O2-inducible H2O2-forming NADPH oxidase is responsible for the hyper O2 sensitivity of Bifidobacterium longum subsp. infantis.

Bifidobacteria are beneficial anaerobes, and their O2 sensitivity levels differ among species as a function of unknown molecular mechanisms. Bifidobacterium longum subspecies infantis (B. infantis), a predominant colonizer of the gastrointestinal tract of infants, showed a hyper O2-sensitive growth profile with accompanying a production of H2O2. In this study, we characterized an NADPH oxidase as a key enzyme responsible for this microbe's hyper O2 sensitivity. A dominant active elution peak of H2O2-forming NADPH oxidase activity was detected in the first step of column chromatography, and the purified NADPH oxidase (NPOX) was identified as a homolog of nitroreductase family proteins. The introduction of the gene encoding B. infantis NPOX (npoxA) into O2-tolerant Bifidobacterium minimum made the strain O2 sensitive and allowed it to produce H2O2. Knockout of the npoxA gene in B. infantis decreased the production of H2O2 and mitigated its B. infantis hyper O2 sensitivity. A transcript of B. infantis npoxA is induced by O2, suggesting that the aerobic production of toxic H2O2 is functionally conserved in B. infantis.

Cytosolic T3-binding protein modulates dynamic alteration of T3-mediated gene expression in cells.

µ-Crystallin (CRYM) is also known as NADPH-dependent cytosolic T3-binding protein. A study using CRYM-null mice suggested that CRYM stores triiodothyronine (T3) in tissues. We previously established CRYM-expressing cells derived from parental GH3 cells. To examine the precise regulation of T3-responsive genes in the presence of CRYM, we evaluated serial alterations of T3-responsive gene expression by changing pericellular T3 concentrations in the media. We estimated the constitutive expression of three T3-responsive genes, growth hormone (GH), deiodinase 1 (Dio1), and deiodinase 2 (Dio2), in two cell lines. Subsequently, we measured the responsiveness of these three genes at 4, 8, 16, and 24 h after adding various concentrations of T3. We also estimated the levels of these mRNAs 24 and 48 h after removing T3. The levels of constitutive expression of GH and Dio1 were low and high in C8 cells, respectively, while Dio2 expression was not significantly different between GH3 and C8 cells. When treated with T3, Dio2 expression was significantly enhanced in C8 cells, while there were no differences in GH or Dio1 expression between GH3 and C8 cell lines. In contrast, removal of T3 retained the mRNA expression of GH and Dio2 in C8 cells. These results suggest that CRYM expression increases and sustains the T3 responsiveness of genes in cells, especially with alteration of the pericellular T3 concentration. The heterogeneity of T3-related gene expression is dependent on cellular CRYM expression in cases of dynamic changes in pericellular T3 concentration.

Hodgkin's disease of the thoracic vertebrae.

BACKGROUND CONTEXT: Hodgkin's disease rarely occurs in the spine, which is usually a setting for the advanced form of the disease. PURPOSE: To describe an unusual case of isolated, primary spinal Hodgkin's disease and to draw attention to this disease as a possible diagnosis in patients with mixed inflammatory cell infiltrate lesions located in the thoracic spine. STUDY DESIGN/SETTING: A case report of a 28-year-old woman who presented with back pain and progressive weakness in the lower extremities as a result of spinal cord compression from Hodgkin's disease of the thoracic vertebrae. METHODS: We report a new case of spinal cord compression resulting from Hodgkin's disease of the thoracic vertebrae. Decompression surgery was performed in the patient, followed by antibiotic treatment. RESULTS: Antibiotic therapy temporarily improved inflammation and fever. However, magnetic resonance imaging (MRI) evaluation showed that the inflammatory reaction in the lesion was not completely resolved. The disease progressed and later investigations revealed Hodgkin's disease, which improved with a course of chemotherapy and radiation. CONCLUSIONS: Hodgkin's disease should be considered in the differential diagnosis of spinal neoplastic lesions with clinical features similar to spondylitis. Because MRI evaluation showed that the vertebral disc was maintained in this case, the presence of a tumor rather than inflammation should have been suspected.

Enhancement of acetyl-CoA: 1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine acetyltransferase activity by hydrogen peroxide.

The synthesis of platelet-activating factor (PAF) by human umbilical vein endothelial cell (HUVEC) in response to H2O2 was significantly increased in a concentration-dependent manner. When HUVEC were pretreated with diethyl maleate, which depletes intracellular glutathione, PAF synthesis was enhanced 3-fold upon 5 mM H2O2-treatment. Intracellular redox was involved in regulating PAF synthesis, since the addition of antioxidants such as N-acetylcysteine, pyrrolidinecarbodithioic acid (PDTC), and Trolox reduced PAF production in H2O2-treated HUVEC. The activity of acetyl-CoA: 1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine acetyltransferase, which is involved in the last step of PAF synthesis, was also activated in H2O2-treated cells. However, exogenous lyso-PAF addition had not effected to acetyltransferase activity. The acetyltransferase activity responded quickly to H2O2-treatment, but the activation was transitory. A tyrosine kinase inhibitor and a calmodulin antagonist blocked acetyltransferase activity in H2O2-stimulated cells, suggesting that tyrosine kinase and calcium/calmodulin-dependent protein kinase are involved in regulating acetyltransferase activity. These observations suggest that H2O2 is one of the modulators of lyso-PAF acetyltransferase activity via a phosphorylation system and platelet-activating factor (PAF) synthesis.

Neurogenic bladder in patients with cervical compressive myelopathy.

We examined the urinary disturbances in 56 consecutive patients with cervical compressive myelopathy using the latest International Continence Society classification. Of the 56 patients with cervical compressive myelopathy, 29 (52%) had some urinary subjective complaints, whereas the remaining 27 (48%) had none. Urologic examination indicated that 8 of these 29 (28%) patients with urinary complaints had urologic disorders other than neurogenic bladder. Of the remaining 21 patients, only 6 (25%) were judged to have neurogenic bladder on urodynamic study. Urodynamic study may be of limited value in diagnosing urinary disturbance in cervical myelopathy. Further, four cases (83%) showed underactive bladder activity in voiding phase, and only one case (17%) showed overactive bladder activity in filling phase. These results were contrary to those of previous studies indicating that cervical compressive myelopathy is associated with overactive bladder activity in filling phase. There were no significant differences in motor or sensory Japanese Orthopedic Association scores between the patients with and without urinary complaints. However, the patients with urinary complaints had significantly longer durations of myelopathy and delayed motor evoked potential latencies than those without urinary complaints. After surgery, 19 of the 21 (90%) patients with urinary complaints showed recovery from urinary disturbance. Operations in patients with cervical myelopathy were also effective against urinary disturbance. Urinary complaints may be an indication for surgical treatment despite the results of urodynamic study.

Alteration of gene expressions by the overexpression of mitochondrial phospholipid hydroperoxide glutathione peroxidase (mtPHGPx).

To determine the effect on gene expression of trace levels of reactive oxygen species from mitochondria, we used the mRNA differential display technique to compare gene expression in two cell lines: M15, which overexpresses mitochondrial phospholipid hydroperoxide glutathione peroxidase (mtPHGPx), in rat basophilic leukemia RBL-2H3 cells, and a control cell line, S1. We isolated 27 differentially expressed genes, including 10 previously unreported sequences. These genes included cytoskeletal proteins (beta-tubulin, nonmuscle myosin alkali light chain, and vimentin), growth or proliferation regulators [growth differentiation factor 1 (Gdf-1), Rap1a, and inhibitor of growth 3 (Ing3)], and others. Although the expression of most of the isolated genes did not respond to ROS (hydrogen peroxide) or antioxidant (pyrolidine dithiocarbamate) treatment, the expression of Gdf-1 was downregulated by hydrogen peroxide treatment. Thus, low levels of ROS produced in mitochondria during normal cellular metabolism can modulate gene expression.