Photocatalytically active titanium dioxide (TiO₂) is widely used as a self-cleaning and self-disinfecting material in many applications to keep environments biologically clean. Several studies on the inactivation of bacteria and viruses by photocatalytic reactions have also been reported; however, only few studies evaluated the spectrum of the microbicidal activity with photocatalysis for various species. There is a need to confirm the expected effectiveness of disinfection by photocatalysis against multidrug-resistant bacteria and viruses. In this study, microbicidal activity of photocatalysis was evaluated by comparing the inactivation of various species of bacteria and viruses when their suspensions were dropped on the surface of TiO₂-coated glass. Gram-positive bacteria, e.g., methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecalis, and penicillin-resistant Streptococcus pneumoniae, were easily inactivated by photocatalysis, whereas some gram-negative bacteria, e.g., Escherichia coli and multidrug-resistant Pseudomonas aeruginosa, were gradually inactivated by photocatalysis. Influenza virus, an enveloped virus, was significantly inactivated by photocatalysis compared with feline calicivirus, a non-enveloped virus. The effectiveness of microbicidal activity by photocatalysis may depend on the surface structure. However, they are effectively inactivated by photocatalysis on the surface of TiO₂-coated glass. Our data emphasize that effective cleaning and disinfection by photocatalysis in nosocomial settings prevents pathogen transmission.

Prostate cancer (PCa) is the most common malignant carcinoma that develops in men in Western countries. MicroRNA (miRNA) have the potential to be used as biomarkers and therapeutic targets for the treatment of various cancers. We found significantly higher expression of miR-30d in 3 PCa cell lines (PC3, DU145 and LNCaP) compared with 2 normal prostate cell lines (RWPE-1 and PrSc) using miRNA microarrays and qPCR. Clinicopathological study revealed that miR-30d expression levels were significantly higher in cancer tissue samples than in the paired normal controls (P = 0.03). Furthermore, the miR-30d-high group had shorter time to biochemical recurrence (P = 0.026). MiR-30d overexpressed PCa cells promoted proliferation and invasion in vitro. Inoculation of miR-30d depleted PCa cells dramatically reduced tumor volumes in vivo. Using reporter gene assay, we identified miR-30d as a downregulator of SOCS1 expression by directly binding to 3’-UTR of SOCS1. MiR-30d regulated the expression of phospho-STAT3, MMP-2 and MMP-9 through the downregulation of SOCS1. The levels of SOCS1 mRNA and protein were significantly down-regulated in prostate cancer tissues. Consistently, miR-30d expression was inversely correlated with SOCS1 expression (P = 0.03). The miR-30d-high/SOCS1-low group was associated with an increased risk of early biochemical recurrence (P = 0.0057). Taken together, miR-30d appears to be a novel independent prognostic marker of PCa progression that allows clinicians to identify patients who need more intensive treatments.

The International Organization for Standardization (ISO) was used to evaluate antibacterial activity by titanium dioxide (TiO₂) photocatalysis since 2006. We evaluated photocatalytic inactivation of Qβ and T4 bacteriophages induced by low-intensity, long-wavelength ultraviolet A (UVA; 0.1 mW cm⁻² and 0.001 mW cm⁻²) irradiation on a TiO₂-coated glass plate using the ISO methodology. The results indicated that both bacteriophages were inactivated at 0.001 mW cm⁻²UVA. The intensity of UV light, including long-wavelength light (UVA), is very low in an actual indoor environment. Thus, TiO₂ photocatalysis can be beneficial for inactivating viruses in an indoor environment. Experiments using qPCR and bovine serum albumin degradation assume that viral inactivation is caused by outer viral protein disorder and not by viral RNA reduction by reactive oxygen species produced during TiO₂ photocatalysis. Furthermore, we showed that the ISO methodology for standard testing of antibacterial activity by TiO₂ photocatalysis can be applied to assess antiviral activity.

Photocatalysts are promising materials for solid-state antiviral coatings to protect against the spread of pandemic coronavirus disease (COVID-19). This paper reports that copper oxide nanoclusters grafted with titanium dioxide (Cu_xO/TiO₂) inactivated the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, including its Delta variant, even under dark condition, and further inactivated it under illumination with a white fluorescent bulb. To investigate its inactivation mechanism, the denaturation of spike proteins of SARS-CoV-2 was examined by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS-PAGE) and enzyme-linked immunosorbent assay (ELISA). In addition to spike proteins, fragmentation of ribonucleic acids in SARS-CoV-2 was investigated by real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR). As a result, both spike proteins and RNAs in the SARS-CoV-2 virus were damaged by the Cu_xO/TiO₂ photocatalyst even under dark condition and were further damaged under white fluorescent bulb illumination. Based on the present antiviral mechanism, the Cu_xO/TiO₂ photocatalyst will be effective in inactivating other potential mutant strains of SARS-CoV-2. The Cu_xO/TiO₂ photocatalyst can thus be used to reduce the infectious risk of COVID-19 in an indoor environment, where light illumination is turned on during the day and off during the night.

Prostatic diseases are characterized by increased activity of cytokines, growth factors, and cyclooxygenases- (COX-) 1 and 2. Activation of COX-1 and COX-2 results in increased levels of prostaglandins and the induction of angiogenic, antiapoptotic and inflammatory processes. Inhibition of COX enzymes by members of the widely used nonsteroidal anti-inflammatory drug (NSAID) class of drugs decreases prostaglandin production, and exerts a variety of anti-inflammatory, antipyretic, and antinociceptive effects. While numerousin vitro,in vivo, and clinical studies have shown that NSAIDs inhibit the risk and progression of prostatic diseases, the relationship between NSAIDs and such diseases remains controversial. Here we review the literature in this area, critically analyzing the benefits and caveats associated with the use of NSAIDs in the treatment of prostatic diseases.