Yumiko Sugiura

In vitro toxicity of indium arsenide to alveolar macrophages evaluated by magnetometry, cytochemistry and morphological analysis

The present study was conducted to clarify the toxicity of Indium arsenide (InAs) particles to alveolar macrophages of hamsters by cytomagnetometry, enzyme release assays and morphological examinations. One million alveolar macrophages obtained from hamsters were exposed to 60 microg of ferrosoferric oxide and 2, 4, 10 and 20 microg of InAs particles. Relaxation, which is the rapid decline of strength of the remanent magnetic fields radiating from the alveolar macrophages, was insignificantly delayed and decay constants were not changed due to exposure to such doses of InAs. Because the relaxation is thought to be associated with the cytoskeleton, the exposure to InAs may not have impaired their motor function. An LDH release assay and morphological findings indicate slight damage to macrophages. DNA electrophoresis and the TUNEL method revealed neither necrotic changes nor apoptotic changes. Thus, InAs particles at such doses hardly cause cytostructural changes and cell death.

Effects of zinc on cadmium-induced alterations in hepatic functions and blood glucose of rats.

The role of zinc (Zn) in preventing cadmium (Cd)-induced alterations of liver function and carbohydrate metabolism was studied in female rats. The animals were divided into four groups. To the diet for Group I was added 200 micrograms Cd/g of diet, to that for Group II was added 200 micrograms Zn/g of diet, and to that for Group III were added 200 micrograms Cd/g and 200 micrograms Zn/g of diet. Group IV was the control group fed normal diet. At the 11th, 26th, and 40th week of exposure, one-third of each group of animals were sacrificed and serum GPT and ALP activities, and glucose and insulin levels were measured. At the 26th and 40th week, serum GPT activity of Group I was significantly higher compared with those of Groups III and IV, and the serum glucose value of Group I was lower than that of Group III. At the 40th week, the serum insulin value of Group I was significantly higher than that of Group III. From these results, it is suggested that orally administered Zn prevents Cd-induced alterations of liver functions and the regulation of blood glucose in rats.

Skin irritation to glass wool or continuous glass filaments as observed by a patch test among human Japanese volunteers.

Glass wool and continuous glass filaments have been used in industry. We examined the irritability of those among Japanese. A patch test was performed on 43 volunteers for the followings: glass wool for non-residential use with and without a urea-modified phenolic resin binder, that for residential use with and without the binder, and continuous glass filaments with diameters of 4, 7, 9, and 13 µm. Materials were applied to an upper arm of each volunteer for 24 h. The skin was observed at 1 and 24 h after the removal. At 1 h after removal, slight erythema was observed on the skin of a woman after the exposure to glass wool for residential use without the binder. Erythema was observed on the skin of another woman at 1 h after a 24-h exposure to glass wool for non-residential use without the binder. There were no reactions at 24 h after the removal. The low reactions in the patch test suggested that the irritability caused by glass wool, irrespective of a resin component, could be induced mechanically, and that the irritability caused by continuous glass filaments with resin could be slight and either mechanical or chemical.

Safety Evaluation of Self-assembling Peptide Gel after Intracranial Administration to Rats Using the Open Field Test

Self-assembling peptides have been developed as clinical materials, which could scaffold to regenerate nerve cells and hemostatic materials in vivo. However, there has not been enough information for their in vivo application. The safety of self-assembling peptides for the application on the brain was examined using behavioral tests for each rat in this study. Self-assembling peptide gel was administered to the surface of the brain at a volume of 20 µL at 1.5%. After 2 months, the open field test and the prepulse inhibition (PPI) test were performed. There were no significant differences between the peptide gel and the control groups in locomotor distances and in %PPIs in the PPI test. The mean values of the percentage of time the rats stayed in the central area of the open field during the first 5 min and instances of center rearing or face washing in the peptide gel group were significantly higher than those in the control. There were amorphous substance in the subarachnoid region, and infiltrations of mononuclear cells were also observed in the self-assembling peptide gel group. Although the meaning of the effects observed in this study was not fully elucidated, the self-assembling gel produced marginal but significant behavioral and histological effects.