Atsuo Iwasawa

Disinfection potential of electrolyzed solutions containing sodium chloride at low concentrations

Electrolyzed products of sodium chloride solution were examined for their disinfection potential against hepatitis B virus (HBV) and human immunodeficiency virus (HIV) in vitro. Electrolysis of 0.05% NaCl in tap water was carried out for 45 min at room temperature using a 3 A electric current in separate wells installed with positive and negative electrodes. The electrolyzed products were obtained from the positive well. The oxidation reduction potential (ORP), pH and free chlorine content of the product were 1053 mV, pH 2.34 and 4.20 ppm, respectively. The products modified the antigenicity of the surface protein of HBV as well as the infectivity of HIV in time- and concentration-dependent manner. Although the inactivating potential was decreased by the addition of contaminating protein, recycling of the product or continuous addition of fresh product may restore the complete disinfection against bloodborne pathogens.

Cytotoxicity of ophthalmic solutions with and without preservatives to human corneal endothelial cells, epithelial cells and conjunctival epithelial cells

Purpose:  The cytotoxicity of a range of commercial ophthalmic solutions in the presence and absence of preservatives was assessed in human corneal endothelial cells (HCECs), corneal epithelia and conjunctival epithelia using in vitro techniques.

Aberrant Expression of Serpin Squamous Cell Carcinoma Antigen 2 in Human Tumor Tissues and Cell Lines: Evidence of Protection from Tumor Necrosis Factor-Mediated Apoptosis

Abstract Squamous cell carcinoma antigens (SCCA) 1 and 2 are highly homologous proteins of the serpin family, although they inhibit different types of proteinases. We investigated the expression of both SCCA mRNAs in tumor tissues, in various cell lines (A431, SAS, Ca9, HeLa, SKGIIIa, HSC-2, HSC-3, HSC-4 and KB) and in HSC cell lines in the presence of tumor necrosis factor α (TNFα). The expression of SCCA2 mRNA could be differentiated from that of SCCA1 in tumor tissues and cell lines by means of reverse transcriptionpolymerase chain reaction (RTPCR). The ratio between SCCA1 and SCCA2 mRNA expression showed selective expression of SCCA2 mRNA in SCC tissues from the uterine cervix compared to SCC tissues from the esophagus or skin. In addition, a significant level of SCCA2 mRNA expression was detected in the HSC-4 cell line, but not in Ca9, HeLa, SKGIIIa, or HSC-3 cells. In contrast, SCCA1 mRNA was detected in all samples tested. These results suggest that the level of expression of SCCA2 mRNA detected by RTPCR can be used to evaluate the status of SCC tumors. Next, we studied the effect of TNFα on SCCA1 and SCCA2 mRNA expression in HSC cell lines. SCCA1 mRNA expression was constantly increased in the three HSC cells examined with increasing time of exposure to TNFα. In contrast, SCCA2 mRNA expression was specific for HSC-4 cells. The survival rate of HSC-4 cells pretreated with TNFα (6.3 ng/ml) for 48 h was found to be 72%, compared with 42% and 9% for HSC-3 and HSC-2 cells, respectively, after apoptotic stimulation by TNFα (10 ng/ml) and cycloheximide (10 g/ml) for 18 h. Furthermore, selective expression of SCCA2 mRNA in HSC-4 pretreated with TNFα protected these cells from TNFαmediated apoptosis. Thus, SCCA2 overexpression in squamous tumor cells contributed to their survival by protecting them against TNFαinduced apoptosis.

Monoclonal antibodies as probes to detect conformational changes in the rat cysteine proteinase inhibitor cystatin A

Five monoclonal antibodies (MAbs), 77, 114, 138, 175 and 187, were established for rat cystatin A. MAbs 77, 114, 138 and 175 were shown to belong to the IgG1 subclass, whereas MAb 187 was an IgM. These MAbs partially suppressed inhibitory activity of rat cystatin A to papain. Their epitopes were mapped in detail on the molecule by examining the reactivities of the MAbs with NH2-terminally truncated forms and fragments of rat cystatin A by an enzyme-linked immunosorbent assay (ELISA), and by reactivity with the inhibitor on immunoblotting. In competitive binding assays the MAbs did not compete with each other, indicating that the epitopes recognized by these MAbs were substantially different. The conformational epitope recognized by the three MAbs 114, 138 and 175 belonged to one group that was highly sensitive to denaturation, but those epitopes were unchanged by NH2-terminal truncation. MAb 187 was able to recognize a linear epitope present in amino acid residues 15-50 in the NH2-terminal region. MAbs 77 and 114 reacted weakly with mouse cystatin A but not at all with human cystatin A, whereas MAb 187 reacted similarly with mouse cystatin A but at about half that level with human. The MAbs produced in this study should be useful tools for detecting conformational changes in the rat cystatin A molecule.