using an antiserum specific for C protein. In infected cells, C protein was detected exclusively in the cytoplasm as granular fluorescence, which coincided very well with the distribution of nucleocapsid protein NP and phosphoprotein P, which were also detected with specific antisera. This suggested that these proteins are present together in inclusions, probably forming nucleocapsids. In contrast, when the NP and C proteins were individually expressed in COS cells by transfection with expression plasmids containing cDNA for these proteins, their distribution patterns in the cytoplasm were found to be quite different from each other. Protein-blot analyses of purified virions revealed the presence of a significant amount of the C protein in virions, which indicated that C protein is integrated into virions. Under conditions in which most of the envelope-associated proteins, such as HN, F, and M, were removed from the virions by a detergent, the C protein remained tightly associated with the nucleocapsids--about 40 molecules per nucleocapsid.
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