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2-Mercaptoethanol increases the optical density of assay solutions at wavelengths between 280 to 400 nm, and therefore interferes with the measurement of protein concentration by the microbiuret method. Protein concentration can be determined in the presence of 2-mercaptoethanol up to 6 mM by modification of the method as follows: after the precipitation of protein by trichloroacetic acid in the presence of deoxycholate, the precipitate is resolubilized with NaOH solution. Dithiothreitol interfered with the protein determinations could by made in the presence of 4 mM of dithiothreitol with the modified microbiuret method. This modified method is time-saving and more reliable than other methods for protein determination, such as Lowry's method, in the presence of sulfhydryl reagents.

Ferric nitrilotriacetate (Fe3+-NTA) solution showed maximum absorbance at pH 7.5. The iron was in ferric high-spin state and coordinated octahedrally with a relatively symmetric structure and also probably pentagonally. A spin trapping technique employing 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) yielded a DMPO spin adduct of unknown radical with three doublets (DMPO-Z) and a simple nitroxide radical (Y-NO.) in serum from rats injected intraperitoneally with Fe3+-NTA. When the Fe3+-NTA solution was diluted 500-fold with 50 mM NTA solution, DMPO-Z, Y-NO. and an additional signal, DMPO-OH were observed. The DMPO-Z signal was suppressed by a decrease in oxygen tension, alpha-tocopherol and 3-tert-butyl-4-hydroxy-anisole (BHA). The DMPO-OH signal was suppressed in the presence of ethanol and catalase. Fe2+-NTA solution hardly produced DMPO spin adducts. The Fe3+-NTA solution produced a strong DMPO-OH signal in the presence of H2O2. Rose Bengal solution, a singlet oxygen generating system, produced the same DMPO adducts. Fe3+-NTA reacted with oxygen in solution. The oxygen was activated and might be similar to singlet molecular oxygen. In the presence of H2O2, the Fe3+-NTA solution generated a hydroxyl radical. Fe3+-NTA itself generated free radicals, but Fe2+-NTA did not.

Adenovirus 12-induced tumor has been so far considered to be an undifferentiated sarcoma, but in the present study it has been possible to obtain such electronmicroscopic findings that substantiate well the theory of the neuro-ectodermal supporting cell origin as suggested by the observation at optical level. In other words, a specific clinging picture of cellular membranes and the presence of desmosomes have been demonstrated. In addition, though only in rare instances, the presence of virus-like particles have been verified, and some comments have been made about the relation between tumor and the appearance of virus as well as about carcinogenic mother cell.

A new instrument for visual field examination with binocular fixation is described. The binocular vision was dissociated with polarizing plates. Only the point of fixation was visible to both eyes while the testing chart (Amsler chart) was visible to one eye in the use of this apparatus. The examination was done with both the patient's eyes open. With the use of this apparatus, not only was the visual line fixed steadily in order to detect various changes of the central visual field due to maculopathy or optic neuropathy and these changes were detected accurately and quickly, but also suppression scotoma associated with amblyopia or squint could be detected quantitatively.

Narrow-band imaging (NBI) is a novel optical technique that uses narrow bandwidth filters in a video endoscope system to improve the diagnostic capability of endoscopes in characterizing tissues. It is well known that early identification of neoplasia in the gastrointestinal tract using this technique might make it possible to reduce the suffering of patients caused by loss of function or severe complications after radical surgery. Several reports have introduced this system as a preoperative examination to evaluate the lateral spread of the neoplastic lesions in the oropharynx or hypopharynx. We experienced a case with hypopharyngeal cancer in which we were able to avoid underestimating cancer lesions following insufficient resection using the NBI system. A 62-year-old female underwent partial hypopharyngectomy with the margin estimated by an NBI view coupled with reconstruction of the hypopharynx while preserving the larynx. The resected specimen was cut into serial sections for a detailed pathology examination. The surgical margin seemed to be wide enough and it could be assumed that if possible we should observe these cancers with conventional electroendoscopy and NBI before treatment.