SOD-1 deletions in Caenorhabditis elegans alter the localization of intracellular reactive oxygen species and show molecular compensation

Superoxide dismutase (SOD) is an enzyme that catalytically removes the superoxide radical (*O2-) and protects organisms from oxidative damage during normal aging. We demonstrate that not only the cytosolic *O2- level but also the mitochondrial *O2- level increases in the deletion mutants of sod-1 gene encoding Cu/Zn SOD in Caenorhabditis elegans (C. elegans). Interestingly, this suggests that the activity of SOD-1, which so far has been thought to act mainly in cytoplasm, helps to control the detoxification of *O2- also in the mitochondria. We also found functional compensation by other SODs, especially the sod-5 gene, which was induced several fold in the mutants. Therefore, the possibility exists that the compensative expression of sod-5 gene in the sod-1 deficit is associated with the insulin/insulin-like growth factor-1 (Ins/IGF-1) signaling pathway, which regulates longevity and stress resistance of C. elegans because the sod-5 gene may be a target of the pathway.

Atypical cilia of the human nasal mucosa

Typical and atypical ultrastructural features of the cilia in the human nasal mucosa are reported in this paper. The specimens were taken from patients with the diagnosis of allergic rhinitis or chronic sinusitis. Most of the cilia showed a typical 9 + 2 arrangement of the axial filament complexes, but atypical axonemes such as 9 + 4, 8 + 2 and 10 + 2 patterns were found in six cilia of three patients. The supernumerary central fibrils were observed in one cilium only, whereas atypical patterns of the peripheral fibrils were found in five cilia. Cilia which contained a multiple axial filament complex, so-called compound clia, were also found in the mucosa of the chronic sinusitis cases. On the basis of their ultrastructural appearance, we classified these cilia into two groups, an "adhesive type" and a "bulging type." The former had a columnar shape of variable diameter, whereas the latter had a balloon-like form. The former contained closely packed multiple axial filament complexes whereas the latter possessed only sparse and irregularly oriented complexes. Electron-lucent lumina which were formed by the remnants of the ciliary membrane were frequently found in the former's transitional portion, but never in the latter.

Antioxidant activity and inhibitory effect of Gamazumi (Viburnum dilatatum THUNB.) on oxidative damage induced by water immersion restraint stress in rats

The antioxidant activity and antiulcer effects of Gamazumi (Viburnum dilatatum THUNB.) fruit squeezing solution (GSS) were investigated. GSS including no antioxidant additive showed strong antioxidant activity by the XYZ-dish method and the electron spin resonance (ESR) method. GSS showed to have no negative effect on growth of rats for 2 weeks of feeding with free access to GSS. After feeding, the GSS group showed a significant inhibitory effect on gastric ulcer formation by water immersion restraint stress for 6 hours compared with the Water group. Plasma, liver and stomach concentrations of lipid peroxide in the GSS group were reduced rather than the water group. Furthermore, the activities of plasma lactic dehydrogenase, amylase and creatine phosphokinase are ordinarily increased by stress; however these activities in the GSS group decreased to the level in the Control group having no stress. The physiological effects of GSS were similar to, or higher than, those of 0.1% (-)-epigallocatechin gallate (EGCg) solution. These effects of EGCg and GSS were similar to the order of antioxidant activity against hydroxyl radical found by both the XYZ-dish and the ESR methods. It was concluded that after ingestion of GSS, during the period of strong antioxidant activity in the body, it could prevent stress-induced oxidative damage.

Mitochondrial reactive oxygen species generation by the SDHC V69E mutation causes low birth weight and neonatal growth retardation

We have previously demonstrated that excessive mitochondrial reactive oxygen species caused by mutations in the SDHC subunit of Complex II resulted in premature death in C. elegans and Drosophila, tumors in mouse cells and infertility in transgenic mice. We now report the generation and initial characterization of conditional transgenic mice (Tet-mev-1) using our uniquely developed Tet-On/Off system, which equilibrates transgene expression to endogenous levels. The mice experienced mitochondrial respiratory chain dysfunction that induced reactive oxygen species overproduction. The mitochondrial oxidative stress resulted in excessive apoptosis leading to low birth weight and growth retardation in the neonatal developmental phase in Tet-mev-1 mice.

Detection of PrPSc in sheep at the preclinical stage of scrapie and its significance for diagnosis of insidious infection

A field sheep insidiously infected with natural scrapie was diagnosed at the preclinical stage through detection of the core fragment of PrpSc (PrPcore) in peripheral lymph nodes by the biopsy method. Three out of 32 euthanized healthy sheep were found positive for PrPcore in the spleen and lymph nodes. Mice that were inoculated with spleen homogenate of one of these sheep showed clinical signs of scrapie and were positive for PrPcore in their brain samples. These results suggest that the detection of PrPcore is significant for diagnosis in the preclinical phase of scrapie.

Toxicity of root canal sealers on rat bone cells in primary culture

The cytotoxic effects on cultured rat bone cells of newly-developed root canal sealers and commercially available sealers were compared. Various root canal sealers were applied to cultured bone cells obtained from rat calvaria by the enzyme digestion method. Measurement of [3H]-thymidine incorporation, alkaline phosphatase activity, and calcium release were performed after 24 and 48 h. No significant difference was found in cellular DNA synthesis and alkaline phosphatase activity between cells exposed to New B-1, New B-5 and controls after exposure for 24 and 48 h. Cells in contact with Tubliseal, Diaket and AH-26 demonstrated a significant difference from controls in DNA synthesis and alkaline phosphatase activity. Calcium release at 24 h was significantly different in the cells treated with New B-1 and New B-5 than in controls. No appreciable difference was found, however, between New B-6, Sealapex and controls. At 48 h, cells treated with New B-1, New B-5 and New B-6 showed differed significantly difference from controls, but the cells exposed to Sealapex did not. The newly-developed root canal sealers had lower toxicity in vitro than five types of commercially available root canal sealers.

Stereo acuity in patients with unilateral macular hole and after unilateral macular hole surgery

PURPOSE

To investigate stereo acuity levels in patients with unilateral idiopathic macular hole and after surgical intervention.

METHODS

In 31 consecutive patients with a unilateral macular hole and 46 consecutive patients who underwent successful unilateral macular hole surgery, complete ocular examinations, including orthoptic examinations and microperimetry using the scanning laser ophthalmoscope, were performed.

RESULTS

A significantly positive correlation was found between VA and stereo acuity (r = 0.87, P < 0.01). After successful surgery, stereo acuity also correlated with the presence or absence of absolute and/or relative scotoma, and was best in eyes without scotomata. Patients with unilateral idiopathic macular hole, suppression, and symptom duration of 24 months or longer had no stereoscopic vision.

CONCLUSIONS

The results indicated that in patients with unilateral idiopathic macular hole and after surgery, stereo acuity correlated with VA. Patients with unilateral macular hole should be operated upon as early as possible, resulting in better VA and better stereo acuity.

Chromium (VI)-induced transformation is enhanced by Zn deficiency in BALB/c 3T3 cells

Hexavalent chromium [Cr(VI)] is a carcinogenic heavy metal that is reduced to intermediate oxidation states, such as Cr(V) and Cr(IV), in the process of forming stable Cr(III) forms; it is these intermediate forms that are thought to be responsible for much of the DNA damage and mutations that are induced by Cr(VI). Metallothionein (MT), a heavy metal-binding protein, is induced by zinc and other heavy metals and protects cells from the toxic effects of these metals by sequestering them. MT cannot bind Cr, but by scavenging reactive oxygen species through its cysteine residues, it may act as a protective factor against Cr(VI)-induced DNA lesions by reducing Cr(VI) directly to Cr(III), thereby avoiding the creation of the toxic intermediates. Here, we showed that Zn deficiency decreased MT expression in BALB/3T3 clone A31-1-1 cells and caused them to become highly susceptible to Cr(VI)-induced transformation. To obtain Zn-deficient cultures, cells were cultured in medium supplemented with 10% Chelex(®)-100 chelating resin-treated FBS. The increase in susceptibility to transformation was abolished by culturing the cells with supplemental Zn (50 µM). Previously, we reported that Cr(VI) inhibits MT transcription by preventing the zinc-dependent formation of a complex of metal response element-binding transcription factor-1 (MTF-1) and the co-activator p300. Our results suggest that the carcinogenicity of Cr(VI) is enhanced by MTF-1 dysfunction.